arXiv subjects

Yu-Liang Yan

Publications and source records attributed to Yu-Liang Yan.

At least 37 records · Page 2Linked to original sources

arXiv2022

Centrality dependence and isospin effect on $\Wpm$ and $\Zn$ productions in nucleus-nucleus collisions at $\sNN=5.02$~TeV

In this paper, the centrality dependent $\Zn$ and $\Wpm$ production and the isospin effect in $\Wpm$ production are investigated with a parton and hadron cascade model PACIAE in Pb--Pb collisions at $\sNN=5.02$~TeV. ALICE data of $\Zn$ production in Pb--Pb collisions at $\sNN=5.02$~TeV are found to be reproduced fairly well. The prediction on $\Wpm$ production in the same collision system is given as well. An interesting isospin effect is observed in exploring the charge asymmetry between $\Wp$ and $\Wm$ as a function of the asymmetry between number of valence $u$- and $d$-quarks varied from small to large collision systems at center-of-mass energy 5.02 TeV. The results serve as a important benchmarks for understanding the initial conditions of heavy-ion collisions.

hep-ph↗

arXiv2021

Dynamical simulation on production of ${\rm W}^{\pm}$ and ${\rm Z}^{0}$ bosons in p-p, p-Pb (Pb-p), and Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV with PACIAE

In this paper, production of ${\rm W}^{\pm}$ and ${\rm Z}^{0}$ vector bosons in p-p, p-Pb (Pb-p), and Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV is dynamically simulated with a parton and hadron cascade model PACIAE. ALICE data of ${\rm Z}^{0}$ production is found to be reproduced fairly well. A prediction for ${\rm W}^{\pm}$ production is given in the same collision systems, at the same energy and at the same energy. An interesting isospin-effect is observed in the sign-change of $μ^{\pm}$ charge asymmetry in pp, pn, np, and nn collisions and in minimum bias p-Pb, Pb-p and Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV, respectively.

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arXiv2021

The study of exotic state $Z_c^{\pm}(3900)$ decaying to $J/ψπ^{\pm}$ in the $pp$ collisions at $\sqrt{s}$ = 1.96, 7, and 13 TeV

A dynamically constrained phase-space coalescence model plus PACIAE model was used to predict the exotic resonant state $Z_c^{\pm}(3900)$ yield, transverse momentum distribution, and the rapidity distribution with $|y| < 6$ and $p_T < 10$ GeV/c in $pp$ collisions at $\sqrt{s} = 1.96, 7$ and 13 TeV, respectively. The yield of the $Z_c^{\pm}(3900)$ is estimated to be around $10^{-6}$ to $10^{-5}$. We also present the energy dependence of the transverse momentum distributions and rapidity distributions for ${Z_c^{+}(3900)}$ and ${Z_c^{-}(3900)}$. The production of ${Z_c^{+}(3900)}$ and its anti-particle ${Z_c^{-}(3900)}$ is found to be quite similar to each other.

hep-ph↗

arXiv2020

Towards a qualitative hadron-parton correspondence in the nuclear modification factor

In this work, we propose a method to show the correspondence between hadron and its quark component nuclear modification factors. A parton and hadron cascade model PACIAE based on the PYTHIA6.4 is employed to calculate the hadron and its quark component nuclear modification factors in the 0-5\% most central $Pb+Pb$ collisions at $\sqrt{s_{NN}}$=2.76 TeV. It turns out that the hadron nuclear modification factor is usually smaller than that of its quark component. On the other hand, it is shown in our study that the "dead cone effect" is more likely to be identified with the quarks and mesons but not with the baryon states obviously.

