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

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.

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

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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.

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simulation of Centennial-scale Drought Events over Eastern China during the Past 1500 Years

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Journal of Meteorological Research 2017年第1期31卷 17-27页

作者： Weiyi SUN Jian LIU Zhiyuan WANG key laboratory for virtual geographic environment(nanjing normal university) ministry of educationstate key laboratory cultivation base of geographical environment evolution(jiangsu province)School of Geography ScienceNanjing Normal UniversityNanjing 210023 Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical ScienceNanjing Normal UniversityNanjing 210023 Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023

The characteristics and causes of centennial-scale drought events over eastern China during the past 1500 years were explored based on simulations of the Community Earth System Model （CESM）. The results show that centenni- al-scale drought events over eastern China occurred during the periods of 622-735 （Drought period 1, D1） and 1420-1516 （Drought period 2, D2） over the past 1500 years, which is comparable with climate proxy data. In D1, the drought center occurred in northern China and the Yangtze River valley; however, in southern China, precipitation was much more than usual. In D2, decreased precipitation was found across almost the whole region of eastern China. The direct cause of these two drought events was the weakened East Asian summer monsoon, and the specif- ic process was closely linked to the air-sea interaction of the Indo-Pacific Ocean. In DI, regions of maximum cool- ing were observed over the western Pacific, which may have led to anomalous subsidence, weakening the Walker cir- culation, and reducing the northward transport of water vapor. Additionally, upward motion occurred over southern China, strengthening convection and increasing precipitation. In D2, owing to the decrease in the SST, subsidence dominated the North Indian Ocean, blocking the low-level cross-equatorial flow, enhancing the tropical westerly an- omalies, and reducing the northward transport of moisture. Additionally, descending motion appeared in eastern China, subsequently decreasing the precipitation over the whole region of eastern China. The anomalous cooling of the Indo-Pacific Ocean SST may have been caused by the persistently low solar irradiation in D1; whereas, in D2, this characteristic may have been influenced not only by persistently low solar irradiation, but frequent volcanic erup- tions too.

关键词： CESM centennial-scale drought eastern China East Asian summer monsoon

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Perturbative QCD factorization of ργ⋆→π

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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.

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Hidden-bottom pentaquarks

arXiv

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arXiv 2018年

作者： Yang, Gang Ping, Jialun Segovia, Jorge Department of Physics State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua University Beijing100084 China Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China E-08193 Spain

The LHCb Collaboration has recently reported strong evidences of the existence of pentaquark states in the hidden-charm baryon sector, the so-called Pc(4380)+and Pc(4450)+signals. Five-quark bound states in the hidden-charm sector were explored by us using, for the quark-quark interaction, a chiral quark model which successfully explains meson and baryon phenomenology, from the light to the heavy quark sector. We extend herein such study but to the hidden-bottom pentaquark sector, analyzing possible bound-states with spin-parity quantum numbers JP= 1/2±, 3/2±and 5/2±, and in the 1/2 and 3/2 isospin sectors. We do not find positive parity hidden-bottom pentaquark states;however, several candidates with negative parity are found with dominant baryon-meson structures Σ(∗)bB(∗). The calculated distances among any pair of quarks within the bound-state reflect that molecular-type bound-states are favored when only color-singlet configurations are considered in the coupled-channels calculation whereas compact pentaquarks, which are also deeply bound, can be found when hidden-color configurations are added. Finally, our findings resemble the ones found in the hidden-charm sector but, as expected, we find in the hidden-bottom sector larger binding energies and bigger contributions of the hidden-color configurations. Copyright © 2018, The Authors. All rights reserved.

关键词： Hadrons

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Exploring Dynamical Phase Transitions in the XY Chain through Linear Quench: Early and Long-term Perspectives

arXiv

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arXiv 2024年

作者： Cao, Kaiyuan Tong, Peiqing Zhejiang Lab Hangzhou311100 China 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

