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Rare semileptonic decays of heavy mesons in the heavy quark limit

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Chinese Physics C 2010年第2期34卷 262-266页

作者：李海波杨茂志 Institute of High Energy Physics CAS School of Physics Nankai University

We study the branching ratios of D^＋ → D^0e^＋ν, Ds^＋ → D^0e^＋ν, Bs^0→B^＋e^-^-ν, Ds^＋→D^＋e^-e^＋ and Bs^0→B^0e^-e^＋ rare semileptonic decay processes, which are induced by decays of light quarks, the heavy quarks remain unchanged. The branching ratios of these decay processes are estimated in the heavy quark limit and with SU（3） flavor symmetry. We find that the decay rates are very tiny in the framework of the Standard Model. We also estimate the sensitivities of the measurements of these rare decays at the future experiments, such as BES-Ⅲ, super-B and LHC-b. Observations of these decays may shed some light on new physics beyond the standard model.

关键词： weak decay heavy quark flavor symmetry

An experimental review of open heavy flavor and quarkonium production at RHIC

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Nuclear Science and Techniques 2020年第8期31卷 72-103页

作者： Ze-Bo Tang Wang-Mei Zha Yi-Fei Zhang State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

Open heavy flavors and quarkonia are unique probes of the hot–dense medium produced in heavy-ion collisions. Their production in p+p collisions also constitutes an important test of QCD. In this paper, we review selected results on the open heavy flavors and quarkonia generated in the p+p and heavy-ion collisions at the Relativistic heavy Ion Collider. The physical implications are also discussed.

关键词： heavy flavor heavy quark quarkonium quark–gluon plasma heavy-ion collisions QCD

Is J^(PC)=3^(-+) molecule possible?

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Chinese Physics C 2015年第2期39卷 7-14页

作者：朱伟刘言锐姚涛 School of Physics Shandong University

The confirmation of charged charmonium-like states indicates that heavy quark molecules should exist. Here we discuss the possibility of a molecule state with ^PC=3^-＋. In a one-boson-exchange model investigation for the S wave C=＋ D^＊D2^＊ states, one finds that the strongest attraction is in the case J= 3 and I=0 for both π and σ exchanges. Numerical analysis indicates that this hadronic bound state might exist if a phenomenological cutoff parameter around 2.3 GeV （1.5 GeV） is reasonable with a dipole （monopole） type form factor in the one-pion- exchange model. The cutoff for binding solutions may be reduced to a smaller value once the σ exchange contribution is included. If a state around the D^＊D2^＊ threshold （≈4472 MeV） in the channel J/ψω （P wave） is observed, the heavy quark spin symmetry implies that it is not ace meson and the jPC are likely to be 3^-＋.

关键词： exotic state molecule heavy quark

heavy flavor quenching and flow:the roles of initial condition,pre-equilibrium evolution,and in-medium interaction

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Chinese Physics C 2020年第11期44卷 127-137页

作者：李树清邢文静刘峰磊曹杉杉秦广友 Department of Physics and Information Engineering Jining UniversityQufu 273155China Institute of Particle Physics and Key Laboratory of quark and Lepton Physics(MOE) Central China Normal UniversityWuhan 430079China Cyclotron Institute Texas A&M UniversityCollege StationTexas77843USA Department of Physics and Astronomy Wayne State UniversityDetroitMichigan 48201USA Nuclear Science Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA

Within an advanced Langevin-hydrodynamics framework coupled to a hybrid fragmentation-coalescence hadronization model,we study heavy flavor quenching and flow in relativistic heavy-ion collisions.We investigate how the initial heavy quark spectrum,the in-medium energy loss and hadronization mechanisms of heavy quarks,the evolution profile of the pre-equilibrium stage,the medium flow,and the temperature dependence of heavy quark diffusion coefficients influence the suppression and elliptic flow of heavy mesons at the RHIC and the LHC.Our results show that the different modeling of initial conditions,pre-equilibrium evolution,and in-medium interactions can individually yield uncertainties of approximately 10-40% in D meson suppression and flow at a low transverse momentum.We also find that proper combinations of collisional versus radiative energy loss,coalescence versus fragmentation in hadronization,and the inclusion of medium flow are the most important factors for describing the suppression and elliptic flow of heavy mesons.

关键词： quark-gluon plasma heavy-ion collisions jet quenching heavy quark

NLO effects for Ω_(QQQ) baryons in QCD Sum Rules

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Chinese Physics C 2021年第9期45卷 44-54页

作者：吴仁华左羽生孟策马滟青赵光达 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China Center for High Energy Physics Peking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China

We study the triply heavy baryonsΩ_(QQQ)(Q=c,b)in the QCD sum rules by performing the first calculation of the next-to-leading order(NLO)contribution to the perturbative QCD part of the correlation functions.Compared with the leading order(LO)result,the NLO contribution is found to be very important to theΩ_(QQQ).This is because the NLO not only results in a large correction but also reduces the parameter dependence,making the Borel platform more distinct,especially for the Q_(bbb)in the MS scheme,where the platform appears only at NLO but not at LO.Particularly,owing to the inclusion of the NLO contribution,the renormalization schemes(MS and On-Shell)dependence and the scale dependence are significantly reduced.Consequently,after including the NLO contribution to the perturbative part in the QCD sum rules,the masses are estimated to be 4.53_)0.11)^(+0.26) GeV forΩ_(ccc) and14.27_(-0.32)^(+0.33) GeV forΩ_(bbb),where the results are obtained atμ=M_(B) with errors including those from the variation of the renormalization scaleμin the range(0.8-1.2)M_(B).A careful study of theμdependence in a wider range is further performed,which shows that the LO results are very sensitive to the choice ofμwhereas the NLO results are considerably better.In addition to theμ=M_(B) result,a more stable value,(4.75-4.80)GeV,for theΩ_(ccc) mass is found in the range ofμ=(1.2-2.0)M_(B),which should be viewed as a more relevant prediction in our NLO approach because of μ dependence.

关键词： baryon heavy quark QCD sum rules NLO correction