Transverse-energy distribution in proton-nucleus collisions at high energy

International Nuclear Information System (INIS)

Liu, F.H.

2001-01-01

Based on the model of nuclear-collision geometry, the independent N - N collision picture and participant contribution picture are used to describe the transverse-energy distribution in p-A collisions at high energy. In the independent N - N collision picture, the energy loss of leading proton in each p-N collision is considered. The calculated results are in agreement with the experimental data of p-Al, p-Cu, p-U collisions at 200 GeV/c. (author)

Investigation of Rare Particle Production in High Energy Nuclear Collisions

International Nuclear Information System (INIS)

Crawford, Henry J.; Engelage, Jon M.

1999-01-01

Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. We have produced the electronics and software for the STAR trigger and will begin to use these tools to search for anti-nuclei and strange hadrons when RHIC turns on later this year

High energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

Bhalla, K.B.

1980-01-01

An attempt is made to explain nucleus-nucleus collisions based on nuclear emulsion experiments. Peripheral and central collisions are described in detail. Assuming the fireball model, the concepts of geometry, kinematics and thermodynamics in this model are discussed. Projectile and target fragmentations are studied. The advantages of using nuclear emulsions as detectors, are mentioned. Proton-nucleus collisions and nucleus-nucleus collisions are compared. Interactions, of projectiles such as Ca, B and C on targets such as Pb, Ag, Br etc. at very high energies (approximately 300 to 1700 Gev) are listed. A comparison of the near multiplicities in these interactions is given. A generalized explanation is given on the processes involved in these interactions. (A.K.)

High energy nuclear collisions

Indian Academy of Sciences (India)

We review some basic concepts of relativistic heavy-ion physics and discuss our understanding of some key results from the experimental program at the relativistic heavy-ion collider (RHIC). We focus in particular on the early time dynamics of nuclear collisions, some result from lattice QCD, hard probes and photons.

Characteristics of particle production in high energy nuclear collisions a model-based analysis

CERN Document Server

Guptaroy, P; Bhattacharya, S; Bhattacharya, D P

2002-01-01

The present work pertains to the production of some very important negatively charged secondaries in lead-lead and gold-gold collisions at AGS, SPS and RHIC energies. We would like to examine here the role of the particular version of sequential chain model (SCM), which was applied widely in the past in analysing data on various high-energy hadronic collisions, in explaining now the latest findings on the features of particle production in the relativistic nucleus-nucleus collisions. The agreement between the model of our choice and the measured data is found to be modestly satisfactory in cases of the most prominent and abundantly produced varieties of the secondaries in the above-stated two nuclear collisions. (25 refs).

High energy nuclear collisions: Theory overview

Indian Academy of Sciences (India)

1012 K, were deconfined and existed as a quark gluon plasma (QGP). These ideas can be tested in collisions of nuclei at ultra-relativistic energies. At the relativistic heavy-ion collider (RHIC), nuclei as heavy as gold are accelerated to an energy of 100 GeV per nucleon. A total energy of 40 TeV is available in the collision of.

Some comments on the behaviour of the excited nuclear matter formed in nuclear collisions at high energies

International Nuclear Information System (INIS)

Besliu, Calin; Jipa, Alexandru; Argintaru, Dan

2003-01-01

In the last years many experiments have been performed in different laboratories to investigate the behaviour of the nuclear matter formed in nuclear collisions at high energies. Therefore, many experimental results are available at present. For explaining these experimental results a lot of models have been proposed. A very large number of concepts have been used. Taking into account some own experimental results obtained in proton-nucleus and nucleus-nucleus collisions at energies between a few A GeV and a few hundred A GeV we comments in the frame a phenomenological geometric picture the main experimental results on charged particle multiplicities, participants, cross sections, momentum spectra, temperature slopes, nuclear matter flow, size and structure of the participant regions, antiparticle to particle ratios and chemical potential. Some jumps in the dependencies of some interesting physical quantities on the available energies in the centre of mass system can be reported. Trends to behaviours like-saturation of some physical quantities are observed, too. Therefore, some connections with the possible phase transitions in nuclear matter are included. A few specific signals of different phase transitions in nuclear matter are suggested. (authors)

Heavy-flavor production and medium properties in high-energy nuclear collisions --What next?

NARCIS (Netherlands)

Aarts, G.; Aichelin, J.; Allton, C.; Arnaldi, R.; Bass, S. A.; Bedda, C.; Brambilla, N.; Bratkovskaya, E.; Braun-Munzinger, P.; Bruno, G. E.; Dahms, T.; Das, S. K.; Dembinski, H.; Djordjevic, M.; Ferreiro, E. G.; Frawley, A.; Gossiaux, P. B.; Granier de Cassagnac, R.; Grelli, A.; He, Ming; Horowitz, W. A.; Innocenti, G. M.; Jo, M.; Kaczmarek, O.; Kuijer, P; Laine, M.; Lombardo, M. P.; Mischke, A.; Munhoz, M. G.; Nahrgang, M.; Nguyen, Mai; Oliveira da Silva, A. C.; Petreczky, P.; Rothkopf, A.; Schmelling, M.; Scomparin, E.; Song, Ting; Stachel, J.; Suaide, A. A P; Tolos, L.; Trzeciak, B.; Uras, A.; van Doremalen, L.; Vermunt, L.; Vigolo, S.; Xu, N.; Ye, Z.; Zanoli, H.J.C.; Zhuang, P.

2017-01-01

Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results

High energy collisions of nuclei: experiments

International Nuclear Information System (INIS)

Heckman, H.H.

1977-09-01

Heavy-ion nuclear reactions with projectile energies up to 2.1 GeV/A are reviewed. The concept of ''rapidity'' is elucidated, and the reactions discussed are divided into sections dealing with target fragmentation, projectile fragmentation, and the intermediate region, with emphasis on the production of light nuclei in high-energy heavy-ion collisions. Target fragmentation experiments using nuclear emulsion and AgCl visual track detectors are also summarized. 18 figures

On Markov processes in the hadron-nuclear and nuclear-nuclear collisions at superhigh energies

International Nuclear Information System (INIS)

Lebedeva, A.A.; Rus'kin, V.I.

2001-01-01

In the article the possibility of the Markov processes use as simulation method for mean characteristics of hadron-nuclear and nucleus-nuclear collisions at superhigh energies is discussed. The simple (hadron-nuclear collisions) and non-simple (nucleus-nuclear collisions) non-uniform Markov process of output constant spectrum and absorption in a nucleon's nucleus-target with rapidity y are considered. The expression allowing to simulate the different collision modes were obtained

Global flow of glasma in high energy nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Chen, Guangyao; Fries, Rainer J., E-mail: rjfries@comp.tamu.edu

2013-06-25

We discuss the energy flow of the classical gluon fields created in collisions of heavy nuclei at collider energies. We show how the Yang–Mills analog of Faraday's Law and Gauss' Law predicts the initial gluon flux tubes to expand or bend. The resulting transverse and longitudinal structure of the Poynting vector field has a rich phenomenology. Besides the well-known radial and elliptic flow in transverse direction, classical quantum chromodynamics predicts a rapidity-odd transverse flow that tilts the fireball for non-central collisions, and it implies a characteristic flow pattern for collisions of non-symmetric systems A+B. The rapidity-odd transverse flow translates into a directed particle flow v{sub 1} which has been observed at RHIC and LHC. The global flow fields in heavy ion collisions could be a powerful check for the validity of classical Yang–Mills dynamics in high energy collisions.

High energy nuclear collisions in the few GeV/nucleon region: projectile and target fragmentation

International Nuclear Information System (INIS)

Schroeder, L.S.

1980-06-01

A general review of nucleon-nucleus and nucleus-nucleus collisions for incident energies <10 GeV/nucleon is presented. The division of these interactions into peripheral and central collisions is briefly discussed. Subjects treated include the following: target and projectile fragmentation systematics, production of exotic nuclear fragments, studies of multiparticle final states, total cross section measurements, results from an experiment that indicate the production of projectile fragments with an anomalously short reaction mean free path, high-energy particle production at backward angles beyond simple N-N kinematic limits, and recent results on backward particle emission in studies with the Berkeley streamer chamber. Both the particle and nuclear physics aspects that are present are considered. A brief discussion of future trends in this energy range ends the presentation. 65 references, 37 figures

Angular pattern of minijet transverse energy flow in hadron and nuclear collisions

International Nuclear Information System (INIS)

Leonidov, A.V.; Ostrovsky, D.M.

2002-01-01

The azimuthal asymmetry of a minijet system produced at the early stage of nucleon-nucleon and nuclear collisions in a central rapidity window is studied. We show that, in pp collisions, the minijet-transverse-energy production in a central rapidity window is essentially unbalanced in azimuth because of asymmetric contributions in which only one minijet hits the acceptance window. We further study the angular pattern of the transverse-energy flow generated by semihard degrees of freedom at the early stage of high-energy nuclear collisions and its dependence on the number of semihard collisions in the models either including or neglecting soft contributions to the inelastic cross section at RHIC and LHC energies, as well as on the choice of infrared cutoff

Angular pattern of minijet transverse energy flow in hadron and nuclear collisions

International Nuclear Information System (INIS)

Leonidov, A.V.; Ostrovsky, D.M.

2000-01-01

The azimuthal asymmetry of a minijet system produced at the early stage of nucleon-nucleon and nuclear collisions in a central rapidity window is studied. We show that in pp collisions the minijet transverse energy production in a central rapidity window is essentially unbalanced in the azimuth due to asymmetric contributions in which only one minijet hits the acceptance window. We further study the angular pattern of the transverse energy flow generated by the semihard degrees of freedom at the early stage of high energy nuclear collisions and its dependence on the number of semihard collisions in the models both including and neglecting soft contributions to the inelastic cross section at RHIC and LHC energies as well as on the choice of the infrared cutoff. (orig.)

On the nuclear fragmentation mechanisms in nuclear collisions at intermediate and high energies

International Nuclear Information System (INIS)

Jipa, Al; Besliu, C.; Felea, D.

2004-01-01

The nuclear fragmentation mechanisms can be discussed by taking into account different scales related to the fragment sizes. Considering two fragmentation mechanisms of the nuclei at the same incident energy an analysis of the experimental results obtained was done. Goldhaber formula was improved by analyzing the discrepancies between data and theories concerning the projectile fragmentation. We implied that the projectile fragmentation process would be governed by the distribution of nucleon momenta in the projectile after the collision occurred. We used in our analysis protons from the 4 He + 7 Li at 4.5 GeV/c per nucleon incident momentum, as well as from 40 Ar + 12 C at 213 AMeV bombarding energy. We proved that in order to proceed in analyzing the projectile fragmentation process at intermediate and high energies one has to consider the dependence σ 0 on the apparent temperature of projectile nucleus after the collision took place. The generalized Bertsch correction for light projectile nuclei and fragments was used and the number of spatial correlations between identical nucleons having anticorrelated momenta was found. Thus we found apparent temperature values close to the separation energies of the considered fragments per number of fragments. The temperatures associated to kinetic energy spectra of the projectile fragments were calculated following two methods. The results from Bauer's method were compared with those obtained by fitting the kinetic energy distributions of the projectile fragments in the rest frame of the projectile with a Maxwellian curve. We also accomplished the comparison of the experimental results with similar events simulated with RQMD 2.4. All the results obtained suggested two nuclear fragmentation mechanisms: a sudden fragmentation by explosive mechanisms, like shock waves and a slow fragmentation by the 'fission' of the spectator regions, mainly because of the interactions with the particles or fragments emitted from the

High energy nuclear collisions: Theory overview

Energy Technology Data Exchange (ETDEWEB)

Fries, R.J.

2010-08-01

We review some basic concepts of relativistic heavy-ion physics and discuss our understanding of some key results from the experimental program at the relativistic heavy-ion collider (RHIC). We focus in particular on the early time dynamics of nuclear collisions, some result from lattice QCD, hard probes and photons.

Forward-backward multiplicity fluctuation and longitudinal harmonics in high-energy nuclear collisions

Science.gov (United States)

Jia, Jiangyong; Radhakrishnan, Sooraj; Zhou, Mingliang; Huo, Peng

2016-12-01

Forward-backward (FB) multiplicity fluctuation in high-energy nuclear collisions can be quantified by two-particle pseudo-rapidity correlation function and its expansion into Legendre polynomials. The corresponding coefficients represent different fluctuation modes in longitudinal direction. The leading term corresponds to the asymmetry of numbers of the participants from the two colliding nuclei. This method is tested in events generated from AMPT and HIJING model. The an signal are found to be strongly dampened in AMPT than in HIJIGN, due to weaker short-range correlaitons and final-state effects in AMPT. Two-particle correlation also reveals an intresting shallow minimum around Δη ≈ 0 in AMPT events, which is absent in HIJING results. The method opens a new avenue to elucidate the particle production mechanism and early time dynamics in heavy-ion collisions.

2006-2007 Academic training programme: QCD and high energy nuclear collision

CERN Multimedia

HR Department

2007-01-01

LECTURE SERIES 7, 8, 9 May QCD and high energy nuclear collisions D. Kharzeev, Brookhaven National Laboratory, USA 11:00 to 12:00 - Main Auditorium, Bldg. 500 on 7 and 8 May, Council Chamber on 9 May Six years ago, Relativistic Heavy Ion Collider at Brookhaven started colliding heavy nuclei at record center-of-mass energies of up to 200 GeV/nucleon. Very soon, the Large Hadron Collider at CERN will push the energy of the ions to an astounding 5 TeV/nucleon. What can be learnt from the experiments at these machines? What do we know about the physics of super--dense matter already? I will argue that heavy ion accelerators bring us to the new frontiers of physical knowledge by creating strong color fields and very high densities of partons, at which qualitatively new phenomena emerge. I will also discuss the cross-disciplinary implications for cosmology, astrophysics, and connections to condensed matter physics.

2006-2007 Academic training programme: QCD and high energy nuclear collisions

CERN Multimedia

HR Department

2007-01-01

LECTURE SERIES 7, 8, 9 May 2007 11:00 to 12:00 - Main Auditorium, Bldg. 500 on 7 and 8 May, Council Chamber on 9 May QCD and high energy nuclear collisions D. Kharzeev, Brookhaven National Laboratory, USA Six years ago, the Relativistic Heavy Ion Collider at Brookhaven started colliding heavy nuclei at record center-of-mass energies of up to 200 GeV/nucleon. Very soon, the Large Hadron Collider at CERN will push the energy of the ions to an astounding 5 TeV/nucleon. What can be learnt from the experiments at these machines? What do we know about the physics of super--dense matter already? I will argue that heavy ion accelerators bring us to the new frontiers of physical knowledge by creating strong color fields and very high densities of partons, at which qualitatively new phenomena emerge. I will also discuss the cross-disciplinary implications for cosmology, astrophysics, and connections to condensed matter physics.

Formation and disintegration of high-density nuclear matter in heavy-ion collisions

International Nuclear Information System (INIS)

Kitazoe, Yasuhiro; Matsuoka, Kazuo; Sano, Mitsuo

1976-01-01

The formation of high-density nuclear matter which may be expected to be attained in high-energy heavy-ion collisions and the subsequent disintegration of dense matter are investigated by means of the hydrodynamics. Head-on collisions of identical nuclei are considered in the nonrelativistic approximation. The compressed density cannot exceed 4 times of the normal one so long as the freedom of only nucleons is considered, and can become higher than 4 times when other freedoms such as the productions of mesons and also nucleon isobars are additionally taken into account. The angular distributions for ejected particles predominate both forwards and backwards at low collision energies, corresponding to the formation of nuclear density less than 2 times of the normal density and become isotropic at the point of 2 times of the normal one. As the collision energy increases further, lateral ejection is intensified gradually. (auth.)

Reaction mechanism in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Tanihata, Isao.

1982-04-01

The reaction mechanism in high energy heavy-ion collision is discussed. The discussion is mainly based on the experimental data. Empirical equations have been given for the total cross-sections of nucleus-nucleus reactions and the reaction cross-sections. These cross-sections are well described by the geometrical size of the colliding nuclei. The cross-sections are also understood by microscopic calculation. The charged particle multiplicity gives additional information about the geometrical aspect of heavy ion collision. The data suggested that the total energy, independent of projectile size, is most important for determining the multiplicity. The inclusive proton spectrum in a heavy ion collision showed two distinct regions. The one is the fragment region, and the other the participant region. The spectral shapes of inclusive pion spectra are reasonably well explained by the Coulomb interaction of pions with nuclear fragments. The high energy heavy ion reaction occurs in the overlap region of the projectile and target. This has been tested by measuring the number of participants for various reactions. The space and the time structure of the collision are also discussed in this paper as well as the dynamical aspects of the collision. (Kato, T.)

Transverse energy production in high energy nuclear collisions and the equation of state of nuclear matter

International Nuclear Information System (INIS)

Doss, K.G.R.; Gustafsson, H.A.; Gutbrod, H.H.; Kolb, B.; Ludewigt, B.; Poskanzer, A.M.; Ritter, H.G.; Schmidt, H.R.; Lawrence Berkeley Lab., CA; Kampert, K.H.; Loehner, H.

1987-08-01

In nuclear collisions of AU+Au, Nb+Nb and Ca+Ca at bombarding energies between 150 and 800 MeV per nucleon transverse energy and transverse momenta of light particles are studied event by event at θ = 90 0 in the center of mass system. At all energies a rise of the mean transverse energy per nucleon is observed with increasing charged particle multiplicity. Particularly large values of E perpendicular to have been found for 3 He-fragments. The hydrodynamical picture is discussed for a possible separation of the collective flow and the thermal parts of the E perpendicular to -spectrum. From this, evidence for a rather stiff equation of state is found. (orig.)

Jets in high energy nucleon-nucleon collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1982-01-01

From the experimental studies of high-energy hardon-nucleon and nucleon-nucleon collisions, by means of nuclear targets applied as detectors, it follows that particles are produced via intermediate objects created first in a 2 → 2 type endoergic reaction. These objects, called generons, decay in flight into finally observed particles and resonances after their lifetime tausub(g) > or approximately 10 - 22 s. The jet structure of the outcome in nucleon-nucleon collisions is a simple and indispensable consequence of this particle production mechanism. The picture of the jet structure in the collision outcome observed in the CMS of the colliding nucleons depends on the energy of these nUcleons. New particle production scheme is proposed, which can be tested experimentally; corresponding simple relations between characteristics of colliding nucleons and of produced jets are proposed for a testing

Strangeness and charm production in high energy heavy ion collisions

International Nuclear Information System (INIS)

Xu, Nu

2001-01-01

We discuss the dynamical effects of strangeness and charm production in high energy nuclear collisions. In order to understand the early stage dynamical evolution, it is necessary to study the transverse momentum distributions of multi-strange hadrons like Ξ and Ω and charm mesons like J/Ψ as a function of collision centrality

QMD and JAM calculations for high energy nucleon-nucleus collisions

International Nuclear Information System (INIS)

Niita, Koji

2002-01-01

We describe the two simulation codes, QMD and JAM (Jet AA Microscopic Transport Model), for high energy nuclear reactions. QMD can treat the nucleus-nucleus reactions as well as nucleon-nucleus reactions based on the molecular dynamics. We have applied the QMD code intensively to nucleon-nucleus reactions and checked its validity. The cross sections obtained by the QMD are now used for evaluation of high energy nuclear data in JAERI. JAM is a hadronic cascade code including the resonance and string model for the hadron-hadron collisions at high energy up to 200 GeV. We have developed a high energy particle transport code NMTC/JAM by including the JAM code for the intra-nuclear cascade part. (author)

Probing the nuclear symmetry energy with heavy-ion collisions

Directory of Open Access Journals (Sweden)

De Filippo E.

2015-01-01

Full Text Available Heavy ion collisions (HIC have been widely used to extract the parametrization of symmetry energy term of nuclear equation of state as a function of barionic density. HIC in fact are a unique tool in terrestrial laboratories to explore the symmetry energy around the saturation density (ρ0 = 0.16fm−3 from sub-saturation densities (Fermi energies towards compressed nuclear matter (ρ > 2 − 3ρ0 that can be reached at relativistic energies, as a function of different conditions of temperature, mass asymmetry and isospin. One of the main study at present is to reach a coherent description of EOS of asymmetric nuclear matter from heavy ion collisions of stable and exotic nuclei, nuclear structure studies and astrophysical observations. In this work an overview of the current status of the research is shortly reviewed together with new perspectives aimed to reduce the present experimental and theoretical uncertainties.

Transverse momentum in high-energy nuclear collisions: Collective expansion

International Nuclear Information System (INIS)

Wang, X.; Hwa, R.C.

1987-01-01

Hadron production in the central region in high-energy nuclear collisions is investigated. The hydrodynamical expansion of a locally thermalized system is studied for both the cases with and without phase transition. The case with phase transition is considered by using a sound-velocity function c/sub s/(T) parametrized to fit the energy density determined in a lattice gauge calculation. The effect of a transverse rarefaction wave is included in the calculation of the temperature profile of the expanding fluid. The transverse-momentum distribution of hadrons is calculated by collecting all the hadrons produced when the hadron gas is cooled down to a freeze-out temperature at different times in the expansion. Fluctuation in initial temperature and radius is allowed due to variation in impact parameter. On the basis of a study of the thermalization process in the parton model we impose a constraint on the initial temperature and the thermalization time, the simultaneous variation of both of which gives rise to a relationship between the average transverse momentum and rapidity density. We have found that there is no so-called ''plateau'' region in that relationship. The implication on the diagnostics of a quark-gluon plasma is discussed

High energy gamma-ray production in nuclear reactions

International Nuclear Information System (INIS)

Pinston, J.A.; Nifenecker, H.; Nifenecker, H.

1989-01-01

Experimental techniques used to study high energy gamma-ray production in nuclear reactions are reviewed. High energy photon production in nucleus-nucleus collisions is discussed. Semi-classical descriptions of the nucleus-nucleus gamma reactions are introduced. Nucleon-nucleon gamma cross sections are considered, including theoretical aspects and experimental data. High energy gamma ray production in proton-nucleus reactions is explained. Theoretical explanations of photon emission in nucleus-nucleus collisions are treated. The contribution of charged pion currents to photon production is mentioned

Intermediate/high energy nuclear physics

International Nuclear Information System (INIS)

Vary, J.P.

1992-01-01

Progress during the last year is reviewed under the following topics: relativistic hadron--nucleus and nucleus--nucleus collisions (heavy meson production, photon production and fragmentation functions--direct photon production with the QCM and photon fragmentation functions, Cronin efffect and multiple scattering, effective nuclear parton distributions); solving quantum field theories in nonperturbative regime; light-front dynamics and high-spin states (soft form factor of the pion and nucleon for transverse and longitudinal momentum transfers, light front spinors for high-spin objects); high-energy spin physics; relativistic wave equations, quarkonia, and e + e - resonances; associated production of Higgs boson at collider energies, and microscopic nuclear many-body theory and reactions. 135 refs

High energy hadron-hadron collisions

International Nuclear Information System (INIS)

Chou, T.T.

