Affiliation:
1. Joint Institute for Nuclear Research (JINR), Joliot-Curie 20, Dubna 141980, Russia
2. Faculty of Physics and Technology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
Abstract
The Beam Energy Scan (BES) program at RHIC aims to explore the QCD phase diagram, including the search for the evidence of the 1st order phase transition from hadronic matter to Quark-Gluon Plasma (QGP) and the location of the QCD critical point. One of the features previously observed in the study of QGP is the effect of suppression of particle production with high transverse momenta pT (>2 GeV/c) at energies sNN = 62.4–200 GeV, which was deduced from the charged-particle nuclear modification factor (RCP) measured using the data from Beam Energy Scan Program Phase I (BES-I) of STAR experiment. In 2018, STAR has collected over 500 million events from Au+Au collisions at sNN = 27 GeV as a part of the STAR BES-II program, which is about a factor of 10 higher than BES-I 27 GeV data size. In this report, we present new measurements of charged particle production and the nuclear modification factor RCP, from this new 27 GeV data set and compare them with the BES-I results. The new measurements extend the previous BES-I results to higher transverse momentum range, which allows better exploration of the jet quenching effects at low RHIC energies, and may help to understand the effects of the formation and properties of QGP at these energies.
Funder
Russian Science Foundation
Reference24 articles.
1. The RHIC Beam Energy Scan program in STAR and what’s next …;Odyniec;J. Phys. Conf. Ser.,2013
2. Adamczyk, L. et al. [STAR Collaboration] (2018). Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at sNN = 7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. Phys. Rev. Lett., 121, 032301.
3. Arsene, I. et al. [BRAHMS Collaboration] (2005). Quark gluon plasma and color glass condensate at RHIC? The Perspective from the BRAHMS experiment. Nucl. Phys. A, 757, 1–27.
4. Back, B.B. et al. [PHOBOS Collaboration] (2005). The PHOBOS perspective on discoveries at RHIC. Nucl. Phys. A, 757, 28–101.
5. Adams, J. et al. [STAR Collaboration] (2005). Experimental and theoretical challenges in the search for the quark gluon plasma: The STAR Collaboration’s critical assessment of the evidence from RHIC collisions. Nucl. Phys. A, 757, 102–183.