Unraveling proton strangeness: Determination of the strangeness sigma term with statistical significance

Abstract

This study delves into the contribution of the strange quark within the proton, which influences several fundamental proton properties. By establishing a robust relationship between the proton’s quantum anomalous energy and the sigma term, we successfully extract the contribution of the strangeness sigma term in the proton, obtaining it from parametrized fits of the differential cross section using exponential and dipole forms. The extracted sigma term values are estimated to be <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>455.62</a:mn><a:mo>±</a:mo><a:mn>64.60</a:mn><a:mtext> </a:mtext><a:mi>MeV</a:mi></a:mrow></a:math> (exponential fit) and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mn>337.74</c:mn><c:mo>±</c:mo><c:mn>106.79</c:mn><c:mtext> </c:mtext><c:mi>MeV</c:mi></c:mrow></c:math> (dipole fit). Additionally, we present novel results for the proton trace anomalous energy, observing values of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mn>0.13</e:mn><e:mo>±</e:mo><e:mn>0.02</e:mn></e:math> (exponential fit) and <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mn>0.15</g:mn><g:mo>±</g:mo><g:mn>0.03</g:mn></g:math> (dipole fit). Our analysis integrates the novel data from the <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>J</i:mi><i:mo>/</i:mo><i:mi>ψ</i:mi><i:mo>−</i:mo><i:mn>007</i:mn></i:math> and GlueX Collaborations, to some extent providing an experimental phenomenological window into the nonzero strange quark content inside proton, with the statistical significances <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mn>7.1</k:mn><k:mi>σ</k:mi></k:math> (exponential fit) and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mn>3.2</m:mn><m:mi>σ</m:mi></m:math> (dipole fit), respectively. Furthermore, we discuss the possibility of scheme independence in the extraction results and examine the uniformity of sigma terms obtained from the datasets provided by the two collaborations. Our analysis may reveals compatibility between the extracted results of the respective experiments. Published by the American Physical Society 2024

Locations

• Physical review. D/Physical review. D. - View - PDF
• arXiv (Cornell University) - View - PDF