检索结果-内蒙古大学图书馆

arXiv 2020年

作者： Jin, Su-Ping Hu, Xue-Qing 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 systematically the semileptonic decays Bs → K(∗)+− 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 q2 region using the PQCD approach, and we also take the available Lattice QCD results at the end point qmax2 as additional input to improve the extrapolation of the form factors to the high q2 region. We calculated the branching ratios and other twelve kinds of physical observables: AFB(l), PL, FLK∗ and the angular observables Pi and Pj′. From our studies, we find the following points: (a) for Bs → Kl+l− decays, the PQCD and "PQCD+Lattice" predictions for branching ratios (BRs) B(Bs → Kl+l−), the ratios of the BRs RKeµ,µτ and the longitudinal polarization asymmetry of the leptons PL agree well within errors;(b) the "PQCD+Lattice" prediction B(Bs → K∗µ+µ−) = (2.58+0−0..6960)×10−8 does agree well with the LHCb measured value (2.9 ± 1.1) × 10−8;(c) for the ratios RKeµ∗ and RKµτ∗, the PQCD and "PQCD+Latatice" predictions agree very well and have a small error less than 10% due to the cancellation of the theoretical uncertainties in the ratios of the branching ratios;(d) for the angular observables P1,2,3 and P4′,5,6,8 , our theoretical predictions for each lepton l− are consistent within errors;(e) the theoretical predictions of the angular observables P3 and P6′,8 are less than 10−2 in absolute value, but the magnitude of P1,2 and P4′,5 are larger than 0.2;and (f) the PQCD and "PQCD+Lattice" predictions of the binned values of all considered observables in the two q2-bins [0.1 − 0.98]GeV2 and [1.1 − 6]GeV2 generally agree with each other and also be consistent with the LCSR results within errors. We believe that above predictions could be measured by future LHCb and Belle-II experiments. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum theory

来源：评论

学校读者我要写书评

暂无评论

The global existence and large time behavior of smooth compressible fluid in an infinitely expanding ball, I: 3D Euler equations

arXiv

引用

arXiv 2017年

作者： Xu, Gang Yin, Huicheng Faculty of Science Jiangsu University Zhenjiang Jiangsu212013 China School of Mathematical Sciences Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

We concern with the global existence and large time behavior of compressible fluids (including the inviscid gases, viscid gases, and 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 this paper, as the first part of our three papers, we will confirm this physical phenomenon for the compressible inviscid fluids by obtaining the exact lower and upper bound on the density function. Copyright © 2017, The Authors. All rights reserved.

关键词： Euler equations

来源：评论

学校读者我要写书评

暂无评论

Exploring the effects of phase modulation on the dynamics of the kicked rotor systems

引用

Physical Review E 2022年第1期105卷 014212-014212页

作者： Mengyao Li Yingying Xiao Yongchun Tao Yi Gao Peiqing Tong Center for Quantum Transport and Thermal Energy Science Jiangsu Key Lab on Opto-Electronic Technology School of Physics and Technology Nanjing Normal University Nanjing 210023 China School of Physics and Technology Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 China

Inspired by the recent experimental progress in the time-driven phase transition in quantum chaos, we investigate comprehensively the energy diffusion of a kicked rotor in the presence of phase modulation. In the classical case, we found that there always exists anomalous diffusion as long as the phase is modulated periodically and changes by 0 or π from kick to kick. On the contrary, for quasiperiodic and random phase modulation, anomalous diffusion is suppressed. On the other hand, in the quantum case, there exist only ballistic energy diffusion and dynamical localization in the standard and periodically shifted cases, while random phase modulation destroys the quantum coherence and totally suppresses the dynamical localization. Furthermore, the quasiperiodic phase modulation is an intermediate phase between the standard case and the random one. In both the classical and quantum cases, quasiperiodic phase modulation is inequivalent to random phase modulation at large kicking times (>103), thus caution has to be taken when dealing with these two kinds of phase modulation in experiments.

关键词： Cold atoms & matter waves 1-dimensional systems

来源：评论

学校读者我要写书评

暂无评论

On the global existence and stability of 3-D viscous cylindrical circulatory flows

arXiv

引用

arXiv 2017年

作者： Yin, Huicheng Zhang, Lin 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

In this paper, we are concerned with the global existence and stability of a 3-D perturbed viscous circulatory flow around an infinite long cylinder. This flow is described by 3-D compressible Navier-Stokes equations. By introducing some suitably weighted energy spaces and establishing a priori estimates, we show that the 3-D cylindrical symmetric circulatory flow is globally stable in time when the corresponding initial states are perturbed suitably small. Copyright © 2017, The Authors. All rights reserved.

