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Multiple scattering approach to X-ray absorption spectroscopy

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Nuclear Science and Techniques 2003年第1期14卷 9-19页

作者： M.BENFATTO infn laboratori nazionali di Frascati 00044 Frascati Italy

In this paper we present the state of the art of the theoretical background needed for analyzing X-ray absorption spectra in the whole energy range. The multiple-scattering (MS) theory is presented in detail with some applications on real systems. We also describe recent progress in performing geometrical fitting of the XANES (X-ray absorption near-edge structure) energy region and beyond using a full multiple-scattering approach.

关键词： X-ray absorption spectroscopy X-ray absorption near-edge structure. Multiple-scattering theory

BABAR measurement of baryon time-like form factors via initial state radiation

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Chinese Physics C 2010年第6期34卷 860-862页

作者： R.Baldini Ferroli Enrico Fermi Center infn Laboratori Nazionali di Frascati

BABAR has measured with unprecedented accuracy the e^＋e^- → pp and e^＋e^- →∧∧ cross sections by means of the initial state radiation technique, which has the advantages of good efficiency, good energy resolution and full angular acceptance, even exactly at threshold. A peculiar feature of these cross sections is their non-vanishing values at threshold. In the case of charged baryons, this phenomenon is expected according to the Coulomb interaction between the outgoing baryon and antibaryon. Once this Coulomb enhancement factor is taken into account, the striking result is achieved that the proton form factor at threshold is ｜GP（4Mp^2）｜ = 1, that is what is expected for pointlike fermion pairs, in spite of the proton structure. However a Coulomb enhancement factor is not expected for neutral fermions, likely in contradiction with the BABAR data. Qualitatively this behaviour is consistent with Coulomb interactions at the valence quark level.

关键词： baryon form factor Initial state radiation BABAR

Breaking the brain barrier:cell competition in neural development and disease

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Neural Regeneration Research 2024年第9期19卷 1863-1864页

作者： Patrizia Morciano Daniela Grifoni Department of“Life Health and Environmental Sciences”University of L’AquilaItaly “infn-laboratori nazionali del Gran Sasso” AssergiItaly

General information on cell competition:Social behaviors are the basis of biological *** species and populations,cell communities experience Darwinian ecological interactions,and in case space and nutrient availabilit... 详细信息

关键词： neural barrier throughout

On the Expansion and Fate of the Universe

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Journal of Modern Physics 2012年第11期3卷 1722-1726页

作者： Aldo Bonasera laboratori nazionali del sud INFN Catania Italy

The evolution of the universe from an initial dramatic event, the Big-Bang, is firmly established. Hubble’s law [1] (HL) connects the velocity of galactic objects and their relative distance: v(r) = Hr, where H is the Hubble constant. In this work we suggest that HL is not valid at large distances because of total energy conservation. We propose an expansion of the velocity in terms of their relative distance and produce a better fit to the available experimental data. Using a simple “dust” universe model, we can easily calculate under which conditions an (unstable) equilibrium state can be reached and we estimate the values of the matter present in the universe as well as the “dark energy”. Within the same formalism we can derive the “deceleration parameter”. We do not need to invoke any “dark energy”, its role being played by the kinetic correction. The resulting picture is that the universe might reach an unstable equilibrium state whose fate will be decided by fluctuations: either collapse or expand forever.

关键词： Big-Bang Hubble’s Law

Exotic break-up modes in heavy ion reactions up to Fermi energies

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Nuclear Science and Techniques 2015年第2期26卷 124-130页

作者： Maria Colonna Virgil Baran Stefano Burrello Mariangela Di Prima Paolo Napolitani Carmelo Rizzo infn-laboratori nazionali del sud Via S Sofia 62Catania I-95123Italy NIPNE-HH Bucharest UniversityBucharest 077125Romania IPN CNRS/IN2P3Universite' Paris-Sud 11Orsay cedex 91406France

