Physics and Astronomy › Nuclear and High Energy Physics

Dark Matter and Cosmic Phenomena

Works Count: 49624

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This cluster of papers focuses on the evidence, candidates, and constraints related to particle dark matter, including cosmic ray measurements, axion cosmology, WIMP detection methods, and implications for cosmology and astrophysics. It covers a wide range of experimental and theoretical approaches to understanding the nature of dark matter in the universe.

Keywords

Dark Matter; Cosmic Rays; Axions; WIMPs; Particle Physics; Galactic Center; Direct Detection; Fermi Telescope; Cosmology; Neutrinos

Fuzzy Cold Dark Matter: The Wave Properties of Ultralight Particles

2000-08-07

Wayne Hu , Rennan Barkana , Andrei Gruzinov

Cold dark matter (CDM) models predict small-scale structure in excess of observations of the cores and abundance of dwarf galaxies. These problems might be solved, and the virtues of CDM … Cold dark matter (CDM) models predict small-scale structure in excess of observations of the cores and abundance of dwarf galaxies. These problems might be solved, and the virtues of CDM models retained, even without postulating ad hoc dark matter particle or field interactions, if the dark matter is composed of ultralight scalar particles (m approximately 10(-22) eV), initially in a (cold) Bose-Einstein condensate, similar to axion dark matter models. The wave properties of the dark matter stabilize gravitational collapse, providing halo cores and sharply suppressing small-scale linear power.

LXXIX. The scattering of α and β particles by matter and the structure of the atom

1911-05-01

E. Rutherford

Review of Particle Physics

2012-07-20

J. Beringer , J-F. Arguin , R. M. Barnett +7 more

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, … This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, ${V}_{\mathit{cb}}$ ${V}_{\mathit{ub}}$, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter.A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov/.The 2012 edition of Review of Particle Physics is published for the Particle Data Group as article 010001 in volume 86 of Physical Review D.This edition should be cited as: J. Beringer et al. (Particle Data Group), Phys. Rev. D 86, 010001 (2012).

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Searching for Dark Matter Annihilation from Milky Way Dwarf Spheroidal Galaxies with Six Years of Fermi Large Area Telescope Data

2015-11-30

M. Ackermann , A. Albert , B. Anderson +7 more

The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on gamma-ray observations of Milky Way dSphs … The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on gamma-ray observations of Milky Way dSphs based on 6 years of Fermi Large Area Telescope data processed with the new Pass 8 event-level analysis. None of the dSphs are significantly detected in gamma rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass $\lesssim$ 100 GeV annihilating via quark and $\tau$-lepton channels.

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Cosmic strings and domain walls

1985-05-01

Alexander Vilenkin

A cosmological bound on the invisible axion

1983-01-01

L. F. Abbott , P. Sikivie

End to the Cosmic-Ray Spectrum?

1966-04-25

K. Greisen

The primary cosmic-ray spectrum has been measured up to an energy of $10^{20}$ eV, and several groups have described projects under development or in mind to investigate the spectrum further, … The primary cosmic-ray spectrum has been measured up to an energy of $10^{20}$ eV, and several groups have described projects under development or in mind to investigate the spectrum further, into the energy range $10^{21}-10^{22}$ eV. This note predicts that above $10^{20}$ eV the primary spectrum will steepen abruptly, and the experiments in preparation will at last observe it to have a cosmologically meaningful termination.

A simple solution to the strong CP problem with a harmless axion

1981-08-01

Michael Dine , Willy Fischler , Mark Srednicki

Experimental Tests of the "Invisible" Axion

1983-10-17

P. Sikivie

Experiments are proposed which address the question of the existence of the "invisible" axion for the whole allowed range of the axion decay constant. These experiments exploit the coupling of … Experiments are proposed which address the question of the existence of the "invisible" axion for the whole allowed range of the axion decay constant. These experiments exploit the coupling of the axion to the electromagnetic field, axion emission by the sum, and/or the cosmological abundance and presumed clustering of axions in the halo of our galaxy.

Cosmology of the invisible axion

1983-01-01

John Preskill , Mark B. Wise , Frank Wilczek

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The not-so-harmless axion

1983-01-01

Michael Dine , Willy Fischler

Search for Neutrinos from the Sun

1968-05-20

R. Davis , D.S. Harmer , Kenneth C. Hoffman

A search was made for solar neutrinos with a detector based upon the reaction ${\mathrm{Cl}}^{37}(\ensuremath{\nu}, {e}^{\ensuremath{-}}){\mathrm{Ar}}^{37}$. The upper limit of the product of the neutrino flux and the cross sections … A search was made for solar neutrinos with a detector based upon the reaction ${\mathrm{Cl}}^{37}(\ensuremath{\nu}, {e}^{\ensuremath{-}}){\mathrm{Ar}}^{37}$. The upper limit of the product of the neutrino flux and the cross sections for all sources of neutrinos was 3\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}36}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ per ${\mathrm{Cl}}^{37}$ atom. It was concluded specifically that the flux of neutrinos from ${\mathrm{B}}^{8}$ decay in the sun was equal to or less than 2\ifmmode\times\else\texttimes\fi{}${10}^{6}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ at the earth, and that less than 9% of the sun's energy is produced by the carbon-nitrogen cycle.

Secluded WIMP dark matter

2008-03-07

Maxim Pospelov , Adam Ritz , M.B. Voloshin

We consider a generic mechanism via which thermal relic WIMP dark matter may be decoupled from the Standard Model, namely through a combination of WIMP annihilation to metastable mediators with … We consider a generic mechanism via which thermal relic WIMP dark matter may be decoupled from the Standard Model, namely through a combination of WIMP annihilation to metastable mediators with subsequent delayed decay to Standard Model states. We illustrate this with explicit examples of WIMPs connected to the Standard Model by metastable bosons or fermions. In all models, provided the WIMP mass is greater than that of the mediator, it can be secluded from the Standard Model with an extremely small elastic scattering cross-section on nuclei and rate for direct collider production. In contrast, indirect signatures from WIMP annihilation are consistent with a weak scale cross-section and provide potentially observable γ-ray signals. We also point out that γ-ray constraints and flavor physics impose severe restrictions on MeV-scale variants of secluded models, and identify limited classes that pass all the observational constraints.

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Review of mathematics, numerical factors, and corrections for dark matter experiments based on elastic nuclear recoil

1996-12-01

J.D. Lewin , P.F. Smith

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Constraints imposed by<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>CP</mml:mi></mml:math>conservation in the presence of pseudoparticles

1977-09-15

R.D. Peccei , Helen R. Quinn

We elaborate on an earlier discussion of $\mathrm{CP}$ conservation of strong interactions which includes the effect of pseudoparticles. We discuss what happens in theories of the quantum-chromodynamics type when we … We elaborate on an earlier discussion of $\mathrm{CP}$ conservation of strong interactions which includes the effect of pseudoparticles. We discuss what happens in theories of the quantum-chromodynamics type when we include weak and electromagnetic interactions. We find that strong $\mathrm{CP}$ conservation remains a natural symmetry if the full Lagrangian possesses a chiral U(1) invariance. We illustrate our results by considering in detail a recent model of (weak) $\mathrm{CP}$ nonconservation.

First Results from the LUX Dark Matter Experiment at the Sanford Underground Research Facility

2014-03-04

D. S. Akerib , H. M. Araújo , X. Bai +7 more

The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for the first … The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for the first time in the underground laboratory in February 2013. We report results of the first WIMP search data set, taken during the period from April to August 2013, presenting the analysis of 85.3 live days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10(-46) cm(2) at a WIMP mass of 33 GeV/c(2). We find that the LUX data are in disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.

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Weak-Interaction Singlet and Strong<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>CP</mml:mi></mml:math>Invariance

1979-07-09

Jihn E. Kim

Strong $\mathrm{CP}$ invariance is automatically preserved by a spontaneously broken chiral ${\mathrm{U}(1)}_{4}$ symmetry. A weak-interaction singlet heavy quark $Q$, a new scalar meson ${\ensuremath{\sigma}}^{0}$, and a very light axion are … Strong $\mathrm{CP}$ invariance is automatically preserved by a spontaneously broken chiral ${\mathrm{U}(1)}_{4}$ symmetry. A weak-interaction singlet heavy quark $Q$, a new scalar meson ${\ensuremath{\sigma}}^{0}$, and a very light axion are predicted. Phenomenological implications are also included.

