Analysis of spectral modification of $\varphi$ mesons at finite density using a transport approach in the 12 GeV pA reactions

Abstract

The hadron spectrum at finite density is an important observable for exploring the origin of hadron masses. In the KEK-PS E325 experiment, the di-electron decays of phi mesons inside and outside nuclei were measured using 12 GeV pA reactions. In the previous analysis, a significant excess was observed on the low-mass side of the phi meson peak in the data for slow-moving phi mesons ($\beta \gamma =p_{\varphi }/m_{\varphi }<1.25$) with the Cu target, and in-medium vector meson spectral modification was verified. We newly employed the PHSD transport approach to take into account the time evolution of spatial density distribution of the target nuclei. Consistent with the previous analysis, a significant excess was observed in the present analysis as well. It was found that incorporating momentum dependence into the spectral modification leads to better agreement with the experimental results. For the slow-moving $\varphi$ mesons with the Cu target, the newly obtained modification parameters are consistent with those from the previous analysis within the uncertainties.

28 pages, 12 figures

References in corpus (7)

• Parton transport and hadronization from the dynamical quasiparticle point of view
• Constraining the strangeness content of the nucleon by measuring the $\varphi$ meson mass shift in nuclear matter
• In-medium effects in strangeness production in heavy-ion collisions at (sub-)threshold energies
• $\varphi$ meson self-energy in nuclear matter from $\varphi N$ resonant interactions
• Near-threshold $\varphi$ meson production in proton-nucleus reactions and $\varphi$ width in finite nuclei
• $\varphi$ Production in In-In Collisions at 158 AGeV
• Nuclear mass number dependence of inclusive production of omega and phi mesons in 12 GeV p + A collisions