In this study, we investigate the $R^2$ corrections to the dissociation of heavy quarkonium in the Gauss-Bonnet gravitational background. We analyze the impact of the Gauss-Bonnet parameter $\lambda_{\rm GB}$ on the spectral function of charmonium and bottomonium and examine the effect of $\lambda_{\rm GB}$ on the dissociation of heavy quarkonium. Our results show that $\lambda_{\rm GB}$ reduces the peak height and increases the peak width of the spectral function, suggesting that $\lambda_{\rm GB}$ enhances the dissociation of heavy quarkonium. We also discuss the variation in the dissociation of heavy quarkonium with the ratio of shear viscosity to entropy density and observe that the dissociation is easier in more perfect plasma. Additionally, we observe that the temperature decreases the peak height and widens the peak, thereby accelerating the dissociation.

China

Zhou-Run Zhu

Manman Sun

Rui Zhou

Jinzhong Han

$\textit{R}$ $^{2}$ corrections to holographic heavy quarkonium dissociation * Rui Zhou supported by the Science and Technology Development Plan Project of Henan Province, China (242102230085), the National Natural Science Foundation of China (12404470), the High Level Talents Research and Startup Foundation Projects for Doctors of Zhoukou Normal University, China (ZKNUC2023017). Manman Sun supported by the National Natural Science Foundation of China (12305076). Zhou-Run Zhu supported by the High Level Talents Research and Startup Foundation Projects for Doctors of Zhoukou Normal University, China (ZKNUC2023018)

A special class of four-point correlation functions in the maximally supersymmetric Yang-Mills theory is given by the square of the Fredholm determinant of a generalized Bessel kernel. In this note, we re-express its logarithmic derivatives in terms of a two-dimensional Riemann-Hilbert problem. We solve the latter in the null limit making use of the Deift-Zhou steepest descent. We reproduce the exact octagonal anomalous dimension in 't Hooft coupling and provide its novel formulation as the convolution of a non-linear quasiclassical phase with the Fermi distribution in the limit of the infinite chemical potential.

United States

A.V. Belitsky

Null octagon from Deift-Zhou steepest descent

We study the thermodynamic properties of asymmetric quark matter and large mass quark stars within the confined-isospin-density-dependent-quark-mass model. We find that the quark matter symmetry energy should be very large in order to describe the recent discovered heavy compact stars PSR J0348+0432 ( $$\text {2.01}\pm \text {0.04}M_{\odot }$$  <math> <mrow> <mtext>2.01</mtext> <mo>±</mo> <mtext>0.04</mtext> <msub> <mi>M</mi> <mo>⊙</mo> </msub> </mrow> </math>  ), MSP J0740+6620 ( $$\text {2.14}\pm ^\text {0.10}_\text {0.09}M_{\odot }$$  <math> <mrow> <mtext>2.14</mtext> <msubsup> <mo>±</mo> <mtext>0.09</mtext> <mtext>0.10</mtext> </msubsup> <msub> <mi>M</mi> <mo>⊙</mo> </msub> </mrow> </math>   of 68.3 $$\%$$  <math> <mo>%</mo> </math>   credibility interval and  $$\text {2.14}\pm ^\text {0.20}_\text {0.18}M_{\odot }$$  <math> <mrow> <mtext>2.14</mtext> <msubsup> <mo>±</mo> <mtext>0.18</mtext> <mtext>0.20</mtext> </msubsup> <msub> <mi>M</mi> <mo>⊙</mo> </msub> </mrow> </math>   of 95.4 $$\%$$  <math> <mo>%</mo> </math>   credibility interval) and PSR J2215+5135 (2.27 $$\pm ^\text {0.10}_\text {0.09}M_{\odot }$$  <math> <mrow> <msubsup> <mo>±</mo> <mtext>0.09</mtext> <mtext>0.10</mtext> </msubsup> <msub> <mi>M</mi> <mo>⊙</mo> </msub> </mrow> </math>  ) as QSs. The tidal deformability  $$\Lambda _{1.4}$$  <math> <msub> <mi>Λ</mi> <mrow> <mn>1.4</mn> </mrow> </msub> </math>   of the QSs is also investigated in this work, and the result indicates that  $$\Lambda _{1.4}$$  <math> <msub> <mi>Λ</mi> <mrow> <mn>1.4</mn> </mrow> </msub> </math>   may depend on the isospin effects and the strength / orientation distribution of the magnetic fields inside the quark stars.

Peng-Cheng Chu

Yi Zhou

Yao-Yao Jiang

Hong-Yang Ma

He Liu

Xiao-Min Zhang

Xiao-Hua Li

Quark star matter in heavy quark stars

We study the quasi-two-body decays 
					 by employing the perturbative QCD (PQCD) factorization approach, where the charmonia 
					 represents 
					 and 
					. The corresponding decay channels are studied by constructing the kaon-pion distribution amplitude (DA) 
					, which comprises important final state interactions between the kaon and pion in the resonant region. Relativistic Breit-Wigner formulas are adopted to parameterize the time-like form factor 
					 appearing in the kaon-pion DAs. The SU(3) flavor symmetry breaking effect resulting from the mass difference between the kaon and pion is taken into account, which makes significant contributions to the longitudinal polarizations. The observed branching ratios and the polarization fractions of 
					 are accommodated by tuning hadronic parameters for the kaon-pion DAs. The PQCD predictions for 
					 modes from the same set of parameters can be tested by precise data obtained in the future from LHCb and Belle II experiments.
				

Ya Li

Zhou Rui

Zhen-Jun Xiao

P-wave contributions to B(s)→ψKπ decays in perturbative QCD approach Supported by the National Natural Science Foundation of China (11947013, 11605060, 11775117, 11547020); Ya Li is also Supported by the Natural Science Foundation of Jiangsu Province (BK20190508) and the Research Start-up Funding of Nanjing Agricultural University; Zhou Rui is Supported in part by the Natural Science Foundation of Hebei Province (A2019209449)

The Cooling Storage Ring (CSR) External-target Experiment (CEE) will be the first large-scale nuclear physics experimental device at the CSR of the Heavy-Ion Research Facility in Lanzhou (HIRFL) in China. A new T0 detector has been proposed to measure the multiplicity, angular distribution and timing information of charged particles produced in heavy-ion collisions at the target region. Multi-gap resistive plate chamber (MRPC) technology was chosen as part of the construction of the T0 detector, which provides precision event collision times (T0) and collision geometry information. The prototype was tested with hadron and heavy-ion beams to study its performance. By comparing the experimental results with a Monte Carlo simulation, the time resolution of the MRPCs are found to be better than $$\sim 50$$ <math><mrow><mo>∼</mo><mn>50</mn></mrow></math>  ps. The timing performance of the T0 detector, including both detector and readout electronics, is found to fulfil the requirements of the CEE.

Dongdong Hu

Jiaming Lu

Jian Zhou

Peipei Deng

Ming Shao

Yongjie Sun

Lei Zhao

Hongfang Chen

Cheng Li

Zebo Tang

Yifei Zhang

Wenhao You

Guofeng Song

Yitao Wu

Bing Zhu

Extensive beam test study of prototype MRPCs for the T0 detector at the CSR external-target experiment