Cosmology and the fate of dilatation symmetry

1988-06-01

C. Wetterich

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Singularities and Discontinuities of Feynman Amplitudes

1960-09-01

R. E. Cutkosky

The Landau singularities of the amplitude calculated from an arbitrary Feynman graph are considered. It is shown that the discontinuity across a branch cut starting from any Landau singularity is … The Landau singularities of the amplitude calculated from an arbitrary Feynman graph are considered. It is shown that the discontinuity across a branch cut starting from any Landau singularity is obtained by replacing Feynman propagators by delta functions for those lines which appear in the Landau diagram. The general formula is a simple generalization of the unitarity condition. The discontinuity is then considered as an analytic function of the momenta and masses; it is shown that its singularities are a subclass of the singularities of the original amplitude which corresponds to Landau diagrams with additional lines. The general results are illustrated by application to some single loop graphs. In particular, the general formula gives an immediate calculation of the Mandelstam spectral function for fourth-order scattering. Singularities not of the Landau type are discussed and illustrated by the third-order vertex part.

A New Light Boson?

1978-01-23

Steven Weinberg

It is pointed out that a global U(1) symmetry, that has been introduced in order to preserve the parity and time-reversal invariance of strong interactions despite the effects of instantons, … It is pointed out that a global U(1) symmetry, that has been introduced in order to preserve the parity and time-reversal invariance of strong interactions despite the effects of instantons, would lead to a neutral pseudoscalar boson, the "axion," with mass roughly of order 100 keV to 1 MeV. Experimental implications are discussed.

<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>CP</mml:mi></mml:math>Conservation in the Presence of Pseudoparticles

1977-06-20

R. D. Peccei , Helen R. Quinn

We give an explanation of the $\mathrm{CP}$ conservation of strong interactions which includes the effects of pseudoparticles. We find it is a natural result for any theory where at least … We give an explanation of the $\mathrm{CP}$ conservation of strong interactions which includes the effects of pseudoparticles. We find it is a natural result for any theory where at least one flavor of fermion acquires its mass through a Yukawa coupling to a scalar field which has nonvanishing vacuum expectation value.

Quintessence and the Rest of the World: Suppressing Long-Range Interactions

1998-10-12

Sean M. Carroll

A nearly massless, slowly rolling scalar field $\ensuremath{\varphi}$ may provide most of the energy density of the current Universe. One potential difficulty with this idea is that couplings to ordinary … A nearly massless, slowly rolling scalar field $\ensuremath{\varphi}$ may provide most of the energy density of the current Universe. One potential difficulty with this idea is that couplings to ordinary matter should lead to observable long-range forces and time dependence of the constants of nature. I explore the possibility that an approximate global symmetry serves to suppress such couplings even further. Such a symmetry would allow a coupling of $\ensuremath{\varphi}$ to the pseudoscalar ${F}_{\ensuremath{\mu}\ensuremath{\nu}}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{F}}^{\ensuremath{\mu}\ensuremath{\nu}}$ of electromagnetism, which would rotate the polarization state of radiation from distant sources. This effect is fairly well constrained, but it is conceivable that future improvements could lead to a detection of a cosmological scalar field.

Observational Evidence for Self-Interacting Cold Dark Matter

2000-04-24

David N. Spergel , Paul J. Steinhardt

Cosmological models with cold dark matter composed of weakly interacting particles predict overly dense cores in the centers of galaxies and clusters and an overly large number of halos within … Cosmological models with cold dark matter composed of weakly interacting particles predict overly dense cores in the centers of galaxies and clusters and an overly large number of halos within the Local Group compared to actual observations. We propose that the conflict can be resolved if the cold dark matter particles are self-interacting with a large scattering cross section but negligible annihilation or dissipation. In this scenario, astronomical observations may enable us to study dark matter properties that are inaccessible in the laboratory.

Formation of galaxies and large-scale structure with cold dark matter

1984-10-01

George R. Blumenthal , S. M. Faber , Joel R. Primack +1 more

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Light pseudoscalars, particle physics and cosmology

1987-06-01

Jihn E. Kim

Dark Matter Results from 225 Live Days of XENON100 Data

2012-11-02

E. Aprile , M. Alfonsi , K. Arisaka +7 more

We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso for 13 months during 2011 and 2012. XENON100 features … We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso for 13 months during 2011 and 2012. XENON100 features an ultralow electromagnetic background of (5.3 ± 0.6) × 10(-3) events/(keV(ee) × kg × day) in the energy region of interest. A blind analysis of 224.6 live days × 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the predefined nuclear recoil energy range of 6.6-30.5 keV(nr) are consistent with the background expectation of (1.0 ± 0.2) events. A profile likelihood analysis using a 6.6-43.3 keV(nr) energy range sets the most stringent limit on the spin-independent elastic weakly interacting massive particle-nucleon scattering cross section for weakly interacting massive particle masses above 8 GeV/c(2), with a minimum of 2 × 10(-45) cm(2) at 55 GeV/c(2) and 90% confidence level.

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An anomalous positron abundance in cosmic rays with energies 1.5–100 GeV

2009-04-01

O. Adriani , G. C. Barbarino , G. A. Bazilevskaya +7 more

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Particle dark matter: evidence, candidates and constraints

2004-11-09

Gianfranco Bertone , Dan Hooper , Joseph Silk

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Supersymmetric dark matter

2000-08-01

K. Griest , Marc Kamionkowski

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Phenomenology, astrophysics, and cosmology of theories with submillimeter dimensions and TeV scale quantum gravity

1999-03-23

Nima Arkani–Hamed , Savas Dimopoulos , Gia Dvali

We recently proposed a solution to the hierarchy problem not relying on low-energy supersymmetry or technicolor. Instead, the problem is nullified by bringing quantum gravity down to the TeV scale. … We recently proposed a solution to the hierarchy problem not relying on low-energy supersymmetry or technicolor. Instead, the problem is nullified by bringing quantum gravity down to the TeV scale. This is accomplished by the presence of $n \geq 2$ new dimensions of sub-millimeter size, with the SM fields localised on a 3-brane in the higher dimensional space. In this paper we systematically study the experimental viability of this scenario. Constraints arise both from strong quantum gravitational effects at the TeV scale, and more importantly from the production of massless higher dimensional gravitons with TeV suppressed couplings. Theories with $n>2$ are safe due mainly to the infrared softness of higher dimensional gravity. For $n=2$, the six dimensional Planck scale must be pushed above $\sim 30$ TeV to avoid cooling SN1987A and distortions of the diffuse photon background. Nevertheless, the particular implementation of our framework within type I string theory can evade all constraints, for any $n \geq 2$, with string scale $m_s \sim 1$ TeV. We also explore novel phenomena resulting from the existence of new states propagating in the higher dimensional space. The Peccei-Quinn solution to the strong CP problem is revived with a weak scale axion in the bulk. Gauge fields in the bulk can mediate repulsive forces $\sim 10^6 - 10^8$ times stronger than gravity at sub-mm distances, and may help stabilize the proton. Higher-dimensional gravitons produced on our brane and captured on a different "fat" brane can provide a natural dark matter candidate.