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arXiv2020

Study on the $Ω_{c}^{0}$ States Decaying to $Ξ_{c}^{+}K^{-}$ in $pp$ collisions at $\sqrt{s}=7$, 13 TeV

The production of strange particles $Ξ_{c}^{+}, K^{-}$ is simulated in mid-rapidity $pp$ collisions at $\sqrt{s}=7$ TeV with $0.2 \leq pt \leq 6$~GeV/c using the {\footnotesize PACIAE} model. The results are consistent with LHCb experimental data on $Ξ_{c}^{+}$ and $K^{-}$ yield. Then, a dynamically constrained phase-space coalescence ({\footnotesize DCPC}) model plus {\footnotesize PACIAE} model was used to produce the $Ξ_{c}^{+}K^{-}$ bound states and study the narrow excited $Ω_{c}^{0}$ states through $Ω_{c}^{0} \to Ξ_{c}^{+}K^{-}$ in $pp$ collisions at $\sqrt{s}=7$ and 13 TeV. The yield, transverse momentum distribution, and rapidity distribution of the five new excited $Ω_{c}^{0}$ states of $Ω_{c}(3000)^{0}$, $Ω_{c}(3050)^{0}$, $Ω_{c}(3066)^{0}$,$Ω_{c}(3090)^{0}$and $Ω_{c}(3119)^{0}$ were predicted.

hep-ph↗

arXiv2020

Impact of single string structure and multiple string interaction on strangeness production in Pb+Pb collisions at $\sqrt{S_{NN}} = 2.76$ TeV

We present a systematic study on the strange and multi-strange particles production in Pb+Pb collisions at $\sqrt{S_{NN}} = 2.76$ TeV based on the PACIAE model simulations. Two different mechanisms, namely the single string structure variations and multiple string interactions, are implemented in the simulations. These modifications give rise to an enhancement of the string tension value involved in the Lund string fragmentation framework and generate more strange particles in the hadronic final state. By comparing the simulation results with the ALICE experimental data, it turns out that the inclusion of the variable effective string tension in the PACIAE model is capable to reach an improved agreement between theory and experiment on the strangeness production in Pb+Pb collisions.

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arXiv2019

Forward and backward comparative study of jet properties in pp collisions at \sqrt{s}=7 TeV

We propose a forward method, based on the PYTHIA6.4, to study theoretically the jet properties in the ultra-relativistic pp collisions. In the forward method, the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund srting fragmentation regime, and finally hadronic jets are constructed from the created hadrons. Jet properties calculated in the forward method for pp collisions at \sqrt{s}=7 TeV are comparable with the corresponding ones calculated with usual anti-k_t algorithm (backward method) in the PYTHIA6.4. The comparison between the results in the backward and forward methods may bring benefit to the understanding of the partonic origin of jets in the backward method.

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arXiv2018

Single string structure and multiple string interaction effect on strange particle production in pp collisions at $\sqrt{s}=7$ TeV

We present a systematic study on the strange particle production at the Large Hadron Collider (LHC) in proton-proton (pp) collisions at $\sqrt{s}=$ 7 TeV based on PACIAE simulations. Two different mechanisms accounting for single string structure variations and multiple string interactions are implemented in the simulations. These modifications give rise to increased effective string tension in the Lund fragmentation model and generate more strange particles in the hadronic final state. By comparing the results with a wealth of the LHC data, it is turned out that the inclusion of variable effective string tension is capable to reach an improved agreement between theory and experiment, especially on the recently observed multiplicity dependence of strangeness enhancement in pp collisions. This approach provides us a new method to understand the microscopic picture of the novel high multiplicity pp events collected at the LHC in the string fragmentation framework.

hep-ph↗

arXiv2018

Energy dependence of light (anti)nuclei and (anti)hypertriton production in the Au-Au collision from $\sqrt{s_{\rm{NN}}} =5.0$ to $5020$ GeV

The energy dependence of light (anti)nuclei and (anti)hypertriton production are investigated in central Au-Au collisions from AGS up to LHC energies at midrapidity, using the parton and hadron cascade model (PACIAE) together with the dynamically constrained phase-space coalescence model(DCPC). We find that the yields, yield ratios of the antiparticles to their corresponding particles, the coalescence parameters $B_A$ and the strangeness population factor $s_3$ of light (anti)nuclei and (anti)hypertriton strongly depend on the energy. Furthermore, we analyze and discuss the strangeness population factor $s_3$ and the coalescence parameters $B_A$, and find a transition point near by 20 GeV. These results thus suggest the potential usefulness of the $s_3$ and $B_A$ of light nuclei production in relativistic heavy-ion collisions as a direct probe of the transition point associated with the QCD critical phenomena. The results from PACIAE+DCPC model are well consistent with experimental data.