1990-01-01

Results of a study on high energy collision with the geometrical model are summarized in three parts: (i) the elastic hadron-hadron collision, (ii) the inelastic hadron-hadron collision, and (iii) the e + e - annihilation. The geometrical description of high-energy elastic scattering developed earlier is still in general agreement with experiments at the CERN-S bar ppS energies. A simple one-parameter expression for the blackness of bar pp system has been proposed recently which describes very well all existing data from ISR to S bar ppS energies. The geometrical description has also been extended to include processes of fragmentation and diffraction dissociation and other phenomena. In the past five years, a unified physical picture for multiparticle emission in hadron-hadron and e + e - collisions was developed. It focuses on the idea of the wide range of values for the total angular momentum in hadron-hadron collisions. An extension of this consideration yields a theory for the momentum distribution of the outgoing particles which agrees with bar pp and e + e - collision experiments. The results and conclusions of this theory have been extrapolated to higher energies and yielded many predictions which can be experimentally tested. 37 refs

Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies.

Science.gov (United States)

Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Drees, K A; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

2003-10-24

We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.

High energy nuclear excitations

International Nuclear Information System (INIS)

Gogny, D.; Decharge, J.

1983-09-01

The main purpose of this talk is to see whether a simple description of the nuclear excitations permits one to characterize some of the high energy structures recently observed. The discussion is based on the linear response to different external fields calculated using the Random Phase Approximation. For those structure in heavy ion collisions at excitation energies above 50 MeV which cannot be explained with such a simple approach, we discuss a possible mechanism for this heavy ion scattering

Observation of strong azimuthal asymmetry between slow and fast particles from high energy nuclear collisions

International Nuclear Information System (INIS)

Gustafsson, H.A.; Gutbrod, H.H.; Kolb, B.; Loehner, H.; Ludewigt, B.; Poskanzer, A.M.; Renner, T.; Riedesel, H.; Ritter, H.G.; Siemiarczuk, T.; Stepaniak, J.; Warwick, A.; Wieman, H.

1984-10-01

Evidence is presented for the strong azimuthal asymmetry between slow and fast fragments in nuclear collisions in the energy interval of 0.4 to 1 GeV per nucleon. The asymmetry gets stronger when incident energy and impact parameter decrease. The results on the A dependence of the azimuthal asymmetry are also presented. (orig.)

Semihard interactions in nuclear collisions based on a unified approach to high energy scattering

International Nuclear Information System (INIS)

Drescher, H.J.; Hladik, M.; Werner, K.; Ostapchenko, S.; Centre National de la Recherche Scientifique, 44 - Nantes

1998-01-01

Our ultimate goal is the construction of a model for interactions of two nuclei in the energy range between several tens of GeV up to several TeV per nucleon in the centre-of-mass system. Such nuclear collisions are very complex, being composed of many components, and therefore some strategy is needed to construct a reliable model. The central point of our approach is the hypothesis, that the behavior of high energy interactions is universal (universality hypothesis). A model for nuclear interactions in a modular fashion is proposed. The individual modules, based on the universality hypothesis, are identified as building blocks for more elementary interactions (like e + e - , lepton-proton), and can therefore be studied in a much simpler context. With these building blocks under control, a quite reliable model is developed for nucleus-nucleus scattering, providing in particular very useful tests for the complicated numerical procedures using Monte Carlo techniques. (author)

Deconfinement and nuclear collisions

International Nuclear Information System (INIS)

Sarma, Nataraja

1992-01-01

Expensive experiments to detect a deconfined parton phase have been done and are being planned. In these experiments it is hoped that nuclear collisions at relativistic energies will exhibit signals of this new phase. So far all the results may be interpreted in terms of independent nucleon-nucleon interactions. These elementary collisions at very high energies are therefore worth examination since each such collision produces a highly excited entity which emits a large number of hadrons. In the hadronic phase this results in the GS multiplicity distribution. In the parton phase, parton branching results in the popular negative binomial distribution. Though neither the GS nor the NB distribution alone agrees with the data beyond 200 GeV, it is fitted exceedingly well by a weighted sum of the two distributions. Since the negative binomial distribution arises from the branching of partons, we interpret the increase with energy of the negative binomial component in the weighted sum as the onset of a deconfined phase. The rising cross section for the negative binomial component parallels very closely the inclusive cross section for hadron jets which is also considered a consequence of partons branching. The consequences of this picture to nuclear collisions is discussed. (author). 8 refs., 9 figs., 3 tabs

Achieving high baryon densities in the fragmentation regions in heavy ion collisions at top RHIC energy

International Nuclear Information System (INIS)

Li, Ming; Kapusta, Joseph I.

2017-01-01

Heavy ion collisions at extremely high energy, such as the top energy at RHIC, exhibit the property of transparency where there is a clear separation between the almost net-baryon-free central rapidity region and the net-baryon-rich fragmentation region. We calculate the net-baryon rapidity loss and the nuclear excitation energy using the energy-momentum tensor obtained from the McLerran-Venugopalan model. Nuclear compression during the collision is further estimated using a simple space-time picture. The results show that extremely high baryon densities, about twenty times larger than the normal nuclear density, can be achieved in the fragmentation regions. (paper)

The picture of the nuclei disintegration mechanism - from nucleus-nucleus collision experimental data at high energies

International Nuclear Information System (INIS)

Strugalska-Gola, E.; Strugalski, Z.

1997-01-01

Experimental data on nuclear collisions at high energies, mainly obtained from photographic emulsions, are considered from the point of view of the picture of the nuclear collision processes mechanisms prompted experimentally. In fact, the disintegration products of each nucleus involved in a nuclear collision, in its own rest-frame, are similar to that produced by the impact of a number of nucleons of velocity equal to that of the moving primary nucleus

Heavy-flavor production and medium properties in high-energy nuclear collisions. What next?

Energy Technology Data Exchange (ETDEWEB)

Aarts, G.; Allton, C. [Swansea University, Swansea (United Kingdom); Aichelin, J.; Gossiaux, P.B.; Nahrgang, M. [Universite de Nantes, SUBATECH, Ecole des Mines de Nantes, Nantes (France); Arnaldi, R.; Scomparin, E. [INFN, Sezione di Torino, Torino (Italy); Bass, S.A. [Duke University, Durham, NC (United States); Bedda, C.; Grelli, A.; Trzeciak, B.; Doremalen, L. van; Vermunt, L.; Vigolo, S. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); Brambilla, N. [Technische Universitaet Muenchen, Physik-Department and Excellence Cluster Universe, Garching (Germany); Technische Universitaet Muenchen, Institute for Advanced Study, Munich (Germany); Bratkovskaya, E. [GSI Helmholtzzentrum fuer Schwerionenforschung, Research Division and ExtreMe Matter Institute EMMI, Darmstadt (Germany); Frankfurt University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Braun-Munzinger, P. [GSI Helmholtzzentrum fuer Schwerionenforschung, Research Division and ExtreMe Matter Institute EMMI, Darmstadt (Germany); Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bruno, G.E. [Dipartimento di Fisica and INFN, Bari (Italy); European Organization for Nuclear Research, Geneva (Switzerland); Dahms, T. [Technische Universitaet Muenchen, Physik-Department and Excellence Cluster Universe, Garching (Germany); Das, S.K. [University of Catania, Catania (Italy); Dembinski, H.; Schmelling, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Djordjevic, M. [University of Belgrade, Institute of Physics, Belgrade (Serbia); Ferreiro, E. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Frawley, A. [Florida State University, Tallahassee, FL (United States); Granier de Cassagnac, R.; Jo, M.; Nguyen, M. [Ecole Polytechnique, Laboratoire Leprince-Ringuet, Palaiseau (France); He, M. [Nanjing University of Science and Technology, Department of Applied Physics, Nanjing (China); Horowitz, W.A. [University of Cape Town, Department of Physics, Rondebosch (South Africa); Innocenti, G.M. [Massachusetts Institute of Technology, Cambridge, MA (United States); Kaczmarek, O. [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan (China); University of Bielefeld, Bielefeld (Germany); Kuijer, P.G. [National Institute for Subatomic Physics, Amsterdam (Netherlands); Laine, M. [University of Bern, AEC, Institute for Theoretical Physics, Bern (Switzerland); Lombardo, M.P. [INFN - Laboratori Nazionali di Frascati, Frascati (Italy); Mischke, A. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); National Institute for Subatomic Physics, Amsterdam (Netherlands); Munhoz, M.G.; Suaide, A.A.P. [Universidade de Sao Paulo (USP), Sao Paulo (Brazil); Oliveira da Silva, A.C.; Zanoli, H.J.C. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); Universidade de Sao Paulo (USP), Sao Paulo (Brazil); Petreczky, P. [Brookhaven National Laboratory, Upton, NY (United States); Rothkopf, A. [Ruprecht-Karls-Universitaet Heidelberg, Institute for Theoretical Physics, Heidelberg (Germany); Song, T. [Frankfurt University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Stachel, J. [Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Tolos, L. [Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Institut de Ciencies de l' Espai (IEEC-CSIC), Bellaterra (Spain); Uras, A. [Domaine Scientifique de la Doua, Institute of Nuclear Physics, Villeurbanne Cedex (France); Xu, N. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Ye, Z. [University of Illinois, Chicago, IL (United States); Zhuang, P. [Tsinghua University, Beijng Shi (China)

2017-05-15

Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results from experiments and theoretical developments regarding open and hidden heavy-flavor dynamics have been debated at the Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, which was held in October 2016 in Leiden, The Netherlands. In this contribution, we summarize identified common understandings and developed strategies for the upcoming five years, which aim at achieving a profound knowledge of the dynamical properties of the quark-gluon plasma. (orig.)

A plausible picture of high-energy proton-nucleus collisions

International Nuclear Information System (INIS)

Kim, C.O.

1976-01-01

Results experimentally obtained from jets of E(p)=10-10 3 GeV in nuclear emulsion show that the target nucleus in proton-nucleus collisions seems to present ''limiting fragmentation''. In the same energy range, proton-nucleus collisions resemble closely proton-proton collisions and asymmetric shape of rapidities is only caused by the break-up products of heavy targets [fr

Electromagnetic radiation from nuclear collisions at RHIC energies

CERN Document Server

Turbide, Simon; Frodermann, Evan; Heinz, Ulrich

2008-01-01

The hot and dense strongly interacting matter created in collisions of heavy nuclei at RHIC energies is modeled with relativistic hydrodynamics, and the spectra of real and virtual photons produced at mid-rapidity in these events are calculated. Several different sources are considered, and their relative importance is compared. Specifically, we include jet fragmentation, jet-plasma interactions, the emission of radiation from the thermal medium and from primordial hard collisions. Our calculations consistently take into account jet energy loss, as evaluated in the AMY formalism. We obtain results for the spectra, the nuclear modification factor (R_AA), and the azimuthal anisotropy (v_2) that agree with the photon measurements performed by the PHENIX collaboration at RHIC.

HARD PARTON PHYSICS IN HIGH ENERGY NUCLEAR COLLISIONS. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP, VOLUME 17

Energy Technology Data Exchange (ETDEWEB)

CARROLL,J.

1999-09-10

The RIKEN-BNL center workshop on ''Hard parton physics in high energy nuclear collisions'' was held at BNL from March 1st-5th! 1999. The focus of the workshop was on hard probes of nucleus-nucleus collisions that will be measured at RHIC with the PHENIX and STAR detectors. There were about 45 speakers and over 70 registered participants at the workshop, with roughly a quarter of the speakers from overseas. About 60% of the talks were theory talks. A nice overview of theory for RHIC was provided by George Sterman. The theoretical talks were on a wide range of topics in QCD which can be classified under the following: (a) energy loss and the Landau-Pomeranchuk-Migdal effect; (b) minijet production and equilibration; (c) small x physics and initial conditions; (d) nuclear parton distributions and shadowing; (e) spin physics; (f) photon, di-lepton, and charm production; and (g) hadronization, and simulations of high pt physics in event generators. Several of the experimental talks discussed the capabilities of the PHENIX and STAR detectors at RHIC in measuring high pt particles in heavy ion collisions. In general, these talks were included in the relevant theory sessions. A session was set aside to discuss the spin program at RHIC with polarized proton beams. In addition, there were speakers from 08, HERA, the fixed target experiments at Fermilab, and the CERN fixed target Pb+Pb program, who provided additional perspective on a range of issues of relevance to RHIC; from jets at the Tevatron, to saturation of parton distributions at HERA, and recent puzzling data on direct photon production in fixed target experiments, among others.

Quarkonium production in high energy proton-proton and proton-nucleus collisions

International Nuclear Information System (INIS)

Conesa del Valle, Z.; Corcella, G.; Fleuret, F.; Ferreiro, E.G.; Kartvelishvili, V.; Kopeliovich, B.; Lansberg, J.P.; Lourenco, C.; Martinez, G.; Papadimitriou, V.; Satz, H.; Scomparin, E.; Ullrich, T.; Teryaev, O.; Vogt, R.; Wang, J.X.

2011-01-01

We present a brief overview of the most relevant current issues related to quarkonium production in high energy proton-proton and proton-nucleus collisions along with some perspectives. After reviewing recent experimental and theoretical results on quarkonium production in pp and pA collisions, we discuss the emerging field of polarisation studies. Afterwards, we report on issues related to heavy-quark production, both in pp and pA collisions, complemented by AA collisions. To put the work in broader perpectives, we emphasize the need for new observables to investigate the quarkonium production mechanisms and reiterate the qualities that make quarkonia a unique tool for many investigations in particle and nuclear physics.

Jet and Leading Hadron Production in High-energy Heavy-ion Collisions

International Nuclear Information System (INIS)

Wang, Xin-Nian

2005-01-01

Jet tomography has become a powerful tool for the study of properties of dense matter in high-energy heavy-ion collisions. I will discuss recent progresses in the phenomenological study of jet quenching, including momentum, colliding energy and nuclear size dependence of single hadron suppression, modification of dihadron correlations and the soft hadron distribution associated with a quenched jet

Statistical calculation of complete events in medium-energy nuclear collisions

International Nuclear Information System (INIS)

Randrup, J.

1984-01-01

Several heavy-ion accelerators throughout the world are presently able to deliver beams of heavy nuclei with kinetic energies in the range from tens to hundreds of MeV per nucleon, the so-called medium or intermediate energy range. At such energies a large number of final channels are open, each consisting of many nuclear fragments. The disassembly of the collision system is expected to be a very complicated process and a detailed dynamical description is beyond their present capability. However, by virtue of the complexity of the process, statistical considerations may be useful. A statistical description of the disassembly yields the least biased expectations about the outcome of a collision process and provides a meaningful reference against which more specific dynamical models, as well as the data, can be discussed. This lecture presents the essential tools for formulating a statistical model for the nuclear disassembly process. The authors consider the quick disassembly (explosion) of a hot nuclear system, a so-called source, into multifragment final states, which complete according to their statistical weight. First some useful notation is introduced. Then the expressions for exclusive and inclusive distributions are given and the factorization of an exclusive distribution into inclusive ones is carried out. In turn, the grand canonical approximation for one-fragment inclusive distributions is introduced. Finally, it is outlined how to generate a statistical sample of complete final states. On this basis, a model for statistical simulation of complete events in medium-energy nuclear collisions has been developed

High-energy hadron-hadron collisions

International Nuclear Information System (INIS)

Yang, C.N.

1983-01-01

While high energy collision experiments yield a wealth of complicated patterns, there are a few general and very striking features that stand out. Because of the universality of these features, and because of the dominating influence they have on high energy phenomena, it is the authors opinion that a physical picture of high energy collisions must address itself first of all to these features before going into specific details. In this short talk these general and striking features are stated and a physical picture developed in the last few years to specifically accommodate these features is described. The picture was originally discussed for elastic scattering. But it leads naturally, indeed inevitably as they shall discuss, to conclusions about inelastic processes, resulting in an idea called the hypothesis of limiting fragmentation

High energy hadron-nucleus collision

International Nuclear Information System (INIS)

Takagi, Fujio

1983-02-01

This is a lecture note concerning high energy hadron-nucleus collision. The lecture gives the inelastic total cross section and the Glanber approximate multiple scattering formula at first. The mechanism of nuclear spallation is described in a cylindrical image. The multiplicity, the one particle distribution and the time-space structure of particle production are discussed. Various models are presented. The attenuation of forward particles and the structure of hadrons are discussed for each model. The atomic number (A) dependence of the production of large transverse momentum particles and jet, and the A dependence of charged multiplicity are presented. The backward production of particles and many body correlation are discussed. Lepton pair production and the initial interaction of constituents, collective interaction, multi quark state and phase transition are described. (Kato, T.)

A perspective on relativistic nuclear collisions

International Nuclear Information System (INIS)

Glendenning, N.K.; Paris-11 Univ., 91 - Orsay

1979-01-01

A quasi-dynamical model for the disassembly of a high energy hadronic fireball has been developed. It is fund that some signals from the early high density stage are expected to survive the expansion stage. Indeed cetain signals, the π /N and K / N ratio at high kinetic energy, are so qualitatively unique in their dependance on target projectile mass, that we believe they will survive a refinement of the collision dynamics. Therefore a determination of the assymptotic form of the hadron spectrum can be made by studying nuclear collisions. The required energies are high (approximately 10 GeV/ nucleon in C.M.), but they are within the reach of present technology

Multiparticle correlations and intermittency in high energy collisions

CERN Document Server

Bozek, P

1992-01-01

In this work the analysis of the intermittency signal observed in high energy experi- ments is done using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e + e~ annihilation data. The language of the self-similar distribution func- tions, which is used in this work, is shown to be largely equivalent to the well known a-model. In the case of the ultrarelativistic nuclear collisions, where the Monte-Carlo simulations fail to reproduce the data, we argue that the observed intermittency pattern is a signal of some nonlinear effect beyond the simple superposition of nucleon-nucleon collisions. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of t...

Kaon production in intermediate-energy nuclear collisions

International Nuclear Information System (INIS)

Russkikh, V.N.; Ivanov, Yu.B.

1992-01-01

Production of positive kaons in nuclear collisions at intermediate energies (∝ 1-2 GeV/nucleon) is studied within the 3-dimensional fluid dynamics combined with the hadrochemical kinetics for strangeness production. Sensitivity of the kaon probe to a form of the nuclear equation of state is analyzed. The model reproduces total and differential cross sections of Ne+NaF→K + +X and Ne+Pb→K + +X reactions at E lab =2.1 GeV/nucleon, provided a soft equation of state is used. The pion-production data are also well described employing the same equation of state. Predictions are made for the current experiment on kaon production at the SIS accelerator. The obtained results are compared with the predictions of other models. (orig.)

Mean charged hadron multiplicities in high-energy collisions

Energy Technology Data Exchange (ETDEWEB)

Albini, E [Istituto di Matematica dell' Universita Cattolica di Brescia (Italy); Capiluppi, P; Giacomelli, G; Rossi, A M [Bologna Univ. (Italy). Istituto di Fisica

1976-03-01

A collection of mean charged hadron multiplicities per inelastic collision in various high-energy processes is presented. An extensive list of fits of as a function of energy is presented and discussed. As the energy increases the multiplicities for different collisions tend to a unique curve, independent of the type of colliding particles.

Introduction to the nuclear physics at very high energy

International Nuclear Information System (INIS)

Kodama, T.

1985-01-01

An introduction to the nuclear physics at very high energies on the basis of relativistic nucleus-nucleus, hadron-nucleus and hadron-hadron collisions is made. Some theoretical models used nowadays to explain the experimental data, such as Quantum Chromodynamics, String Model, etc... are presented. (L.C.) [pt

A high-energy nuclear database proposal

International Nuclear Information System (INIS)

Brown, D.A.; Vogt, R.; UC Davis, CA

2006-01-01

We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from the Bevalac, AGS and SPS to RHIC and LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems, and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, we propose periodically performing evaluations of the data and summarizing the results in topical reviews. (author)

Investigation of rare particle production in high energy nuclear collisions. Progress report, December 15, 1997--December 14, 1998

International Nuclear Information System (INIS)

Crawford, H.J.; Engelage, J.

1998-01-01

The program is an investigation of the hadronization process through experimental measurement of rare particle production in high energy nuclear interactions. These interactions provide an environment similar in energy density to the conditions in the Big Bang. The authors are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. They have completed the first physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. They have prototyped the STAR trigger and are in the process of fabricating its components and installing them in the STAR detector

High energy hadron-hadron collisions. Annual progress report

International Nuclear Information System (INIS)

Chou, T.T.

1979-03-01

Work on high energy hadron-hadron collisions in the geometrical model, performed under the DOE Contract No. EY-76-S-09-0946, is summarized. Specific items studied include the behavior of elastic hadron scatterings at super high energies and the existence of many dips, the computation of meson radii in the geometrical model, and the hadronic matter current effects in inelastic two-body collisions

Study of proton-nucleus collisions at high energies based on the hydrodynamical model

International Nuclear Information System (INIS)

Masuda, N.; Weiner, R.M.

1978-01-01

We study proton-nucleus collisions at high energies using the one-dimensional hydrodynamical model of Landau with special emphasis on the effect of the size of the target nucleus and of the magnitude of velocity of sound of excited hadronic matter. We convert a collision problem of a proton and a nucleus with a spherical shape into that of a proton and a one-dimensional nuclear tunnel whose length is determined from the average impact parameter. By extending the methods developed by Milekhin and Emelyanov, we obtain the solutions of the hydrodynamical equations of proton-nucleus collisions for arbitrary target tunnel length and arbitrary velocity of sound. The connection between these solutions and observable physical quantities is established as in the work of Cooper, Frye, and Schonberg. Extensive numerical analyses are made at E/sub lab/ = 200 GeV and for the velocity of sound u = 1/√3 of a relativistic ideal Bose gas and u = 1/(7.5)/sup 1/2/ of an interacting Bose gas. In order to compare proton-nucleus collisions with proton-proton collisions, all the analyses are made in the equal-velocity frame. We find the following results. (1) In comparing the number of secondary particles produced in p-A collisions N/sub p/A with those in p-p collisions N/sub p/p, while most of the excess of N/sub p/A over N/sub p/p is concentrated in the backward rapidity region, there exists also an increase of N/sub p/A with A in the forward rapidity region. This result is at variance with the predictions of the energy-flux-cascade model and of the coherent-production model. (2) The excess energies are contained exclusively in the backward region. We also find evidence for new phenomena in proton-nucleus collisions. (3) The existence of an asymmetry of average energies of secondary particles between forward and backward regions, in particular, >> for larger nuclear targets. Thus, energetic particles are predominantly produced in the backward region

Simulation of a Local Collision of SC Wall Using High Energy Absorbing Steel

Energy Technology Data Exchange (ETDEWEB)

Yoo, H. K.; Chung, C. H.; Park, J.; Lee, J. W. [Dankook University, Yongin (Korea, Republic of); Kim, S. Y. [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2011-05-15

Local damage evaluations for nuclear power plant(NPP) design are performed against turbine impact, tornado impact, airplane engine impact, etc., where turbine is a internal source of impact, whereas tornado and airplane engine are external sources of impact. The thickness of NPP wall structure is determined at initial design stage not to be penetrated by local impacts. This study investigated the local damage of NPP substructure against internal turbine impact. Simulation of local collisions of SC wall in NPP structure, which consists of two models: one using general steel and the other using high energy absorbing steel, were performed. The performance of SC wall using ductile high energy absorbing steel can be greatly improved on local collisions when compared with that of general steel

Simulation of a Local Collision of SC Wall Using High Energy Absorbing Steel

International Nuclear Information System (INIS)

Yoo, H. K.; Chung, C. H.; Park, J.; Lee, J. W.; Kim, S. Y.

