检索结果-南通市图书馆

Effects of nuclear charge fluctuations on dilepton photoproduction

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2020年第2期72卷 60-64页

作者： Guansong Li Kai Zhou baoyi chen Department of Physics Tianjin UniversityTianjin 300350China Frankfurt Institute for Advanced Studies Ruth-Moufang-Straβe 1D-60438 Frankfurt am MainGermany Institut für Theoretische Physik Goethe-Universitat FrankfurtMax-von-Laue-Str.1D-60438 Frankfurt am MainGermany

Fluctuations of dilepton production from two photon interactionsγγ→l^+l^-are studied in semicentral and peripheral nuclear *** on the Weizsacker-Williams approach,electromagnetic(EM)fields generated by moving nuclear charges are approximated as quasi-real *** fluctuating EM fields in each collision event are hard to be measured directly in experiments due to its short lifetime,we study the dilepton photoproduction with fluctuating EM fields,which are crucial for the EM fields induced chiral and charged particle evolutions,and calculate the relative standard deviation of the dilepton mass spectrum with the event-by-event fluctuating nuclear charge *** fluctuation effect becomes smaller in more peripheral collisions where the shift of proton positions is implicit for EM fields outside the *** uncertainty of effective impact parameter△b on the standard deviation is also studied,and its effect is around one-third of the effect of nuclear charge fluctuations when△b is taken as^1 fm.

关键词： heavy ion collisions photoproduction quark gluon plasma

Fast heating dissociation of Υ(1S) in heavy ion collisions at RHIC

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2020年第12期44卷 158-162页

作者： Yunpeng Liu baoyi chen Department of Applied Physics School of ScienceTianjin UniversityTianjin 300072China

By adopting the adiabatic assumption in the cooling process,we discuss a novel mechanism ofΥ(1S)suppression that occurs due to the fast heating process at the early stage of the fireball,instead of its finite decay width in a finite temperature medium generated by heavy ion *** calculate the transition probability after the fast heating dissociation as a function of the temperature of the medium and the nuclear modification factor in central collisions and find that the suppression is not negligible at RHIC,even if the width ofΥ(1S)becomes zero.

关键词： relativistic heavy-ion collision quark-gluon plasma heavy quarkonium adiabatic theorem

Finite Size Effect on Gluon Dissociation of J/ψin Relativistic Heavy Ion Collisions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2024年第10期41卷 38-42页

作者： Jingjing Wang baoyi chen Yunpeng Liu Department of Applied Physics Tianjin UniversityTianjin 300350China

Thermal quantities,including the the entropy density and gluon spectrum,of quark matter within a box that is finite in the longitudinal direction are calculated using a bag *** the assumption of entropy conservation,the corresponding gluon dissociation rate of J/ψis *** reaches a maximum at a certain longitudinal size L_(m),below which the suppression is weak even if the temperature becomes higher than that without the finite size effect,and above which the dissociation rate approaches to the thermodynamic limit gradually with increasing longitudinal size of the fireball.

关键词： entropy dissociation finite

Critical Temperature of Deconfinement in a Constrained Space Using a Bag Model at Vanishing Baryon Density

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2020年第11期37卷 16-20页

作者： Zonghou Han baoyi chen Yunpeng Liu Department of Applied Physics Tianjin UniversityTianjin 300350China

The geometry of fireballs in relativistic heavy ion collisions is approximated by a static box,which is infinite in two directions while finite in the other *** critical temperature of deconfinement phase transition is calculated explicitly in the MIT bag model at vanishing baryon *** is found that the critical temperature shifts to a value higher than that in an unconstrained space.

关键词： density. space. critical

Investigating color screening in proton-nucleus collisions with complex potentials

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2022年第11期46卷 203-211页

作者： Liuyuan Wen Xiaojian Du Shuzhe Shi baoyi chen Department of Physics Tianjin UniversityTianjin 300350China Fakultat fur Physik Universitat BielefeldD-33615 BielefeldGermany Center for Nuclear Theory Department of Physics and AstronomyStony Brook UniversityStony BrookNew York11784USA

Color screening and parton inelastic scattering modify the heavy-quark antiquark potential in mediums consisting of particles from quantum chromodynamics(QCD),leading to the suppression of quarkonium production in relativistic heavy-ion *** to the small charm/anti-charm(cc)pair production number in proton-nucleus(pA)collisions,the correlation between different cc pairs is negligible,which makes the Schrödinger equation viable for tracking the evolution of only one cc *** employ the time-dependent Schrödinger equation with an in-medium cc potential to study the evolution of charmonium wave functions in a hydrodynamic-like QCD medium produced in pA *** explore different parametrizations of real and imaginary parts of the cc potential and calculate the nuclear modification factors(R_(pA))of J/ψ and ψ(2S)in √s_(NN)=5.02 TeV energy p-Pb collisions at the Large Hadron Collider(LHC).Comparing strong and weak screening scenarios with experimental data in this approach,we arrive at the conclusion that color screening is weak at temperatures close to the deconfined phase ***,the imaginary part of the potential is crucial in describing the experimental data,which is consistent with widely studied semi-classical approaches,where dissociation rates are essential.

