第五届粒子所“青年之星”2019年度学术论坛

The radial distribution of $D^0$ mesons in jets probes the diffusion of charm quark relative to the jet axis and provides a new perspective to study the interaction mechanisms between heavy quarks and the medium in the nucleus-nucleus collisions. The in-medium parton propagations are described by a Monte Carlo transport model which uses the next-to-leading order (NLO) plus parton shower (PS)...

Heavy-flavor quarks (charm and beauty) play an important role in probing the Quark-Gluon Plasma (QGP) formed in the heavy-ion collisions. Due to their heavy masses, charm and beauty quarks are formed in hard scattering processes on a timescale shorter than the QGP formation time at LHC energy. Therefore, they experience all the phases of the medium evolution interacting with the medium...

Charm quarks are excellent probes of properties of Quark-Gluon Plasma (QGP) created in ultra-relativistic heavy-ion collisions. They are produced before the QGP is created and their thermalization time is comparable to the lifetime of the QGP. Compared to other open charm mesons, $D_{s}$ mesons are expected to be less sensitive to the interactions in the hadronic phase due to their...

In this paper, we apply the supervised learning method in deep learning to study the critical threshold, the spatial and temporal correlation exponent, and also the characteristic times of directed percolation(DP) in both (1+1) and (2+1) dimensions. DP is a classic type of absorbing phase transition in non-equilibrium phase transitions. The previous machine learning method mainly focuses on...

We study the suppressions of high transverse momentum single hadron and dihadron productions in high-energy heavy-ion collisions based on the framework of a next-to-leading-order perturbative QCD parton model combined with the higher-twist energy loss formalism [1,2]. Our model can provide a consistent description for the nuclear modification factors of single hadron $R_{AA}$ and dihadron...

Relativistic heavy-ion experiments have observed similar quenching effects for (prompt) $D$ mesons compared to charged hadrons for transverse momenta larger than 6-8 GeV, which remains a mystery since heavy quarks typically lose less energies in quark-gluon plasma than light quarks and gluons. Recent measurements of the nuclear modification factors of $B$ mesons and $B$-decayed $D$ mesons by...

We revisit radiative parton energy loss in deeply inelastic scattering (DIS) off a large nucleus within the perturbative QCD approach. We calculate the gluon radiation spectra induced by double parton scattering in DIS without collinear expansion in the transverse momentum of initial gluons as in the original high-twist approach. The final radiative gluon spectrum can be expressed in terms of...

The measurement of reconstructed jets over a wide range in jet energy and jet resolution parameter is required for comprehensive understanding of jet quenching in heavy-ion collisions. Such measurements are challenging, however, due to the presence of complex, uncorrelated background to the jet signal, and the need to minimize biases in the selected jet population imposed by background...

In high energy nuclear collisions, light nuclei can be regarded as a cluster of baryons and their yields are sensitive to the baryon density fluctuations. Thus, the production of light nuclei can be used to study the QCD phase transition, at which the baryon density fluctuation will be enhanced. For example, the ratio of proton ($N(p)$) and triton ($N(t)$) to deuteron ($N(d)$) yields, which...

We study the magnetic field effect on the Schwinger effect and the energy loss of quarks using the AdS/CFT correspondence. The potential analysis of particle pairs transverse and parallel to the magnetic field is performed in this paper. Firstly, we calculate separating length of the particle pairs at finite temperature with magnetic field. It is found that the maximum value of separating...

Loops, which can be found in many different kinds of networks, it is important in many aspects, such as when dealing with spreading dynamics on networks, calculating network dimensions, etc. On the contrary, tree networks in which no loop exits, are simplifications and usually allow for analyticity. There lacks a quantity, however, to tell the ratio of loops which determines the extent of...

By analyzing a 2.93~$\rm fb^{-1}$ data sample of $e^+e^-$ collisions, recorded at a center-of-mass energy of 3.773 $\rm \,GeV$ with the BESIII detector operated at the BEPCII collider, we report the first observation of the semileptonic $D^+$ transition into the axial-vector meson $D^{+} \rightarrow {\bar{K}}_{1}(1270)^{0}e^{+}\nu_{e}$ with a statistical significance greater than...

Motivated by the $2.8\sigma$ discrepancy observed between the BaBar measurement and the Standard Model prediction of the CP asymmetry in $\tau\to K_S\pi\nu_\tau$ decays, as well as the prospects of future measurements at Belle II, we revisit this observable in this paper. Firstly, we reproduce the known CP asymmetry due to $K^0 -\bar{K}^0$ mixing by means of the reciprocal basis, which is...

1.Motivation 2.Description of fixed point 3.Three samples of the potts model 4.locate the fixed point in the phase plane 5.Discuss a possible application at the Beam energy Scan of RHIC

The ALICE detector at the Large Hadron Collider(LHC) is optimized for the studies of the Quark-Gluon Plasma (QGP) created in heavy-ion collisions. Charm quarks are one of the probes that is extensively used to elucidate the properties of the QGP. They are dominantly produced at the initial stage of the collisions via hard partonic scattering processes and experience the whole evolution of the...

As one of the simplest hadronic processes, $\gamma\gamma\rightarrow M^{+}M^{-}$ ($M=\pi,K$) could be a good testing ground for our understanding of the perturbative and nonperturbative structure of QCD, and will be studied with high precision at BELLE-II in the near future. In this paper, we revisit these processes with twist-3 corrections in the perturbative QCD approach based on the $k_{T}$...

We study the radiative decays $h_{c}\rightarrow\gamma\eta^{(\prime)}$ in the framework of perturbative QCD and evaluate analytically the one-loop integrals with the light quark masses kept. Interestingly, the branching ratios $\mathcal{B}(h_{c}\rightarrow\gamma\eta^{(\prime)})$ are insensitive to both the light quark masses and the shapes of $\eta^{(\prime)}$ distribution amplitudes. And it is...

The observed suppression of inclusive jets in heavy-ion collisions at LHC has a very weak $p_{T}$ dependence over a large range of $p_{T}$ = 50-1000 GeV and is almost independent of the colliding energy, though the initial energy density of the formed QGP has increased significantly from $\sqrt{s}$ = 2.76 to 5.02 TeV. This interesting phenomenon is fully investigated in the linear Boltzmann...

The azimuthal angular correlation between a heavy-flavor meson ($J/ \Psi$ and $D^0$) and a light hadron has been measured firstly by the CMS experiment. The elliptic flow of J/psi from the initial state has been successful described not long ago. We investigate the angular correlation between a open heavy flavor meson and a charged light hadron in the Color Glass Condensate framework. Our...

We revisit radiative parton energy loss in deeply inelastic scattering (DIS) off a large nucleus within the perturbative QCD approach. We calculate the gluon radiation spectra induced by double parton scattering in DIS without collinear expansion in the transverse momentum of initial gluons as in the original high-twist approach. The final radiative gluon spectrum can be expressed in terms of...