2011-01-01

Local damage evaluations for nuclear power plant(NPP) design are performed against turbine impact, tornado impact, airplane engine impact, etc., where turbine is a internal source of impact, whereas tornado and airplane engine are external sources of impact. The thickness of NPP wall structure is determined at initial design stage not to be penetrated by local impacts. This study investigated the local damage of NPP substructure against internal turbine impact. Simulation of local collisions of SC wall in NPP structure, which consists of two models: one using general steel and the other using high energy absorbing steel, were performed. The performance of SC wall using ductile high energy absorbing steel can be greatly improved on local collisions when compared with that of general steel

Proposal for a High Energy Nuclear Database

International Nuclear Information System (INIS)

Brown, David A.; Vogt, Ramona

2005-01-01

We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from Bevalac and AGS to RHIC to CERN-LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems, and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, we propose periodically performing evaluations of the data and summarizing the results in topical reviews

Multiplicity distributions in high energy collisions

International Nuclear Information System (INIS)

Giovannini, A.; Lupia, S.; Ugoccioni, R.

1992-01-01

We discuss the important phases in the evolution of our understanding of multiplicity distributions in high energy collisions with particular emphasis to intermittent behavior and shoulder structure problem. (orig.)

Multiplicity distributions in high energy collisions

Energy Technology Data Exchange (ETDEWEB)

Giovannini, A.; Lupia, S.; Ugoccioni, R. (Dipt. di Fisica Teorica, Univ. Turin (Italy) INFN, Turin (Italy))

1992-03-01

We discuss the important phases in the evolution of our understanding of multiplicity distributions in high energy collisions with particular emphasis to intermittent behavior and shoulder structure problem. (orig.).

Mass distribution and multiple fragmentation events in high energy cluster-cluster collisions: evidence for a predicted phase transition

International Nuclear Information System (INIS)

Farizon, B.; Farizon, M.; Gaillard, M.J.; Genre, R.; Louc, S.; Martin, J.; Senn, G.; Scheier, P.; Maerk, T.D.

1996-09-01

Fragment size distributions including multiple fragmentation events have been measured for high energy H 25 + cluster ions (60 keV/amu) colliding with a neutral C 60 target. In contrast to earlier collision experiments with a helium target the present studies do not show a U-shaped fragment mass distribution, but a single power-law falloff with increasing fragment mass. This behaviour is similar to what is known for the intermediate regime in nuclear collision physics and thus confirms a recently predicted scaling from nuclear to molecular collisions

[Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions

International Nuclear Information System (INIS)

Loveland, W.D.

1991-08-01

The work described herein is part of a project involving the study of low energy ( 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of ''best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon 129 Xe with 197 Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon 12 C with 197 Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated

Probing the nuclear matter at high baryon and isospin density with heavy ion collisions

International Nuclear Information System (INIS)

Di Toro, M.; Colonna, M.; Ferini, G.

2010-01-01

Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. High Energy Collisions are studied in order to access nuclear matter properties at high density. Particular attention is devoted to the selection of observables sensitive to the poorly known symmetry energy at high baryon density, of large fundamental interest, even for the astrophysics implications. Using fully consistent covariant transport simulations built on effective field theories we are testing isospin observables ranging from nucleon/cluster emissions, collective flows (in particular the elliptic, squeeze out, part) and meson production. The possibility to shed light on the controversial neutron/proton effective mass splitting in asymmetric matter is also stressed. The "symmetry" repulsion at high baryon density will also lead to an "earlier" hadron-deconfinement transition in n-rich matter. The phase transition of hadronic to quark matter at high baryon and isospin density is analyzed. Nonlinear relativistic mean field models are used to describe hadronic matter, and the MIT bag model is adopted for quark matter. The boundaries of the mixed phase and the related critical points for symmetric and asymmetric matter are obtained. Isospin effects appear to be rather significant. The binodal transition line of the (T,ρ B ) diagram is lowered in a region accessible to heavy ion collisions in the energy range of the new planned FAIR/NICA facilities. Some observable effects of the mixed phase are suggested, in particular a neutron distillation mechanism. Theoretically a very important problem appears to be the suitable treatment of the isovector part of the interaction in effective QCD lagrangian approaches. (author)

(Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions)

Energy Technology Data Exchange (ETDEWEB)

Loveland, W.D.

1991-08-01

The work described herein is part of a project involving the study of low energy (< 10 MeV/A), intermediate energy (10--100 MeV/A) and relativistic (> 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon {sup 129}Xe with {sup 197}Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon {sup 12}C with {sup 197}Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated.

Effective-energy budget in multiparticle production in nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Mishra, Aditya Nath; Sahoo, Raghunath [Indian Institute of Technology Indore, Discipline of Physics, School of Basic Sciences, Indore (India); Sarkisyan, Edward K.G. [CERN, Department of Physics, Geneva 23 (Switzerland); The University of Texas at Arlington, Department of Physics, Arlington, TX (United States); Sakharov, Alexander S. [CERN, Department of Physics, Geneva 23 (Switzerland); Kyungpook National University, Department of Physics, Daegu (Korea, Republic of)

2014-11-15

The dependencies of charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity on the collision energy and on the number of nucleon participants, or centrality, measured in nucleus-nucleus collisions are studied in the energy range spanning a few GeV to a few TeV per nucleon. The approach in which the multiparticle production is driven by the dissipating effective energy of participants is introduced. This approach is based on the earlier proposed consideration, combining the constituent quark picture together with Landau relativistic hydrodynamics shown to interrelate the measurements from different types of collisions. Within this picture, the dependence on the number of participants in heavy-ion collisions are found to be well described in terms of the effective energy defined as a centrality-dependent fraction of the collision energy. For both variables under study, the effective-energy approach reveals a similarity in the energy dependence obtained for the most central collisions and centrality data in the entire available energy range. Predictions are made for the investigated dependencies for the forthcoming higher-energy measurements in heavy-ion collisions at the LHC. (orig.)

Effective-energy budget in multiparticle production in nuclear collisions

International Nuclear Information System (INIS)

Mishra, Aditya Nath; Sahoo, Raghunath; Sarkisyan, Edward K.G.; Sakharov, Alexander S.

2014-01-01

The dependencies of charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity on the collision energy and on the number of nucleon participants, or centrality, measured in nucleus-nucleus collisions are studied in the energy range spanning a few GeV to a few TeV per nucleon. The approach in which the multiparticle production is driven by the dissipating effective energy of participants is introduced. This approach is based on the earlier proposed consideration, combining the constituent quark picture together with Landau relativistic hydrodynamics shown to interrelate the measurements from different types of collisions. Within this picture, the dependence on the number of participants in heavy-ion collisions are found to be well described in terms of the effective energy defined as a centrality-dependent fraction of the collision energy. For both variables under study, the effective-energy approach reveals a similarity in the energy dependence obtained for the most central collisions and centrality data in the entire available energy range. Predictions are made for the investigated dependencies for the forthcoming higher-energy measurements in heavy-ion collisions at the LHC. (orig.)

Nuclear stopping power at high energies

International Nuclear Information System (INIS)

Date, S.; Gyulassy, M.; Sumiyoshi, H.

1985-03-01

Recent p + A → p + X data are analyzed within the context of the multi-chain and additive quark models. We deduce the average energy loss of a baryon as a function of distance traversed in nuclear matter. Consistency of the multi-chain model is checked by comparing the predictions for p + A → π +- + X with data. We discuss the space-time development of baryon stopping and show how longitudinal growth limits the energy deposition per unit length. Predictions are made for the proton spectra to be measured in nucleus-nucleus collisions at CERN and BNL. Finally, we conclude that the stopping domain for central collisions of heavy ions extends up to center of mass kinetic energies KEsub(em) asymptotically equals 3 +- 1 AGev. (author)

Proposal for a high-energy nuclear database

International Nuclear Information System (INIS)

Brown, D.A.; Vogt, R.

2006-01-01

We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from Bevalac, AGS and SPS to RHIC and LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems, and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, we propose periodically performing evaluations of the data and summarizing the results in topical reviews. (author)

Proposal for a High Energy Nuclear Database

International Nuclear Information System (INIS)

Brown, D A; Vogt, R

2005-01-01

The authors propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from Bevalac, AGS and SPS to RHIC and CERN-LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems, and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, they propose periodically performing evaluations of the data and summarizing the results in topical reviews

On the balance energy and nuclear dynamics in peripheral heavy-ion collisions

International Nuclear Information System (INIS)

Chugh, Rajiv; Puri, Rajeev K.

2010-01-01

We present here the system size dependence of balance energy for semi-central and peripheral collisions using quantum molecular dynamics model. For this study, the reactions of Ne 20 +Ne 20 , Ca 40 +Ca 40 , Ni 58 + Ni 58 , Nb 93 +Nb 93 , Xe 131 +Xe 131 , and Au 197 +Au 197 are simulated at different incident energies and impact parameters. A hard equation of state along with nucleon–nucleon cross-sections between 40 and 55 mb explains the data nicely. Interestingly, balance energy follows a power law ∝A τ for the mass dependence at all colliding geometries. The power factor τ is close to –1/3 in central collisions, whereas it is –2/3 for peripheral collisions suggesting stronger system size dependence at peripheral geometries. This also suggests that in the absence of momentum dependent interactions, Coulomb's interaction plays an exceedingly significant role. These results are further analyzed for nuclear dynamics at the balance point. (author)

Production of light fragments in hA collisions at high energies

International Nuclear Information System (INIS)

Braun, M.A.; Vechernin, V.V.

1988-12-01

Production of fast relativistic light fragments in hA collisions at high energies is considered. Direct coalescence of produced nucleons into fragments is shown to be the main mechanism for fragment production. The influence of the nuclear field is small and is not described by the well-known Butler-Pearson formulas. The coalescence coefficient strongly depends on the angle and on the behaviour of the fragment wave function at small internucleon distances. (author). 14 refs, 7 figs

Quark and Gluon Degrees of Freedom in High-Energy Heavy Ion Collisions

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J. [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States); RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)], E-mail: rjfries@comp.tamu.edu

2008-06-01

I discuss some recent progress in our understanding of high energy nuclear collisions. I will focus on two topics which I was lucky to co-pioneer in the recent past. One is recombination of quarks and its interpretation as a signal for deconfinement, the second is electromagnetic radiation from jets passing through a quark gluon plasma. This talk was given during the award ceremony for the 2007 IUPAP Young Scientist Award.

Pion production and fragmentation of nuclei in high energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

Oskarsson, A.

1983-01-01

In collisions between nuclei at high energies one can study the behaviour of nuclear matter under extreme conditions, regarding nuclear density and temperature. The Bevalac and the CERN SC beams have been used and nuclear emulsion and scintillation telescopes have measured the reaction products. Collisions at 50A-200A MeV and at 2A GeV have been investigated. Proton spectra from 12 C induced reactions at 85A MeV have been recorded for different targets. Energetic protons at large angles can be assumed to be emitted from a source moving with half the beam velocity and a temperature between 13 and 17 MeV, depending on the target. In collisions between nuclei, pions can be produced below 290A MeV due to the internal Fermi motion of the nucleons. Subthreshold pion production has been studied for 12 C induced reactions at 85A and 75A Mev. The cross-sections are consistent with a quasi-free nucleon-nucleon scattering picture, involving Fermi motion, Pauli blocking and pion reabsorption. 16 C induced reactions in emulsion have been studied at 75A, 175A and 2000A MeV. It is shown that the excitation of the parts of the nuclei which are not overlapping (the spectators) increases with the beam energy. The 16 O projectile frequently breaks up into multiple He fragments. These events are associated with large impact parameters. Central collisions with Ag, Br target at 50A-110A MeV have been analysed separately. It is shown that the momentum transfer to the target nucleus is limited to a value considerably lower than the full momentum transfer in a fusion reactions. Events are observed where there are numerous fragments with 3< Z<8. These multifragmentation events cannot be understood in a thermal approach. (author)

High energy factorization in nucleus-nucleus collisions, I

CERN Document Server

Gelis, François; Venugopalan, Raju

2008-01-01

We derive a high energy factorization theorem for inclusive gluon production in A+A collisions. Our factorized formula resums i) all order leading logarithms (g^2 \\ln(1/x_{1,2}))^n of the incoming partons momentum fractions, and ii) all contributions (g \\rho_{1,2})^n that are enhanced when the color charge densities in the two nuclei are of order of the inverse coupling-- \\rho_{1,2}\\sim g^{-1}. The resummed inclusive gluon spectrum can be expressed as a convolution of gauge invariant distributions W[\\rho_{1,2}] from each of the nuclei with the leading order gluon number operator. These distributions are shown to satisfy the JIMWLK equation describing the evolution of nuclear wavefunctions with rapidity. As a by-product, we demonstrate that the JIMWLK Hamiltonian can be derived entirely in terms of retarded light cone Green's functions without any ambiguities in their pole prescriptions. We comment on the implications of our results for understanding the Glasma produced at early times in A+A collisions at coll...

High-energy nuclear reaction mechanisms - fission, fragmentation and spallation

International Nuclear Information System (INIS)

Kaufman, S.B.

1987-01-01

Measurements of the correlations in kinetic energy, mass, charge, and angle of coincident fragments formed in high-energy nuclear reactions have helped to characterize the processes of fission, fragmentation and spallation. For example, fission or fission-like two-body breakup mechanisms result in a strong angular correlation between two heavy fragments; in addition, the momentum transfer in the reaction can be deduced from the correlation. Another example is the multiplicity of light charged particles associated with a given heavy fragment, which is a measure of the violence of the collision, thus distinguishing between central and peripheral collisions. A summary of what has been learned about these processes from such studies will be given, along with some suggestions for further experiments

Heavy-ion peripheral collisions in the Fermi energy domain: fragmentation processes or dissipative collisions

International Nuclear Information System (INIS)

Borderie, B.; Rivet, M.F.; Tassan-Got, L.

1990-01-01

For several years a new field in nuclear physics has been opened by the opportunity to accelerate heavy ions through an energy domain including the Fermi energy of nucleons. This new domain has to be seen as a link between dissipative processes observed at low energies, dominated by mean field considerations, and high energy collisions for which nucleon-nucleon collisions play an important role. This paper reviews our present knowledge on peripheral collisions. A reminder of contiguous energy domains is done as well as their extension in the new field. Specific calculations are also presented. Finally a wide comparison between experiments and calculations is performed. A fast dissipative stage proves to be responsible for the dominant mechanisms involved, at least when the incident energy is lower than 50 MeV/nucleon

{gamma}-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

Energy Technology Data Exchange (ETDEWEB)

Korotkikh, V.L.; Chikin, K.A. [Scobeltsyn Institute of Nuclear Physics, Moscow State University (Russian Federation)

2002-06-01

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant {gamma}-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions. (orig.)

γ-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

Science.gov (United States)

Korotkikh, V. L.; Chikin, K. A.

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant γ-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions.

γ-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

International Nuclear Information System (INIS)

Korotkikh, V.L.; Chikin, K.A.

2002-01-01

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant γ-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions. (orig.)

Thermal Bremsstrahlung probing nuclear multifragmentation in nucleus-nucleus collisions around the Fermi energy

International Nuclear Information System (INIS)

D'Enterria, D.G.

2000-05-01

The thermodynamical properties of nuclear matter at moderate temperatures and densities, in the vicinity of the predicted nuclear liquid-gas phase transition, are studied using as experimental probe the hard-photons (E γ > 30 MeV) emitted in nucleus-nucleus collisions. Photon and charged-particle production in four different heavy-ion reactions (Ar 36 + Au 197 , Ag 107 , Ni 58 , C 12 at 60 A*MeV) is measured exclusively and inclusively coupling the TAPS photon spectrometer with two charged-particle and intermediate-mass-fragment detectors covering nearly 4π. We confirm that Bremsstrahlung emission in first-chance (off-equilibrium) proton-neutron collisions (pnγ) is the dominant origin of hard photons. We also firmly establish the existence of a thermal radiation component emitted in second-chance proton-neutron collisions. This thermal Bremsstrahlung emission takes place in semi-central and central nucleus-nucleus reactions involving heavy targets. We exploit this observation i) to demonstrate that thermal equilibrium is reached during the reaction, ii) to establish a new thermometer of nuclear matter based on Bremsstrahlung photons, iii) to derive the thermodynamical properties of the excited nuclear sources and, in particular, to establish a 'caloric curve' (temperature versus excitation energy), and iv) to assess the time-scales of the nuclear break-up process. (author)

Evidence for radial flow of thermal dileptons in high-energy nuclear collisions

CERN Document Server

Arnaldi, R; Castor, J; Chaurand, B; Cicalò, C; Colla, A; Cortese, P; Damjanovic, S; David, A; De Falco, A; Devaux, A; Ducroux, L; Enyo, H; Fargeix, J; Ferretti, A; Floris, M; Förster, A; Force, P; Guettet, N; Guichard, A; Gulkanian, H R; Heuser, J M; Keil, M; Kluberg, L; Lourenço, C; Lozano, J; Manso, F; Martins, P; Masoni, A; Neves, A; Ohnishi, H; Oppedisano, C; Parracho, P; Pillot, P; Poghosyan, T; Puddu, G; Radermacher, E; Ramalhete, P; Rosinsky, P; Scomparin, E; Seixas, J; Serci, S; Shahoyan, R; Sonderegger, P; Specht, H J; Tieulent, R; Usai, G; Veenhof, R; Wöhri, H K

2008-01-01

The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158 AGeV In-In collisions. An excess of pairs above the known meson decays has been reported before. We now present precision results on the associated transverse momentum spectra. The slope parameter Teff extracted from the spectra rises with dimuon mass up to the rho, followed by a sudden decline above. While the initial rise is consistent with the expectations for radial flow of a hadronic decay source, the decline signals a transition to an emission source with much smaller flow. This may well represent the first direct evidence for thermal radiation of partonic origin in nuclear collisions.

Hipse: an event generator for nuclear collisions at intermediate energies

International Nuclear Information System (INIS)

Lacroix, D.; Van Lauwe, A.; Durand, D.

2003-11-01

An event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedicated to the description of nuclear collisions in the intermediate energy range is presented. Based on the sudden approximation and on geometrical hypothesis, it can conveniently simulate heavy-ion interactions at all impact parameters and thus can constitute a valuable tool for the understanding of processes such as neck emission or multifragmentation in peripheral or/and central collisions. After a detailed description of the ingredients of the model, first comparisons with experimental data collected by the INDRA collaboration are shown. Special emphasis is put on the kinematical characteristics of fragments and light particles observed at all impact parameters for Xe+Sn reactions at 25 and 50 MeV/u and Ni + Ni at 82 MeV/u. (authors)

Calculation of Direct photon production in nuclear collisions

CERN Document Server

Cepila, J

2012-01-01

Prompt photons produced in a hard reaction are not expected to be accompanied by any final state interaction, either energy loss or absorption and one should not expect any nuclear effects at high pT . However, data from the PHENIX experiment indicates large-pT suppression in d+Au and central Au+Au collisions that cannot be accompanied by coherent phenomena. We propose a mechanism based on the energy sharing problem at large pT near the kinematic limit that is induced by multiple initial state interactions and that improves the agreement of calculations with PHENIX data. We calculate inclusive direct photon production cross sections in p+p collisions at RHIC and LHC energies using the color dipole approach without any additional parameter. Our predictions are in good agreement with the available data. Within the same framework, we calculate direct photon production rates in d+A and A+A collisions at RHIC energy. We also provide predictions for the same process in p+A collisions at LHC energy. Since the kinema...

Event-by-Event Simulations of Early Gluon Fields in High Energy Nuclear Collisions

Science.gov (United States)

Nickel, Matthew; Rose, Steven; Fries, Rainer

2017-09-01

Collisions of heavy ions are carried out at ultra relativistic speeds at the Relativistic Heavy Ion Collider and the Large Hadron Collider to create Quark Gluon Plasma. The earliest stages of such collisions are dominated by the dynamics of classical gluon fields. The McLerran-Venugopalan (MV) model of color glass condensate provides a model for this process. Previous research has provided an analytic solution for event averaged observables in the MV model. Using the High Performance Research Computing Center (HPRC) at Texas A&M, we have developed a C++ code to explicitly calculate the initial gluon fields and energy momentum tensor event by event using the analytic recursive solution. The code has been tested against previously known analytic results up to fourth order. We have also have been able to test the convergence of the recursive solution at high orders in time and studied the time evolution of color glass condensate.

Numerical analysis of energy density and particle density in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Fu Yuanyong; Lu Zhongdao

2004-01-01

Energy density and particle density in high energy heavy-ion collisions are calculated with infinite series expansion method and Gauss-Laguerre formulas in numerical integration separately, and the results of these two methods are compared, the higher terms and linear terms in series expansion are also compared. The results show that Gauss-Laguerre formulas is a good method in calculations of high energy heavy-ion collisions. (author)

Out-of-equilibrium phenomena in high energy nuclear collisions

CERN Document Server

Serreau, J

2001-01-01

In the first part we study the possibility that a Disoriented Chiral Condensate (DCC) forms when hot hadronic matter is quenched, using the linear sigma model. We formulate an original sampling strategy for the initial field configuration in order to get an estimate of the probability that a potentially observable coherent pion field appears in a heavy-ion collision. We obtain a probability of the order of 1/1000 at CERN SPS energies. Next, we study the correlation between isospin orientations of the distinct modes of the pion field emerging after a quench. We show that this correlation is absent: the distinct modes behave as distinct DCCs. This contradicts the common belief that the state produced in the simplest form of the quench scenario - with a fully thermalized initial state - is identical to the originally proposed DCC. In the second part, we investigate the role of elastic scatterings in the process of kinetic equilibration of gluons produced in the very early times of the collision. We compare the t...

The energy overcompensating disintegrations of residual target nuclei damaged in hadron-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1995-01-01

Massive target nuclei damaged in hadron-nucleus collisions at high energies are used to disintegrate into nuclear fragments. In many cases such breakup is egzoergic - some portion of nuclear energy is released; this portion should be overcompensating the energy used for the nuclear damage, in some cases. 30 refs

Proton multiplicity distributions in high-energy hadron-nuclei collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1979-01-01

The fast proton emission process is analyzed in high-energy hadron-nuclei collisions. The formula describing the proton multiplicity distributions is derived. It describes well enough the proton multiplicity distribution of pion-nuclei and proton-nuclei collisions at 200 and 400 GeV

Origin of the finite nuclear spin and its effect in intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Zhang Guoqiang; Cao Xiguang; Fu Yao

2012-01-01

The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC). The spin of maximal projectile-like fragment is found to depend strongly on impact parameter of a reaction system,while it relates weakly to the collision violence. Some interesting multi-fragmentation phenomena related to the spin are shown. We also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC. (authors)

Rapidity and multiplicity correlations in high energy hadronic collisions

International Nuclear Information System (INIS)

Heiselberg, H.

1993-01-01

Rapidity and multiplicity correlations of particle production in high energy hadronic collisions are studied. A simple model including short range correlations in rapidity due to clustering and long range correlations due to energy conservation is able to describe the two-body correlation functions well hadron-nucleon collisions around lab energies of 250 GeV. In this model fractional moments are calculated and compared to data. The strong rise of the factorial moments in rapidity intervals by size δy∝1 can be explained by long and short range correlation alone whereas the factorial moments approach a constant value at very small δy due to lack of correlations also in agreement with experiment. There is therefore no need for introducing intermittency in the particle production in hadronic collisions at these energies. (orig.)