关键词： heavy-ion collision quarkonium dissociation quark-gluon plasma Schrödinger equation

Open quantum system approach for heavy quark thermalization

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2023年第5期47卷 160-164页

作者：谢卓瑄陈保义 Department of Physics Tianjin UniversityTianjin 300350China

We treat heavy quark as an open quantum system in a hot medium and rederive the stochastic Schrodinger equation(SSE)from the full Schrodinger equation for both heavy quarks and the *** apply the SSE to the dynamical evolutions of a heavy quark(as a system)in the static hot medium(as an environment).Heavy quarks interact with the medium via random scatterings,which exchange the momentum and phase factor randomly between two wave functions of the system and the *** exchange of momentum and phase factor results in the transition between different eigenstates of the *** are included via an external stochastic potential in the Hamiltonian of *** wave functions of a heavy quark are evolved with the stochastic external *** mean wave functions and corresponding momentum distributions of heavy quarks are obtained after the ensemble average over a large set of stochastic wave *** present the thermalization of heavy quarks in the static medium with different coupling strengths.

关键词： quark gluon plasma relativistic heavy-ion collisions open quantum system approach heavy quark

同方期刊数据库

Relativistic correction to the dissociation temperature of B_(c) mesons in a hot medium

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2023年第2期47卷 41-45页

作者：李光玉陈保义刘云朋 Department of Applied Physics Tianjin UniversityTianjin 300350China

By solving two body Dirac equations with potentials at finite temperature,we calculate the dissociation temperature T_(d) of B_(c) mesons in quark-gluon *** is found that T_(d) becomes higher with the relativistic correction than the T_(d) from the Schrodinger *** the short range interaction and the constant term of the potential at the long-range scale have a contribution to the shift of T_(d),while the spin interaction is negligible.

关键词： quark gluon plasma relativistic heavy ion collision heavy flavor two body Dirac equations

Tooth arrangement design of retractable DTH hammer bit used for drilling while casing

在线全文

学校读者我要写书评

暂无评论

Global Geology 2023年第1期26卷 40-46页

作者： ZHANG Boyao chen baoyi YANG Da BO Kun CAO Pinlu College of Construction Engineering Jilin UniversityChangchun 130061China

Down-the-hole(DTH)hammer with casing while drilling(CWD)is a technology that has been proven to be able to alleviate many of the problems faced by complex ***,the drill bit is suffered from rapid wear,low drilling efficiency,and high energy consumption due to the unreasonable tooth arrangement and impact energy selection in drilling process,which affect the application effect of this *** software was used for numerical simulation of rock breaking behavior under impact load with the single,three,and five teeth arrangement drill bit respectively,to improve the application effect and solve the aforementioned technical *** on the calculated parameters of tooth arrangement,we designed a novel drill bit for hard rocks and provided a theoretical basis for the tooth arrangement of largediameter drill bits.

关键词： casing while drilling drill bit tooth arrangement rock breaking ABAQUS

Reliability analysis of retractable drill bit with air reverse circulation used for drilling while casing

在线全文

学校读者我要写书评

暂无评论

Global Geology 2023年第1期26卷 47-56页

作者： WANG Minqi YIN Qilei chen baoyi QI Bo BO Kun CAO Pinlu College of Construction Engineering Jilin UniversityChangchun 130026China

Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and fast penetration rate in hard *** an important component of the CWD system,the structure of the retractable drill bit needs not only to ensure to form stronger reverse circulation,but also to be expandable or retractable as needed,otherwise the drill bit cannot be lift and put down smoothly in the casing,and may lead to drilling *** paper developed a new type of reverse circulation DTH hammer drill bit used for CWD drilling *** retractable performance of this type of drill bit is studied using ADAMS *** results show that it is smoothly expandable and retractable as designed under the conditions of the weight of the bit(WOB)of 0.5–2.0 t and the rotation speed of 30–60 r/*** investigate the reverse circulation effect of the drill bit,Fluent software was used to simulate the flow characteristic inside *** simulation results indicated that it can form strong reverse circulation,and the entrainment ratio h can reach 9.5%.

关键词： DTH hammer drilling air reverse circulation casing-while-drilling retractable drill bit