scholarly journals Energy dependence of J/Ψ production in Au+Au collisions at = 39, 62.4 and 200 GeV from the STAR experiment

2013 ◽  
Vol 458 ◽  
pp. 012009
Author(s):  
Wangmei Zha ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
S. Zhang ◽  
Y. G. Ma ◽  
J. H. Chen ◽  
C. Zhong

The beam energy dependence of correlation lengths (the Hanbury-Brown-Twiss radii) is calculated by using a blast-wave model and the results are comparable with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE measurements. A set of parameters for the blast-wave model as a function of beam energy under study are obtained by fit to the HBT radii at each energy point. The transverse momentum dependence of HBT radii is presented with the extracted parameters for Au+Au collision at sNN = 200 GeV and for Pb+Pb collisions at 2.76 TeV. From our study one can learn that particle emission duration cannot be ignored while calculating the HBT radii with the same parameters. And tuning kinetic freeze-out temperature in a range will result in system lifetime changing in the reverse direction as it is found in RHIC-STAR experiment measurements.


2007 ◽  
Vol 16 (07n08) ◽  
pp. 2476-2483 ◽  
Author(s):  
◽  
MING SHAO ◽  
LIANG LI

Time-Of-Flight (TOF) based on Multi-gap Resistive Plate Chamber (MRPC) detectors have been successfully operating at the STAR experiment since 2003.2,3 The MRPC time resolution is however found to be significantly worse2 (80-90 ps) than that previously obtained in beam test (60 ps).4 In order to fully understand MRPC working principles and operating requirements, an extensive calibration study is performed using data collected by STAR in 200 GeV Au + Au collisions in 2004. The relation between MRPC timing, signal amplitude, incident angle and momentum are discussed. Contributions from tracking properties of STAR-TPC are also studied by simulation. The intrinsic time resolution of the MRPCs used in STAR-TOF, after taking all factors into consideration, is found to be in good agreement with beam test results.


2020 ◽  
Vol 101 (1) ◽  
Author(s):  
J. Adam ◽  
L. Adamczyk ◽  
J. R. Adams ◽  
J. K. Adkins ◽  
G. Agakishiev ◽  
...  

2004 ◽  
Vol 82 (4) ◽  
pp. 263-275 ◽  
Author(s):  
M El-Nadi ◽  
A Abdelsalam ◽  
E A Shaat ◽  
N Ali Mossa ◽  
Z Abou Moussa ◽  
...  

Partial production cross sections of electromagnetic breakup of 32S projectiles at two widely differing energies were measured using an emulsion target. The electromagnetic dissociation represents about 6% and 17% of the total number of nuclear events at Elab/A = 3.7 and 200 GeV, respectively. The experimental electromagnetic cross sections σexpEMD show an energy dependence that is well reproduced by the Weizsacker–Williams approximation. The value of σexpEMD at 200A GeV (with γ >> 1) shows a good agreement with that predicted by the combined model of Pshenichnov et al. Examination of the reactions (γ, p) and (γ, He) reveals that the ratio of 1 p/1 He cross sections is close to unity at Dubna energy (3.7A GeV), while it rapidly increases to 3.0 ± 0.6 at CERN energy (200A GeV). In most of the observed dissociation modes, the total kinetic energy of the fragments in the projectile rest frame is lower than 50 MeV. Nevertheless, it is possible that the contribution of excitation modes of the different multipolarities is determining in this region. PACS No.: 25.70


2007 ◽  
Vol 655 (3-4) ◽  
pp. 104-113 ◽  
Author(s):  
B.I. Abelev ◽  
M.M. Aggarwal ◽  
Z. Ahammed ◽  
B.D. Anderson ◽  
D. Arkhipkin ◽  
...  

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Yifei Zhang ◽  
Haojie Xu ◽  
Wangmei Zha ◽  
Qun Wang

AbstractWe reproduce di-electron spectra in the region of 0 < m e+e < 4 GeV in both minimum bias and central Au+Au collisions at $\sqrt {s_{NN} } $ = 200 GeV measured by the STAR experiment. A cocktail simulation, incorporating STAR acceptance and detector responses, is able to describe the “enhancement” of the low mass region by including an in-medium modification of vector mesons and a thermal di-lepton calculation. We also predict the di-lepton mass spectra in RHIC lower energies via an extrapolation method. The evolution of Di-lepton mass spectra, effective temperature, and possible medium modifications versus colliding energies are studied to explore the QCD phase diagram.


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