Estimation of nuclear destruction in high energy nucleus-nucleus interactions

International Nuclear Information System (INIS)

Uzhinskij, V.V.

1995-01-01

It is assumed that: 1) a projectile particle invokes into target nucleus a cascade of quark-gluon exchanges; 2) the nucleons involved in the cascade are ejected from the nucleus which leads to the nuclear destruction. On these bases a simple model to estimate the nuclear destruction at the fast stage of the interaction is proposed. The allowed region of the model parameters is determined at the proton-emulsion high-energy interaction data analysis: an analysis of gold interactions with nuclei at an energy of 600 MeV/nucleon fixes the parameter values. The distributions on the energy in zero degree calorimeter (T ZDC ) in the interactions of Si+Al, Cu, Pb (14 GeV/nucleon) and Au+Au (10 GeV/nucleon) calculated in the framework of the model and in the cascade-evaporation model (CEM) are presented. The proposed model describes the nuclear destruction at intermediate and high energies better than CEM does. The estimation of the average values of impact parameter and the number of intra-nuclear collisions for Au+Au interactions in the events with different T ZDC is given. 34 refs., 11 figs

Pion production in relativistic collisions of nuclear drops

International Nuclear Information System (INIS)

Alonso, C.T.; Wilson, J.R.; McAbee, T.L.; Zingman, J.A.

1988-09-01

In a continuation of the long-standing effort of the nuclear physics community to model atomic nuclei as droplets of a specialized nuclear fluid, we have developed a hydrodynamic model for simulating the collisions of heavy nuclei at relativistic speeds. Our model couples ideal relativistic hydrodynamics with a new Monte Carlo treatment of dynamic pion production and tracking. The collective flow for low-energy (200 MeV/N) collisions predicted by this model compares favorably with results from earlier hydrodynamic calculations which used quite different numerical techniques. Our pion predictions at these lower energies appear to differ, however, from the experimental data on pion multiplicities. In this case of ultra-relativistic (200 GeV/N) collisions, our hydrodynamic model has produced baryonic matter distributions which are in reasonable agreement with recent experimental data. These results may shed some light on the sensitivity of relativistic collision data to the nuclear equation of state. 20 refs., 12 figs

High-energy limit of collision-induced false vacuum decay

Energy Technology Data Exchange (ETDEWEB)

Demidov, Sergei; Levkov, Dmitry [Institute for Nuclear Research of the Russian Academy of Sciences,60-th October Anniversary Prospect 7a, Moscow, 117312 (Russian Federation)

2015-06-17

We develop a consistent semiclassical description of field-theoretic collision-induced tunneling at arbitrary high collision energies. As a playground we consider a (1+1)-dimensional false vacuum decay initiated by a collision of N particles at energy E, paying special attention to the realistic case of N=2 particles. We demonstrate that the cross section of this process is exponentially suppressed at all energies. Moreover, the respective suppressesion exponent F{sub N}(E) exhibits a specific behavior which is significant for our semiclassical method and assumed to be general: it decreases with energy, reaches absolute minimum F=F{sub min}(N) at a certain threshold energy E=E{sub rt}(N), and stays constant at higher energies. We show that the minimal suppression F{sub min}(N) and threshold energy can be evaluated using a special class of semiclassical solutions which describe exponentially suppressed transitions but nevertheless evolve in real time. Importantly, we argue that the cross section at energies above E{sub rt}(N) is computed perturbatively in the background of the latter solutions, and the terms of this perturbative expansion stay bounded in the infinite-energy limit. Transitions in the high-energy regime proceed via emission of many soft quanta with total energy E{sub rt}; the energy excess E−E{sub rt} remains in the colliding particles till the end of the process.

Inclusive spectra of mesons with large transverse momenta in proton-nuclear collisions at high energies

International Nuclear Information System (INIS)

Lykasov, G.I.; Sherkhonov, B.Kh.

1982-01-01

Basing on the proposed earlier quark model of hadron-nucleus processes with large transverse momenta psub(perpendicular) the spectra of π +- , K +- meson production with large psub(perpendicular) in proton-nucleus collisions at high energies are calculated. The performed comparison of their dependence of the nucleus-target atomic number A with experimental data shows a good agreement. Theoretical and experimental ratios of inclusive spectra of K +- and π +- mesons in the are compared. Results of calculations show a rather good description of experimental data on large psub(perpendicular) meson production at high energies

Fluctuations in high-energy particle collisions

International Nuclear Information System (INIS)

Gronqvist, Hanna

2016-01-01

We study fluctuations that are omnipresent in high-energy particle collisions. These fluctuations can be either of either classical or quantum origin and we will study both. Firstly, we consider the type of quantum fluctuations that arise in proton-proton collisions. These are computable perturbatively in quantum field theory and we will focus on a specific class of diagrams in this set-up. Secondly, we will consider the fluctuations that are present in collisions between nuclei that can be heavier than protons. These are the quantum laws of nature that describe the positions of nucleons within a nucleus, but also the hydrodynamic fluctuations of classical, thermal origin that affect the evolution of the medium produced in heavy-ion collisions. The fluctuations arising in proton-proton collisions can be computed analytically up to a certain order in perturbative quantum field theory. We will focus on one-loop diagrams of a fixed topology. Loop diagrams give rise to integrals that typically are hard to evaluate. We show how modern mathematical methods can be used to ease their computation. We will study the relations among unitarity cuts of a diagram, the discontinuity across the corresponding branch cut and the coproduct. We show how the original integral corresponding to a given diagram can be reconstructed from the information contained in the coproduct. We expect that these methods can be applied to solve more complicated topologies and help in the computation of new amplitudes in the future. Finally, we study the two types of fluctuations arising in heavy-ion collisions. These are related either to the initial state or the intermediate state of matter produced in such collisions. The initial state fluctuations are experimentally observed to give rise to non-Gaussianities in the final-state spectra. We show how these non-Gaussianities can be explained by the random position and interaction energy of 'sources' in the colliding nuclei. Furthermore, we

Inclusive cross sections in AA collisions at high energies

International Nuclear Information System (INIS)

Braun, M.A.

1988-01-01

Inclusive cross sections in AA collisions at high energies are considered in the Glauber multiple scattering theory taking into account many-nucleon collisions. Correspondence is found between the AA amplitude and the effective action of the two-dimensional quantum field theory with exponential interaction. The tree and one-loop contributions are calculated in this formalism. The rules are derived, which relate the absorption part of the AA-collision amplitudes associated with various inclusive cross sections to the absorption parts of NN amplitudes. These rules generalize the well-known Agranowsky-Gribov-Kanchelli rules for hh and hA collisions. Formulas are written for single and double inclusive cross sections in AA collisions

High baryon density from relativistic heavy ion collisions

Energy Technology Data Exchange (ETDEWEB)

Pang, Y.; Kahana, S.H. [Brookhaven National Lab., Upton, NY (United States); Schlagel, T.J. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States)

1993-10-01

A quantitative model, based on hadronic physics, is developed and applied to heavy ion collisions at BNL-AGS energies. This model is in excellent agreement with observed particle spectra in heavy ion collisions using Si beams, where baryon densities of three and four times the normal nuclear matter density ({rho}{sub 0}) are reached. For Au on Au collisions, the authors predict the formation of matter at very high densities (up to 10 {rho}{sub 0}).

Dynamical and statistical aspects of intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Knoll, J.

1987-01-01

The lectures presented deal with three different topics relevant for the discussion of nuclear collisions at medium to high energies. The first lecture concerns a subject of general interest, the description of statistical systems and their dynamics by the concept of missing information. If presents an excellent scope to formulate statistical theories in such a way that they carefully keep track of the known (relevant) information while maximizing the ignorance about the irrelevant, unknown information. The last two lectures deal with quite actual questions of intermediate energy heavy-ion collisions. These are the multi-fragmentation dynamics of highly excited nuclear systems, and the so called subthreshold particle production. All three subjects are self-contained, and can be read without the knowledge about the other ones. (orig.)

Matter in extremis: Ultrarelativistic nuclear collisions at RHIC

Energy Technology Data Exchange (ETDEWEB)

Jacobs, Peter; Wang, Xin-Nian

2004-08-20

We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at {radical}s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state.

Matter in extremis: Ultrarelativistic nuclear collisions at RHIC

International Nuclear Information System (INIS)

Jacobs, Peter; Wang, Xin-Nian

2004-01-01

We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at √s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state

Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions

CERN Document Server

Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Espinoza Beltran, Lucina Gabriela; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blair, Justin Thomas; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Bonora, Matthias; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botta, Elena; Bourjau, Christian; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Cabala, Jan; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Cerkala, Jakub; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crkovska, Jana; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Derradi De Souza, Rafael; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Di Ruzza, Benedetto; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Drozhzhova, Tatiana; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erdemir, Irem; Erhardt, Filip; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Francisco, Audrey; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gajdosova, Katarina; Gallio, Mauro; Duarte Galvan, Carlos; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Garg, Kunal; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; Germain, Marie; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Sanchez Gonzalez, Andres; Gonzalez, Victor; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Grachov, Oleg Anatolievich; Graczykowski, Lukasz Kamil; Graham, Katie Leanne; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Gronefeld, Julius Maximilian; Grosse-Oetringhaus, Jan Fiete; Grosso, Raffaele; Gruber, Lukas; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hamon, Julien Charles; Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Hellbar, Ernst; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Florian; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Hughes, Charles; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Incani, Elisa; Ippolitov, Mikhail; Irfan, Muhammad; Isakov, Vladimir; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacak, Barbara; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Khatun, Anisa; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Jiyoung; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kumar, Ajay; Kumar, Jitendra; Kumar, Lokesh; Kumar, Shyam; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lapidus, Kirill; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Seongjoo; Lehas, Fatiha; Lehner, Sebastian; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Lupi, Matteo; Lutz, Tyler Harrison; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzilli, Marianna; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Melikyan, Yuri; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Mhlanga, Sibaliso; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Mishra, Tribeni; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Munning, Konstantin; Munzer, Robert Helmut; Murakami, Hikari; Murray, Sean; Musa, Luciano; Musinsky, Jan; Naik, Bharati; Nair, Rahul; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Ferreira Natal Da Luz, Pedro Hugo; Nattrass, Christine; Rosado Navarro, Sebastian; Nayak, Kishora; Nayak, Ranjit; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Negrao De Oliveira, Renato Aparecido; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Cabanillas Noris, Juan Carlos; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Orava, Risto; Oravec, Matej; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Davide; Pagano, Paola; Paic, Guy; Pal, Susanta Kumar; Palni, Prabhakar; Pan, Jinjin; Pandey, Ashutosh Kumar; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Pei, Hua; Peitzmann, Thomas; Peng, Xinye; Pereira Da Costa, Hugo Denis Antonio; Peresunko, Dmitry Yurevich; Perez Lezama, Edgar; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Ozelin De Lima Pimentel, Lais; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Poppenborg, Hendrik; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Rami, Fouad; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Ravasenga, Ivan; Read, Kenneth Francis; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Saarinen, Sampo; Sadhu, Samrangy; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sarkar, Debojit; Sarkar, Nachiketa; Sarma, Pranjal; Scapparone, Eugenio; Scarlassara, Fernando; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schmidt, Martin; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Sefcik, Michal; Seger, Janet Elizabeth; Sekiguchi, Yuko; Sekihata, Daiki; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Senyukov, Serhiy; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Mona; Sharma, Monika; Sharma, Natasha; Sheikh, Ashik Ikbal; Shigaki, Kenta; Shou, Qiye; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singhal, Vikas; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Sozzi, Federica; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Stachel, Johanna; Stan, Ionel; Stankus, Paul; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Suljic, Miljenko; Sultanov, Rishat; Sumbera, Michal; Sumowidagdo, Suharyo; Swain, Sagarika; Szabo, Alexander; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Tabassam, Uzma; Takahashi, Jun; Tambave, Ganesh Jagannath; Tanaka, Naoto; Tarhini, Mohamad; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thakur, Dhananjaya; Thomas, Deepa; Tieulent, Raphael Noel; Tikhonov, Anatoly; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trombetta, Giuseppe; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vala, Martin; Valencia Palomo, Lizardo; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vazquez Doce, Oton; Vechernin, Vladimir; Veen, Annelies Marianne; Velure, Arild; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Vickovic, Linda; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Villatoro Tello, Abraham; Vinogradov, Alexander; Vinogradov, Leonid; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Watanabe, Daisuke; Watanabe, Yosuke; Weber, Michael; Weber, Steffen Georg; Weiser, Dennis Franz; Wessels, Johannes Peter; Westerhoff, Uwe; Whitehead, Andile Mothegi; Wiechula, Jens; Wikne, Jon; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Willems, Guido Alexander; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yalcin, Serpil; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yoon, Jin Hee; Yurchenko, Volodymyr; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

2017-01-01

At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark–gluon plasma (QGP). Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions, is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions, but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton–proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The me...

b-jet tagged nuclear modification factors in heavy ion collisions with CMS

CERN Document Server

Jung, Kurt

2014-01-01

The energy loss of jets in heavy-ion collisions is expected to depend on the flavor of the fragmenting parton. Thus, measurements of jet quenching as a function of flavor place powerful constraints on the thermodynamical and transport properties of the hot and dense medium. Measurements of the nuclear modification factors of the heavy-flavor-tagged jets in both PbPb and pPb collisions can quantify such energy loss effects. Specifically, pPb measurements provide crucial insights into the behavior of the cold nuclear matter effect, which is required to fully understand the hot and dense medium effects on jets in PbPb collisions. In this talk, we present the b-jet spectra and the first measurement of the nuclear modification factors as a function of transverse momentum and pseudorapidity, using the high statistics pp, pPb and PbPb data taken in 2011 and 2013.

Microscopic descriptions of high-energy heavy-ion collisions

International Nuclear Information System (INIS)

Bodmer, A.R.

1977-01-01

The essentials of the equation-of-motion (EOM) approach are given and some of its significant and interesting results are described. A framework for the theoretical description of high-energy heavy-ion (HE-HI) collisions is presented; specifically included are a critical assessment of various approaches--EOM calculations, Boltzmann equations/cascade calculations, and hydrodynamics--their relationships and their respective domains of applicability, if any, to HE-HI collisions. 11 figures, 3 tables

Transverse Characteristics of Hadron Production in Elementary and Nuclear Collisions at the CERN SPS Energies

CERN Document Server

AUTHOR|(CDS)2076476; Bialkowska, H

2004-01-01

A comprehensive study of transverse phenomena at CERN-SPS energies has been performed using data collected by the NA49 experiment. Results on p, p, pi+ and pi- production in elementary hadronic interactions (p + p, pi+ +p and pi- + p) as well as in nuclear collisions (centrality-defined p + Pb, C + C, Si + Si And Pb + Pb) are presented. The dependence of transverse momentum spectra, and in particular the - xF correlations, on particle species, collision energy, size and structure of the colliding objects has been investigated. Particle composition, in terms of the nuclear modification factors RpA (pT) for different xF regions – and particle ratios, has been also studied. The whole set of experimental data puts strong constraints on theoretical models aiming at the description of hadron production in the studied reactions.

Angular distributions of nucleons emitted in high energy hadron-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1983-01-01

Angular distributions of ''fast'' protons, of kinetic energy from about 20 to about 400 MeV, emitted in pion-xenon nucleus collisions at 3.5 GeV/c momentum were studied in two groups of events - when particles are produced and when particle production does not occur. The distributions are practically the same in both the groups of events and in subgroups of events with various multiplicities of emitted protons. Comparison of angular distributions of protons emitted in pion-xenon nucleus collisions at 3.5 GeV/c momentum with corresponding angular distributions of protons emitted in proton-emulsion collisions at 300-400 GeV/c momentum is performed. Results obtained allow to conclude that average value of the nucleon emission angle and the nucleon angular distributions do not depend practically on the nuclear matter layer thickness the incident hadron collided with. Fast nucleons emitted from the target nucleus seem did not interact inside the parent nucleus. Fast nucleon angular distributions do not depend on the energy of incident hadron, they are the same for pion-nucleus and for proton-nucleus collisions as well

Physics of Nuclear Collisions at High Energy

Energy Technology Data Exchange (ETDEWEB)

Hwa, Rudolph C. [Univ. of Oregon, Eugene, OR (United States)

2012-05-01

A wide range of problems has been investigated in the research program during the period of this grant. Although the major effort has been in the subject of heavy-ion collisions, we have also studied problems in biological and other physical systems. The method of analysis used in reducing complex data in multiparticle production to simple descriptions can also be applied to the study of complex systems of very different nature. Phase transition is an important phenomenon in many areas of physics, and for heavy-ion collisions we study the fluctuations of multiplicities at the critical point. Human brain activities as revealed in EEG also involve fluctuations in time series, and we have found that our experience enables us to find the appropriate quantification of the fluctuations in ways that can differentiate stroke and normal subjects. The main topic that characterizes the research at Oregon in heavy-ion collisions is the recombination model for the treatment of the hadronization process. We have avoided the hydrodynamical model partly because there is already a large community engaged in it, but more significantly we have found the assumption of rapid thermalization unconvincing. Recent results in studying LHC physics lead us to provide more evidence that shower partons are very important even at low p_T, but are ignored by hydro. It is not easy to work in an environment where the conventional wisdom regards our approach as being incorrect because it does not adhere to the standard paradigm. But that is just what a vibrant research community needs: unconventional approach may find evidences that can challenge the orthodoxy. An example is the usual belief that elliptic flow in fluid dynamics gives rise to azimuthal anisotropy. We claim that it is only sufficient but not necessary. With more data from LHC and more independent thinkers working on the subject what is sufficient as a theory may turn out to be incorrect in reality. Another area of investigation that

Studies of Fluctuation Processes in Nuclear Collisions

Energy Technology Data Exchange (ETDEWEB)

Ayik, Sakir [Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Physics

2016-04-14

The standard one-body transport approaches have been extensively applied to investigate heavy-ion collision dynamics at low and intermediate energies. At low energies the approach is the mean-field description of the time-dependent Hartree-Fock (TDHF) theory. At intermediate energies the approach is extended by including a collision term, and its application has been carried out mostly in the semi-classical framework of the Boltzmann-Uhling-Uhlenbeck (BUU) model. The standard transport models provide a good understanding of the average properties of the collision dynamics in terms of the effective interactions in both low and intermediate energies. However, the standard models are inadequate for describing the fluctuation dynamics of collective motion at low energies and disassembling of the nuclear system into fragments at intermediate energies resulting from the growth of density fluctuations in the spinodal region. Our tasks have been to improve the standard transport approaches by incorporating fluctuation mechanisms into the description. There are mainly two different mechanisms for fluctuations: (i) Collisional fluctuations generated by binary nucleon collisions, which provide the dominant mechanism at intermediate energies, and (ii) One-body mechanism or mean-field fluctuations, which is the dominant mechanism at low energies. In the first part of our project, the PI extended the standard transport model at intermediate energies by incorporating collisional mechanism according to the “Generalized Langevin Description” of Mori formalism. The PI and his collaborators carried out a number of applications for describing dynamical mechanism of nuclear multi fragmentations, and nuclear collective response in the semi-classical framework of the approach, which is known as the Boltzmann-Langevin model. In the second part of the project, we considered dynamical description at low energies. Because of the effective Pauli blocking, the collisional dissipation and

High Energy Nuclear Database: A Testbed for Nuclear Data Information Technology

International Nuclear Information System (INIS)

Brown, D A; Vogt, R; Beck, B; Pruet, J

2007-01-01

We describe the development of an on-line high-energy heavy-ion experimental database. When completed, the database will be searchable and cross-indexed with relevant publications, including published detector descriptions. While this effort is relatively new, it will eventually contain all published data from older heavy-ion programs as well as published data from current and future facilities. These data include all measured observables in proton-proton, proton-nucleus and nucleus-nucleus collisions. Once in general use, this database will have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models for a broad range of experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion, target and source development for upcoming facilities such as the International Linear Collider and homeland security. This database is part of a larger proposal that includes the production of periodic data evaluations and topical reviews. These reviews would provide an alternative and impartial mechanism to resolve discrepancies between published data from rival experiments and between theory and experiment. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This project serves as a testbed for the further development of an object-oriented nuclear data format and database system. By using ''off-the-shelf'' software tools and techniques, the system is simple, robust, and extensible. Eventually we envision a ''Grand Unified Nuclear Format'' encapsulating data types used in the ENSDF, ENDF/B, EXFOR, NSR and other formats, including processed data formats

Collective phenomena in non-central nuclear collisions

International Nuclear Information System (INIS)

Voloshin, Sergei A.; Poskanzer, Arthur M.; Snellings, Raimond

2008-01-01

Recent developments in the field of anisotropic flow in nuclear collision are reviewed. The results from the top AGS energy to the top RHIC energy are discussed with emphasis on techniques, interpretation, and uncertainties in the measurements

Collective phenomena in non-central nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Voloshin, Sergei A.; Poskanzer, Arthur M.; Snellings, Raimond

2008-10-20

Recent developments in the field of anisotropic flow in nuclear collision are reviewed. The results from the top AGS energy to the top RHIC energy are discussed with emphasis on techniques, interpretation, and uncertainties in the measurements.

Hadronic energy spectra from nuclear collisions: Effects from collective transverse flow and the phase transition to quark matter

International Nuclear Information System (INIS)

Heinz, U.

