Observation of the $\Lambda_b^0 \to J/\psi \Xi^- K^+$ and $\Xi_b^0 \to J/\psi \Xi^- \pi^+$ decays

LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb, C. Abellán Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson

Abstract

The first observation of the $\Xi_b^0 \to J/\psi \Xi^- \pi^+$ decay and the most precise measurement of the branching fraction of the $\Lambda_b^0 \to J/\psi \Xi^- K^+$ decay are reported, using proton-proton collision data from the LHCb experiment collected in 2016--2018 at a centre-of-mass energy of 13~TeV, corresponding to an integrated luminosity of 5.4~fb$^{-1}$. Using the $\Lambda_b^0 \to J/\psi \Lambda$ and $\Xi_b^0 \to J/\psi \Xi^-$ decays as normalisation channels, the ratios of branching fractions are measured to be: \[ \frac{\mathcal{B}(\Lambda_b^0 \to J/\psi \Xi^- K^+)}{\mathcal{B}(\Lambda_b^0 \to J/\psi \Lambda)} = (1.17 \pm 0.14 \pm 0.08)\times 10^{-2} \, , \] \[ \frac{\mathcal{B}(\Xi_b^0 \to J/\psi \Xi^- \pi^+)}{\mathcal{B}(\Xi_b^0 \to J/\psi \Xi^-)} = (11.9 \pm 1.4 \pm 0.6)\times 10^{-2}\, , \] where the first uncertainty is statistical and the second systematic.

Locations

• arXiv (Cornell University) - View - PDF