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Reanalysis of the most strange dibaryon within constituent quark models

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Physical Review C 2020年第3期101卷 034004-034004页

作者： Hongxia Huang Xinmei Zhu Jialun Ping Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China Department of Physics Yangzhou University Yangzhou 225009 People's Republic of China

The most strange dibaryon ΩΩ with quantum numbers S=−6, I=0, and JP=0+,1−,2+,3− is reanalyzed in the framework of a quark delocalization color screening model (QDCSM) and chiral quark model (ChQM). The ΩΩ dibaryon with JP=0+ is bound, and the one with other quantum numbers JP=1−,2+,3− are all unbound in our calculation. The low-energy scattering phase shifts, the scattering length, and the effective range of the ΩΩ dibaryon with JP=0+ also support the existence of such strange dibaryon. This dibaryon is showed to be a shallow bound state in QDCSM, while the binding energy becomes much larger in the ChQM by including the effect of the hidden color channels coupling. And the scalar nonet meson exchange in the ChQM also provides more attraction for the ΩΩ system. Experimental search for such most strange dibaryon will provide much information for understanding the hadron-hadron interactions in different quark models.

关键词： Nucleon-nucleon interactions Quark model

Structure of pentaquarks Pc+ in the chiral quark model

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Physical Review D 2017年第1期95卷 014010-014010页

作者： Gang Yang Jialun Ping Fan Wang Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China Department of Physics Nanjing University Nanjing 210093 People’s Republic of China

The recent experimental results of the LHCb Collaboration suggested the existence of pentaquark states with a charmonium. To understand the structure of the states, a dynamical calculation of 5-quark systems with quantum numbers IJP=12(12)±, 12(32)± and 12(52)± is performed in the framework of the chiral quark model with the help of the Gaussian expansion method. The results show that there are several negative parity resonance states while all of the positive parity states are the scattering states. The Pc(4380) state is suggested to be the pentaquark state of Σc*D¯. Although the energy of ΣcD¯* is very close to the mass of Pc(4450), the inconsistent parity prevents the assignment. The calculated distances between quarks confirm the molecular nature of the states.

关键词： Hadron-hadron interactions Quark model Exotic baryons

Dynamical quantum phase transition in quantum spin chains with gapless phases

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arXiv 2021年

作者： Cao, Kaiyuan Ming, Zhong Tong, Peiqing Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

The dynamical quantum phase transitions (DQPTs) in quantum spin chains with gapless phases after a sudden quench are studied. We mainly consider the general systems with asymmetrical quasiparticle excitation spectra and obtain the general expression of the Loschmidt echo as well as the general conditions for the occurrence of DQPTs. As two examples, we study the DQPTs in the XY chains with Dzyaloshinskii-Moriya interaction and XZY-YZX type of three-site interaction. It's found that the DQPTs may not occur in the quench across the quantum phase transitions regardless of whether the quench is from the gapless phase to gapped phase or from the gapped phase to gapless phase. This is different from the DQPTs in the case of quench from the gapped phase to gapped phase, in which the DQPTs will always appear. Besides, we also analyze the different reasons for the absence of DQPTs in the quench from the gapless phase and the gapped phase. © 2021, CC BY.

关键词： Phase transitions

Further study of the NΩ dibaryon within constituent quark models

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Physical Review C 2015年第6期92卷 065202-065202页

作者： Hongxia Huang Jialun Ping Fan Wang Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China Department of Physics Nanjing University Nanjing 210093 People's Republic of China

Inspired by the discovery of the dibaryon d* and the experimental search of NΩ dibaryon with the STAR data, we study the strange dibaryon NΩ further in the framework of the quark delocalization color screening model and the chiral quark model. We have shown NΩ is a narrow resonance in ΛΞ D-wave scattering before. However, the Λ−Ξ scattering data analysis is quite complicated. Here we calculate the low-energy NΩ scattering phase shifts, scattering length, effective range, and binding energy to provide another approach of STAR data analysis. Our results show there exists an NΩ “bound” state, which can be observed by the N−Ω correlation analysis with RHIC and LHC data, or by the new developed automatic scanning system at J-PARC. In addition, we also find that the hidden-color channel coupling is important for the NΩ system to develop intermediate-range attraction.

关键词： DIBARYON QUARK models PHASE shift (Nuclear physics) QUANTUM chromodynamics QUARK-gluon plasma

The effects of KSEA interaction on the ground-state properties of spin chains in a transverse field

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arXiv 2019年

作者： Fu, Hao Zhong, Ming Tong, Peiqing Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

The effects of symmetric helical interaction which is called the Kaplan, Shekhtman, Entin-Wohlman, and Aharony (KSEA) interaction on the ground-state properties of three kinds of spin chains in a transverse field have been studied by means of correlation functions and chiral order parameter. We find that the anisotropic transition of XY chain in a transverse field (XY TF) disappears because of the KSEA interaction. For the other two chains, we find that the regions of gapless chiral phases in the parameter space induced by the DM or XZY -Y ZX type of three-site interaction are decreased gradually with increase of the strength of KSEA interaction. When it is larger than the coefficient of DM or XZY - Y ZX type of three-site interaction, the gapless chiral phases also disappear. Copyright © 2019, The Authors. All rights reserved.