1988-11-01

I give an overview of the processes determining the shape of energy spectra of hadrons emitted in relativistic nuclear collisions, and discuss how one can extract from them information on the presence of collective transverse flow and on the transition to quark-gluon matter in such collisions. 6 refs., 3 figs

High density matter in AGS, SPS and RHIC collisions. Proceedings. Volume 9

International Nuclear Information System (INIS)

1998-01-01

This 1-day workshop focused on phenomenological models regarding the specific question of the maximum energy density achievable in collisions at AGS, SPS and RHIC. The idea was to have 30-minute (or less) presentations of each model--but not the model as a whole, rather then that strongly narrowed to the above physics question. The key topics addressed were: (1) to estimate the energy density in heavy-ion collisions within a model, and to discuss its physical implications; (2) to suggest experimental observables that may confirm the correctness of a model approach--with respect to the energy density estimate; (3) to compare with existing data from AGS and SPS heavy-ion collisions, and to give predictions for the future RHIC experiments. G. Ogilvie started up the workshop with a critical summary of experimental manifestations of high-density matter at the AGS, and gave a personal outlook on RHIC physics. R. Mattiello talked about his newly developed hadron cascade model for applications to AGS and SPS collisions. Next, D. Kharzeev gave a nice introduction of the Glauber approach to high-energy collisions and illustrated the predictive power of this approach in nucleus-nucleus collisions at the SPS. It followed S. Vance with a presentation of the baryon-junction model to explain the observed baryon stopping phenomenon in collisions of heavy nuclei. S. Bass continued with a broad perspective of the UrQMD model, and provided insight into the details of the microscopic dynamical features of nuclear collisions at high energy. J. Sandweiss and J. Kapusta addressed the interesting aspect of photon production in peripherical nuclear collisions due to intense electromagnetic bremstrahlung by the highly charged, fast moving ions. Finally, H. Sorge closed up the one-day workshop with a presentation of his recent work with the RQMD model. This report consists of a summary and vugraphs of the presentations

High density matter in AGS, SPS and RHIC collisions: Proceedings. Volume 9

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-01

This 1-day workshop focused on phenomenological models regarding the specific question of the maximum energy density achievable in collisions at AGS, SPS and RHIC. The idea was to have 30-minute (or less) presentations of each model--but not the model as a whole, rather then that strongly narrowed to the above physics question. The key topics addressed were: (1) to estimate the energy density in heavy-ion collisions within a model, and to discuss its physical implications; (2) to suggest experimental observables that may confirm the correctness of a model approach--with respect to the energy density estimate; (3) to compare with existing data from AGS and SPS heavy-ion collisions, and to give predictions for the future RHIC experiments. G. Ogilvie started up the workshop with a critical summary of experimental manifestations of high-density matter at the AGS, and gave a personal outlook on RHIC physics. R. Mattiello talked about his newly developed hadron cascade model for applications to AGS and SPS collisions. Next, D. Kharzeev gave a nice introduction of the Glauber approach to high-energy collisions and illustrated the predictive power of this approach in nucleus-nucleus collisions at the SPS. It followed S. Vance with a presentation of the baryon-junction model to explain the observed baryon stopping phenomenon in collisions of heavy nuclei. S. Bass continued with a broad perspective of the UrQMD model, and provided insight into the details of the microscopic dynamical features of nuclear collisions at high energy. J. Sandweiss and J. Kapusta addressed the interesting aspect of photon production in peripherical nuclear collisions due to intense electromagnetic bremstrahlung by the highly charged, fast moving ions. Finally, H. Sorge closed up the one-day workshop with a presentation of his recent work with the RQMD model. This report consists of a summary and vugraphs of the presentations.

Thermalization in high energy proton-nucleus collisions

International Nuclear Information System (INIS)

Wedemann, R.S.

1988-03-01

A relativistic proton-nucleus collision using the intranuclear cascade model is studied. The purpose is to verify the equilibration hypothesis at fragmentation time made by many nuclear fragmentation models. (author)

Neural network model for proton-proton collision at high energy

International Nuclear Information System (INIS)

El-Bakry, M.Y.; El-Metwally, K.A.

2003-01-01

Developments in artificial intelligence (AI) techniques and their applications to physics have made it feasible to develop and implement new modeling techniques for high-energy interactions. In particular, AI techniques of artificial neural networks (ANN) have recently been used to design and implement more effective models. The primary purpose of this paper is to model the proton-proton (p-p) collision using the ANN technique. Following a review of the conventional techniques and an introduction to the neural network, the paper presents simulation test results using an p-p based ANN model trained with experimental data. The p-p based ANN model calculates the multiplicity distribution of charged particles and the inelastic cross section of the p-p collision at high energies. The results amply demonstrate the feasibility of such new technique in extracting the collision features and prove its effectiveness

The theory of relativistic heavy ion collisions

International Nuclear Information System (INIS)

1993-07-01

This program began in January 1993. Its primary goals are studies of highly excited matter and its production in nuclear collisions at very high energies. After a general orientation on the project, abstracts describing the contents of completed papers and providing some details of current projects are given. Principal topics of interest are the following: the dynamics of nuclear collisions at very high energies (RHIC and LHC), the dynamics of nuclear collisions at AGS energies, high-temperature QCD and the physics of the quark-gluon plasma, and the production of strangelets and other rare objects

Kinetic energy dissipation in heavy-ion collisions

International Nuclear Information System (INIS)

Fedotov, S.I.; Jolos, R.V.; Kartavenko, V.G.

1979-01-01

Kinetic energy dissipation mechanism is considered in deep inelastic heavy-ion collisions. It is shown that the significant part of the kinetic energy loss can be explained by the excitation of the nuclear matter multipole vibrations. The main contribution of the energy dissipation is given by the time dependent heavy-ion interaction potential renormalized due to the nuclear excitations, rather than by the velocity proportional frictional forces

Color transparency and suppression of high-pT hadrons in nuclear collisions

International Nuclear Information System (INIS)

Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

2011-01-01

The production length l p of a leading (large z h ) hadron produced in hadronization of a highly virtual high-p T parton is short because of the very intensive vacuum gluon radiation and dissipation of energy at the early stage of the process. Therefore, the main part of nuclear suppression of high-p T hadrons produced in heavy ion collisions is related to the survival probability of a colorless dipole propagating through a dense medium. This is subject to color transparency, which leads to a steep rise with p T of the nuclear ratio R AA (p T ), in good agreement with the recent data from the ALICE experiment at the CERN Large Hadron Collider (LHC). No adjustment, except for the medium density, is made, and the transport coefficient is found to be q 0 =0.8 GeV 2 /fm. This is close to the value extracted from the analysis of BNL Relativistic Heavy Ion Collider (RHIC) data for J/Ψ suppression, but is an order of magnitude smaller than the value found from jet quenching data within the energy loss scenario. Although the present calculations have the status of a postdiction, the mechanism and all formulas have been published, and are applied here with no modification, except for the kinematics. At the same time, p T dependence of R AA at the energy of RHIC is rather flat due to the suppression factor steeply falling with rising x T , related to the energy conservation constraints. This factor is irrelevant to the LHC data, since x T is much smaller.

High energy nuclear database: a test-bed for nuclear data information technology

International Nuclear Information System (INIS)

Brown, D.A.; Vogt, R.; Beck, B.; Pruet, J.; Vogt, R.

2008-01-01

We describe the development of an on-line high-energy heavy-ion experimental database. When completed, the database will be searchable and cross-indexed with relevant publications, including published detector descriptions. While this effort is relatively new, it will eventually contain all published data from older heavy-ion programs as well as published data from current and future facilities. These data include all measured observables in proton-proton, proton-nucleus and nucleus-nucleus collisions. Once in general use, this database will have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models for a broad range of experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion, target and source development for upcoming facilities such as the International Linear Collider and homeland security. This database is part of a larger proposal that includes the production of periodic data evaluations and topical reviews. These reviews would provide an alternative and impartial mechanism to resolve discrepancies between published data from rival experiments and between theory and experiment. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This project serves as a test-bed for the further development of an object-oriented nuclear data format and database system. By using 'off-the-shelf' software tools and techniques, the system is simple, robust, and extensible. Eventually we envision a 'Grand Unified Nuclear Format' encapsulating data types used in the ENSDF, Endf/B, EXFOR, NSR and other formats, including processed data formats. (authors)

Mechanism of energy release from nucleus-target in hadron-nucleus collision

International Nuclear Information System (INIS)

Strugalski, Z.; Strugalska-Gola, E.

2000-01-01

The collisions of hadrons (protons, mesons) with 131 Xe nucleus and arising light nuclear fragments as nuclear refraction products have been observed in bubble chamber. Mechanism of energy release during these collisions has been discussed. The quantitative calculations has proved that this phenomena can be treated as potential energy source with use of many different target materials

High-$p_\\mathrm{T}$ probes of $p$+Pb collisions with ATLAS

CERN Document Server

Perepelitsa, Dennis; The ATLAS collaboration

2015-01-01

Measurements of high $p_\\mathrm{T}$ processes in ultrarelativistic proton--nucleus collisions are sensitive to changes in the partonic densities arising from the presence of the nuclear environment. Additionally, such measurements benchmark the so called ``cold nuclear matter'' effects, providing the context within which to understand the strong suppression of high $p_\\mathrm{T}$ processes observed in nucleus--nucleus collisions. Furthermore, measurements of the centrality dependence of jet production at forward (proton-going) rapidities may even shed light on the behavior of the proton wavefunction at large Bjorken-$x$. The latest ATLAS results for inclusive jets and charged particles in 28/nb of $5.02$~TeV proton--lead collisions at the LHC are presented. The centrality in these collisions is characterized through the sum of the transverse energy in the lead-going forward calorimeter. The nuclear modification factors $R_{p\\mathrm{Pb}}$ and $R_\\mathrm{CP}$ are presented for jets and charged particles as a fu...

[Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions]. Nuclear chemistry progress report, August 1, 1990--August 1, 1991

Energy Technology Data Exchange (ETDEWEB)

Loveland, W.D.

1991-08-01

The work described herein is part of a project involving the study of low energy (< 10 MeV/A), intermediate energy (10--100 MeV/A) and relativistic (> 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of ``best`` semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon {sup 129}Xe with {sup 197}Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon {sup 12}C with {sup 197}Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated.

Jet probes of the nuclear and proton wavefunctions in proton--lead collisions with the ATLAS detector

CERN Document Server

Perepelitsa, Dennis; The ATLAS collaboration

2014-01-01

Measurements of high pT processes in ultrarelativistic proton-nucleus collisions are sensitive to changes in the partonic densities arising from the presence of the high-density nuclear environment. Such measurements are thought to serve as a benchmark of the so called "cold nuclear matter" effects, providing the context within which to understand the strong suppression of high pT processes observed in nucleus-nucleus collisions. However, measurements of the centrality dependence of jet production at forward (proton-going) rapidities may additionally shed light on the behavior of the proton wavefunction at large Bjorken-x. The latest ATLAS results for inclusive jets and charged particles in 31/nb of 5.02 TeV proton-lead collisions at the LHC are presented. The centrality in these collisions is characterized through the sum of the transverse energy in the lead-going forward calorimeter. The nuclear modification factors RpPb and RCP are presented for jets and high-pT charged particles as a function of transvers...

6th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions

CERN Document Server

2014-01-01

One of the premier meetings in the field of high-energy nuclear physics, the Hard Probes conference series brings together the experimental and theoretical communities interested in the hard and electromagnetic observables related to nuclear matter at extreme temperatures and densities. Prior to the conference, the University of Cape Town will host a summer school for young physicists in the field. High energy nuclear physics focuses on the science of a trillion degrees. These temperatures were last seen in nature a microsecond after the Big Bang, but mankind recreates them thousands of times a second in particle accelerators such as CERN's Large Hadron Collider and BNL's Relativistic Heavy Ion Collider. At these temperatures, 100,000 times hotter than the center of the sun, the strong force is dominant, and we hope to learn about the fundamental and non-trivial emergent many-body dynamics of the quarks and gluons that make up 99% of the mass of the visible universe. We anticipate the usual format for the H...

Geometric branching model of high-energy hadron-hadron collisions

International Nuclear Information System (INIS)

Chen, W.

1988-01-01

A phenomenological model is proposed to describe collisions between hadrons at high energies. In the context of the eikonal formalism, the model consists of two components: soft and hard. The former only involves the production of particles with small transverse momenta; the latter is characterized by jet production. Geometrical scaling is taken as an essential input to describe the geometrical properties of hadrons as extended objects on the one hand, and on the other to define the soft component in both regions below and above the jet threshold. A stochastical Furry branching process is adopted as the mechanism of soft particle production, while the jet fragmentation and gluon initial-state bremsstrahlung are for the production of hadrons in hard collisions. Impact parameter and virtuality are smeared to describe the statistical averaging effects of hadron-hadron collisions. Many otherwise separated issues, ranging from elastic scattering to parton decay function, are connected together in the framework of this model. The descriptions of many prominent features of hadronic collisions are in good agreement with the observed experimental data at all available energies. Multiplicity distributions at all energies are discussed as a major issue in this paper. KNO scaling is achieved for energies within ISR range. The emergence of jets is found to be responsible not only for the violation of both geometrical scaling and KNO scaling, but also for the continuous broadening of the multiplicity distribution with ever increasing energy. It is also shown that the geometrical size of a hadron reaches an asymptote in the energy region of CERN-SppS. A Monte Carlo version of the model for soft production is constructed

Collision simulations of an exclusive ship of spent nuclear fuels

International Nuclear Information System (INIS)

Kitamura, Ou; Endo, Hisayoshi

2000-01-01

Exclusive ships for sea transport of irradiated nuclear fuels operating in Japanese territorial waters are required to be built with the special hull structure against collision. To comply with the official notice 'KAISA No. 520' issued by the Ministry of Transport, the side structure of any such exclusive ship must be designed to secure the specified energy absorption capability based on Minorsky's ship collision model. The Shipbuilding Research Association of Japan (JSRA) has studied the safety in sea transport of nuclear fuels intermittently for these several decades. Recently, the adoption of finite element method has made detailed collision analyses practicable. Since 1998, the regulation research panel No. 46 of JSRA has carried out a series of finite element collision simulations in order to estimate the realistic damage to a typical exclusive ship of spent nuclear fuels. The expected structural responses, global motions and energy absorption capabilities of both colliding and struck ships during collision were investigated. The results of the investigations have shown that the ship is very likely to withstand the collision even with one of the world's largest ship. This is due mainly to her hull structure specially strengthened beyond the crushing strength of the colliding bow structures. (author)

Impact Parameter Dependence of π"-/π"+ Ratio in Probing the Nuclear Symmetry Energy Using Heavy-Ion Collisions

International Nuclear Information System (INIS)

He, Guo-Qiang; Wei, Gao-Feng; Lu, Yi-Xin; Cao, Xin-Wei

2016-01-01

The impact parameter dependence of π"-/π"+ ratio is examined in heavy-ion collisions at 400 MeV/nucleon within a transport model. It is shown that the sensitivity of π"-/π"+ ratio on symmetry energy shows a transition from central to peripheral collisions; that is, the stiffer symmetry energy leads to a larger π"-/π"+ ratio in peripheral collisions while the softer symmetry energy always leads this ratio to be larger in central collisions. After checking the kinematic energy distribution of π"-/π"+ ratio, we found this transition of sensitivity of π"-/π"+ ratio to symmetry energy is mainly from less energetic pions; that is, the softer symmetry energy gets the less energetic pions to form a smaller π"-/π"+ ratio in peripheral collisions while these pions generate a larger π"-/π"+ ratio in central collisions. Undoubtedly, the softer symmetry energy can also lead more energetic pions to form a larger π"-/π"+ ratio in peripheral collisions. Nevertheless, considering that most of pions are insufficiently energetic at this beam energy, we therefore suggest the π"-/π"+ ratio as a probe of the high-density symmetry energy effective only in central at most to midcentral collisions, thereby avoiding the possible information of low-density symmetry energy carried in π"-/π"+ ratio from peripheral collisions.

The mechanisms of the hadron-nucleus collision processes and of the hadron-nucleus collision induced nuclear reactions - in the light of experimental data

International Nuclear Information System (INIS)

Strugalski, Z.; Strugalska-Gola, E.

1997-01-01

The mechanisms of the hadron-nucleus collision processes and of the hadron-nucleus collision induced nuclear reactions are described - as experimentally based. The target nuclei are damaged definitely and locally in the collisions and the configurations of the nucleons in them became instable. The configuration must transit into stable stages of the nuclear transition reaction products. The difference between the initial internal energy of the unstable residual nucleus and the total final energy of the stable products of the nuclear transition reaction may be released in some cases

Probing vacuum structure in nuclear collisions. Research report period: 1992--1995

International Nuclear Information System (INIS)

Rafelski, J.

1995-02-01

This is a report of the research activities in the field of Relativistic Nuclear Collisions/Theoretical Nuclear Physics of Johann Refelski at University of Arizona, supported by the Department of Energy, Nuclear Physics Division under grant No. DE-FG02-92ER40733. This report comprises: Section 1 surveys the general context of the work and presents summary of wider research objectives; Section 2 reviews the progress in the interpretation of experimental data, primarily related to diagnosis of high density nuclear matter with strange particle production, in heavy ion collisions at 10--200 GeV A; Section 3 presents the status of the studies of a relativistic quantum transport theory and the related vacuum structure and particle production processes; Section 4 presents a compilation of research projects completed under auspices of this program, with a short narrative description of publication contents

High energy structures in heavy ion collisions: a multiphonon description

International Nuclear Information System (INIS)

Chomaz, P.; Blumenfeld, Y.; Frascaria, N.

1984-01-01

Energy spectra of fragments from the 36 Ar + 208 Pb reaction at 11 MeV/n exhibit structures at high excitation energies. These structures are interpreted in terms of target multi-phonon excitations built from giant resonances. The importance of such processes for the kinetic energy dissipation in heavy ion collisions is emphasized

Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

International Nuclear Information System (INIS)

Jacob, N.P. Jr.

1975-07-01

The effect of free-particle collisions in simple ''knockout'' reactions of the form (a,aN) and in more complex nuclear reactions of the form (a,X) was investigated by using protons and pions. Cross sections for the 48 Ti(p,2p) 47 Sc and the 74 Ge(p,2p) 73 Ga reactions were measured from 0.3 to 4.6 GeV incident energy. The results indicate a rise in (p,2p) cross section for each reaction of about (25 +- 3) percent between the energies 0.3 and 1.0 GeV, and are correlated to a large increase in the total free-particle pp scattering cross sections over the same energy region. Results are compared to previous (p,2p) excitation functions in the GeV energy region and to (p,2p) cross section calculations based on a Monte Carlo intranuclear cascade-evaporation model. Cross section measurements for (π/sup +-/, πN) and other more complex pion-induced spallation reactions were measured for the light target nuclei 14 N, 16 O, and 19 F from 45 to 550 MeV incident pion energy. These measurements indicate a broad peak in the excitation functions for both (π,πN) and (π,X) reactions near 180 MeV incident energy. This corresponds to the large resonances observed in the free-particle π + p and π - p cross sections at the same energy. Striking differences in (π,πN) cross section magnitudes are observed among the light nuclei targets. The experimental cross section ratio sigma(π - ,π - n)/sigma(π + ,πN) at 180 MeV is 1.7 +- 0.2 for all three targets. The experimental results are compared to previous pion and analogous proton-induced reactions, to Monte Carlo intranuclear cascade-evaporation calculations, and to a semi-classical nucleon charge exchange model. (108 references) (auth)

Discovery of hydrodynamic behavior in high energy heavy ion collisions

International Nuclear Information System (INIS)

Hamagaki, Hideki

2010-01-01

The objective of high energy heavy ion collision experiments is creating high temperature and high density states to investigate hadron matter properties in such extreme conditions. Since the start of heavy ion collision experiments with BEVALAC, knowledge of the space-time evolution of collision has become indispensable for understanding the hadronic matter properties. This problem is reviewed here from the hydrodynamics view point. Although its importance has been generally recognized since the time of BEVALAC, the hydrodynamic description has not been successful because the hydrodynamic model assuming non-viscous or small fluid had not been considered to be enough to properly describe the space-time evolution of hadron-hadron collisions until the RHIC experiments. Items of the following titles are picked up and reviewed here: Development of heavy ion accelerations; Space-time evolution of hadron collision process and hydrodynamic model; Chemical freezing and kinematical freezing, including transverse momentum spectra at proton-proton collisions and particle spectra in heavy ion collisions; Elliptical azimuthal angle anisotropy; Discovery of hydrodynamic flow at BEVALAC; Problems of incident beam dependence of v2; Elliptic azimuthal angle anisotropy at RHIC; What is it that carries the elliptic anisotropy? Discussion of attainment of thermodynamical equilibrium state at RHIC; and finally investigations of fluid properties other than azimuthal anisotropy, such as, Fluid properties probed by heavy quarks and Observing QCD fluid responses. (S. Funahashi)

Hydrodynamics in high-energy nuclear collisions. Quarterly report 3. quarter 1987

International Nuclear Information System (INIS)

Kataja, Markku.

1989-05-01

This thesis is a review of six publications in which we make use of relativistic hydrodynamics to solve the evolution of matter produced in extremely energetic nucleus-nucleus collisions. In the first one of these papers we study the thermodynamics, the hydrodynamics and the decoupling conditions of such matter. We discuss the initial conditions for the flow, the hydrodynamic equations for the transverse expansion of matter assuming cylindrical symmetry and longitudinal boost invariance and finally present a numeric algorithm, which we use to integrate these equations. In the subsequent three papers this framework is utilized to calculate the transverse momentum spectra of hadrons, the dilepon production and the abundance of strange particles in the final state. The bag model equation of state is used to simulate the first-order phase transition between baryonless hadronic matter and quark-gluon plasma. In the fifth paper we include the particle production from decaying color electric field according to the flux tube model for heavy ion collisions. The hadronization is incorporated by introducing an equilibrium 'mixed state' of hadrons gas, plasma and the color field in analogy to the mixed phase described by the ordinary bag model equation of state. In the last paper I apply a 1+2 dimensional numeric code to analyze a 1+3 dimensional cylindrically symmetric flow of matter assumed to be formed in a central O+Pb collision at 200 GeV/nucleon. The flow data is used to calculte the pseudorapidity distribution of transverse energy for the produced pions

Heterotic Pomeron: high energy hadronic collisions in QCD

International Nuclear Information System (INIS)

Chung-I Tan

1993-01-01

A unified treatment of high energy collisions in QCD is presented. Using a probabilistic approach, both perturbative (hard) and non-perturbative (soft) components are incorporated in a consistent fashion, leading to a ''Heterotic Pomeron''. As a Regge trajectory, it is non linear, approaching 1 in the limit t → -∞. 2 tabs., 9 refs

Low-energy nuclear physics with high-segmentation silicon arrays

International Nuclear Information System (INIS)

Betts, R.R.; Univ. of Illinois, Chicago, IL

1994-01-01

A brief history is given of silicon detectors leading up to the development of ion-implanted strip detectors. Two examples of their use in low energy nuclear physics are discussed; the search for exotic alpha-chain states in 24 Mg and studies of anomalous positron-electron pairs produced in collisions of very heavy ions

High energy particle collisions near black holes

Directory of Open Access Journals (Sweden)

Zaslavskii O. B.

2016-01-01

Full Text Available If two geodesic particles collide near a rotating black hole, their energy in the centre of mass frame Ec.m. can become unbound under certain conditions (the so-called BSW effect. The special role is played here by so-called critical geodesics when one of particles has fine-tuned energy and angular momentum. The nature of geodesics reveals itself also in fate of the debris after collisions. One of particles moving to a remote observer is necessarily near-critical. We discuss, when such a collision can give rise not only unboud Ec.m. but also unbound Killing energy E (so-called super-Penrose process.

A model for high-energy heavy-ion collisions

International Nuclear Information System (INIS)

Myers, W.D.

1978-01-01

A model is developed for high-energy heavy-ion collisions that treats the variation across the overlap region of the target and projectile in the amount of energy and momentum that is deposited. The expression for calculating any observable takes the form of a sum over a series of terms, each one of which consists of a geometric, a kinematic, and a statistical factor. The geometrical factors for a number of target projectile systems are tabulated. (Auth.)

Nuclear suppression in p-A collisions from induced radiation

International Nuclear Information System (INIS)

Arleo, F.; Kolevatov, R.; Peigne, S.; Sami, T.

2016-01-01

The current status of coherent energy loss is reviewed, both in theory and in its phenomenological applications to p-A collisions. The induced energy loss is not bounded in general, but only in the specific situation where the energetic parton is suddenly accelerated (as in deep inelastic scattering) in the nuclear medium. In the situation where the parton is asymptotic, i.e. 'prepared' at t = -∞ and 'tagged' at t = +∞ after crossing a nuclear medium of thickness L (a situation relevant to forward hadron production in p-A collisions), ΔE appears to be proportional to E. Both situations are detailed in the article

Heavy ion collisions at intermediate energy

International Nuclear Information System (INIS)

Bertsch, G.; Amsden, A.A.

