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Transverse momentum dependence of differential directed flow of Λ hyperon within kaon covariant dynamics

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Science China(Physics,Mechanics & Astronomy) 2010年第2期53卷 331-335页

作者： SRISAWAD Pornrad Department of Physics Faculty of ScienceNaresuan University Amphoe Mueany

The transverse momentum distributions of Λ's and proton's directed flows are investigated by using Quantum Molecular Dynamics model (QMD) within the framework of covariant kaon dynamics. The calculated results show that the transverse momentum distribution of differential directed flow of Lambda hyperons is dependent appreciably on the nuclear matter equation of states (EOS). The differential directed flow of Lambda hyperons calculated with soft EOS is consistent with the experimental data,whereas the discrepancy between the results obtained with hard EOS and experimental data increases with increasing the transverse momentum. Although the interaction acting on Λ's by nucleons in the dense medium is attractive,the analysis indicates,that the transverse momentum distribution of proton's directed flow is insensitive to the EOS. The results obtained with both hard and soft EOS are all roughly in agreement with the corresponding data.

关键词： lambda hyperon differential directed flow kaon meson covariant dynamics

Production and decay of polarized hyperon-antihyperon pairs

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Chinese Physics C 2023年第5期47卷 29-48页

作者： Karin Schonning Varvara Batozskaya Patrik Adlarson 周小蓉 Department of Physics and Astronomy Uppsala University Uppsala Sweden Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China National Centre for Nuclear Research WarsawPoland University of Science and Technology of China Hefei 230026China

Polarized hyperon-antihyperon pairs shed light on various unresolved puzzles in contemporary physics:How the strong interaction confines quarks into hadrons, how accurately the Standard Model describes microcosmos and even why our universe consists of so much more matter than antimatter. Thanks to their weak, parity violating decays, hyperons reveal their spin properties. This can be exploited e.g. the decomposition of the electromagnetic structure of hyperons, precision tests of flavour symmetry and searches for CP violation. At the BESⅢ experiment at BEPC-Ⅱ, Beijing, China, hyperon-antihyperon pairs can be produced in abundance. Recently collected large data samples have triggered the development of new methods that provide unprecedented precision and a plethora of new results have emerged. When applied at future high-intensity facilities like PANDA and STCF, precision physics will be taken to a new level which can contribute to the solution to the aforementioned puzzles.

关键词： hyperon polarization CP violation form factors

Two New hyperon Coupling Models in the Light of the Massive Neutron Star PSR J0348+0432

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Communications in Theoretical Physics 2019年第7期71卷 819-825页

作者：洪斌任中洲柏栋 School of Physics Nanjing UniversityNanjing 210093China School of Physics Science and Engineering Tongji UniversityShanghai 200092China Key Laboratory of Advanced Micro-Struetm Materials Ministry of EducationShanghai 200092China

In the context of the relativistic mean field theory,we propose two new hyperon coupling models,namely the limitation model and the potential well depth model,in the light of the observed data for the massive neutron PSR J0348+*** radius of PSR J0348+0432 given by the limitation model is found to be 12.52 km^12.97 km,while the radius given by the potential well depth model is found to be 12.19 km^12.89 *** also calculate the gravitational redshift of PSR J0348+0432 within these two models,for which the limitation model gives 0.346~0.391 and the potential well depth model gives 0.350~*** exploration of these two models shows that,these two models are almost degenerate for neutron stars lighter than 1.85 M⊙,and start to give different results for massive neutron stars heavier than 1.85 M⊙.Therefore,the studies of massive neutron stars could be crucial for discriminating these two models and help deepen our understanding of hyper-nuclear interactions.

关键词： hyperon coupling parameter potential well depth PSR J0348+0432

Prospects for rare and forbidden hyperon decays at BESⅢ

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Frontiers of physics 2017年第5期12卷 1-10页

作者： Hai-Bo Li Institute of High Energy Physics Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China

The study of hyperon decays at the Beijing Electron Spectrometer Ⅲ （BESⅢ） is proposed to investigate the events of J/φ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing Electron-Positron Collider Ⅱ. About 10^6-10^8 hyperons, i.e., ∧, ∑, ∈, and Ω, will be produced in the J/φ and φ（2S） decays with the proposed data samples at BESⅢ. Based on these samples, the measurement sensitivity of the branching fractions of the hyperon decays is in the range of 10^-5-10^-8. In addition, with the known center-of-mass energy and ＂tag technique＂, rare decays and decays with invisible final states can be probed.