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A theory of dark matter

2009-01-27

Nima Arkani–Hamed , Douglas P. Finkbeiner , Tracy R. Slatyer +1 more

We propose a comprehensive theory of dark matter that explains the recent proliferation of unexpected observations in high-energy astrophysics. Cosmic ray spectra from ATIC and PAMELA require a WIMP (weakly … We propose a comprehensive theory of dark matter that explains the recent proliferation of unexpected observations in high-energy astrophysics. Cosmic ray spectra from ATIC and PAMELA require a WIMP (weakly interacting massive particle). with mass ${M}_{\ensuremath{\chi}}\ensuremath{\sim}500--800\text{ }\text{ }\mathrm{GeV}$ that annihilates into leptons at a level well above that expected from a thermal relic. Signals from WMAP and EGRET reinforce this interpretation. Limits on $\overline{p}$ and ${\ensuremath{\pi}}^{0}\mathrm{\text{\ensuremath{-}}}\ensuremath{\gamma}$'s constrain the hadronic channels allowed for dark matter. Taken together, we argue these facts imply the presence of a new force in the dark sector, with a Compton wavelength ${m}_{\ensuremath{\phi}}^{\ensuremath{-}1}\ensuremath{\gtrsim}1\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$. The long range allows a Sommerfeld enhancement to boost the annihilation cross section as required, without altering the weak-scale annihilation cross section during dark matter freeze-out in the early universe. If the dark matter annihilates into the new force carrier $\ensuremath{\phi}$, its low mass can make hadronic modes kinematically inaccessible, forcing decays dominantly into leptons. If the force carrier is a non-Abelian gauge boson, the dark matter is part of a multiplet of states, and splittings between these states are naturally generated with size $\ensuremath{\alpha}{m}_{\ensuremath{\phi}}\ensuremath{\sim}\text{ }\text{ }\mathrm{MeV}$, leading to the eXciting dark matter (XDM) scenario previously proposed to explain the positron annihilation in the galactic center observed by the INTEGRAL satellite; the light boson invoked by XDM to mediate a large inelastic scattering cross section is identified with the $\ensuremath{\phi}$ here. Somewhat smaller splittings would also be expected, providing a natural source for the parameters of the inelastic dark matter (iDM) explanation for the DAMA annual modulation signal. Since the Sommerfeld enhancement is most significant at low velocities, early dark matter halos at redshift $\ensuremath{\sim}10$ potentially produce observable effects on the ionization history of the universe. Because of the enhanced cross section, detection of substructure is more probable than with a conventional WIMP. Moreover, the low velocity dispersion of dwarf galaxies and Milky Way subhalos can increase the substructure annihilation signal by an additional order of magnitude or more.

Sterile neutrinos as dark matter

1994-01-03

Scott Dodelson , Lawrence M. Widrow

The simplest model that can accommodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed (sterile) neutrinos. We consider a single generation of … The simplest model that can accommodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed (sterile) neutrinos. We consider a single generation of neutrinos with a Dirac mass \ensuremath{\mu} and a Majorana mass M for the right-handed component. If M\ensuremath{\gg}\ensuremath{\mu} (standard hot dark matter corresponds to M=0), then sterile neutrinos are produced via oscillations in the early Universe with energy density independent of M. However, M is crucial in determining the large scale structure of the Universe; for M\ensuremath{\sim}100 eV, sterile neutrinos make an excellent warm dark matter candidate.

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Detectability of certain dark-matter candidates

1985-06-15

Mark W. Goodman , Edward Witten

We consider the possibility that the neutral-current neutrino detector recently proposed by Drukier and Stodolsky could be used to detect some possible candidates for the dark matter in galactic halos. … We consider the possibility that the neutral-current neutrino detector recently proposed by Drukier and Stodolsky could be used to detect some possible candidates for the dark matter in galactic halos. This may be feasible if the galactic halos are made of particles with coherent weak interactions and masses 1--${10}^{6}$ GeV; particles with spin-dependent interactions of typical weak strength and masses 1--${10}^{2}$ GeV; or strongly interacting particles of masses 1--${10}^{13}$ GeV.

Three exceptions in the calculation of relic abundances

1991-05-15

K. Griest , D. Seckel

The calculation of relic abundances of elementary particles by following their annihilation and freeze-out in the early Universe has become an important and standard tool in discussing particle dark-matter candidates. … The calculation of relic abundances of elementary particles by following their annihilation and freeze-out in the early Universe has become an important and standard tool in discussing particle dark-matter candidates. We find three situations, all occurring in the literature, in which the standard methods of calculating relic abundances fail. The first situation occurs when another particle lies near in mass to the relic particle and shares a quantum number with it. An example is a light squark with neutralino dark matter. The additional particle must be included in the reaction network, since its annihilation can control the relic abundance. The second situation occurs when the relic particle lies near a mass threshold. Previously, annihilation into particles heavier than the relic particle was considered kinematically forbidden, but we show that if the mass difference is \ensuremath{\sim}5-15%, these "forbidden" channels can dominate the cross section and determine the relic abundance. The third situation occurs when the annihilation takes place near a pole in the cross section. Proper treatment of the thermal averaging and the annihilation after freeze-out shows that the dip in relic abundance caused by a pole is not nearly as sharp or deep as previously thought.

Results from a Search for Dark Matter in the Complete LUX Exposure

2017-01-11

D. S. Akerib , S. Alsum , H. M. Araújo +7 more

We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×104 kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber … We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×104 kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c−2, WIMP-nucleon spin-independent cross sections above 2.2×10−46 cm2 are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10−46 cm2 at 50 GeV c−2.Received 13 October 2016DOI:https://doi.org/10.1103/PhysRevLett.118.021303© 2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle dark matterWeakly interacting massive particlesGravitation, Cosmology & AstrophysicsParticles & Fields

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Ultralight scalars as cosmological dark matter

2017-02-28

Lam Hui , Jeremiah P. Ostriker , Scott Tremaine +1 more

Many aspects of the large-scale structure of the Universe can be described successfully using cosmological models in which $27\ifmmode\pm\else\textpm\fi{}1%$ of the critical mass-energy density consists of cold dark matter (CDM). … Many aspects of the large-scale structure of the Universe can be described successfully using cosmological models in which $27\ifmmode\pm\else\textpm\fi{}1%$ of the critical mass-energy density consists of cold dark matter (CDM). However, few---if any---of the predictions of CDM models have been successful on scales of $\ensuremath{\sim}10\text{ }\text{ }\mathrm{kpc}$ or less. This lack of success is usually explained by the difficulty of modeling baryonic physics (star formation, supernova and black-hole feedback, etc.). An intriguing alternative to CDM is that the dark matter is an extremely light ($m\ensuremath{\sim}{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}$) boson having a de Broglie wavelength $\ensuremath{\lambda}\ensuremath{\sim}1\text{ }\text{ }\mathrm{kpc}$, often called fuzzy dark matter (FDM). We describe the arguments from particle physics that motivate FDM, review previous work on its astrophysical signatures, and analyze several unexplored aspects of its behavior. In particular, (i) FDM halos or subhalos smaller than about $1{0}^{7}(m/{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}{)}^{\ensuremath{-}3/2}$ ${M}_{\ensuremath{\bigodot}}$ do not form, and the abundance of halos smaller than a few times $1{0}^{10}(m/{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}{)}^{\ensuremath{-}4/3}$ ${M}_{\ensuremath{\bigodot}}$ is substantially smaller in FDM than in CDM. (ii) FDM halos are comprised of a central core that is a stationary, minimum-energy solution of the Schr\"odinger-Poisson equation, sometimes called a ``soliton,'' surrounded by an envelope that resembles a CDM halo. The soliton can produce a distinct signature in the rotation curves of FDM-dominated systems. (iii) The transition between soliton and envelope is determined by a relaxation process analogous to two-body relaxation in gravitating N-body systems, which proceeds as if the halo were composed of particles with mass $\ensuremath{\sim}\ensuremath{\rho}{\ensuremath{\lambda}}^{3}$ where $\ensuremath{\rho}$ is the halo density. (iv) Relaxation may have substantial effects on the stellar disk and bulge in the inner parts of disk galaxies, but has negligible effect on disk thickening or globular cluster disruption near the solar radius. (v) Relaxation can produce FDM disks but a FDM disk in the solar neighborhood must have a half-thickness of at least $\ensuremath{\sim}300(m/{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}{)}^{\ensuremath{-}2/3}\text{ }\text{ }\mathrm{pc}$ and a midplane density less than $0.2(m/{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}{)}^{2/3}$ times the baryonic disk density. (vi) Solitonic FDM subhalos evaporate by tunneling through the tidal radius and this limits the minimum subhalo mass inside $\ensuremath{\sim}30\text{ }\text{ }\mathrm{kpc}$ of the Milky Way to a few times $1{0}^{8}(m/{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}{)}^{\ensuremath{-}3/2}$ ${M}_{\ensuremath{\bigodot}}$. (vii) If the dark matter in the Fornax dwarf galaxy is composed of CDM, most of the globular clusters observed in that galaxy should have long ago spiraled to its center, and this problem is resolved if the dark matter is FDM. (viii) FDM delays galaxy formation relative to CDM but its galaxy-formation history is consistent with current observations of high-redshift galaxies and the late reionization observed by Planck. If the dark matter is composed of FDM, most observations favor a particle mass $\ensuremath{\gtrsim}{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}$ and the most significant observational consequences occur if the mass is in the range $1--10\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}$. There is tension with observations of the Lyman-$\ensuremath{\alpha}$ forest, which favor $m\ensuremath{\gtrsim}10--20\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}$ and we discuss whether more sophisticated models of reionization may resolve this tension.

