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A preliminary simulation study of influence of backsplash on the plastic scintillator detector design in HERD experiment

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Radiation Detection Technology and Methods 2021年第3期5卷 332-338页

作者： Peng Hu Zhi-gang Wang Fabio Gargano Francesca Alemanno Corrado Altomare Tian-wei Bao Yong-wei Dong Valerio Formato dimitrios Kyratzis Nicola Mori Lorenzo Pacini Zheng Quan Davide Serini Jun-jing Wang Rui-jie Wang Ming Xu Bo-bing Wu Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Istituto Nazionale di Fisica Nucleare(infn) Sezione di Bari70126 BariItaly Gran Sasso Science Institute(GSSI) 67100 L’AquilaItaly Istituto Nazionale di Fisica Nucleare(infn) Laboratori Nazionali del Gran Sasso67100 L’AquilaItaly dipartimento Interateneo di Fisica dell’Universitàe del Politecnico di bari 70125 BariItaly Istituto Nazionale di Fisica Nucleare(infn) Sezione di Roma Tor Vergata00133 RomeItaly Istituto Nazionale di Fisica Nucleare(infn) Sezione di Firenze50019 Sesto FiorentinoItaly

Background The plastic scintillator detector(PSD)is one of the detectors in the high energy cosmic radiation detection(HERD)facility,which is designed for gamma-ray detection and a redundant charge measurement.Backsplash will lead to a decrease in PSD’s performance of gamma-ray detection and charge measurement,which should be carefully considered.Purpose Two preliminary segmentation schemes of the PSD and two veto strategies have been proposed to suppress the backsplash effect.In this paper,we focus on the influence of the backsplash caused by gamma rays.The gamma-ray trigger efficiency and identification efficiency were studied in the case of different cell sizes and veto strategies,which can provide guidance on the PSD design.Methods A Monte Carlo simulation based on Geant4 has been performed.To simplify the simulation,the PSD is segmented into 1 cm3 cubes which can be easily aggregated into cells with different sizes during analysis.Results and conclusion Side_Veto can be used as a baseline design of veto strategy,whereas Smart_Veto can be selected as an upgraded design.Both the PSD bar cell with a width of less than 11 cm and the PSD tile cell with a width of less than 20 cm can achieve a sufficiently high gamma-ray trigger efficiency(>80%),which realizes the primary goal of the PSD.Meanwhile,both the PSD bar cell with a width of less than 3 cm and the PSD tile cell with a width of less than 20 cm can ensure a sufficiently high gamma-ray identification efficiency(>80%)for photons up to 800 GeV.

关键词： Plastic scintillator detector Gamma-ray detection Backsplash Veto

Energy and Heat Fluctuations in a Temperature Quench

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Communications in Theoretical Physics 2014年第10期61卷 555-570页

作者： M.Zannetti F.Corberi G.Gonnella A.Piscitelli dipartimento di Fisica "E.Caianiello" and CNISMUnità di SalernoUniversità di Salernovia Giovanni Paolo II 13284084 Fisciano (SA)Italy Kavli Institute for Theoretical Physics China the Chinese Academy of Sciences dipartimento di Fisica Università di Bari and INFNSezione di Barivia Amendola 17370126 BariItaly division of Physical Sciences School of Physical and Mathematical SciencesNanyang Technological University21 Nanyang Link637371Singapore

Fluctuations of energy and heat are investigated during the relaxation following the instantaneous temperature quench of an extended system. Results are obtained analytically for the Gaussian model and for the large N model quenched below the critical temperature TC. The main finding is that fluctuations exceeding a critical threshold do condense. Though driven by a mechanism similar to that of Bose–Einstein condensation, this phenomenon is an out-of-equilibrium feature produced by the breaking of energy equipartition occurring in the transient regime. The dynamical nature of the transition is illustrated by phase diagrams extending in the time direction.