We investigate the nonequilibrium dynamics induced by a finite-time linear quench in the XY chain. Initially, we examine the dynamical quantum phase transition, characterized by the nonanalytic behavior of the Loschmidt amplitude. We find distinct behaviors of DQPTs during and following the ramp. Following the ramp, the ramp crossing the critical point hc is the sufficient condition for the occurrence of DQPT, but it is not during the ramp. Through AIA approximation analysis, we establish that adequate distancing from the critical point is crucial for DQPT manifestation during the ramp, elucidating the absence of DQPT as the ramp gets faster. Additionally, we explore another type of dynamical phase transition, describing the long-term relaxation behavior of the order parameter. Our finding indicates that the asymptotic behavior of the time-dependent part induced by the linear quench is equivalent to that following a sudden quench, i.e., time-dependent part exhibits power-law decays of ∼ t−3/2 and ∼ t−1/2 for the ramp to the commensurate and incommensurate phases, respectively. Moreover, we also delve into the steady part, which showcases nonanalytic singularities at the critical point. Copyright © 2024, The Authors. All rights reserved.

关键词： Phase transitions

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Quantum Phase Transitions in the Alternating Xy Chain with Three-Site Interactions

SSRN

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SSRN 2024年

作者： Cao, Kaiyuan Fu, Hao Liu, Xue Zhong, Ming Tong, Peiqing Zhejiang Lab Hangzhou311100 China 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

We investigate the quantum phase transition in the alternating XY chain with the XZX+YZY type of three-spin interactions. We present the exact solution derived by means of the Jordan-Wigner transformation and study the average magnetization, spin correlations, and von Neumann entropy to establish the phase diagram. The phase diagram consists of the ferromagnetic phases, the paramagnetic phases, and the phase with weak magnetization (WM). By examining the nearest-neighbor transverse spin correlation, we probe that in the WM phase, the spins within a supercell generate a cluster with a small total spin, but between the nearest-neighbor supercells are distributed randomly. Especially for the dimerized limit case, the spins within a supercell tend to point to opposite directions of the transverse field. In addition, we also investigate the influence of the three-site interaction, and find that the WM phase is absent as the strength of the three-site interaction increases. © 2024, The Authors. All rights reserved.

关键词： Magnetization

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Quantum phase transitions in the alternating XY chain with three-site interactions

arXiv

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arXiv 2024年

关键词： Magnetization

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Dynamical relaxation behavior of an extended XY chain with a gapless phase following a quantum quench

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Physical Review B 2024年第2期109卷 024303-024303页

作者： Kaiyuan Cao Yayun Hu Peiqing Tong Guangwen Yang Zhejiang Lab Hangzhou 311100 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 China Department of Computer Science and Technology Tsinghua University Haidian District Beijing 100084 China

We investigate the dynamical relaxation behavior of the two-point correlation in extended XY models with a gapless phase after quenches from various initial states. Specifically, we study the XY chain with gapless phase induced by the following additional interactions: Dzyaloshinskii-Moriya interaction and the XZY-YZX type of three-site interaction. When quenching from the gapped phase, we observe that the additional interactions have no effect on the relaxation behavior. The relaxation behavior is δCmn(t)∼t−3/2 and ∼t−1/2 for the quench to the commensurate phase and the incommensurate phase, respectively. However, when quenching from the gapless phase, we demonstrate that the scaling behavior of δCmn(t) is changed to ∼t−1 for the quench to the commensurate phase, and the decay of δCmn(t) follows ∼t−1 or ∼t−1/2 for the quench to the incommensurate phase depending on the parameters of prequench Hamiltonian. We also establish the dynamical phase diagrams based on the dynamical relaxation behavior of δCmn(t) in the extended XY models.

关键词： Dynamical phase transitions Dzyaloshinskii-Moriya interaction Quantum quench XY model

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Clifford algebra-based spatio-temporal modelling and analysis for complex geo-simulation data

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AIP Conference Proceedings 2013年第1期1558卷 542-545页

作者： Wen Luo Zhaoyuan Yu Yong Hu Linwang Yuan Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University No.1 Wenyuan Road Nanjing China Key Laboratory of Virtual Geographic Environment Ministry of Education Nanjing Normal University No.1 Wenyuan Road Nanjing China and Jiangsu Provincial Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal Univer China

The spatio-temporal data simulating Ice-Land-Ocean interaction of Antarctic are used to demonstrate the Clifford algebra-based data model construction, spatio-temporal query and data analysis. The results suggest that Clifford algebra provides a powerful mathematical tool for the whole modelling and analysis chains for complex geo-simulation data. It can also help implement spatio-temporal analysis algorithms more clearly and simply.

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