关键词： Spin dynamics

Influences of weak disorder on dynamical quantum phase transitions of anisotropic XY chain

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arXiv 2019年

作者： Cao, Kaiyuan Li, Wenwen Zhong, Ming Tong, Peiqing Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

In this paper, the effects of disorder on the dynamical quantum phase transitions (DQPTs) in the transverse-field anisotropic XY chain are studied by numerically calculating the Loschmidt echo after quench. We obtain the formula for calculating the Loschmidt echo of the inhomogeneous system in real space. By comparing the results with that of the homogeneous chain, we find that when the quench crosses the Ising transition, the small disorder will cause a new critical point. As the disorder increases, more critical points of the DQPTs will occur, constituting a critical region. In the quench across the anisotropic transition, the disorder will cause a critical region near the critical point, and the width of the critical region increases by the disordered strength. In the case of quench passing through two critical lines, the small disorder leads to the system to have three additional critical points. When the quench is in the ferromagnetic phase, the large disorder causes the two critical points of the homogeneous case to become a critical region. And for the quench in the paramagnetic phase, the DQPTs will disappear for large disorder. Copyright © 2019, The Authors. All rights reserved.

关键词： Phase transitions

Semileptonic decays B/Bs → (D(∗), Ds(∗))lνl in the PQCD approach with the lattice QCD input

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arXiv 2019年

作者： Hu, Xue-Qing Jin, Su-Ping Xiao, Zhen-Jun Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

In this paper, we studied the semileptonic B/Bs → (D(∗),Ds(∗))lνl decays in the framework of the standard model (SM), by employing the perturbative QCD (PQCD) factorization formalism combining with the lattice QCD inputs of the relevant transition form factors. We calculated the branching ratios B(B(s) → D((s∗))lνl) with l = (e,µ.τ), the ratios of the branching ratios R(D(∗)) and R(Ds(∗)) and other physical observables Pτ(D((s∗))), FL(D(∗s)) and AFB(τ). The "PQCD+Lattice" predictions for B(B → D(∗)lνl) and R(D(∗)) do agree well with those currently available experimental measurements within the errors. For the ratios R(Ds) and R(Ds∗), the"PQCD+Lattice" predictions agree well with other known predictions. For both Pτ(D∗) and FL(D∗), our theoretical predictions agree well with the measured values within errors. Our theoretical predictions about the considered semileptonic B/Bs decays could be tested in the near future LHCb and the Belle II experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： Quantum theory

Study of Bs→ φ+-decays in the PQCD factorization approach with lattice QCD input

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arXiv 2020年

作者： Jin, Su-Ping Xiao, Zhen-Jun Department of Physics and Institute of Theoretical Physics Nanjing Normal University Jiangsu Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

In this paper, we studied systematically the semileptonic decays Bs→ φl+l-with l-= (e-, μ-, τ-) by using the perturbative QCD (PQCD) and the "PQCD+Lattice" factorization approach, respectively. We first evaluated all relevant form factors Fi(q2) in the low q2region using the PQCD approach, and we also took the available lattice QCD results at the high-q2region as additional input to improve the extrapolation of Fi(q2) from the low-q2region to the endpoint qmax2. We then calculated the branching ratios and many other physical observables: AFBl, FLφ, S3,4,7, A5,6,8,9and the clean angular observables P1,2,3and P'4,5,6,8. From our studies, we find the following points: (a) the PQCD and "PQCD+Lattice" predictions of B(Bs→ φμ+μ-) are about 7×10-7, which agree well with the LHCb measured values and the QCD sum rule prediction within still large errors;(b) we defined and calculated the ratios of the branching ratios Rφeμand Rφμτ;(c) the PQCD and "PQCD+Lattice" predictions of the longitudinal polarization FL, the CP averaged angular coefficients S3,4,7and the CP asymmetry angular coefficients A5,6,8,9, agree with the LHCb measurements in all considered bins within the still large experimental errors;and (d) for those currently still unknown observables Rφeμ,Rφμτ,AFBl, P1,2,3and P'4,5,6,8, we suggest LHCb and Belle-II Collaboration to measure them in their experiments. © 2020, CC BY.

关键词： Quantum theory

The global existence and large time behavior of smooth compressible fluid in an infinitely expanding ball, III: The 3-D Boltzmann equation

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arXiv 2017年

作者： Yin, Huicheng Zhao, Wenbin School of Mathematical Sciences Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Mathematics and IMS Nanjing University Nanjing210093 China

This paper is a continuation of the works in [34] and [36], where the authors have established the global existence of smooth compressible flows in infinitely expanding balls for inviscid gases and viscid gases, respectively. In this paper, we are concerned with the global existence and large time behavior of compressible Boltzmann gases in an infinitely expanding ball. Such a problem is one of the interesting models in studying the theory of global smooth solutions to multidimensional compressible gases with time dependent boundaries and vacuum states at infinite time. Due to the conservation of mass, the fluid in the expanding ball becomes rarefied and eventually tends to a vacuum state meanwhile there are no appearances of vacuum domains in any part of the expansive ball, which is easily observed in finite time. In the present paper, we will confirm this physical phenomenon for the Boltzmann equation by obtaining the exact lower and upper bound on the macroscopic density function. Copyright © 2017, The Authors. All rights reserved.

关键词： Boltzmann equation