关键词： fluctuations condensation temperature quench relaxation equipartition breaking

A Lattice Boltzmann Study of Phase Separation in Liquid-Vapor Systems with Gravity

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Communications in Computational Physics 2010年第2期7卷 350-361页

作者： Artur Cristea Giuseppe Gonnella Antonio Lamura Victor Sofonea Center for Fundamental and Advanced Technical Research Romanian AcademyBd.Mihai Viteazul 24300223 Timi¸soaraRomania dipartimento di Fisica Universita di Bari and INFNSezione di BariVia Amendola 17370126 BariItaly Istituto Applicazioni Calcolo CNRVia Amendola 122/D70126 BariItaly

Phase separation of a two-dimensional van der Waals fluid subject to a grav-itational force is studied by numerical simulations based on lattice Boltzmann methodsimplemented with a finite difference scheme. A growth e... 详细信息

关键词： Lattice Boltzmann phase separation liquid-vapor gravity

Space, Time, and Their Transformations

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Journal of Systems Engineering and Electronics 1995年第4期6卷 25-44页

作者： F.Selleri (Universita di bari-dipart. di Fisica, infn-sezione di bari,Via Amendola 173, I-70126 bari) Universita di bari-dipart. di Fisica INFN-Sezione di Bari Via Amendola 173 1-70126 Bari

We construct a set T of space-the transformations between inertial systems that are completely equivalent for explaining the experimental evidence, by starting from two empirically based assumptions: (1) The two-way velocity of light is c in all inertial systems and in all directions; (2) Time dilation effects take place with the usual relativistic factor. The Lorentz transformation is an element of T and any two elements of T differ only as to a convention regarding clock synchronization. The simplest choice is to transform time independently of space coordinates (absolute synchronization) and can be called 'inerital transformation.' When accelerations are considered the equivalence is broken and the inertial transformation emerges as closest to physical reality.

关键词： Special relativity Space and time.

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中子的内部结构:来自BESIII的研究

Science Bulletin 2022年第6期67卷 557-560页

作者： Simone Pacetti Rinaldo Baldini Ferroli Andrea Bianconi Egle Tomasi-Gustafsson dipartimento di Fisica e Geologia and INFN Sezione di Perugia1-06123 PerugiaItaly Laboratori Nazionali di Frascati dell'infn 1-00044 FrascatiItaly dipartimento di Ingegneria dell'Informazione Brescia1-25133 BresciaItaly INFN Sezione di Pavia1-27100 PaviaItaly DPhN IRFUCEAUniversitéParis-Saclay1-91191 Gif-sur-Yvette CedexFrance

The BESⅢCollaboration has recently published a new precise measurement of the time-like neutron form factor(FF)[1].In the light of the remarkable accuracy and of the wideness of the explored kinematical range,these data represent an unprecedented tool for highlighting and studying specific features of the neutron FF.Until a few years ago,the only available data were those obtained by the FENICE experiment at Frascati,in the’90s[2].

关键词： BESⅢ precise

CPT INVARIANCE TESTS IN NEUTRAL KAON DECAY

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Chinese Physics C 2016年第10期40卷 707-709页

作者： M. Antonelli LNF-infn, Frascati LNF-infn Frascati infn sezione di Napoli

CPT theorem is based on three assumptions： quantum field theory, locality, and Lorentz invariance, and thus it is a fundamental probe of our basic understanding of particle physics. Strangeness oscillation in K^0 -K^... 详细信息

关键词： CPT定理介子衰变 Lorentz 中性测试变性量子场论粒子物理

Comparison of Proton Shower Developments in the BGO Calorimeter of the Dark Matter Particle Explorer between GEANT4 and FLUKA Simulations

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Chinese Physics Letters 2020年第11期37卷 114-120页