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Review of particle physics. Particle Data Group

2004-06-01

S. Eidelman , G. Höhler , R. Sekhar Chivukula +7 more

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Review of Particle Physics

2008-08-05

C. Amsler , M. Doser , M. Antonelli +7 more

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Search for new physics with atoms and molecules

2018-06-29

M. S. Safronova , Dmitry Budker , David DeMille +3 more

Advances in atomic physics, such as cooling and trapping of atoms and molecules and developments in frequency metrology, have added orders of magnitude to the precision of atom-based clocks and … Advances in atomic physics, such as cooling and trapping of atoms and molecules and developments in frequency metrology, have added orders of magnitude to the precision of atom-based clocks and sensors. Applications extend beyond atomic physics and this article reviews using these new techniques to address important challenges in physics and to look for variations in the fundamental constants, search for interactions beyond the standard model of particle physics, and test the principles of general relativity.

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Dark Matter Search Results from a One Ton-Year Exposure of XENON1T

2018-09-12

E. Aprile , J. Aalbers , F. Agostini +7 more

We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection … We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30±0.01) ton, resulting in a 1.0 ton yr exposure. The energy region of interest, [1.4,10.6] keV_{ee} ([4.9,40.9] keV_{nr}), exhibits an ultralow electron recoil background rate of [82_{-3}^{+5}(syst)±3(stat)] events/(ton yr keV_{ee}). No significant excess over background is found, and a profile likelihood analysis parametrized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6 GeV/c^{2}, with a minimum of 4.1×10^{-47} cm^{2} at 30 GeV/c^{2} and a 90% confidence level.

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Review of Particle Physics

2018-08-17

Masaharu Tanabashi , Katsuro Hagiwara , Ken‐ichi Hikasa +7 more

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873 new measurements from 758 papers, we list, evaluate, and average measured properties of gauge … The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873 new measurements from 758 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 118 reviews are many that are new or heavily revised, including a new review on Neutrinos in Cosmology.Starting with this edition, the Review is divided into two volumes. Volume 1 includes the Summary Tables and all review articles. Volume 2 consists of the Particle Listings. Review articles that were previously part of the Listings are now included in volume 1.The complete Review (both volumes) is published online on the website of the Particle Data Group (http://pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is also available.The 2018 edition of the Review of Particle Physics should be cited as: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018).

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Review of Particle Physics

2022-08-01

Ronald Workman , Volker Burkert , V. Credé +7 more

Abstract The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,143 new measurements from 709 papers, we list, evaluate, and average measured properties of … Abstract The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,143 new measurements from 709 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily revised, including a new review on Machine Learning, and one on Spectroscopy of Light Meson Resonances. The Review is divided into two volumes. Volume 1 includes the Summary Tables and 97 review articles. Volume 2 consists of the Particle Listings and contains also 23 reviews that address specific aspects of the data presented in the Listings. The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print, as a web version optimized for use on phones, and as an Android app.

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Cosmic strings

1995-05-01

Mark Hindmarsh , T. W. B. Kibble

The topic of cosmic strings provides a bridge between the physics of the very small and the very large. They are predicted by some unified theories of particle interactions. If … The topic of cosmic strings provides a bridge between the physics of the very small and the very large. They are predicted by some unified theories of particle interactions. If they exist, they may help to explain some of the largest-scale structures seen in the Universe today. They are 'topological defects' that may have been formed at phase transitions in the very early history of the Universe, analogous to those found in some condensed matter systems-vortex lines in liquid helium, flux tubes in type-II superconductors, or disclination lines in liquid crystals. In this review, we describe what they are, why they have been hypothesized and what their cosmological implications would be. The relevant background from the standard models of particle physics and cosmology is described in section 1. In section 2, we review the idea of symmetry breaking in field theories, and show how the defects formed are constrained by the topology of the manifold of degenerate vacuum states. We also discuss the different types of cosmic strings that can appear in different field theories. Section 3 is devoted to the dynamics of cosmic strings, and section 4 to their interaction with other fields. The formation and evolution of cosmic strings in the early Universe is the subject of section 5, while section 6 deals with their observational implications. Finally, the present status of the theory is reviewed in section 7.

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Axion cosmology

2016-06-29

David J. E. Marsh

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String axiverse

2010-06-28

Asimina Arvanitaki , Savas Dimopoulos , Sergei Dubovsky +2 more

String theory suggests the simultaneous presence of many ultralight axions possibly populating each decade of mass down to the Hubble scale 10^-33eV. Conversely the presence of such a plenitude of … String theory suggests the simultaneous presence of many ultralight axions possibly populating each decade of mass down to the Hubble scale 10^-33eV. Conversely the presence of such a plenitude of axions (an "axiverse") would be evidence for string theory, since it arises due to the topological complexity of the extra-dimensional manifold and is ad hoc in a theory with just the four familiar dimensions. We investigate how upcoming astrophysical experiments will explore the existence of such axions over a vast mass range from 10^-33eV to 10^-10eV. Axions with masses between 10^-33eV to 10^-28eV cause a rotation of the CMB polarization that is constant throughout the sky. The predicted rotation angle is of order \alpha~1/137. Axions in the mass range 10^-28eV to 10^-18eV give rise to multiple steps in the matter power spectrum, that will be probed by upcoming galaxy surveys. Axions in the mass range 10^-22eV to 10^-10eV affect the dynamics and gravitational wave emission of rapidly rotating astrophysical black holes through the Penrose superradiance process. When the axion Compton wavelength is of order of the black hole size, the axions develop "superradiant" atomic bound states around the black hole "nucleus". Their occupation number grows exponentially by extracting rotational energy from the ergosphere, culminating in a rotating Bose-Einstein axion condensate emitting gravitational waves. This mechanism creates mass gaps in the spectrum of rapidly rotating black holes that diagnose the presence of axions. The rapidly rotating black hole in the X-ray binary LMC X-1 implies an upper limit on the decay constant of the QCD axion f_a<2*10^17GeV, much below the Planck mass. This reach can be improved down to the grand unification scale f_a<2*10^16GeV, by observing smaller stellar mass black holes.

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Supersymmetric dark matter

1996-03-01

Gerard Jungman , Marc Kamionkowski , K. Griest

There is almost universal agreement among astronomers that most of the mass in the Universe and most of the mass in the Galactic halo is dark. Many lines of reasoning … There is almost universal agreement among astronomers that most of the mass in the Universe and most of the mass in the Galactic halo is dark. Many lines of reasoning suggest that the dark matter consists of some new, as yet undiscovered, weakly-interacting massive particle (WIMP). There is now a vast experimental effort being surmounted to detect WIMPS in the halo. The most promising techniques involve direct detection in low-background laboratory detectors and indirect detection through observation of energetic neutrinos from annihilation of WIMPs that have accumulated in the Sun and/or the Earth. Of the many WIMP candidates, perhaps the best motivated and certainly the most theoretically developed is the neutralino, the lightest superpartner in many supersymmetric theories. We review the minimal supersymmetric extension of the Standard Model and discuss prospects for detection of neutralino dark matter. We review in detail how to calculate the cosmological abundance of the neutralino and the event rates for both direct- and indirect-detection schemes, and we discuss astrophysical and laboratory constraints on supersymmetric models. We isolate and clarify the uncertainties from particle physics, nuclear physics, and astrophysics that enter at each step in the calculation. We briefly review other related dark-matter candidates and detection techniques.

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Review of Particle Physics

2016-10-01

C. Patrignani , Kaustubh Agashe , G. Aielli +7 more

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge … The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.