关键词： BESⅢ J/φ decay hyperon rare decay FCNC lepton flavor violation

Study of the s → dv■ rare hyperon decays in the Standard Model and new physics

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Chinese Physics C 2019年第9期43卷 26-32页

作者：胡晓会赵振兴 INPAC Shanghai Key Laboratory for Particle Physics and Cosmology MOE Key Laboratory for Particle Physics Astrophysics and CosmologySchool of Physics and Astronomy Shanghai Jiao-Tong University

FCNC processes offer important tools to test the Standard Model(SM)and to search for possible new *** this work,we investigate the s→dννrare hyperon decays in SM and *** find that in SM the branching ratios for these rare hyperon decays range from 10^-14 to 10^-*** all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5%to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2~7.

关键词： branching ratios rare hyperon decays form factors light-front approach new physics

Analysis of strong decays of SU(3)partners ofΩ(2012)baryon

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Chinese Physics C 2024年第8期48卷 34-41页

作者： T.M.Aliev S.Bilmis M.Savci Department of Physics Middle East Technical UniversityAnkara 06800Turkey TUBITAK ULAKBIM Ankara 06510Turkey

We estimate the coupling constants and decay widths of the SU(3)partners of theΩ(2012)hyperon,as discovered by the BELLE Collaboration,using the distribution amplitudes of the octet baryons within the light cone sum rules *** study includes a comparison of the obtained results for the relevant decay widths with those derived within the framework of the flavor SU(3)*** observe a good agreement between the predictions of both ***,our result on the decay width ofΩ→ΞK is compatible with the existing experimental result within the uncertainties of the model *** results can provide helpful insights for determining the nature of the SU(3)partners of theΩ(2012)baryon.

关键词： coupling constants light cone sum rule hyperon

Production of light nuclei and hypernuclei at High Intensity Accelerator Facility energy region

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Nuclear Science and Techniques 2017年第4期28卷 84-90页

作者： Peng Liu Jin-Hui Chen Yu-Gang Ma Song Zhang Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049 China

Heavy-ion collisions are powerful tools for studying hypernuclear *** develop a dynamical coalescence model coupled with an ART model(version1.0) to study the production rates of light nuclear clusters and hypernuclei in heavy-ion reactions,for instance,the deuteron(d),triton(t),helium(~3He),and hypertriton(_A^3H)in minimum bias(0-80%centrality)~6Li+^(12)C reactions at beam energy of 3.5A *** penalty factor for light clusters is extracted from the yields,and the distributions of 0 angle of particles,which provide direct suggesetions about the location of particle detectors in the near future facility-High Intensity heavy-ion Accelerator Facility(HIAF) are *** calculation demonstrates that HIAF is suitable for studying hypernuclear physics.

关键词： Heavy-ion accelerator facility hyperon Hypernuclei Coalescence Light nuclei

Background Simulation of a Fission Fragment Chamber in the Experiment of ^(209)Bi(e,e’K^+)^(209)_ ΛPb

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Plasma Science and Technology 2012年第5期14卷 415-418页

作者：宋玉收刘辉兰席印印颜强胡碧涛 College of Nuclear Science and Technology Harbin Engineering University School of Nuclear Science and Technology Lanzhou University

An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of the fission fragment detector （FFD） was dramaticlly crashed by the background particles in comparison with that during the test without beam. The scattering of the high intensity （500 nA） primary electrons was the dominant cause. Using the GEANT4 toolkit, this report simulates the experimental situation of the target chamber in which the FFD was located. The simulation results indicate that the background particles were dominantly （~ electrons, and protons and alpha particles were the important heavy background particles. The performance of the multi-wire proportional chambers （MWPCs） depends not only on the background-particle intensity but also the current density, which was also given by the simulation code. Furthermore, the measures to suppress the background particles were also investigated with the simulation code.

关键词： fission fragments hyperon background particles Monte Carlo simulation

Hypertriton and light nuclei production at Λ-production subthreshold energy in heavy-ion collisions

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Chinese Physics C 2011年第8期35卷 741-746页

作者：张松陈金辉马余刚许长补蔡翔舟马国亮钟晨 Shanghai Institute of Applied Physics the Chinese Academy of Sciences Brookhaven National Laboratory UptonNew York11973USA

High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coales- cence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron （d）, triton （t）, helion （3He）, and hypertriton （~H） at subthreshold energy of A production （= 1 GeV per nucleon）. We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor （S3 =3H/（3He ×∧/p）） shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few μb in ^36Ar＋^36Ar, ^40Ca＋^40Ca and ^56Ni＋^56Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR （Lanzhou/China） at A subthreshold energy are suitable for breaking new ground in hypernuclear physics.

关键词： hyperon hypernuclei dynamic coalescence