关键词： Viscous flow

来源：评论

学校读者我要写书评

暂无评论

Semileptonic decays Bc → (ηc, J/ψ)lν¯l in the "PQCD + Lattice" approach

arXiv

引用

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 decays Bc− → (ηc,J/ψ)l−ν¯l by employing the PQCD factorization approach, using the newly defined distribution amplitudes of the Bc meson and the new kind of parametrization for extrapolation of the form factors, and also taking into account the lattice QCD results about the relevant form factors at several points. We found the following main results: (a) the PQCD predictions for the branching ratios of Bc → (ηc,J/ψ)lν¯ decays will become a little smaller by about (5 − 16)% when the lattice input are taken into account in the extrapolation of the relevant form factors;(b) the PQCD predictions for the ratio Rηc,J/ψ and the longitudinal polarization Pτ are Rηc = 0.34±0.01,RJ/ψ = 0.28±0.01, Pτ(ηc) = 0.37±0.01 and Pτ(J/ψ) = −0.55±0.01;and (c) after the inclusion of the lattice input the theoretical predictions changed slightly: Rηc = 0.31 ± 0.01, RJ/ψ = 0.27 ± 0.01, Pτ(ηc) = 0.36 ± 0.01 and Pτ(J/ψ) = −0.53 ± 0.01. The theoretical predictions for RJ/ψ agree with the measured one within errors, and other predictions could be tested in the near future LHCb experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： Forecasting

来源：评论

学校读者我要写书评

暂无评论

Quasi-two-body decays Bc → D(s)[ρ(770), ρ(1450), ρ(1700) →]ππ in the perturbative QCD factorization approach

arXiv

引用

arXiv 2017年

作者： Ma, Ai-Jun Li, Ya 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 Nanjing Jiangsu210023 China

In this paper, we studied the quasi-two-body Bc → D(s)[ρ(770), ρ(1450), ρ(1700) →]ππ decays by employing the perturbative QCD (PQCD) factorization approach. The two-pion distribution amplitudes φππ are applied to include the final-state interactions between the pion pair, while the time-like form factors Fπ(w2) associated with the P-wave resonant states ρ(770), ρ(1450) and ρ(1700) are extracted from the experimental data of the e+e-annihilation. We found that: (a) the PQCD predictions for the branching ratios of the quasi-two-body Bc → D(s)[ρ(770), ρ(1450), ρ(1700) →]ππ decays are in the order of 10-9 to 10-5 and the direct CP violations around (10 - 40)% in magnitude;(b) the two sets of the large hierarchy R1a,1b,1c and R2a,2b,2c for the ratios of the branching ratios of the considered decays are defined and can be understood in the PQCD factorization approach, while the self-consistency between the quasi-two-body and two-body framework for Bc → D(s)[ρ(770) →]ππ and Bc → D(s)ρ(770) decays are confirmed by our numerical results;(c) taking currently known B(ρ(1450) → ππ) and B(ρ(1700) → ππ) as input, we extracted the theoretical predictions for B(Bc → Dρ(1450)) and B(Bc → Dρ(1700)) from the PQCD predictions for the decay rates of the quasi-two-body decays Bc → D[ρ(1450), ρ(1700) →]ππ. All the PQCD predictions will be tested in the future experiments. Copyright © 2017, The Authors. All rights reserved.

关键词： Hadrons

来源：评论

学校读者我要写书评

暂无评论

Theoretical study of a d* resonance in the coupled 3D3−3G3 partial waves of nucleon-nucleon scattering

引用

Physical Review C 2014年第6期90卷 064003-064003页

作者： Hongxia Huang Jialun Ping Chengrong Deng Fan Wang Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 China School of Mathematics and Physics Chongqing Jiaotong University Chongqing 400074 China Department of Physics Nanjing University Nanjing 210093 China

We calculated the phase shifts of the coupled 3D3−3G3 partial waves of nucleon-nucleon scattering taking into account the 7S3 Δ−Δ channel coupling in the framework of two constituent quark models: the quark delocalization color screening model and the chiral quark model. Our results show that there is a resonance from 7S3ΔΔ coupling to the 3D3NN and 3G3NN partial waves in both of these two models, which is consistent with the d* resonance observed by WASA-at-COSY collaboration. The resonance structure in the 3D3NN partial wave is remarkable, whereas in the 3G3NN phase shifts there is only a small bump around the resonance energy. This result is in agreement with the recent experimental results of WASA-at-COSY Collaboration.