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Planck 2015 results. XIII. Cosmological parameters

2015-02-05

P. A. R. Ade , N. Aghanim , M. Arnaud +7 more

We present results based on full-mission Planck observations of temperature and polarization anisotropies of the CMB. These data are consistent with the six-parameter inflationary LCDM cosmology. From the Planck temperature … We present results based on full-mission Planck observations of temperature and polarization anisotropies of the CMB. These data are consistent with the six-parameter inflationary LCDM cosmology. From the Planck temperature and lensing data, for this cosmology we find a Hubble constant, H0= (67.8 +/- 0.9) km/s/Mpc, a matter density parameter Omega_m = 0.308 +/- 0.012 and a scalar spectral index with n_s = 0.968 +/- 0.006. (We quote 68% errors on measured parameters and 95% limits on other parameters.) Combined with Planck temperature and lensing data, Planck LFI polarization measurements lead to a reionization optical depth of tau = 0.066 +/- 0.016. Combining Planck with other astrophysical data we find N_ eff = 3.15 +/- 0.23 for the effective number of relativistic degrees of freedom and the sum of neutrino masses is constrained to < 0.23 eV. Spatial curvature is found to be |Omega_K| < 0.005. For LCDM we find a limit on the tensor-to-scalar ratio of r <0.11 consistent with the B-mode constraints from an analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP data leads to a tighter constraint of r < 0.09. We find no evidence for isocurvature perturbations or cosmic defects. The equation of state of dark energy is constrained to w = -1.006 +/- 0.045. Standard big bang nucleosynthesis predictions for the Planck LCDM cosmology are in excellent agreement with observations. We investigate annihilating dark matter and deviations from standard recombination, finding no evidence for new physics. The Planck results for base LCDM are in agreement with BAO data and with the JLA SNe sample. However the amplitude of the fluctuations is found to be higher than inferred from rich cluster counts and weak gravitational lensing. Apart from these tensions, the base LCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.

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Review of Particle Physics

2020-07-13

P. Żyła , R.M. Barnett , J. Beringer +7 more

Abstract The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,324 new measurements from 878 papers, we list, evaluate, and average measured properties of … Abstract The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,324 new measurements from 878 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily revised, including a new review on High Energy Soft QCD and Diffraction and one on the Determination of CKM Angles from B Hadrons. The Review is divided into two volumes. Volume 1 includes the Summary Tables and 98 review articles. Volume 2 consists of the Particle Listings and contains also 22 reviews that address specific aspects of the data presented in the Listings. The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print and as a web version optimized for use on phones as well as an Android app.

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On the Origin of the Cosmic Radiation

1949-04-15

Enrico Fermi

A theory of the origin of cosmic radiation is proposed according to which cosmic rays are originated and accelerated primarily in the interstellar space of the galaxy by collisions against … A theory of the origin of cosmic radiation is proposed according to which cosmic rays are originated and accelerated primarily in the interstellar space of the galaxy by collisions against moving magmetic fields. One of the features of the theory is that it yields naturally an inverse power law for the spectral distribution of the cosmic rays. The chief difficulty is that it fails to explain in a straight-forward way the heavy nuclei observed in the primary radiation.

CMB constraints on loop-induced decays of leptophilic dark matter

2025-06-25

NULL AUTHOR_ID | Physical review. D/Physical review. D.

Dark-matter-induced transients over cosmic time: The role of star formation history profiles

2025-06-24

Heinrich Steigerwald | Physical review. D/Physical review. D.

First Search for Ultralight Dark Matter Using a Magnetically Levitated Particle

2025-06-24

D. W. P. Amaral , Dennis G. Uitenbroek , Tjerk H. Oosterkamp +1 more | Physical Review Letters

We perform the first search for ultralight dark matter using a magnetically levitated particle. A submillimeter permanent magnet is levitated in a superconducting trap with a measured force sensitivity of … We perform the first search for ultralight dark matter using a magnetically levitated particle. A submillimeter permanent magnet is levitated in a superconducting trap with a measured force sensitivity of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>0.2</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>fN</a:mi><a:mo>/</a:mo><a:msqrt><a:mrow><a:mi>Hz</a:mi></a:mrow></a:msqrt></a:mrow></a:math>. We find no evidence of a signal and derive limits on dark matter coupled to the difference between baryon and lepton number, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>B</c:mi><c:mo>−</c:mo><c:mi>L</c:mi></c:math>, in the mass range <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mo stretchy="false">(</e:mo><e:mn>1.10360</e:mn><e:mo>−</e:mo><e:mn>1.10485</e:mn><e:mo stretchy="false">)</e:mo><e:mo>×</e:mo><e:msup><e:mrow><e:mn>10</e:mn></e:mrow><e:mrow><e:mo>−</e:mo><e:mn>13</e:mn></e:mrow></e:msup><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>eV</e:mi><e:mo>/</e:mo><e:msup><e:mrow><e:mi>c</e:mi></e:mrow><e:mrow><e:mn>2</e:mn></e:mrow></e:msup></e:mrow></e:math>. Our most stringent limit on the coupling strength is <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>g</i:mi><i:mrow><i:mi>B</i:mi><i:mo>−</i:mo><i:mi>L</i:mi></i:mrow></i:msub><i:mo>≲</i:mo><i:mn>2.98</i:mn><i:mo>×</i:mo><i:msup><i:mn>10</i:mn><i:mrow><i:mo>−</i:mo><i:mn>21</i:mn></i:mrow></i:msup></i:math>. We propose the POLONAISE (Probing Oscillations using Levitated Objects for Novel Accelerometry In Searches of Exotic physics) experiment, which features short-, medium-, and long-term upgrades that will give us leading sensitivity in a wide mass range, demonstrating the promise of this novel quantum sensing technology in the hunt for dark matter. Published by the American Physical Society 2025

Positive neutrino masses with DESI DR2 via matter conversion to dark energy

2025-06-23

NULL AUTHOR_ID | Physical Review Letters

Probing benchmark models of hidden-sector dark matter with DAMIC-M

2025-06-23

NULL AUTHOR_ID | Physical Review Letters

Composite heavy axionlike dark matter

2025-06-23

NULL AUTHOR_ID | Physical Review Letters

Flavor Phenomenology of Light Dark Sectors

2025-06-23

Jorge Martin Camalich , Robert Ziegler | Annual Review of Nuclear and Particle Science

The dark sector offers a compelling theoretical framework for addressing the nature of dark matter while potentially solving other fundamental problems in physics. This review focuses on light dark-flavored sector … The dark sector offers a compelling theoretical framework for addressing the nature of dark matter while potentially solving other fundamental problems in physics. This review focuses on light dark-flavored sector models, in which the flavor structure of the interactions with the Standard Model is nontrivial and distinguishes among different fermion families. Such scenarios feature flavor violation that leads to unique experimental signatures, such as flavor-changing neutral current decays of heavy hadrons (kaons, D and B mesons, baryons) and leptons (muons and taus) with missing energy carried away by light dark-sector particles. In this article, we review their motivation, summarize current constraints, highlight discovery opportunities in ongoing and future flavor experiments, and discuss implications for astrophysics and cosmology.

Cosmic censorship in a dual collider

2025-06-23

NULL AUTHOR_ID | Physical Review Letters

Constraints on the cosmic-ray electron spectrum above 25 TeV from the LHAASO experiment

2025-06-23

NULL AUTHOR_ID | Physical review. D/Physical review. D.

Exploring Axion-Like Particle from observation of FSRQ Ton 599 by Fermi-LAT

2025-06-22

Jun Li , Xiao-Jun 毕效军 Bi , L. Q. Gao +1 more | Chinese Physics C

Abstract High energy photons traveling through astrophysical magnetic fields have the potential to undergo oscillations with axion-like particles (ALPs), resulting in modifications to the observed photon spectrum. High energy $\gamma-$ray … Abstract High energy photons traveling through astrophysical magnetic fields have the potential to undergo oscillations with axion-like particles (ALPs), resulting in modifications to the observed photon spectrum. High energy $\gamma-$ray sources with significant magnetic field strengths provide an ideal setting to investigate this phenomenon. Ton 599, a flat spectrum radio quasar with a magnetic field strength on the order of Gauss in its emission region, presents a promising opportunity for studying ALP-photon oscillations. In this study, we analyze the effects of ALP-photon oscillations on the $\gamma$-ray spectrum of Ton 599 as observed by Fermi-LAT. Our investigation considers the potential influences of the broad-line region and dusty torus on the $\gamma-$ray spectrum of Ton 599. We set the constraints on the ALP parameters at the $95\%$ confidence level, and find that the constraints on $g_{a\gamma}$ can reach approximately $2 \times 10^{-12}~\mathrm{GeV}^{-1}$ for $m_a \sim 10^{-9}~\mathrm{eV}$.