作者：蒋维岳川崔明阳李翔袁强 Francesca Alemanno Paolo Bernardini Giovanni Catanzani 陈占方 Ivan De Mitri 董铁矿 Giacinto Donvito David Francois Droz Piergiorgio Fusco Fabio Gargano 郭东亚 dimitrios Kyratzis 雷仕俊刘杨 Francesco Loparco 马鹏雄 Giovanni Marsella Mario Nicola Mazziotta 潘旭彭文溪 Antonio Surdo Andrii Tykhonov 魏逸丰余玉洪藏京京张亚鹏张永杰张云龙 Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Gran Sasso Science Institute(GSSI) Viale F.Crispi 7I-67100L'AquilaItaly Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Gran SassoVia G.Acitelli 22I-67100AssergiL'AquilaItaly dipartimento di Matematica e Fisica E.De Giorgi Universitàdel SalentoI-73100 LecceItaly Istituto Nazionale di Fisica Nucleare(infn)-sezione di Lecce I-73100 LecceItaly infn Section of Perugia I-06100 PerugiaItaly University of Perugia I-06100 PerugiaItaly Istituto Nazionale di Fisica Nucleare(infn)-sezione di bari I-70125BariItaly Department of Nuclear and Particle Physics University of GenevaCH-1211Switzerland dipartimento Interateneo“M.Merlin”dell'Universitàdegli Studi di bari e del Politecnico di bari I-70125BariItaly dipartimento di Fisica e Chimica“E.Segrè” via delle Scienze Edificio 17UniversitàDegli Studi di PalermoI-90128PalermoItaly Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

The DArk Matter Particle Explorer(DAMPE)is a satellite-borne detector for high-energy cosmic rays and y-rays.To fully understand the detector performance and obtain reliable physical results,extensive simulations of the detector are necessary.The simulations are particularly important for the data analysis of cosmic ray nuclei,which relies closely on the hadronic and nuclear interactions of particles in the detector material.Widely adopted simulation softwares include the GEANT4 and FLUKA,both of which have been implemented for the DAMPE simulation tool.Here we describe the simulation tool of DAMPE and compare the results of proton shower properties in the calorimeter from the two simulation softwares.Such a comparison gives an estimate of the most significant uncertainties of our proton spectral analysis.

关键词： material. GEANT4 calorimeter

A model to explain the angular distribution of J/Ψ and Ψ(2S) decay into ■ and ■

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Chinese Physics C 2019年第2期43卷 31-36页

作者： M.Alekseev A.Amoroso R.Baldini Ferroli I.Balossino M.Bertani D.Bettoni F.Bianchi J.Chai G.Cibinetto F.Cossio F.De Mori M.Destefanis R.Farinelli L.Fava G.Felici I.Garzia M.Greco L.Lavezzi C.Leng M.Maggiora A.Mangoni S.Marcello G.Mezzadri S.Pacetti P.Patteri A.Rivetti M.Da Rocha Rolo M.Savrié S.Sosio S.Spataro L.Yan Università di Torino infn sezione di Torino infn Laboratori Nazionali di Frascati infn sezione di Ferrara Institute of High Energy Physics Università di Ferrara Università del Piemonte Orientale Università di Perugia infn sezione di Perugia

BESⅢ data show a particular angular distribution for the decay of J/Ψ and Ψ(2 S) mesons into ■ and Σ~0Σ~0 hyperons: the angular distribution of the decay Ψ(2 S) →Σ~0Σ~0 exhibits an opposite trend with respect to the other three channels: J/Ψ→■, J/Ψ→Σ~0Σ~0 and Ψ(2 S) →■. We define a model to explain the origin of this phenomenon.

关键词： J/ψandψ(2S)hadronic decays effective Lagrangian model polarization parameters

Two-flavor hybrid stars with the Dyson-Schwinger quark model

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Chinese Physics C 2017年第11期41卷 110-116页

作者：魏金标陈欢 H.-J.Schulze School of Mathematics and Physics China University of Geosciences infn sezione di Catania Dipartimento di FisicaUniversitá di Catania

We study the properties of two-flavor quark matter in the Dyson-Schwinger model and investigate the possible consequences for hybrid neutron stars,with particular regard to the two-solar-mass limit.We find that with some extreme values of the model parameters,the mass fraction of two-flavor quark matter in heavy neutron stars can be as high as 30 percent and the possible energy release during the conversion from nucleonic neutron stars to hybrid stars can reach 1052 erg.

关键词： hybrid stars quark matter equation of state Dyson-Schwinger equations