1978-01-01

Two types of measurement are proposed for the analysis of heavy ion collisions in the range of energy of 20--200 MeV/A. First, measurement of the longitudinal component of the kinetic energy of the collision products characterizes the impact parameter of the collision. The distribution in this quantity allows the dissipation in the theoretical models to be determined. A second kind of measurement is that of the coefficients of a spherical harmonic expansion of the angular distribution of the products. Besides giving independent information on the impact parameter and reaction dynamics, measurement of these coefficients offers the possibility of measuring the stiffness of the equation of state of nuclear matter. These ideas are explored in the context of a hydrodynamic model for the collision. In the purely hydrodynamic model there is a large measurable asymmetry in the angular distribution, but the dependence on the equation of state is small

QCD and high-energy nuclear collisions

CERN Multimedia

CERN. Geneva

2007-01-01

Six years ago, Relativistic Heavy Ion Collider at Brookhaven started colliding heavy nuclei at record center-of-mass energies of up to 200 GeV/nucleon. Very soon, the Large Hadron Collider at CERN will push the energy of the ions to an astounding 5 TeV/nucleon. What can be learnt from the experiments at these machines? What do we know about the physics of super--dense matter already? I will argue that heavy ion accelerators bring us to the new frontiers of physical knowledge by creating strong color fields and very high densities of partons, at which qualitatively new phenomena emerge. I will also discuss the cross-disciplinary implications for cosmology, astrophysics, and connections to condensed matter physics.

Thermal Bremsstrahlung probing nuclear multifragmentation in nucleus-nucleus collisions around the Fermi energy; Bremsstrahlung thermique comme sonde de la multifragmentation nucleaire dans les collisions noyau-noyau aux energies de Fermi

Energy Technology Data Exchange (ETDEWEB)

D' Enterria, D.G

2000-05-15

The thermodynamical properties of nuclear matter at moderate temperatures and densities, in the vicinity of the predicted nuclear liquid-gas phase transition, are studied using as experimental probe the hard-photons (E{sub {gamma}} > 30 MeV) emitted in nucleus-nucleus collisions. Photon and charged-particle production in four different heavy-ion reactions (Ar{sup 36} + Au{sup 197}, Ag{sup 107}, Ni{sup 58}, C{sup 12} at 60 A*MeV) is measured exclusively and inclusively coupling the TAPS photon spectrometer with two charged-particle and intermediate-mass-fragment detectors covering nearly 4{pi}. We confirm that Bremsstrahlung emission in first-chance (off-equilibrium) proton-neutron collisions (pn{gamma}) is the dominant origin of hard photons. We also firmly establish the existence of a thermal radiation component emitted in second-chance proton-neutron collisions. This thermal Bremsstrahlung emission takes place in semi-central and central nucleus-nucleus reactions involving heavy targets. We exploit this observation i) to demonstrate that thermal equilibrium is reached during the reaction, ii) to establish a new thermometer of nuclear matter based on Bremsstrahlung photons, iii) to derive the thermodynamical properties of the excited nuclear sources and, in particular, to establish a 'caloric curve' (temperature versus excitation energy), and iv) to assess the time-scales of the nuclear break-up process. (author)

Energy transfer in diatom/diatom molecular collisions

International Nuclear Information System (INIS)

Sohlberg, K.W.

1992-01-01

In a collision of two molecules, the translational energy of the collision may be redistributed into internal energy of rotation, vibration, or electron motion, in one or both of the colliding partners. In addition, internal energy in one or more of these modes may be open-quotes quenchedclose quotes into translation, leading to a superelastic collision. Such energy transfer may take place by a number of mechanisms. This energy transfer is of fundamental importance in understanding chemical reaction dynamics. Nearly all chemical reactions take place through a bimolecular collision process (or multiple bimolecular collisions) and the quantum state specificity of the reaction can have a major role in determining the kinetics of the reaction, In particular, the author has investigated vibrational energy transfer in collisions between two diatomic molecules. In addition to serving as models for all molecular collision process, gas phase collisions of these species are ubiquitous in atmospheric phenomena which are of critical importance in answering the current questions about the human induced degradation of the earth's atmospheric. Classical trajectory methods have been used to explore the excitation of vibrations in gas-phase collisions of the nitrogen molecular ion with its parent molecule. The near symmetry of the reactants is shown to result in a high probability that the two molecules are excited by an equal amount of energy. This provides a possible explanation of the molecular beam measurements which show that the total number of vibrational energy quanta excited in the collision is, with a high probability that the two molecules are excited by an equal amount of energy. This provides a possible explanation of the molecular beam measurements which show that the total number of vibrational energy quanta excited in the collision is, with a high probability, even

High energy photons production in nuclear reactions

International Nuclear Information System (INIS)

Nifenecker, H.; Pinston, J.A.

1990-01-01

Hard photon production, in nucleus-nucleus collisions, were studied at beam energies between 10 and 125 MeV. The main characteristics of the photon emission are deduced. They suggest that the neutron-proton collisions in the early stage of the reaction are the main source of high energy gamma-rays. An overview of the theoretical approaches is given and compared with experimental results. Theoretical attempts to include the contribution of charged pion exchange currents to photon production, in calculations of proton-nucleus-gamma and nucleus-nucleus-gamma reactions, showed suitable fitting with experimental data

On transient effects in violent nuclear collisions

International Nuclear Information System (INIS)

Suraud, E.; Belkacem, M.; Feng-Shou Zhang; Academia Sinica, Lanzhou, GS

1993-01-01

It is shown that the numerical simulations of the recently developed Boltzmann-Langevin model exhibit large dynamical fluctuations in momentum space during the early stages of heavy-ion collisions, which arise from an interplay between the nuclear meanfield and binary collisions. It is pointed out that this transient behaviour provides an initial seed for the development of density fluctuations, and could strongly influence the particle production cross-sections at subthreshold energies. (author) 13 refs.; 3 figs

Expansion, thermalization, and entropy production in high-energy nuclear collisions

International Nuclear Information System (INIS)

Heiselberg, H.; Wang, X.

1996-01-01

The thermalization process is studied in an expanding parton gas using the Boltzmann equation with two types of collision terms. In the relaxation time approximation we determine the criteria under which a time-dependent relaxation time leads to thermalization of the partons. We calculate the entropy production due to collisions for the general time-dependent relaxation time. In a perturbative QCD approach on the other hand, we can, given the initial conditions, estimate the effective relaxation time due to elastic collisions; this will be an upper limit only since radiative processes will also contribute to thermalization. We find that the parton gas does thermalize eventually but only after having undergone a phase of free streaming and gradual equilibration where considerable entropy is produced (open-quote open-quote after burning close-quote close-quote). The final entropy and thus particle density depends on the collision time as well as the initial conditions (a open-quote open-quote memory effect close-quote close-quote). Results for entropy production are presented based upon various model estimates of early parton production. copyright 1996 The American Physical Society

Explosion-evaporation model for fragment production in intermediate-energy nuclear collisions

International Nuclear Information System (INIS)

Fai, G.; Randrup, J.

1981-01-01

Nuclear collisions at intermediate energies may create transient systems of hot nuclear matter that decay into many nuclear fragments. The disassembly of such a nuclear fireball is described as a two-stage process. In the primary explosion stage the system quickly fragments into nucleons and composite nuclei according to the available phase space. The explosion produces excited nuclei with half-lives longer than the time associated with the breakup. In the secondary evaporation stage, these nuclei decay, first by sequential emission of light particles (neutrons, protons, alphas), later by electromagnetic radiation. The secondary stage in general changes the relative abundancies of the various fragment species. This general feature makes it essential to take account of the composite fragments before using d/p as a measure of the entropy of the initial source. The formation of unbound nuclei at the explosion stage also has the desirable effect of enhancing the final abundancies of particularly stable nuclei, e.g., 4 He. For neutron-excessive sources the presence of composite nuclei amplifies the ratio of observed neutrons and protons; this effect persists for heavier mirror systems. Predictions of the model are qualitatively compared to available experimental data. The model offers a convenient way to augment existing dynamical models, such as intra-nuclear cascade and nuclear fluid dynamics, to yield actual nuclear fragments rather than merely matter distributions

Universal behavior of charged particle production in heavy ion collisions at RHIC energies

Science.gov (United States)

Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Phobos Collaboration

2003-04-01

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √ SNN = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/ overlinepp and e +e - data. / in nuclear collisions at high energy scales with √ s in a similar way as Nch in e +e - collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

Directory of Open Access Journals (Sweden)

Raghunath Sahoo

2015-01-01

Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

Baryon, charged hadron, Drell-Yan and J/ψ production in high energy proton-nucleus collisions

International Nuclear Information System (INIS)

Gale, Charles; Jeon, Sangyong; Kapusta, Joseph

1999-01-01

We show that the distributions of outgoing protons and charged hadrons in high energy proton-nucleus collisions are described rather well by a linear extrapolation from proton-proton collisions. The only adjustable parameter required is the shift in rapidity of a produced charged meson when it encounters a target nucleon. Its fitted value is 0.16. Next, we apply this linear extrapolation to precisely measured Drell-Yan cross sections for 800 GeV protons incident on a variety of nuclear targets which exhibit a deviation from linear scaling in the atomic number A. We show that this deviation can be accounted for by energy degradation of the proton as it passes through the nucleus if account is taken of the time delay of particle production due to quantum coherence. We infer an average proper coherence time of 0.4±0.1 fm/c, corresponding to a coherence path length of 8±2 fm in the rest frame of the nucleus. Finally, we apply the linear extrapolation to measured J/ψ production cross sections for 200 and 450 GeV/c protons incident on a variety of nuclear targets. Our analysis takes into account energy loss of the beam proton, the time delay of particle production due to quantum coherence, and absorption of the J/ψ on nucleons. The best representation is obtained for a coherence time of 0.5 fm/c, which is consistent with Drell-Yan production, and an absorption cross section of 3.6 mb, which is consistent with the value deduced from photoproduction of the J/ψ on nuclear targets

Photon and dilepton production in high-energy heavy-ion collisions

Indian Academy of Sciences (India)

2015-05-07

May 7, 2015 ... Photons; dileptons; Relativistic Heavy Ion Collider; Large Hadron Collider; quark ... the collisions produces relatively high pT photons, often referred to ..... energy have been found for identified charged hadrons at RHIC [25].

Quarkonium production in high energyproton-proton and proton-nucleus collisions

Energy Technology Data Exchange (ETDEWEB)

del Valle, Z C; Corcella, G; Fleuret, F; Ferreiro, E G; Kartvelishvili, V; Kopeliovich, B; Lansberg, J P; Lourenco, C; Martinez, G; Papadimitriou, V; Satz, H; Scomparin, E; Ullrich, T; Teryaev, O; Vogt, R; Wang, J X

2011-03-14

We present a brief overview of the most relevant current issues related to quarkonium production in high energy proton-proton and proton-nucleus collisions along with some perspectives. After reviewing recent experimental and theoretical results on quarkonium production in pp and pA collisions, we discuss the emerging field of polarization studies. Afterwards, we report on issues related to heavy-quark production, both in pp and pA collisions, complemented by AA collisions. To put the work in broader perpectives, we emphasize the need for new observables to investigate the quarkonium production mechanisms and reiterate the qualities that make quarkonia a unique tool for many investigations in particle and nuclear physics.

Performance Limitations in High-Energy Ion Colliders

CERN Document Server

Fischer, Wolfram

2005-01-01

High-energy ion colliders (hadron colliders operating with species other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. However, the experiments also expect flexibility with frequent changes in the collision energy, lattice configuration, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams, attention must be paid to space charge, charge exchange, and intra-beam scattering effects. The latter leads to luminosity lifetimes of only a few hours for heavy ions. Ultimately cooling at full energy is needed to overcome this effect. Currently, the Relativistic Heavy Ion Collider at BNL is the only operating high-energy ion collider. The Large Hadron Collider, under construction at CERN, will also run with heavy ions.

Transverse Energy in nucleus-nucleus collisions: A review

International Nuclear Information System (INIS)

Tincknell, M.

1988-01-01

The status of Transverse Energy (E/sub T/) in relativistic nucleus-nucleus collisions at the Brookhaven AGS and the CERN SPS is reviewed. The definition of E/sub T/ and its physical significance are discussed. The basic techniques and limitations of the experimental measurements are presented. The acceptances of the major experiments to be discussed are shown, along with remarks about their idiosyncrasies. The data demonstrate that the nuclear geometry of colliding spheres primarily determines the shapes of the observed spectra. Careful account of the acceptances is crucial to comparing and interpreting results. It is concluded that nuclear stopping power is high, and that the amount of energy deposited into the interaction volume is increasing with beam energy even at SPS energies. The energy densities believed to be obtained at the SPS are close to the critical values predicted for the onset of a quark-gluon plasma. 25 refs., 8 figs

Multiparticle Collectivity from Initial State Correlations in High Energy Proton-Nucleus Collisions

Science.gov (United States)

Dusling, Kevin; Mace, Mark; Venugopalan, Raju

2018-01-01

Qualitative features of multiparticle correlations in light-heavy ion (p +A ) collisions at RHIC and LHC are reproduced in a simple initial state model of partons in the projectile coherently scattering off localized domains of color charge in the heavy nuclear target. These include (i) the ordering of the magnitudes of the azimuthal angle n th Fourier harmonics of two-particle correlations vn{2 }, (ii) the energy and transverse momentum dependence of the four-particle Fourier harmonic v2{4 }, and (iii) the energy dependence of four-particle symmetric cumulants measuring correlations between different Fourier harmonics. Similar patterns are seen in an Abelian version of the model, where we observe v2{2 }>v2{4 }≈v2{6 }≈v2{8 } of two, four, six, and eight particle correlations. While such patterns are often interpreted as signatures of collectivity arising from hydrodynamic flow, our results provide an alternative description of the multiparticle correlations seen in p +A collisions.

Computer simulation studies of high energy collision cascades

International Nuclear Information System (INIS)

Robinson, M.T.

1991-07-01

A modified binary collision approximation allowing the proper order of the collisions in time was used to study cascades in Cu and Au at primary kinetic energies up to 100 keV. Nonlinearities were approximated by letting already-stopped cascade atoms become targets in later collisions, using an improved method of locating potential targets to extend the calculations to energies much higher than heretofore. Beside the effect of the approximate nonlinearity, the effect of thermal disorder in the targets was examined. Target redisplacements reduce the damage in Cu by 3% at most, but in Au they reduce it by amounts up to 20% at 100 keV. Thermal disorder is also important: by disrupting crystal effects, the damage is reduced significantly. 11 refs., 4 figs

Energy density, stopping and flow in ultrarelativistic heavy ion collisions

International Nuclear Information System (INIS)

Sorge, H.; von Keitz, A.; Mattiello, R.; Stoecker, H.; Greiner, W.

1990-01-01

The Lorentz invariant molecular dynamics approach (RQMD) is employed to investigate the space-time evolution of heavy ion collisions at energies (E kin = 10AGeV hor-ellipsis 200AGeV). The calculations for various nucleus nucleus reactions show a high degree of stopping power. The importance of secondary rescattering at these beam energies is demonstrated. The computed nucleon rapidity distributions are compared to available experimental data. It is demonstrated that nonlinear, collective effects like full stopping of target and projectile and matter flow could be expected for heavy projectiles only. For nuclear collisions in the Booster era at BNL and for the lead beam at CERN SPS the authors predict a stimulating future: then a nearly equilibrated, long lived (8 fm/c) macroscopic volume of very high energy density (> 1 GeV/fm 3 ) and baryon density (> 5 times ground state density) is produced

Soft electromagnetic bremsstrahlung in inelastic hadronic collisions at high and intermediate energies

International Nuclear Information System (INIS)

Rueckl, R.

1978-01-01

Electromagnetic bremsstrahlung in hadronic collisions was studied extensively at low and intermediate energies. It was found that the infrared divergent term of the cross section describes the data well up to surprisingly large photon energies. Using essentially the same soft photon approximation, production of low mass-low energy electron pairs via internal conversion of soft virtual bremsstrahlung accompanying the production of charged hadrons in hadron-hadron collisions at very high and intermediate energies. The resulting electron yields explain, at least in part, the direct electrons with small transverse momenta seen at the ISR, and are in no contradiction to the rates observed at LAMPF

Z-scaling in proton-nucleus collisions at high energies

International Nuclear Information System (INIS)

Zborovsky, I.; Tokarev, M.V.; Panebrattsev, Yu.A.; Skoro, G.P.

1997-01-01

New scaling, z-scaling, in the inclusive particle production in pA collisions is studied. The scaling function H A (z) is expressed via the inclusive cross section of particle production Ed 3 σ/dq 3 and the particle multiplicity density dN/dη at pseudorapidity η=0 in the corresponding nucleon-nucleon (NN) center-of-mass (CMS) system. The dependence of H A (z) on scaling variable z, the center-of-mass energy √, and the detection angle θ is investigated. The available experimental data on inclusive particle production (π ± , K ± ) in pA interactions at high energies are used to verify the universality of z-scaling found in hadron-hadron collisions. The A-dependence of H A (z) for π + -meson production is studied. It is shown that the experimental data >from pd collisions confirm the scaling properties of the function H d (z). Some predictions for H au (z) concerning production of π + -mesons in pAu interaction using the HIJING Monte Carlo code have been made. The obtained results can be of interest for future experiments at RHI and LHC in searching the signals of quark-gluon plasma formation

Strangeness in nuclear collisions

International Nuclear Information System (INIS)

Gazdzicki, M.; Roehrich, D.

1996-01-01

Data on the mean multiplicity of strange hadrons produced in minimum bias proton-proton and central nucleus-nucleus collisions at momenta between 2.8 and 400 GeV/c per nucleon have been compiled. The multiplicities for nucleon-nucleon interactions were constructed. The ratios of strange particle multiplicity to participant nucleon as well as to pion multiplicity are larger for central nucleus-nucleus collisions than for nucleon-nucleon interactions at all studied energies. The data at AGS energies suggest that the latter ratio saturates with increasing masses of the colliding nuclei. The strangeness to pion multiplicity ratio observed in nucleon-nucleon interactions increases with collision energy in the whole energy range studied. A qualitatively different behaviour is observed for central nucleus-nucleus collisions: the ratio rapidly increases when going from Dubna to AGS energies and changes little between AGS and SPS energies. This change in the behaviour can be related to the increase in the entropy production observed in central nucleus-nucleus collisions at the same energy range. The results are interpreted within a statistical approach. They are consistent with the hypothesis that the quark gluon plasma is created at SPS energies, the critical collision energy being between AGS and SPS energies. (orig.)

Inner-shell excitation in heavy ion collisions up to intermediate incident energies

International Nuclear Information System (INIS)

Reus, T. de.

1987-04-01

Electronic excitations in collisions of very heavy ions with a total nuclear charge Z greater than 1/α ≅ 137 at bombarding energies reaching from 3.6 MeV/n up to 100 MeV/n are the subject of this thesis. The dynamical behaviour of the electron-positron-field is described within a semiclassical model, which is reviewed and extended to include electronic interactions via a mean field. A detailed comparison with experimental data of K-vacancy formation, δ-electron and positron emission shows an improved agreement compared with former calculations. Structures in spectra of positrons emitted in sub- and supercritical collision are discussed in two respects: Firstly as a signal of the vacuum decay in supercritical electromagnetic fields which evolve in the vicinity of long living giant nuclear molecules. Secondly as an atomic effect, which might be related to an instaneous formation of molecular 1sσ- and 2p 1/2 σ- levels. However, beyond this speculation the emission spectra of electrons and positrons in deep inelastic reactions have proven to be a powerful tool for measuring nuclear reaction or delay times in the order of 10 -21 s. This property was transfered to the domain of intermediate energy collisions. In first order perturbation theory we derived a scaling law, exhibiting how nuclear stopping times could be extracted from the emission spectra of high energetic δ-electrons. Quantitative calculations within a coupled channel code have been carried out for the system Pb+Pb, yielding cross sections of up to 20 nb for the emission of electrons with a kinetic energy of 50 MeV in 60 MeV/n-collisions. (orig./HSI)

Triple parton scatterings in high-energy proton-proton collisions arXiv

CERN Document Server

d'Enterria, David

2017-01-01

A generic expression to compute triple parton scattering cross sections in high-energy proton-proton (pp) collisions is presented as a function of the corresponding single parton cross sections and the transverse parton profile of the proton encoded in an effective parameter σeff,TPS. The value of σeff,TPS is closely related to the similar effective cross section that characterizes double parton scatterings, and amounts to σeff,TPS=12.5±4.5  mb. Estimates for triple charm (cc¯) and bottom (bb¯) production in pp collisions at LHC and FCC energies are presented based on next-to-next-to-leading-order perturbative calculations for single cc¯, bb¯ cross sections. At s≈100  TeV, about 15% of the pp collisions produce three cc¯ pairs from three different parton-parton scatterings.

Mechanisms of High Energy Hadron-Nucleus and Nucleus-Nucleus Collision Processes

International Nuclear Information System (INIS)

Strugalski, Z.

1994-01-01

Mechanisms of high energy hadron-nucleus and nucleus-nucleus collision processes are depicted qualitatively, as prompted experimentally. In hadron-nucleus collisions the interaction of the incident hadron in intranuclear matter is localized in small cylindrical volume, with the radius as large as the strong interaction range is, centered on the hadron course in the nucleus. The nucleon emission is induced by the hadron in its passing through the nucleus; particles are produced via intermediate objects produced in 2 → 2 endoergic reactions of the hadron and its successors with downstream nucleons. In nucleus-nucleus collisions, the outcome of the reaction appears as the composition of statistically independent hadron-nucleus collision outcomes at various impact parameters. Observable effects supporting such mechanisms are discussed. 51 refs

Exploring the Nuclear Phase Diagram with Beam Energy Scans

International Nuclear Information System (INIS)

Horvat, Stephen

2017-01-01

The nuclear phase diagram is mapped using beam energy scans of relativistic heavy-ion collisions. This mapping is possible because different collision energies develop along different trajectories through the phase diagram. High energy collisions will evolve though a crossover phase transition according to lattice QCD, but lower collision energies may traverse a first order phase transition. There are hints for this first order phase transition and its critical endpoint, but further measurements and theoretical guidance is needed. In addition to mapping the phase transition, beam energy scans allow us to see if we can turn off the signatures of deconfinement. If an observable is a real signature for the formation of the deconfined state called quark-gluon plasma, then it should turn off at sufficiently low collision energies. In this summary talk I will show the current state of the field using beam energy scan results from RHIC and SPS, I will show where precise theoretical guidance is needed for understanding recent measurements, and I will motivate the need for more data and new measurements from FAIR, NICA, RHIC, and the SPS. (paper)

A review of experimental results obtained in Au-Au collisions at the RHIC-BNL energies using BRAHMS experimental set-up

International Nuclear Information System (INIS)

Jipa, Alexandru

2003-01-01

Ultrarelativistic heavy ion collisions are useful tools to investigate highly excited dense nuclear matter. At sufficiently high temperature, nuclear matter is expected to undergo a phase transition to quark-gluon plasma. Therefore, new experiments have been proposed to investigate the behaviour of the highly excited dense nuclear matter. One of the experiments performed at the Relativistic Heavy Ion Collider from Brookhaven National Laboratory is the BRAHMS Experiment. In the three running years many experimental data have been obtained. These data permitted to establish significant experimental results on charged pion, charged kaon, proton and antiproton production in Au-Au collisions at 130 A GeV and 200 A GeV in CMS. The present work summarizes the main experimental results on charged particle multiplicities, rapidity distributions, momentum spectra, antiparticle to particle ratios and connects these results with some interesting physical quantities. Their dependencies on the available energies in the CMS in similar collisions are included. Interesting behaviours with the increase of this energy are reported. The most interesting are related to the behaviour of the antiproton to proton ratio on the collision centrality and on the available energy in the centre of mass system, the strangeness production, Coulomb repulsion and slope parameters of the momentum spectra. A few new steps in the knowledge of the behaviour of the highly excited and dense nuclear matter can be reported. (authors)

[Search for strange quark matter and antimatter produced in high energy heavy ion collisions

International Nuclear Information System (INIS)

1992-01-01

This document describes the development and progress of our group's research program in high energy heavy ion physics. We are a subset of the Yale experimental high energy physics effort (YAUG group) who became interested in the physics of high energy heavy ions in 1988. Our interest began with the possibility of performing significant searches for strange quark matter. As we learned more about the subject and as we gained experimental experience through our participation in AGS experiment 814, our interests have broadened. Our program has focused on the study of new particles, including (but not exclusively) strange quark matter, and the high sensitivity measurement of other composite nuclear systems such as antinuclei and various light nuclei. The importance of measurements of the known, but rare, nuclear systems lies in the study of production mechanisms. A good understanding of the physics and phenomenology of rare composite particle production in essential for the interpretation of limits to strange quark matter searches. We believe that such studies will also be useful in probing the mechanisms involved in the collision process itself. We have been involved in the running and data analysis for AGS E814. We have also worked on the R ampersand D for AGS E864, which is an approved experiment designed to reach sensitivities where there will be a good chance of discovering strangelets or of setting significant limits on the parameters of strange quark matter

Violent heavy ion collisions around the Fermi energy

International Nuclear Information System (INIS)

Borderie, B.