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Dynamical dark energy from an ultralight axion

2025-06-21

NULL AUTHOR_ID | Physical review. D/Physical review. D.

From 100 kpc to 10 Gpc: Dark matter self-interactions before and after DESI observation

2025-06-21

NULL AUTHOR_ID | Physical review. D/Physical review. D.

Characterizing CJPL’s Site-Specific Neutrino Floor as the Neutrino Fog Boundary

2025-06-20

Yingjie Fan , Xuewen Liu , N. Zhou | Chinese Physics C

Abstract The neutrino floor, a theoretical sensitivity limit for dark matter (DM) direct detections, is being redefined as the boundary of a dynamic “neutrino fog”, where neutrino signals become inevitable, … Abstract The neutrino floor, a theoretical sensitivity limit for dark matter (DM) direct detections, is being redefined as the boundary of a dynamic “neutrino fog”, where neutrino signals become inevitable, obscuring DM detection due to the statistical and systematic uncertainties. This study provides the first site-specific analysis of the neutrino floor at China Jinping Underground Laboratory (CJPL), leveraging its unique geographic and environmental characteristics. We quantify how CJPL’s suppressed atmospheric neutrino flux (around 30% lower than Laboratori Nazionali del Gran Sasso (LNGS)) reshapes the neutrino floor, thereby enabling improved sensitivity to high-mass WIMPs (m DM > 10GeV). Using a gradient-based framework, we derive CJPL’s neutrino floor and estimate the detection prospects for the PandaX-xT experiment. Our results demonstrate that a 500 tonne-year exposure with PandaX-xT could touch the floor, probing cross-sections down to σ χ N ∼ 3x10−49 cm^2 at a DM mass of 70 GeV/c2. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

On the CP properties of spin-0 dark matter

2025-06-20

Atri Dey , J. Hernández-Sánchez , Venus Keus +2 more | Journal of High Energy Physics

A bstract Aiming to uncover the CP properties of spin-0 particle Dark Matter (DM), we explore a two-component DM scenario within the framework of 3-Higgs Doublet Models (3HDMs), a well-motivated … A bstract Aiming to uncover the CP properties of spin-0 particle Dark Matter (DM), we explore a two-component DM scenario within the framework of 3-Higgs Doublet Models (3HDMs), a well-motivated set-up previously studied due to the complementarity of its collider and astrophysical probes. We devise benchmark points in which the two components of DM have same CP in one case and opposite CP in another. We then show several cross section distributions of observables at collider experiments where the two cases are clearly distinguishable.

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Stable dark matter from Pauli blocking in the degenerate fermion background with quantum field theory

2025-06-19

Wonsub Cho , Ki-Young Choi , Junghoon Joh +1 more | Physics of the Dark Universe

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Dark matter substructure: A lensing perspective

2025-06-19

NULL AUTHOR_ID | Physical review. D/Physical review. D.

Atoms as electron accelerators for new physics searches

2025-06-19

Fernando Arias-Aragón , Giovanni Grilli di Cortona , Enrico Nardi +1 more | Journal of High Energy Physics

A bstract Due to Heisenberg’s uncertainty principle, atomic electrons localized around the nucleus exhibit a characteristic momentum distribution that, in elements with high atomic number, remains significant up to relativistic … A bstract Due to Heisenberg’s uncertainty principle, atomic electrons localized around the nucleus exhibit a characteristic momentum distribution that, in elements with high atomic number, remains significant up to relativistic values. Consequently, in fixed-target experiments, atoms can effectively act as electron accelerators, increasing the centre-of-mass energy in collisions with beam particles. In this work, we leverage this effect to explore its potential for new physics searches. We consider positrons from beams of various energies annihilating with atomic electrons in a 74 W fixed target. We compute the production rates of new vector bosons and pseudoscalar particles as functions of their couplings and masses. We show that the electron-at-rest approximation significantly underestimates the mass reach for producing these new states compared to the results obtained by properly accounting for atomic electron momenta. In particular, we estimate the sensitivity for detecting these new particles using the positron beam at the Beam Test Facility linac at the Laboratori Nazionali di Frascati, the H4 beamline in the CERN North Area, and the proposed Continuous Electron Beam Accelerator Facility of Jefferson Laboratory.

Scalar Rayleigh Dark Matter: current bounds and future prospects

2025-06-18

D. Barducci , Dario Buttazzo , Alessandro Dondarini +4 more | Journal of High Energy Physics

A bstract Dark Matter can interact with electroweak gauge bosons via higher-dimensional operators, in spite of being neutral under gauge interactions, much like neutral atoms interact with photons through Rayleigh … A bstract Dark Matter can interact with electroweak gauge bosons via higher-dimensional operators, in spite of being neutral under gauge interactions, much like neutral atoms interact with photons through Rayleigh scattering. This study explores effective interactions between a real scalar Dark Matter particle, singlet under the SM gauge group, and electroweak gauge bosons. We present a comprehensive analysis of current constraints and projected sensitivities from both lepton and hadron colliders as well as direct and indirect detection experiments in testing Rayleigh Dark Matter interactions. We find that, thanks to the complementarity between collider experiments and cosmological probes, thermally produced Rayleigh Dark Matter at the hundreds of GeV scale can be thoroughly tested with the next generation of experiments. For lighter candidates, upcoming forecasts will explore uncharted parameter space, significantly surpassing the thermal Dark Matter benchmark.

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Towards a robust model-independent test of the DAMA/LIBRA dark matter signal: ANAIS-112 results with six years of data

2025-06-18

NULL AUTHOR_ID | Physical Review Letters

Neutrinos from the Sun can discover dark matter-electron scattering

2025-06-17

NULL AUTHOR_ID | Physical review. D/Physical review. D.

ALP production from abelian gauge bosons: beyond hard thermal loops

2025-06-17

Mathias Becker , Julia Harz , Enrico Morgante +2 more | Journal of High Energy Physics

A bstract Previous computations of feebly interacting particle production have encountered issues with unphysical (negative) interaction rates at soft momenta. We address this problem by studying the production of Axion-Like … A bstract Previous computations of feebly interacting particle production have encountered issues with unphysical (negative) interaction rates at soft momenta. We address this problem by studying the production of Axion-Like Particles (ALPs) coupled to U(1)-gauge fields, employing the full form of 1PI-resummed gauge boson propagators. This approach avoids the need for matching or subtraction procedures. We find that the ALP production rate remains positive across all momentum scales and identify the dominant production mechanisms. At soft ALP momenta ( p ≲ g 2 T ), interactions involving two spacelike gauge bosons dominate the production rate, surpassing other channels by an order of magnitude. In particular, using the full gauge boson propagator suggests that at even softer momenta ( p ≲ g 4 T ), production involving two timelike gauge bosons becomes significant, potentially exceeding other contributions by another order of magnitude. We also find that a leading order accurate result for momenta g 4 T ≲ p ≲ g 2 T still requires extensions beyond the 1PI resummation. Using these insights, we update the thermal ALP abundance and refine the estimate of the average ALP momentum, providing important input for structure formation constraints on ALP dark matter in the keV mass range.

