AUTHOR=Wang Qi , Liu Fu-Hu , Olimov Khusniddin K. 

TITLE=Initial-State Temperature of Light Meson Emission Source From Squared Momentum Transfer Spectra in High-Energy Collisions

JOURNAL=Frontiers in Physics

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2021.792039

DOI=10.3389/fphy.2021.792039

ISSN=2296-424X

ABSTRACT=<p>The squared momentum transfer spectra of light mesons, <italic>π</italic><sup>0</sup>, <italic>π</italic><sup>+</sup>, <italic>η</italic>, and <italic>ρ</italic><sup>0</sup>, produced in high-energy virtual photon-proton (<italic>γ</italic>*<italic>p</italic>) → meson + nucleon process in electron-proton (<italic>ep</italic>) collisions measured by the CLAS Collaboration are analyzed by the Monte Carlo calculations, where the transfer undergoes from the incident <italic>γ</italic>* to emitted meson or equivalently from the target proton to emitted nucleon. In the calculations, the Erlang distribution from a multi-source thermal model is used to describe the transverse momentum spectra of emitted particles. Our results show that the average transverse momentum (⟨<italic>p</italic><sub><italic>T</italic></sub>⟩) and the initial-state temperature (<italic>T</italic><sub><italic>i</italic></sub>) increase from lower squared photon virtuality (<italic>Q</italic><sup>2</sup>) and Bjorken variable (<italic>x</italic><sub><italic>B</italic></sub>) to higher one. This renders that the excitation degree of emission source, which is described by ⟨<italic>p</italic><sub><italic>T</italic></sub>⟩ and <italic>T</italic><sub><italic>i</italic></sub>, increases with increasing of <italic>Q</italic><sup>2</sup> and <italic>x</italic><sub><italic>B</italic></sub>.</p>