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arXiv2015

The specific charged hadron multiplicity in ep and eD semi-inclusive deep-inelastic scattering in the PYTHIA and PACIAE models

We employed the PYTHIA 6.4 model and the extended parton and hadron cascade model PACIAE 2.2 to comparatively investigate the DIS normalized specific charged hadron multiplicity in the 27.6 GeV electron semi-inclusive deep-inelastic scattering off proton and deuteron. The PYTHIA and PACIAE results calculated with default model parameters not well and fairly well reproduce the corresponding HERMES data, respectively. In addition, we have discussed the effects of the differences between the PYTHIA and PACIAE models.

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arXiv2014

An upgraded issue of the parton and hadron cascade model, PACIAE 2.2

The parton and hadron cascade model PACIAE 2.1 (cf. Comput. Phys. Commun.184 (2013) 1476) has been upgraded to the new issue of PACIAE 2.2. By this new issue the lepton-nucleon and lepton-nucleus (inclusive) deep inelastic scatterings can also be investigated. As an example, the PACIAE 2.2 model is enabled to calculate the specific charged hadron multiplicity in the $e^-$+p and $e^-$+D semi-inclusive deep-inelastic scattering at 27.6 GeV electron beam energy. The calculated results are well comparing with the corresponding HERMES data. Additionally, the effect of model parameters αand βin the Lund string fragmentation function on the multiplicity is studied.

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arXiv2014

On the lepton-nucleon neutral and charged current deep inelastic scattering cross sections

Based on the requirement in the simulation of lepton-nucleus deep inelastic scattering (DIS), we construct a fortran program LDCS 1.0 calculating the differential and total cross sections for the unpolarized charged lepton-unpolarized nucleon and neutrino-unpolarized nucleon neutral current (charged current) DIS at leading order. Any set of the experimentally fitted parton distribution functions could be employed directly. The mass of incident and scattered leptons is taken into account and the boundary conditions calculating the single differential and total cross section are studied. The calculated results well agree with the corresponding experimental data which indicating the LDCS 1.0 program is good. It is also turned out that the effect of tauon mass is not negligible in the GeV energy level.

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arXiv2014

Systematic study of elliptic flow parameter in the relativistic nuclear collisions at RHIC and LHC energies

We employed the new issue of a parton and hadron cascade model PACIAE 2.1 to systematically investigate the charged particle elliptic flow parameter $v_2$ in the relativistic nuclear collisions at RHIC and LHC energies. With randomly sampling the transverse momentum $x$ and $y$ components of the particles generated in string fragmentation on the circumference of an ellipse instead of circle originally, the calculated charged particle $v_2(η)$ and $v_2(p_T)$ fairly reproduce the corresponding experimental data in the Au+Au/Pb+Pb collisions at $\sqrt{s_{NN}}$=0.2/2.76 TeV. In addition, the charged particle $v_2(η)$ and $v_2(p_T)$ in the p+p collisions at $\sqrt s$=7 TeV as well as in the p+Au/p+Pb collisions at $\sqrt{s_{NN}}$=0.2/5.02 TeV are predicted.