关键词： NUCLEON-nucleon scattering NEUTRON resonance QUARK models DELOCALIZATION energy QUANTUM chromodynamics

来源：评论

学校读者我要写书评

暂无评论

B→ππ decays and effects of the next-to-leading order contributions

引用

Physical Review D 2014年第1期90卷 014029-014029页

作者： Ya-Lan Zhang Xue-Yan Liu Ying-Ying Fan Shan Cheng Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China

In this paper we perform a systematic study for the three B→(π+π−,π+π0,π0π0) decays in the perturbative QCD (pQCD) factorization approach with the inclusion of all currently known next-to-leading order (NLO) contributions from various sources. We found that (a) for the CP-averaged decay rates Br(B0→π+π−) and Br(B+→π+π0), the NLO pQCD predictions agree with the data within one standard deviation; (b) for Br(B0→π0π0), however, although the NLO contributions can provide a ∼100% enhancement to the leading-order (LO) result, it is still not large enough to interpret the data; and (c) for the CP-violating asymmetries of B0→π+π− decay, the NLO pQCD predictions for the central values of Aππ and Sππ have the same sign as the data but are still smaller in magnitude than the measured values. We also examined the relative strength of the LO and NLO contributions from different sources.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Thermodynamically Consistent Hybrid Computational Models for Fluid-Particle Interactions

SSRN

引用

SSRN 2023年

作者： Hong, Qi Wang, Qi School of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing211106 China MIIT Nanjing211106 China Key Laboratory of Numerical Simulation for Large Scale Complex Systems Nanjing Normal University Ministry of Education Nanjing210023 China Department of Mathematics University of South Carolina ColumbiaSC29208 United States

We introduce a novel computational framework designed to explore the dynamic interactions between fluid and solid particles or structures immersed in a viscous fluid medium. This innovative framework harnesses the power of the phase-field-embedding method, in which each solid component, whether rigid or elastic, is characterized by a volume-preserving phase field. The unified velocity within the fluid-solid ensemble governs the movement of both solid particles and the surrounding fluid, specifically for passive particles. Active particles, however, are not only influenced by this unified velocity but are also driven by their self-propelling velocities. To capture exclusive volume interactions among particles and between particles and boundaries, we employ repulsive potential forces at a coarser scale. These forces effectively model repulsion and collision effects. Rigid particles maintain structural integrity by enforcing a zero velocity gradient tensor within their spatial domains, necessitating the introduction of a constraining stress tensor. In contrast, elastic particles are governed by a quasi-linear constitutive equation describing the elastic stress within their domains, allowing for accurate modeling of their deformations. The motion of solid particles is tracked by monitoring the dynamics of their centers of mass. This approach facilitates the development of a hybrid, thermodynamically consistent hydrodynamic model applicable to both rigid and elastic particles. Adhering to the generalized Onsager principle, this model spans the entire computational domain. To numerically solve this thermodynamically consistent model for elastic particles, we present a structure-preserving numerical algorithm. Notably, in the limit of an infinite elastic modulus, this algorithm converges to the one employed for modeling rigid particles. Finally, we substantiate the effectiveness, accuracy, and stability of our proposed scheme through a series of numerical experiments. Thes

关键词： Hydrodynamics

来源：评论

学校读者我要写书评

暂无评论

Perturbative QCD factorization of ργ⋆→π

引用

Physical Review D 2014年第7期90卷 076001-076001页

作者： Shan Cheng Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China

In this paper, we firstly verify that the factorization hypothesis is valid for the exclusive process ργ⋆→π at the next-to-leading order (NLO) with the collinear factorization approach, and then extend this proof to the case of the kT factorization approach. We particularly show that at the NLO level, the soft divergences in the full quark level calculation could be canceled completely as for the πγ⋆→π process where only the pseudoscalar π meson is involved, and the remaining collinear divergences can be absorbed into the NLO hadron wave functions. The full amplitudes can be factorized as the convolution of the NLO wave functions and the infrared-finite hard kernels with these factorization approaches. We also write out the NLO meson distribution amplitudes in the form of nonlocal matrix elements.

关键词： YANG-Baxter equation QUARKS WAVE functions MESONS PARTICLE physics

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：