Transition scale and spectral exponents in asymmetric light-ion collisions at RHIC
Transition scale and spectral exponents in asymmetric light-ion collisions at RHIC
Waqas, Prof. Muhammad 1Bietenholz, Prof. Wolfgang 2Olimov, Prof. Khusniddin K. 3Ajaz, Dr. Muhammad 4Slimane, Prof. Jihane Ben 5Al-Essa, Prof. Laila A. 6Haj Ismail, Dr. Abd Al Karim7
作者信息
- 1. Hubei University of Automotive Technology CEIE
- 2. UNAM
- 3. Academy of Sciences of the Republic of Uzbekistan
- 4. Abdul Wali Khan University Mardan
- 5. Northern Border University
- 6. Princess Nourah bint Abdulrahman University
- 7. Ajman University
- 折叠
摘要
A generalized Fokker-Planck form is used to examine the transverse momentum ($p_{\rm T}$) spectra of neutral pions generated in small-system asymmetric collisions, $p$-Al, $p$-Au, $d$-Au, and $^3$He-Au, at $\sqrt{s_{NN}}=200~{\rm GeV}$. This framework provides a cohesive phenomenological interpolation of particle production over a broad range of transverse momenta. In the generalized form, the function is employed as an empirical shape descriptor rather than as a literal stationary solution of the transport equation. We extract the energy scale governing the transition between a thermal and a hard regime, the effective temperature ($T$), and the exponents determining the high-momentum falloff from fits to PHENIX data. $T$ increases monotonically with the collision centrality and colliding system size, ranging from about 0.33~GeV in peripheral $p$-Al collisions to 0.45~GeV in central $^3$He-Au collisions. This increase is correlated with the average number of participant nucleons, $\la N_{\rm part}\ra$, and the charged‑particle pseudorapidity density, $\la dN_{\rm ch}/d\eta \ra$, indicating that larger and more central collisions create a denser, more strongly interacting medium that freezes out at a higher temperature. The acquired transition scale and power-law exponents follow consistent patterns across systems and centralities, revealing systematic trends in the sharpness of the transition from thermal to hard processes. The most significant observation is the near-constancy of the transition scale across all centralities in $^{3}\mathrm{He}$-Au collisions, indicating saturation of this energy scale when the heavy gold target governs the collision geometry. Our findings demonstrate that the generalized Fokker-Planck form is a sensitive phenomenological probe of the spectral shape and freeze-out conditions in the medium produced even in small-system relativistic collisions, and it consistently describes pion spectra in this set of collisions.
Abstract
A generalized Fokker-Planck form is used to examine the transverse momentum ($p_{\rm T}$) spectra of neutral pions generated in small-system asymmetric collisions, $p$-Al, $p$-Au, $d$-Au, and $^3$He-Au, at $\sqrt{s_{NN}}=200~{\rm GeV}$. This framework provides a cohesive phenomenological interpolation of particle production over a broad range of transverse momenta. In the generalized form, the function is employed as an empirical shape descriptor rather than as a literal stationary solution of the transport equation. We extract the energy scale governing the transition between a thermal and a hard regime, the effective temperature ($T$), and the exponents determining the high-momentum falloff from fits to PHENIX data. $T$ increases monotonically with the collision centrality and colliding system size, ranging from about 0.33~GeV in peripheral $p$-Al collisions to 0.45~GeV in central $^3$He-Au collisions. This increase is correlated with the average number of participant nucleons, $\la N_{\rm part}\ra$, and the chargedparticle pseudorapidity density, $\la dN_{\rm ch}/d\eta \ra$, indicating that larger and more central collisions create a denser, more strongly interacting medium that freezes out at a higher temperature. The acquired transition scale and power-law exponents follow consistent patterns across systems and centralities, revealing systematic trends in the sharpness of the transition from thermal to hard processes. The most significant observation is the near-constancy of the transition scale across all centralities in $^{3}\mathrm{He}$-Au collisions, indicating saturation of this energy scale when the heavy gold target governs the collision geometry. Our findings demonstrate that the generalized Fokker-Planck form is a sensitive phenomenological probe of the spectral shape and freeze-out conditions in the medium produced even in small-system relativistic collisions, and it consistently describes pion spectra in this set of collisions.关键词
Heavy-ion collision/Monte Carlo simulation/Intermediate heavy ion reactions引用本文复制引用
Waqas, Prof. Muhammad,Bietenholz, Prof. Wolfgang,Olimov, Prof. Khusniddin K.,Ajaz, Dr. Muhammad,Slimane, Prof. Jihane Ben,Al-Essa, Prof. Laila A.,Haj Ismail, Dr. Abd Al Karim.Transition scale and spectral exponents in asymmetric light-ion collisions at RHIC[EB/OL].(2026-09-11)[2026-09-16].https://chinaxiv.org/abs/202609.00112.学科分类
天文学