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arXiv2013

Systematic study for particle transverse momentum asymmetry in minimum bias pp collisions at LHC energies

In PYTHIA6 (PYTHIA8) once the transverse momentum $p_T$ of a generated particle is randomly sampled, $p_x$ and $p_y$ are set on the circle with radius of $p_T$ randomly. This may largely suppress the development of the final hadronic state transverse momentum anisotropy from the initial state spatial asymmetry. We modify PYTHIA6.4 by randomly setting $p_x$ and $p_y$ on the circumference of an ellipse with the half major and minor axes being $p_T(1+δ_p)$ and $p_T(1-δ_p)$, respectively. The modified PYTHIA6.4 is then employed to systematically study the charged particle transverse momentum asymmetry in the minimum bias pp collisions at $\sqrt s$=0.9, 7, and 14 TeV. The ALICE data on the transverse sphericity as a function of charged multiplicity, $ (N_{ch})$, are well reproduced with the modified PYTHIA6.4. It is found that the predicted charged particle $v_2$ upper limit is a measurable value, $\sim 0.12$, in the minimum bias pp collisions at $\sqrt s$=7 TeV. We suggest a systematic measurement for the particle transverse momentum sphericity, eccentricity (ellipticity), and elliptic flow parameter.

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arXiv2012

PACIAE 2.1: An updated issue of the parton and hadron cascade model PACIAE 2.0

We have updated the parton and hadron cascade model PACIAE 2.0 for relativistic nuclear collisions (cf. Comput. Phys. Comm. 183(2012)333) to the new issue of PACIAE 2.1. The PACIAE model is based on PYTHIA. In the PYTHIA model, once the generated particle/parton transverse momentum $p_T$ is randomly selected, its component of $[p_x,p_y]$ was originally put on the circle with radius $p_T$ randomly. It is now replaced by put on the circumference of ellipse with half major and minor axes of $p_T(1+δ_p)$ and $p_T(1-δ_p)$, respectively, in order to investigate better the transverse momentum anisotropy in final hadronic state.

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arXiv2012

Comparative study for non-statistical fluctuation of net- proton,baryon, and charge multiplicities

We calculate the real and non-statistical higher moment excitation functions ($\sqrt{s_{NN}}$ = 11.5 to 200 GeV) for the net-proton, net-baryon, and the net-charge number event distributions in the relativistic Au+Au collisions with the parton and hadron cascade model PACIAE. It turned out that because of the statistical fluctuation dominance it is very hard to see signature of the CP singularity in the real higher moment excitation functions. It is found that the property of higher moment excitation functions are significantly dependent on the window size, and hence the CP signatures may show only in a definite window for a given conserved observable non-statistical higher moments. But for a given widow size, the CP singularity may show only in the non-statistical higher moment excitation functions of a definite conserved observable.

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arXiv2012

Antimatter production in central Au+Au collisions at $\sqrt{s_{\rm{NN}}}$=200 GeV

We have used the dynamically constrained phase space coalescence model to investigate the production of light nuclei (anti-nuclei) based on the 1.134$\times 10^7$ hadronic final states generated by the PACIAE model for the 0-5% most central Au+Au collisions at $\sqrt{s_{\rm{NN}}}$=200 GeV with $|y| <$1 and $p_T<$5 acceptances. The STAR data of $\bar{_{\barΛ}^ 3H}$, ${_Λ^3 H}$, $^3{\bar{He}}$, and $^3{He}$ yields and ratios are well reproduced by the corresponding PACIAE results. The transverse momentum distribution of $\bar{^3{He}}$ (${^3{He}}$) and $\bar{_{\barΛ}^3H}$ (${_Λ^3H}$) is also given. It turned out that the transverse momentum distribution of light nuclei is close to that of the corresponding anti-nuclei.

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arXiv2012

Strange quark suppression and strange hadron production in pp collisions at RHIC and LHC

The parton and hadron cascade model PACIAE based on PYTHIA was utilized to systematically investigate the strange particle production in pp collisions at the RHIC and LHC energies. Taking the mechanism of reduction of the strange quark suppression into account the STAR and ALICE data of strange particle production in pp collisions are well reproduced. It turned out that the K/π ratio as a function of reaction energy in pp collisions shows slightly increasing from sqrt(s)=0.2 to 0.9 TeV and then turning to saturation.

hep-ph↗