1985-01-01

Experimental results on central collisions will be presented and it will be shown that a fusion process still occurs; deexcitation of the hot fused systems formed will be discussed. Then, from the qualitative evolution of central collision products from different reactions studied in the E/A range 20-84 MeV, the vanishing of fusion processes will be inferred; it will be discussed in terms of critical energy deposit and maximum excitation energy per nucleon that nuclei can carry. Finally results concerning the large production of light fragments (3 < approximately Z < approximately 12) experimentally observed in the Fermi energy domain will be presented and discussed in terms of a multifragmentation of the whole nuclear system or of part of it for intermediate impact parameter collisions (109 refs, 49 fig)

Theoretical interpretation of high-energy nuclear collisions

International Nuclear Information System (INIS)

Fai, G.

1990-08-01

In the following, I briefly summarize the research results and progress under this project in the time period January 1, 1988--July 31, 1990. Published and unpublished research in this time period focused on aspects of nuclear disassembly, nuclear dynamics, and subnucleonic degrees of freedom in model field theories

Energy dependence of the ionization of highly excited atoms by collisions with excited atoms

International Nuclear Information System (INIS)

Shirai, T.; Nakai, Y.; Nakamura, H.

1979-01-01

Approximate analytical expressions are derived for the ionization cross sections in the high- and low-collision-energy limits using the improved impulse approximation based on the assumption that the electron-atom inelastic-scattering amplitude is a function only of the momentum transfer. Both cases of simultaneous excitation and de-excitation of one of the atoms are discussed. The formulas are applied to the collisions between two excited hydrogen atoms and are found very useful for estimating the cross sections in the wide range of collisions energies

Rapidity distributions in unequal nuclei collision at high energies and hydrodynamic model

International Nuclear Information System (INIS)

Zhuang Pengfei; Wang Zhengqing; Liu Liansou

1986-01-01

The mechanism of high-energy A'-A collisions (A>A', A'sup(1/3)>>1) and the space-time evolution of the fluid formed in the collision are analysed. The corresponding 1+1 dimensional hydrodynamic equations are set up. The average rapidity distributions are estimated and compared with cosmic ray data. The origin of the unsymmetry of rapidity distributions is explained. (orig.)

Rapidity distributions in unequal nuclei collision at high energies and hydrodynamical model

International Nuclear Information System (INIS)

Zhuang Pengfei; Wang Zhengqing

1987-01-01

The mechanism of high-energy A'-A collision (A > A', A' 1/3 >> 1) and the space-time evolution of the fluid formed in the collision are analysed. The corresponding 1 + 1 dimensional hydrodynamical equations are established. The average rapidity distributions are estimated and compared with some cosmic ray events. The origin of the nonsymmetry of rapidity distribution is explained

The mechanism of nuclear energy release in nucleus-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.; Strugalska-Gola, E.

1998-01-01

The mechanism of intranuclear energy release in reactions induced by nucleus-nucleus collisions at energies higher than ∼ 0.5 GeV/nucl. is presented - as prompted experimentally. The intranuclear energy release goes through local damages of the colliding nuclei

Balance Function in High-Energy Collisions

International Nuclear Information System (INIS)

Tawfik, A.; Shalaby, Asmaa G.

2015-01-01

Aspects and implications of the balance functions (BF) in high-energy physics are reviewed. The various calculations and measurements depending on different quantities, for example, system size, collisions centrality, and beam energy, are discussed. First, the different definitions including advantages and even short-comings are highlighted. It is found that BF, which are mainly presented in terms of relative rapidity, and relative azimuthal and invariant relative momentum, are sensitive to the interaction centrality but not to the beam energy and can be used in estimating the hadronization time and the hadron-quark phase transition. Furthermore, the quark chemistry can be determined. The chemical evolution of the new-state-of-matter, the quark-gluon plasma, and its temporal-spatial evolution, femtoscopy of two-particle correlations, are accessible. The production time of positive-negative pair of charges can be determined from the widths of BF. Due to the reduction in the diffusion time, narrowed widths refer to delayed hadronization. It is concluded that BF are powerful tools characterizing hadron-quark phase transition and estimating some essential properties

Hawking-Unruh Hadronization and Strangeness Production in High Energy Collisions

CERN Document Server

Castorina, P

2014-01-01

The thermal multihadron production observed in different high energy collisions poses many basic problems: why do even elementary, $e^+e^-$ and hadron-hadron, collisions show thermal behaviour? Why is there in such interactions a suppression of strange particle production? Why does the strangeness suppression almost disappear in relativistic heavy ion collisions? Why in these collisions is the thermalization time less than $\\simeq 0.5$ fm/c? We show that the recently proposed mechanism of thermal hadron production through Hawking-Unruh radiation can naturally answer the previous questions. Indeed, the interpretation of quark- antiquark pairs production, by the sequential string breaking, as tunneling through the event horizon of colour confinement leads to thermal behavior with a universal temperature, $T \\simeq 170$ Mev,related to the quark acceleration, a, by $T=a/2\\pi$. The resulting temperature depends on the quark mass and then on the content of the produced hadrons, causing a deviation from full equilib...

Photon production in relativistic nuclear collisions at SPS and RHIC energies

CERN Document Server

Turbide, S; Rapp, R; 10.1142/S0217751X0402258X

2004-01-01

Chiral Lagrangians are used to compute the production rate of photons from the hadronic phase of relativistic nuclear collisions. Special attention is paid to the role of the a/sub 1/ pseudovector. Calculations that include strange meson reactions, form factors, the use of consistent vector spectral densities, the emission from a quark-gluon plasma, and primordial nucleon-nucleon collisions reproduce the photon spectra measured at the Super Proton Synchrotron (SPS). Some predictions for the Relativistic Heavy Ion Collider (RHIC) are made.

Multinucleon interactions in collisions with nuclei at high energies

International Nuclear Information System (INIS)

Braun, M.A.

1988-11-01

The parton picture of multiple hA and AA scattering at high energies is developed. It is shown that it leads to the standard Glauber amplitude provided the number of partons in a hadron is distributed according to Poisson's law. Within this picture collisions of more than a pair of nucleons are considered. For AA scattering a two-dimensional effective quantum field theory is constructed which allows to conveniently calculate contributions to the amplitude with a given number of loops. The AGK rules for AA scattering are established. Inclusive cross-sections for particle production in hA and AA collisions are studied both in the non-cumulative and cumulative kinematical regions. (author). 13 refs, 9 figs

Quark model and high-energy nuclear experiments

International Nuclear Information System (INIS)

Bialas, A.

1979-05-01

Theoretical aspects of the measurements of production of low transverse momentum secondaries in high-energy hadron-nucleus and nucleus-nucleus collisions are discussed. Applications of the quark model to those processes are discussed in some detail. 58 references

Quark model and high-energy nuclear experiments

Energy Technology Data Exchange (ETDEWEB)

Bialas, A.

1979-05-01

Theoretical aspects of the measurements of production of low transverse momentum secondaries in high-energy hadron-nucleus and nucleus-nucleus collisions are discussed. Applications of the quark model to those processes are discussed in some detail. 58 references.

Novel High Transverse Momentum Phenomena in Hadronic and Nuclear Collisions

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC

2009-04-10

I discuss a number of novel phenomenological features of QCD in high transverse momentum reactions. The presence of direct higher-twist processes, where a proton is produced directly in the hard subprocess, can explain the 'baryon anomaly' - the large proton-to-pion ratio seen at RHIC in high centrality heavy ion collisions. Direct hadronic processes can also account for the deviation from leading-twist PQCD scaling at fixed x{sub T} = 2 p{sub T}/{radical}s. I suggest that the 'ridge' --the same-side long-range rapidity correlation observed at RHIC in high centrality heavy ion collisions is due to the imprint of semihard DGLAP gluon radiation from initial-state partons which have transverse momenta biased toward the trigger. A model for early thermalization of the quark-gluon medium is also outlined. Rescattering interactions from gluon-exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam-Tung relation in Drell-Yan reactions, nuclear shadowing--all leading-twist dynamics not incorporated in the light-front wavefunctions of the target computed in isolation. Anti shadowing is shown to be quark flavor specific and thus different in charged and neutral deep inelastic lepton-nucleus scattering. I also discuss other aspects of quantum effects in heavy ion collisions, such as tests of hidden color in nuclear wavefunctions, the use of diffraction to materialize the Fock states of a hadronic projectile and test QCD color transparency, and the important consequences of color-octet intrinsic heavy quark distributions in the proton for particle and Higgs production at high x{sub F}. I also discuss how the AdS/CFT correspondence between Anti-de Sitter space and conformal gauge theories allows one to compute the analytic form of frame-independent light

Prediction of catastrophe theory for heavy-ion collisions at high energies

International Nuclear Information System (INIS)

Kuchin, I.A.

2002-01-01

Studying the nature of limiting fragmentation of nuclei in high energy heavy-ion collisions has shown that the dynamic system of the nucleus is inclined to enter a nonequilibrium state, schottische and disintegrate on separate nucleons under conditions typical to each collision. There is a question: how the phenomenon of multifragmentation is possible here, i. e. formation of several nucleus with masses on interval from a nucleon up to a material nucleus A in a final state. What is it - debris of a material nucleus or newly created daughter nuclei? The purpose of offered report is discussion of this question. The initial for us statement is taken from the theory of dynamic systems. Chaos is a result of hashing of phase space which is carried out by means of operations of distension and compression. The appropriate transformation are called baker-transformation or Smale's horseshoe. The geometrical picture of chaos is a folded relief of multi-dimensional phase space. The stochastic amplification is understood as growth of folder number and their size. In typical interactions of massive ions, chaos formation conditions are provided automatically due to alternate force influence of Coulomb and Yukawa fields - compression is replaced by distension, and distension - by compression. Extending this representation on a case of massive ion collision, we supplement it accounting a possibility of constituents (nucleons) strong interaction on small distances. The easiest way to make it is approximating minima of potential function V(x, c) in catastrophe theory by rectangular holes of Fermi-gas in nuclear physics. The catastrophe theory is necessary to find connection between channels of fragments birth of different charge and masses, proceeding from the general form of a multi-dimensional phase space relief (a kind of potential function). The main result which can be taken from this theory at the given stage of researches consists in the general form of a curve of a

Nuclear matter flow in the Kr+Au collisions at 43 MeV/u

International Nuclear Information System (INIS)

Bougault, R.; Delaunay, F.; Genoux-Lubain, A.; Lebrun, C.; Lecolley, J.F.; Lefebvres, F.; Louvel, M.; Steckmeyer, J.C.; Aloff, J.C.; Bilwes, B.; Bilwes, R.; Glaser, M.; Rudolf, G.; Scheibling, F.; Stuttge, L.

1989-01-01

When heavy nuclei collide at energy far above the Coulomb barrier we may study the property of nuclear matter in temperature and also density regions far away from the equilibrium. We then hope to study dynamical effects related to the compressibility and the two body collision term. At relativistic energies, some collective effects (flow, bounce off) have been established from a shape analysis done with a large number of light particles with Z ≤ 10. For incident energies lower than 100 MeV/u we may expect that the number of nuclear species formed will be smaller and that a large part of the nuclear matter involved in the collision will be shared in a limited number of heavy fragments (Z ≥ 10). If dynamical effects are still present at GANIL energies they ought to manifest themselves through the properties of the produced fragments (masses, emission angles, velocities and correlated variables). We will present an analysis of heavy nuclei collisions at 43 MeV/u based on as exclusive as possible detection of large fragments

High transverse momentum resonance production in Pb-Pb, pp and p-Pb collisions at LHC

CERN Document Server

Nayak, Kishora

2015-01-01

Resonance production in heavy-ion collisions is expected to be a sensitive probe to the proper- ties of strongly interacting matter produced in such collisions. The production of resonances at high transverse momentum will help us to understand the mechanism of particle production and parton energy loss in the medium formed in ultra-relativistic heavy-ion collisions. We report the measurements of K ∗ 0 ( τ ∼ 4 fm/ c ) and φ ( τ ∼ 42 fm/ c ) production at high transverse momen- tum in pp, p–Pb and Pb–Pb collisions at LHC energies and nuclear modification factors. These measurements are compared to corresponding results for the other produced hadrons like charged kaons and protons. Some aspects of resonance production and particle production in general are discussed.

HEND: A Database for High Energy Nuclear Data

International Nuclear Information System (INIS)

Brown, D; Vogt, R

2007-01-01

We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. The database will be searchable and cross-indexed with relevant publications, including published detector descriptions. It should eventually contain all published data from older heavy-ion programs such as the Bevalac, AGS, SPS and FNAL fixed-target programs, as well as published data from current programs at RHIC and new facilities at GSI (FAIR), KEK/Tsukuba and the LHC collider. This data includes all proton-proton, proton-nucleus to nucleus-nucleus collisions as well as other relevant systems and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of experiments. To enhance the utility of the database, we propose periodic data evaluations and topical reviews. These reviews would provide an alternative and impartial mechanism to resolve discrepancies between published data from rival experiments and between theory and experiment. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support

Hadron-nucleus collisions

International Nuclear Information System (INIS)

Strugalski, Z.

1981-01-01

Qualitative picture of high energy hadron-nucleus collision process, emerging from the analysis of experimental data, is presented. Appropriate description procedure giving a possibility of reproducing various characteristics of this process in terms of the data on elementary hadron-nucleon interaction is proposed. Formula reproducing hadron-nucleus collision cross sections is derived. Inelastic collision cross sections for pion-nucleus and proton-nucleus reactions at wide energy interval are calculated for Pb, Ag, and Al targets. A-dependence of cross sections for pion-nucleus and proton-nucleus collisions at nearly 50 GeV/c momentum were calculated and compared with existing experimental data. Energy dependence of cross sections for hadron-nucleus collisions is determined simply by energy dependence of corresponding cross sections for hadron-nucleon collisions; A-dependence is determined simply by nuclear sizes and nucleon density distributions in nuclei

Definition and measurement of entropy in high energy heavy ion collisions

International Nuclear Information System (INIS)

Remler, E.A.

1986-01-01

This talk has two parts: the first on the definition and the second on the measurement of entropy. The connection to nuclear thermodynamics can be retained without the local equilibrium assumption via two steps. The first is relatively simple and goes as follows. The authors make the certainly reasonable assumption that in central collisions, at the moment of maximum compression, the state is similar to one or more fireballs and that the total entropy of each fireball approximates that of an equilibrated system at the same total energy and average density. This entropy, if measurable, would determine much of the thermodynamic properties of nuclear matter. The second step therefore concerns measurement of this entropy. This paper develops a method by which entropy may be measured using a minimum amount of theory. In particular, it is not based on any assumption local equilibrium

[Intermediate/high energy nuclear physics

International Nuclear Information System (INIS)

1987-01-01

We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. We have solved a non-trivial model field theory in the strong coupling regime using a discretized light front quantization (DLFQ) scheme. The method we developed expands upon the method of Pauli and Brodsky by incorporating a dynamical treatment of the vacuum. This is a major result since we have shown directly that the light-cone vacuum is not structureless as has been traditionally claimed by some particle theorists. We have thus succeeded in elucidating the consequences of spontaneous symmetry breaking in light-cone quantization. We now propose to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We will complete our analysis of the SLAC NE3 data to explicate the degree to which they confirm the QCM prediction of ''steps'' in the ratio of nuclear structure functions when Bjorken x exceeds unity. In another effort, we will perform a search for narrow resonances in electron-positron interactions high in the continuum using the Bethe-Salpeter equation. We have completed our development of microscopic effective Hamiltonians for nuclear structure which include the explicit treatment of delta resonances. These effective Hamiltonians were successfully used in constrained mean field calculations evaluating conditions for nuclei to undergo a transition from nucleon matter to delta matter. 73 refs

Dose equivalent near the bone-soft tissue interface from nuclear fragments produced by high-energy protons

Science.gov (United States)

Shavers, M. R.; Poston, J. W.; Cucinotta, F. A.; Wilson, J. W.

1996-01-01

During manned space missions, high-energy nucleons of cosmic and solar origin collide with atomic nuclei of the human body and produce a broad linear energy transfer spectrum of secondary particles, called target fragments. These nuclear fragments are often more biologically harmful than the direct ionization of the incident nucleon. That these secondary particles increase tissue absorbed dose in regions adjacent to the bone-soft tissue interface was demonstrated in a previous publication. To assess radiological risks to tissue near the bone-soft tissue interface, a computer transport model for nuclear fragments produced by high energy nucleons was used in this study to calculate integral linear energy transfer spectra and dose equivalents resulting from nuclear collisions of 1-GeV protons transversing bone and red bone marrow. In terms of dose equivalent averaged over trabecular bone marrow, target fragments emitted from interactions in both tissues are predicted to be at least as important as the direct ionization of the primary protons-twice as important, if recently recommended radiation weighting factors and "worst-case" geometry are used. The use of conventional dosimetry (absorbed dose weighted by aa linear energy transfer-dependent quality factor) as an appropriate framework for predicting risk from low fluences of high-linear energy transfer target fragments is discussed.

Geometric and electronic structures of molecular ions from high energy collisions

International Nuclear Information System (INIS)

Groeneveld, K.O.

1983-01-01

This chapter examines the characteristics of heavy ion collision and of beam foil spectroscopy. It discusses the kinematic consequences of the high energies and presents results from ''Coulomb explosion'' and structure determination of molecular ions. It demonstrates that studies of molecular ions with accelerators can provide electronic and geometric structure information of molecules or molecular ions and points out that the understanding of the microscopic processes at such high energies is incomplete and needs further experimental and theoretical efforts

Photon and dilepton production in high-energy heavy-ion collisions

Indian Academy of Sciences (India)

2015-05-07

May 7, 2015 ... The recent results on direct photons and dileptons in high-energy heavy-ion collisions, obtained particularly at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) are reviewed. The results are new not only in terms of the probes, but also in terms of the precision. We shall discuss the ...

Introduction to the study of particle accelerators. Atomic, nuclear and high energy physics for engineers

International Nuclear Information System (INIS)

Warnecke, R.R.

1975-01-01

This book is destined for engineers taking part in the design building and running of nuclear physics and high-energy physics particle accelerators. It starts with some notions on the theory of relativity, analytical and statistical mechanics and quantum mechanics. An outline of the properties of atomic nuclei, the collision theory and the elements of gaseous plasma physics is followed by a discussion on elementary particles: characteristic parameters, properties, interactions, classification [fr

Proton rapidity distribution in nucleus-nucleus collisions at high energy

International Nuclear Information System (INIS)

Liu, F.H.

2002-01-01

The proton rapidity distributions in nucleus-nucleus collisions at the Alternating Gradient Synchrotron (AGS) and the Super Proton Synchrotron (SPS) energies are analysed by the revised thermalized cylinder model. The calculated results are compared and found to he in agreement with the experimental data of Si-AI and Si-Pb collisions at 14.6 A GeV/c, Pb-Pb collisions at 158 A GeV/c, and S-S collisions at 200 A GeV/c. (Author)

Central collisions in intermediate energy heavy-ion reactions

International Nuclear Information System (INIS)

Wong, C.Y.

1979-01-01

The critical collisions in intermediate energy heavy-ion reactions are examined from both a microscopic and macroscopic viewpoint. In the microscopic description the proper tool is the extended TDHF approximation involving both the mean field and the particle collisions. To understand the underlying physics, the effect of the mean field and the effect of particle collisions are studied separately. It is found that th sudden increase in the density of the overlapping region can cause the volcano effect, leading to the complete disintegration of one of the nuclei. The self-consistent mean field also gives rise to the bunching instability when the two Fermi spheres of the colliding nucleons separate. The collision between nucleons, on the other hand, leads to irreversible dissipation, thermalization, and the possibility of a hydrodynamical description of the dynamics. Next is studied the dynamics of central collisions using the hydrodynamical description for many combinations of targets and projectiles at different energies. The formation of shock waves, sidesplash, and the complete disintegration of the whole nucleus are examined. Nuclear viscosity is found to affect the angular distribution of the reaction products and also the maximum compression ratio achieved during the collision. 28 references

J/psi production in proton-nucleus collisions at ALICE: cold nuclear matter really matters

CERN Multimedia

CERN. Geneva

2013-01-01

Heavy quarkonia are expected to be sensitive to the properties of strongly interacting matter, at both low and high temperatures. In nucleus-nucleus collisions, a phase transition to a deconfined state of quarks and gluons (Quark-Gluon Plasma) is thought to take place once the temperature of the system exceeds a critical temperature of the order of 150-200 MeV. The deconfined state can induce a suppression of charmonium (due to color screening, dominant at SPS and RHIC energies), which can be overturned at LHC energy by the (re)combination of the large number of free c and cbar quarks, taking place when the system cools down below the critical temperature. Cold nuclear matter also has an influence on heavy quarkonia. Such effects can be studied in proton-nucleus collisions, where no deconfined state is expected to be created. At LHC energy, they mainly include nuclear shadowing, gluon saturation, break-up of the quarkonium states, and parton energy loss in the initial and final state. The study of these eff...

Modeling defect production in high energy collision cascades

International Nuclear Information System (INIS)

Heinisch, H.L.; Singh, B.N.