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Illuminating the Physics of Dark Energy with the Discovery Simulations

2025-06-17

Gillian D. Beltz-Mohrmann , Adrian Pope , A. Alarcon +7 more | The Open Journal of Astrophysics

In this paper, we present the Discovery simulations: a new pair of high-resolution N-body simulations motivated by the DESI Y1 BAO cosmological constraints on dark energy. The Discovery simulations were … In this paper, we present the Discovery simulations: a new pair of high-resolution N-body simulations motivated by the DESI Y1 BAO cosmological constraints on dark energy. The Discovery simulations were run with identical initial conditions, and differ only in their cosmological parameters. The first simulation is based on a flat cosmology, while the second is based on a cosmology, with particular parameter values chosen based on the DESI analysis which includes constraints from BAO with CMB priors. Both simulations evolve <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mn>6720</mml:mn><mml:mn>3</mml:mn></mml:msup></mml:math> particles in a box with a side length of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>L</mml:mi><mml:mrow><mml:mi mathvariant="normal">b</mml:mi><mml:mi mathvariant="normal">o</mml:mi><mml:mi mathvariant="normal">x</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>1.5</mml:mn></mml:mrow></mml:math> Gpc, leading to a mass resolution of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>∼</mml:mo><mml:mn>4</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mn>8</mml:mn></mml:msup></mml:mrow></mml:math> in each simulation. In this work we demonstrate the impact of the cosmology on the matter power spectrum, halo mass function, and halo mass accretion rate. We also populate halos with galaxies using a novel forward model for in-situ star formation, and examine the way in which changes to cosmology manifest as changes in star formation history. The Discovery simulations provide a testbed for alternative cosmological probes that may offer additional constraining power beyond BAO, such as higher-order summary statistics and observables in the nonlinear regime. Halo catalogs from the Discovery simulations are publicly available and can be downloaded from the HACC Simulation Data Portal.

Search for the inelastic scattering of dark matter massive particles on the 178m2Hf isomer

2025-06-17

V. I. Kirischuk , S. S. Drapey , А.М. Savrasov +1 more | EPL (Europhysics Letters)

Abstract The results of the new experimental search for dark matter using the 178m2Hf isomer are presented. The γ-rays that are not emitted during the spontaneous decay of this isomer … Abstract The results of the new experimental search for dark matter using the 178m2Hf isomer are presented. The γ-rays that are not emitted during the spontaneous decay of this isomer but might arise from the population of excited nuclear levels in 178Hf due to the inelastic scattering with dark matter massive particles are analyzed in detail. The limits on the half-life of the dark-matter-induced transitions, obtained from limits on these γ-ray intensities, have been improved by about 55 times, from 1.79 × 105 yr to T1/2 > 99 × 105 yr. Further progress of such experimental efforts is discussed.&#xD;

Chiral gravitational wave background from audible axion via Nieh–Yan term

2025-06-17

Baoyu Xu , K. Y. Ding , Hong Su +2 more | Physics of the Dark Universe

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Investigation of hadronic cross sections of cosmic ray carbon and oxygen on BGO from 200 GeV to 10 TeV energy at the DAMPE experiment

2025-06-16

NULL AUTHOR_ID | Physical review. D/Physical review. D.

COZMIC. I. Cosmological Zoom-in Simulations with Initial Conditions Beyond Cold Dark Matter

2025-06-16

Ethan O. Nadler , Rui An , Vera Gluscevic +2 more | The Astrophysical Journal

Abstract We present 72 cosmological dark-matter--only N -body zoom-in simulations with initial conditions beyond cold, collisionless dark matter (CDM), as the first installment of the COZMIC suite. We simulate Milky … Abstract We present 72 cosmological dark-matter--only N -body zoom-in simulations with initial conditions beyond cold, collisionless dark matter (CDM), as the first installment of the COZMIC suite. We simulate Milky Way (MW) analogs with linear matter power spectra P ( k ) for (i) thermal-relic warm dark matter (WDM) with masses m WDM ∈ [3, 4, 5, 6, 6.5, 10]keV, (ii) fuzzy dark matter (FDM) with masses m FDM ∈ [25.9,69.4, 113, 151, 185, 490] × 10 −22 eV, and (iii) interacting dark matter (IDM) with a velocity-dependent elastic proton scattering cross section σ = σ 0 v n , relative particle velocity scaling n ∈ [2, 4], and dark matter mass m IDM ∈ [10 −4 , 10 −2 , 1] GeV. Subhalo mass function (SHMF) suppression is significantly steeper in FDM versus WDM, while dark acoustic oscillations in P ( k ) can reduce SHMF suppression for IDM. We fit SHMF models to our simulation results and derive new bounds on WDM and FDM from the MW satellite population, obtaining m WDM > 5.9 keV and m FDM > 1.4 × 10 −20 eV at 95% confidence; these limits are ≈10% weaker and 5× stronger than previous constraints owing to the updated transfer functions and SHMF models, respectively. We estimate IDM bounds for n = 2 ( n = 4) and obtain σ 0 < 1.0 × 10 −27 cm 2 , 1.3 × 10 −24 cm 2 , and 3.1 × 10 −23 cm 2 ( σ 0 < 9.9 × 10 −27 cm 2 , 9.8 × 10 −21 cm 2 , and 2.1 × 10 −17 cm 2 ) for m IDM = 10 −4 , 10 −2 , and 1 GeV, respectively. Thus, future development of IDM SHMF models can improve IDM cross section bounds by up to a factor of ∼20 with current data. COZMIC presents an important step toward accurate small-scale structure modeling in beyond-CDM cosmologies, critical to upcoming observational searches for dark matter physics.

Polarimetric searches for axion dark matter and high-frequency gravitational waves using optical cavities

2025-06-15

NULL AUTHOR_ID | Physical review. D/Physical review. D.

The Compton-thick AGN Population and the NH Distribution of Low-mass AGN in our Cosmic Backyard

2025-06-14

A. Annuar , D. M. Alexander , P. Gandhi +7 more | Monthly Notices of the Royal Astronomical Society

Abstract We present a census of the Compton-thick (CT) active galactic nucleus (AGN) population and the column density (NH) distribution of AGN in our cosmic backyard using a mid-infrared selected … Abstract We present a census of the Compton-thick (CT) active galactic nucleus (AGN) population and the column density (NH) distribution of AGN in our cosmic backyard using a mid-infrared selected AGN sample within 15 Mpc. The column densities are measured from broadband X-ray spectral analysis, mainly using data from Chandra and NuSTAR. Our sample probes AGN with intrinsic 2–10 keV luminosities of L2-10, int = 1037-1043 erg s−1, reaching a parameter space inaccessible to more distant samples. We directly measure a 32$^{+30}_{-18}\%$ CT AGN fraction and obtain an NH distribution that agrees with that inferred by the Swift-BAT survey. Restricting the sample to the largely unexplored domain of low-luminosity AGN with L2 − 10, int ≤ 1042 erg s−1, we found a CT fraction of $19^{+30}_{-14}\%$, consistent with those observed at higher luminosities. Comparing the host-galaxy properties between the two samples, we find consistent star formation rates, though the majority of our galaxy have lower stellar masses (by ≈0.3 dex). In contrast, the two samples have very different black hole mass (MBH) distributions, with our sample having ≈1.5 dex lower mean mass (MBH ∼ 106 M⊙). Additionally, our sample contains a significantly higher number of LINERs and H ii-type nuclei. The Eddington ratio range probed by our sample, however, is the same as Swift-BAT, although the latter dominates at higher accretion rates, and our sample is more evenly distributed. The majority of our sample with λEdd ≥ 10−3 tend to be CT, while those with λEdd &lt; 10−3 are mostly unobscured or mildly obscured.

Search for sub-eV axion-like particles in a quasi-parallel stimulated resonant photon-photon collider with “coronagraphy”

2025-06-13

Yuri Kirita , Airi Kodama , Kensuke Homma +7 more | Journal of High Energy Physics

A bstract Axion-like particles (ALPs) have been searched for with a quasi-parallel stimulated resonant photon-photon collider sensitive to the sub-eV mass range by focusing two-color near-infrared pulse lasers into a … A bstract Axion-like particles (ALPs) have been searched for with a quasi-parallel stimulated resonant photon-photon collider sensitive to the sub-eV mass range by focusing two-color near-infrared pulse lasers into a vacuum. In this work, we have developed a specialized coronagraphy to mitigate the dominant background photons from optical elements by introducing an eclipse filter. The observed number of signal-like photons was found to be consistent with residual background photons from optical elements through an additional test by degrading the focal point overlapping factor between the two lasers. We then extended the exclusion region in the relation between ALP-photon coupling, g/M , and the ALP mass m , reaching the most sensitive point g/M = 5 . 45 × 10 − 7 GeV − 1 at m = 0 . 15 eV for pseudoscalar ALPs.