We discussed recent studies, within the framework of transport theories, on heavy ion reactions between charge asymmetric systems, from low up to Fermi energies. We concentrated on the analysis of ternary breakup events of dynamical origin occurring in semi-central reactions, where the formation of excited systems in various conditions of shape, excitation energy and spin is observed. At beam energies around 20 A Me V, we showed how this fragmentation mode emerges from the combined action of surface(neck) instabilities and angular momentum effects, leading to the observation of three aligned massive fragments in the exit channel. At Fermi energies, a transition towards a prompt emission of small fragments from the neck region with larger relative velocity with respect to projectile and target remnants is observed. We also focus on isospin sensitive observables, aiming at extracting information on the density dependence of the isovector part of the nuclear effective interaction and of the nuclear symmetry energy.

关键词：重离子反应费米能量不对称系统情调有效相互作用激发系统不稳定性分散模式

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

Proton and neutron alignments of the K~π=5/2^- band in ^(79)Kr

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Nuclear Science and Techniques 2000年第1期11卷 27-33页

作者： PAN Qiang-Yan1 De Poll M2 De Angelis G2 , Fahlander C2 Bazzacco D2 Farnea E2 Napoli D R2 Spolaore P2 (1Institute of Modeal Physics, the Chinese Academy of Sciences, Lanzhou 730000 2laboratori nazionali de Legnaro, infn, 35030 Legnaro (PD), Italia 中科院近代物理所甘肃兰州 730000 laboratori nazionali de Legnaro INFN 35030

An experimental study of high-spin states in 79Kr has been performed at the GASP array using the reaction 55Mn(30Si, αpn). Nine new states along with 10 new gamma ray transitions were found in the Kπ=5/2- band in 79Kr. Three band crossings, associated with the alignments of a πg9/2 pair and a πg9/2 pair and also a high-j 5h11/2 intrude orbital, were observed at rotational frequency h=0.50, 0.65 and 0.90 MeV, respectively. A cranked shell model analysis has been made to interpret the experimental results.

关键词：氪79 高自旋态原子核质子队列中子队列自旋轨道形态

Number-of-constituent-quark scaling of elliptic flow:a quantitative study

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Nuclear Science and Techniques 2022年第3期33卷 152-159页

作者： Meng Wang Jun-Qi Tao Hua Zheng Wen-Chao Zhang Li-Lin Zhu Aldo Bonasera School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710119China Department of Physics Sichuan UniversityChengdu 610064China Cyclotron Institute Texas A&M UniversityCollege StationTX 77843USA laboratori nazionali del sud INFNVia Santa Sofia6295123 CataniaItaly

The number-of-constituent-quark(NCQ)scaling behavior of the elliptic flow of identified particles produced in A+A collisions is studied quantitatively using an empirical function that fits the experimental v_(2) data available from the RHIC and *** most common approach for NCQ scaling involves(1)doing a scaling of the experimental v_(2) data of an identified particle with its NCQ,(2)doing the same to its transverse momentum or energy,then(3)combining all the scaled data and identifying the NCQ behavior by intuitively looking(since the measured experimental data are discrete).We define two variables(d_(1),d_(2))to describe NCQ scaling quantitatively and simultaneously,and identify the approximate region where the NCQ scaling *** approach could be applied to study NCQ or other scaling phenomena in future experiments.

关键词： Number-of-constituent-quark scaling Heavyion collisions Elliptic flow

Nucleon form factors:the space-time connection

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Chinese Physics C 2010年第6期34卷 874-876页

作者： S.Pacetti infn Laboratori Nazionali di Frascati Museo Storico della Fisica e Centro Studi e Ricerche 'E.Fermi'

Analyticity of nucleon form factors allows to derive sum rules which, using space-like and time-like data as input, can give unique information about behaviors in energy regions not experimentally accessible. Taking advantage from new time-like data on proton-antiproton differential cross section and hence the possibility to separate electric and magnetic form factors also in the time-like region, we verify the consistency of the asymptotic behavior predicted by the perturbative QCD for the proton magnetic form factor.

关键词： dispersion relations nucleon form factors pQCD