Shadow of quadrupole-deformed compact objects in a local dark-matter shell

2025-06-12

Shokoufe Faraji , João Luís Rosa | Astronomy and Astrophysics

This work investigated observational properties, namely the shadow and photon ring structure, of emission profiles originating near compact objects. In particular, we considered a distorted and deformed compact object characterized … This work investigated observational properties, namely the shadow and photon ring structure, of emission profiles originating near compact objects. In particular, we considered a distorted and deformed compact object characterized by two quadrupole parameters and surrounded by an optically thin and geometrically thin accretion disk with different emission profiles modeled by Johnson's standard-unbound (SU) distribution in the reference frame of the emitter. Under these assumptions, we produced the observed intensity profiles and shadow images for a face-on observer. Our results indicate that, due to the fact that modifications of the quadrupole parameters affect the radius of the innermost stable circular orbit (ISCO) and the unstable photon orbits on the equatorial plane, the observed shadow images and their properties are significantly influenced by the quadrupole parameters and emission profiles. Furthermore, we analyzed the impact of the presence of a dark-matter halo in the observational imprints considered and verified that both the increase in the matter contained in the halo or the decrease in the length-scale of the halo led to an increase in the size of the observed shadow. Our results indicate potential degeneracies between the observational features of distorted and deformed compact objects with those of spherically symmetric black holes, which could be assessed by a comparison with the current and future generation of optical experiments in gravitational physics.

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A MARVEL-ous Study of How Well Galaxy Shapes Reflect Dark Matter Halo Shapes in Cold Dark Matter Simulations

2025-06-12

Blake Keith , Ferah Munshi , Alyson Brooks +6 more | The Astrophysical Journal

Abstract We present a 3D shape analysis of both dark matter (DM) and stellar matter (SM) in simulated dwarf galaxies to determine whether stellar shape traces DM shape. Using 80 … Abstract We present a 3D shape analysis of both dark matter (DM) and stellar matter (SM) in simulated dwarf galaxies to determine whether stellar shape traces DM shape. Using 80 central and satellite dwarf galaxies from three simulation suites (“Marvelous Massive Dwarfs,” “Marvelous Dwarfs,” and the “DC Justice League”) spanning stellar masses of 10 6 –10 10 M ⊙ , we measure 3D shapes through the moment of inertia tensor at twice the effective radius to derive axis ratios ( C / A and B / A ) and triaxiality. We find that stellar shape does follow DM halo shape for our dwarf galaxies. However, the presence of a stellar disk in more massive dwarfs ( M * ≳ 10 7.5 M ⊙ ) pulls the distribution of stellar C / A ratios to lower values, while in lower-mass galaxies the gravitational potential remains predominantly shaped by DM. Similarly, stellar triaxiality generally tracks DM triaxiality, with this relationship being particularly strong for nondisky galaxies and weaker in disky systems. These correlations are reinforced by strong alignment between the SM and DM axes, particularly in disk galaxies. Further, we find no detectable difference in either SM or DM shapes when comparing two different supernova feedback implementations, demonstrating that shape measurements are robust to different implementations of baryonic feedback in dwarf galaxies. We also observe that a dwarf galaxy’s shape is largely unperturbed by recent mergers. This comprehensive study demonstrates that stellar shape measurements can serve as a reliable tool for inferring DM shapes in dwarf galaxies.

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Multi-component dark matter and Galactic 511 keV γ-ray emission

2025-06-11

Sarif Khan , Jinsu Kim , Jong‐Kuk Kim +1 more | Journal of High Energy Physics

A bstract We study multi-component dark matter scenarios and the Galactic 511 keV γ -ray emission line signal in the framework of a local, dark U(1) D extension of the … A bstract We study multi-component dark matter scenarios and the Galactic 511 keV γ -ray emission line signal in the framework of a local, dark U(1) D extension of the Standard Model. A light vector dark matter particle associated with the dark U(1) D may decay and annihilate to electron-positron pairs. The produced positrons may in turn form positroniums that subsequently annihilate to two photons, accounting for the observed line signal of the Galactic 511 keV γ -ray emission. Three scenarios are investigated. First, we consider the minimal U(1) D extension where a dark gauge boson and a dark Higgs boson are newly introduced to the particle content. As a second scenario, we consider WIMP-type dark matter with the introduction of an extra dark fermion which, in addition to the dark gauge boson, may contribute to the dark matter relic abundance. It is thus a multi-component dark matter scenario with a UV-complete dark U(1) D symmetry. In particular, the vector dark matter may account for a small fraction of the total dark matter relic abundance. Finally, we consider the scenario where the dark matter particles are of the FIMP-type. In this case, both the light vector and fermion dark matter particles may be produced via the freeze-in and super-WIMP mechanisms. Considering theoretical and observational constraints, we explore the allowed parameter space where the Galactic 511 keV γ -ray line signal and the dark matter relic can both be explained. We also discuss possible observational signatures.

Correlations for the constants values of the Standard Model for electromagnetic, strong and weak interactions of fundamental particles

2025-06-06

V. V. Khruschov | Izmeritel`naya Tekhnika

It is carried out the comparative analysis of some theoretical and phenomenological relations among constants of the extended Standard Model for electromagnetic, strong and weak interactions of fundamental particles (further … It is carried out the comparative analysis of some theoretical and phenomenological relations among constants of the extended Standard Model for electromagnetic, strong and weak interactions of fundamental particles (further the extended Standard Model) in order to find possible correlations for constants in the quark and lepton sectors. Availability of such correlations may attest to some connections for constants in the framework of a theory more general than the extended Standard Model. A number of theoretical relations among constants are considered and an accuracy of fulfi llment of these relations obtained in the main approximation of the extended Standard Model is evaluated. Then phenomenological relations between masses of current and constituent quarks and their mixing angles are considered. A typical estimation of accuracy of these theoretical and phenomenological relations is obtained. A phenomenological relation for constituent quark masses and a mixing angle for quarks is suggested. The quark-lepton complementarity relation for quark and neutrino mixing angles is verifi ed. Functional dependences for coupling constants of electromagnetic, strong and weak interactions on the square of a four-dimensional vector of energy and momentum are represented. An example of a grand unifi cation theory is demonstrated together with possible levels of spontaneous violation of its gauge symmetry to the gauge symmetry of the extended Standard Model. It is pointed out that additional Higgs particles are appeared at these levels of spontaneous violation. The quark-lepton complementarity relation verifi ed in the article for quark and neutrino mixing angles can be a consequence of a fundamental link between Cabibbo-Kobayashi-Maskava and Pontecorvo-Maki-Nakagava-Sakata matrices in a future grand unifi cation theory. In this case the received result will promote finding of such theory.

The neutron veto of the XENONnT experiment: Results with demineralized water

2024-12-18

E. Aprile , J. Aalbers , K. Abe +7 more

Radiogenic neutrons emitted by detector materials are one of the most challenging backgrounds for the direct search of dark matter in the form of weakly interacting massive particles (WIMPs). To … Radiogenic neutrons emitted by detector materials are one of the most challenging backgrounds for the direct search of dark matter in the form of weakly interacting massive particles (WIMPs). To mitigate this background, the XENONnT experiment is equipped with a novel gadolinium-doped water Cherenkov detector, which encloses the xenon dual-phase time projection chamber (TPC). The neutron veto (NV) tags neutrons via their capture on gadolinium or hydrogen, which release $\gamma$-rays that are subsequently detected as Cherenkov light. In this work, we present the key features and the first results of the XENONnT NV when operated with demineralized water in the initial phase of the experiment. Its efficiency for detecting neutrons is $(82\pm 1)\,\%$, the highest neutron detection efficiency achieved in a water Cherenkov detector. This enables a high efficiency of $(53\pm 3)\,\%$ for the tagging of WIMP-like neutron signals, inside a tagging time window of $250\,\mathrm{\mu s}$ between TPC and NV, leading to a livetime loss of $1.6\,\%$ during the first science run of XENONnT.

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