1993-01-01

A multi-model approach roach (MMA) to simulating defect production processes at the atomic scale is described that incorporates molecular dynamics (MD), binary collision approximation (BCA) calculations and stochastic annealing simulations. The central hypothesis of the MMA is that the simple, fast computer codes capable of simulating large numbers of high energy cascades (e.g., BCA codes) can be made to yield the correct defect configurations when their parameters are calibrated using the results of the more physically realistic MD simulations. The calibration procedure is investigated using results of MD simulations of 25 keV cascades in copper. The configurations of point defects are extracted from the MD cascade simulations at the end of the collisional phase, similar to the information obtained with a binary collision model. The MD collisional phase defect configurations are used as input to the ALSOME annealing simulation code, and values of the ALSOME quenching parameters are determined that yield the best fit to the post-quenching defect configurations of the MD simulations

Beam energy dependence of d and d ‾ production in Au+Au collisions at RHIC

Science.gov (United States)

Yu, Ning; STAR Collaboration

2017-11-01

The binding energy of light nuclei is small compared to the temperature of the system created in heavy-ion collisions. Consequently, the yields of light nuclei can be used to probe the freeze-out properties, such as correlation volume and local baryon density of the medium created in high-energy nuclear collisions. In this paper, we report the results of deuteron and anti-deuteron production in Au+Au collision at √{sNN} = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV, measured by STAR at RHIC. The collision energy, centrality and transverse momentum dependence of the coalescence parameter B2 for deuteron and anti-deuteron production are discussed. We find the values of B2 for anti-deuterons are systematically lower than those for deuterons indicating the correlation volume of anti-baryon are larger than that of baryon. In addition, the values of B2 are found to vary with collision energy and show a broad minimum around √{sNN} = 20GeV, implying a change of the equation of state of the medium in these collisions.

Two-dimensional multiplicity fluctuation analysis of target residues in nuclear collisions

International Nuclear Information System (INIS)

Dong-Hai, Zhang; Yao-Jie, Niu; Li-Chun, Wang; Wen-Jun, Yan; Li-Juan, Gao; Ming-Xing, Li; Li-Ping, Wu; Hui-Ling, Li; Jun-Sheng, Li

2010-01-01

Multiplicity fluctuation of the target residues emitted in the interactions in a wide range of projectile energies from 500 A MeV to 60 A GeV is investigated in the framework of two-dimensional scaled factorial moment methodology. The evidence of non-statistical multiplicity fluctuation is found in 16 O–AgBr collisions at 60 A GeV, but not in 56 Fe–AgBr collisions at 500 A MeV, 84 Kr–AgBr collisions at 1.7 A GeV, 16 O–AgBr collisions at 3.7 A GeV and 197 Au–AgBr collisions at 10.7 A GeV. (nuclear physics)

Testing the black disk limit in $pp$ collisions at very high energy

OpenAIRE

Brogueira, P.; de Deus, J. Dias

2011-01-01

We use geometric scaling invariant quantities to measure the approach, or not, of the imaginary and real parts of the elastic scattering amplitude, to the black disk limit, in $pp$ collisions at very high energy.

Energy loss effect in high energy nuclear Drell-Yan process

International Nuclear Information System (INIS)

Duan, C.G.; Song, L.H.; Huo, L.J.; Li, G.L.

2003-01-01

The energy loss effect in nuclear matter, which is a nuclear effect apart from the nuclear effect on the parton distribution as in deep-inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the measured Drell-Yan production cross sections for 800 GeV proton incident on a variety of nuclear targets are analyzed within the Glauber framework which takes into account the energy loss of the beam proton. It is shown that the theoretical results with considering the energy loss effect are in good agreement with the FNAL E866 data. (orig.)

Fifth high-energy heavy-ion study

International Nuclear Information System (INIS)

1981-10-01

This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest available in the cosmic radiation. The lower range, particularly below 100 MeV/nucleon, will be under intense study in the near future with machines such as the upgraded Bevalac, Michigan State University Superconducting Cyclotron, GANIL in France, and the SC at CERN. Recently, the high energy collision regime has been expanded by the successful operation of the CERN ISR with alpha particles. Second, in addition to an extensive program of invited talks, we decided for the first time to actively solicit contributions. Forty-seven individual items from the conference were prepared separately for the data base

Fifth high-energy heavy-ion study

Energy Technology Data Exchange (ETDEWEB)

1981-10-01

This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest available in the cosmic radiation. The lower range, particularly below 100 MeV/nucleon, will be under intense study in the near future with machines such as the upgraded Bevalac, Michigan State University Superconducting Cyclotron, GANIL in France, and the SC at CERN. Recently, the high energy collision regime has been expanded by the successful operation of the CERN ISR with alpha particles. Second, in addition to an extensive program of invited talks, we decided for the first time to actively solicit contributions. Forty-seven individual items from the conference were prepared separately for the data base. (GHT)

Energy dependence of opaqueness for pp collisions at high energies

CERN Document Server

Chou, T T

1978-01-01

Opaqueness of pp collisions is evaluated at three CERN-ISR energies. Comparisons with predictions of the factorisable eikonal models and the scaling hypothesis are made. It appears that results are in favour of the factorisable models. (20 refs).

Numerical magneto-hydrodynamics for relativistic nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Inghirami, Gabriele [Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Goethe-Universitaet, Institute for Theoretical Physics, Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Forschungszentrum Juelich, John von Neumann Institute for Computing, Juelich (Germany); Del Zanna, Luca [Universita di Firenze, Dipartimento di Fisica e Astronomia, Firenze (Italy); INAF - Osservatorio Astrofisico di Arcetri, Firenze (Italy); INFN - Sezione di Firenze, Firenze (Italy); Beraudo, Andrea [INFN - Sezione di Torino, Torino (Italy); Moghaddam, Mohsen Haddadi [INFN - Sezione di Torino, Torino (Italy); Hakim Sabzevari University, Department of Physics, P. O. Box 397, Sabzevar (Iran, Islamic Republic of); Becattini, Francesco [Universita di Firenze, Dipartimento di Fisica e Astronomia, Firenze (Italy); INFN - Sezione di Firenze, Firenze (Italy); Bleicher, Marcus [Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Goethe-Universitaet, Institute for Theoretical Physics, Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Forschungszentrum Juelich, John von Neumann Institute for Computing, Juelich (Germany)

2016-12-15

We present an improved version of the ECHO-QGP numerical code, which self-consistently includes for the first time the effects of electromagnetic fields within the framework of relativistic magneto-hydrodynamics (RMHD). We discuss results of its application in relativistic heavy-ion collisions in the limit of infinite electrical conductivity of the plasma. After reviewing the relevant covariant 3 + 1 formalisms, we illustrate the implementation of the evolution equations in the code and show the results of several tests aimed at assessing the accuracy and robustness of the implementation. After providing some estimates of the magnetic fields arising in non-central high-energy nuclear collisions, we perform full RMHD simulations of the evolution of the quark-gluon plasma in the presence of electromagnetic fields and discuss the results. In our ideal RMHD setup we find that the magnetic field developing in non-central collisions does not significantly modify the elliptic flow of the final hadrons. However, since there are uncertainties in the description of the pre-equilibrium phase and also in the properties of the medium, a more extensive survey of the possible initial conditions as well as the inclusion of dissipative effects are indeed necessary to validate this preliminary result. (orig.)

Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions

Czech Academy of Sciences Publication Activity Database

Adam, J.; Adamová, Dagmar; Bielčík, J.; Bielčíková, Jana; Brož, M.; Čepila, J.; Contreras, J. G.; Eyyubova, G.; Ferencei, Jozef; Horák, D.; Křížek, Filip; Kučera, Vít; Mareš, Jiří A.; Petráček, V.; Pospíšil, Jan; Šumbera, Michal; Vaňát, Tomáš; Závada, Petr

2017-01-01

Roč. 13, č. 6 (2017), s. 535-539 ISSN 1745-2473 R&D Projects: GA MŠk(CZ) LG15052 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : ALICE collaboration * heavy ion collisions * multiplicity Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D) OBOR OECD: Nuclear physics; Particles and field physics (FZU-D) Impact factor: 22.806, year: 2016

Global features of nucleus-nucleus collisions in ultrarelativistic domain

International Nuclear Information System (INIS)

Savina, M.V.; Shmatov, S.V.; Slavin, N.V.; Zarubin, P.I.

1998-01-01

HIJING generator simulation of nucleus-nucleus collisions at ultrarelativistic energies is presented. It is shown that the global characteristics of nucleus-nucleus collisions, such as distribution of a charged multiplicity, total and electromagnetic transverse energy over pseudorapidity are rather sensitive to some predictions of models of high-exited nuclear medium formation, namely parton energy losses in dense nuclear matter. These losses result in appearance of a broad maximum in global variable distributions over pseudorapidity. The most profound of this effect occurs at central heavy ion collisions at LHC energy

On the nuclear fragmentation mechanisms in nuclear collisions at intermediate and high energies

International Nuclear Information System (INIS)

Jipa, Al.; Besliu, C.; Felea, D.; Iliescu, B.; Ristea, O.; Ristea, M.; Calin, C.; Horbuniev, A.; Arsene, I.; Esanu, T.; Ochesanu, S.; Caramarcu, C.; Bordeianu, C.; Rosu, I.; Grossu, V.; Zgura, I.S.; Stan, E.; Mitu, C.; Potlog, M.; Cherciu, M.; Stefan, I.

2004-01-01

The nuclear fragmentation mechanisms can be discussed taking into account different scales. These scales are related to the fragment sizes. Taking into account the possible different fragmentation mechanisms of the nuclei at the same incident energy an analysis of the experimental results obtained in different experiments performed at the JINR Dubna (Russia), KEK Tsukuba (Japan), GSI Darmstadt (Germany) is done. Results on apparent temperatures, angular distributions, fragment momentum spectra, multiplicities of the intermediate mass fragments are used to analyse the competition between two possible nuclear fragmentation mechanisms, namely: a sudden fragmentation by explosive mechanisms, like shock waves, and a slow fragmentation by the 'fission' of the spectator regions, mainly, because of the interactions with the particles or fragments emitted from the participant region at transverse angles on the incident nucleus, in CMS.Some connections with chaos dynamics and fractal structure of the fragmentation patterns are included. (authors)

The gluon condensation at high energy hadron collisions

Energy Technology Data Exchange (ETDEWEB)

Zhu, Wei, E-mail: weizhu@mail.ecnu.edu.cn [Department of Physics, East China Normal University, Shanghai 200241 (China); Lan, Jiangshan [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2017-03-15

We report that the saturation/CGC model of gluon distribution is unstable under action of the chaotic solution in a nonlinear QCD evolution equation, and it evolves to the distribution with a sharp peak at the critical momentum. We find that this gluon condensation is caused by a new kind of shadowing–antishadowing effects, and it leads to a series of unexpected effects in high energy hadron collisions including astrophysical events. For example, the extremely intense fluctuations in the transverse-momentum and rapidity distributions of the gluon jets present the gluon-jet bursts; a sudden increase of the proton–proton cross sections may fill the GZK suppression; the blocking QCD evolution will restrict the maximum available energy of the hadron–hadron colliders.

[Research in theoretical nuclear physics

International Nuclear Information System (INIS)

1993-01-01

Research in progress and plans for future investigations are briefly summarized for the following areas: light-ion structure and reactions; nuclear structure; peripheral heavy-ion reactions at medium and high energy; medium-energy heavy-ion collisions and properties of highly excited nuclear matter; and high-energy heavy-ion collisions and QCD plasma

Application of the non-extensive statistical approach to high energy particle collisions

Science.gov (United States)

Bíró, Gábor; Barnaföldi, Gergely Gábor; Biró, Tamás Sándor; Ürmössy, Károly

2017-06-01

In high-energy collisions the number of created particles is far less than the thermodynamic limit, especially in small colliding systems (e.g. proton-proton). Therefore final-state effects and fluctuations in the one-particle energy distribution are appreciable. As a consequence the characterization of identified hadron spectra with the Boltzmann - Gibbs thermodynamical approach is insuffcient [1]. Instead particle spectra measured in high-energy collisions can be described very well with Tsallis -Pareto distributions, derived from non-extensive thermodynamics [2, 3]. Using the Tsallis q-entropy formula, a generalization of the Boltzmann - Gibbs entropy, we interpret the microscopic physics by analysing the Tsallis q and T parameters. In this paper we give a quick overview on these parameters, analyzing identified hadron spectra from recent years in a wide center-of-mass energy range. We demonstrate that the fitted Tsallis-parameters show dependency on the center-of-mass energy and particle species. Our findings are described well by a QCD inspired evolution ansatz. Based on this comprehensive study, apart from the evolution, both mesonic and barionic components found to be non-extensive (q > 1), beside the mass ordered hierarchy observed in parameter T.

Direct photons in nuclear collisions at fair energies

International Nuclear Information System (INIS)

Kiselev, S. M.

2009-01-01

Using the extrapolation of existing data, estimations of prompt-photon production at FAIR energies have been made. At y = y c.m. the rapidity density of prompt photons with p t > 1.5 GeV/c per central Au + Au event at 25 A GeV is estimated as ∼10 -4 . With the planned beam intensity 10 9 per second and 1% interaction probability, for 10% of most central events one can expect the prompt-photon rate ∼10 2 photons per second. Direct photons from the hadron scenario of ion collisions generated by the Hadron-String-Dynamics (HSD) transport approach with implemented meson scatterings πρ → πγ, ππ → ργ have been analyzed. Photons from short-living resonances (e.g., ω → π 0 γ) decaying during the dense phase of the collision should be considered as direct photons. They contribute significantly in the direct photon spectrum at p t = 0.5-1 GeV/c. At the FAIR energy 25 A GeV in Au + Au central collisions the HSD generator predicts, as a lower estimate, γ direct /γ ( π 0 ) ≅ 0.5% in the region p t = 0.5-1 GeV/c. At p t = 1.5-2 GeV/c γ prompt / γ ( π 0 ) ≅ 2%. Thermal direct photons have been evaluated with the Bjorken Hydro-Dynamics (BHD) model. The BHD spectra differ strongly from the HSD predictions. The direct-photon spectrum is very sensitive to the initial temperature parameter T 0 of the model. The 10-MeV increase in the T 0 value leads to ∼2 times higher photon yield.

Search for Fractionally Charged Nuclei in High-Energy Oxygen-Lead Collisions

CERN Multimedia

2002-01-01

We propose to use stacks of CR-39 plastic track detectors to look for fractionally charged projectile fragments produced in collisions of high-energy oxygen, sulfur, and calcium nuclei with a lead target. The expected charge resolution is @s^z~=~0.06e for fragments with 17e/3~@$<$~Z~@$<$~23e/3. We request that two target + stack assemblies be exposed to 1~x~10|5 oxygen nuclei at maximum available energy.

New results on nuclear multifragmentation in nucleon-nucleus and nucleus-nucleus collisions at relativistic energies

International Nuclear Information System (INIS)

Besliu, Calin; Jipa, Alexandru; Iliescu, Bogdan; Felea, Daniel

2002-01-01

Some new aspects on the multifragmentation processes in nucleus-nucleus and nucleon-nucleus collisions at high energies are discussed in this work. Experimental data obtained in international collaborations (for example, MULTI Collaboration with KEK Tsukuba (Japan) and SKM 200 Collaboration with JINR Dubna (Russia)) are used to discuss new mechanisms in the target nucleus fragmentation. Correlations with stopping power, participant region size and energy density are included. Comparisons of the experimental results with the predictions of a phenomenological geometric model of intermediate mass fragment multiplicity, caloric curves and angular distributions are also presented. These results are used for global description of the multifragmentation processes in nucleon-nucleus and nucleus-nucleus collisions at relativistic energies. The size of the participant region and the average intermediate mass fragments multiplicity are taken into consideration using the free space probability. A few correlations between the deposited energy in the participant region and stability state of the intermediate mass fragments are presented in this work. The importance of the collision geometry in the multifragmentation processes is stressed. The results suggest different time moments for the incident nucleus fragmentation and for the target nucleus fragmentation. The associated entropies are distinct. (authors)

Probabilistic risk assessment on maritime spent nuclear fuel transportation (Part II: Ship collision probability)

International Nuclear Information System (INIS)

Christian, Robby; Kang, Hyun Gook

2017-01-01

This paper proposes a methodology to assess and reduce risks of maritime spent nuclear fuel transportation with a probabilistic approach. Event trees detailing the progression of collisions leading to transport casks’ damage were constructed. Parallel and crossing collision probabilities were formulated based on the Poisson distribution. Automatic Identification System (AIS) data were processed with the Hough Transform algorithm to estimate possible intersections between the shipment route and the marine traffic. Monte Carlo simulations were done to compute collision probabilities and impact energies at each intersection. Possible safety improvement measures through a proper selection of operational transport parameters were investigated. These parameters include shipment routes, ship's cruise velocity, number of transport casks carried in a shipment, the casks’ stowage configuration and loading order on board the ship. A shipment case study is presented. Waters with high collision probabilities were identified. Effective range of cruising velocity to reduce collision risks were discovered. The number of casks in a shipment and their stowage method which gave low cask damage frequencies were obtained. The proposed methodology was successful in quantifying ship collision and cask damage frequency. It was effective in assisting decision making processes to minimize risks in maritime spent nuclear fuel transportation. - Highlights: • Proposes a probabilistic framework on the safety of spent nuclear fuel transportation by sea. • Developed a marine traffic simulation model using Generalized Hough Transform (GHT) algorithm. • A transportation case study on South Korean waters is presented. • Single-vessel risk reduction method is outlined by optimizing transport parameters.

Influence of the nuclear autocorrelation function on the positron production in heavy-ion collisions

International Nuclear Information System (INIS)

Tomoda, T.; Weidenmueller, H.A.

1983-01-01

The influence of a nuclear reaction on atomic positron production in heavy-ion collisions is investigated. Using statistical concepts, we describe the nuclear S matrix for a heavy-ion induced reaction as a statistically fluctuating function of energy. The positron production rate is then dependent on the autocorrelation function of this S matrix, and on the ratio of the ''direct'' versus the ''fluctuating'' part of the nuclear cross section. Numerical calculations show that in this way, current experimental results on positron production in heavy-ion collisions can be reproduced in a semiquantitative fashion

Very high energy probes of the quark-gluon plasma

International Nuclear Information System (INIS)

Ludlam, T.; Paige, F.; Madansky, L.

1984-01-01

Among the penetrating probes of nuclear matter the most frequently discussed have been those which involve the detection of photons or leptons with m/sub T/ approx. = P/sub T/ < 3 GeV. This is the expected range of emission from a hot, thermalized plasma of quarks and gluons. The suggestion has been made that in very high energy collisions of nuclei the properties of high P/sub T/ jets may also reflect the characteristics of the nuclear medium through which the parent partons have propagated just after the collision. In this note we expand on the possible uses of such a probe

Studies on the dynamics of heavy ion collisions at intermediate energies

International Nuclear Information System (INIS)

David, C.; Hartnack, C; Aichelin, J.

1997-01-01

We use the Quantum Molecular Dynamics model for the investigation of the dynamics of heavy ion collisions at intermediate energies. A detailed comparison between different versions of the models demonstrate the influence of not exactly known parameters in the description of nuclei like interaction range or initial densities and thus describes the limits of predictive power. The dynamics of the reaction are discussed quite similarly in the different models. A radial expansion with a linear velocity profile is found at central collisions. A strong interaction of pions with nuclear matter is reported. This interaction is strongly influenced by the lifetime of baryonic resonances in nuclear matter. These lifetimes depend strongly on the mass distribution of the resonances. These mass distributions are influenced by the momentum distribution in the nuclei. Here the inclusion of the spectral function shows visible effects. These effects influence the energy dissipation in nuclei and thus enter e.g. into the analysis of p + A collisions for the GEDEON project. (author)

Determination of kinetic coefficients for proton-nucleus collisions at high energy

International Nuclear Information System (INIS)

Rizzato, C.M.

1987-01-01

From the effective proton dynamics, the approximations in the context of high energy collisions which lead to the Boltzmann equation, are established. From this equation, general expressions for the kinetic coefficients are deduced. Using a simple model, analytical expressions for kinetic coefficients are obtained. The importance of the effect of Pauli blocking is also shown. (author) [pt

Isospin effects in intermediate energy heavy ion collision

International Nuclear Information System (INIS)

Liu Jianye; Zuo Wei; Yang Yanfang; Zhao Qiang; Guo Wenjun

2001-01-01

Based on the achievements for the intermediate energy heavy ion collision in authors' recent work and the progresses in the world, the isospin effects and the dependence of the entrance channel conditions on them in the intermediate energy heavy ion collisions were introduced, analysed and commended. From the calculation results by using isospin dependence quantum molecular dynamics, it is clear to see that the nuclear stopping power strongly depends on the in-medium isospin dependence nucleon-nucleon cross section and weakly on the symmetry potential in the energy region from about Fermi energy to 150 MeV/u and the intermediate mass fragment multiplicity also sensitively depends on the in-medium isospin dependent nucleon-nucleon cross section and weakly on the symmetry potential in a selected energy region. But the preequilibrium emission neutron-proton ratio is quite contrary, it sensitively depends on the symmetry potential and weakly on the in-medium isospin dependent nucleon-nucleon cross section. In addition to the nuclear stopping sensitively depending on the beam energy, impact parameter and the mass of colliding system and weakly on the neutron-proton ratio of the colliding systems with about the same mass, the preequilibrium emission neutron-neutron ratio sensitively depends on the beam energy and the neutron-proton ratio of colliding system, but weakly on the impact parameter. From above results it is proposed that the nuclear stopping is a new probe to extract the information on the in-medium isospin dependence nucleon-nucleon cross section in energy region from about Fermi energy to 150 MeV/u and the preequilibrium emission neutron-proton ratio is a good probe for extracting the information about the symmetry potential from the lower energy to about 150 MeV/u

Quark Energy Loss and Shadowing in Nuclear Drell-Yan Process

Institute of Scientific and Technical Information of China (English)

DUAN Chun-Gui; CUI Shu-Wen; YAN Zhan-Yuan

2005-01-01

The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic IA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions should not include Drell-Yan experimental data.

Quark Energy Loss and Shadowing in Nuclear Drell-Yan Process

International Nuclear Information System (INIS)

Duan Chungui; Cui Shuwen; Yan Zhanyuan

2005-01-01

The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic lA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions should not include Drell-Yan experimental data.

Hard scattering contribution to particle production in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Pareek, Pooja; Mishra, Aditya Nath; Sahoo, Pragati; Sahoo, Raghunath

2014-01-01

Global observables like the multiplicity of produced charged particles and transverse energy, are the key observables used to characterize the properties of the matter created in heavy-ion collisions. In order to study the dependence of the charged particle density on colliding system, center of mass energy and collision centrality, there have been measurements starting few GeV to TeV energies at LHC. There is a need to understand the particle production contribution coming from the QCD hard processes, which scale with number of binary nucleon-nucleon collisions, N coll and soft processes scaling with number of participant nucleons, N part

Analysis of $\\pi^{0},\\eta$ and $\\omega$ mesons in pp collisions with a high energy photon trigger at ALICE

CERN Document Server

Yano, Satoshi

High energy heavy ion collision is a powerful and unique tool to achieve the high density and temperature like the early universe. At normal temperature, partons are confined in nucleons and they can not move freely due to the asymp- totic freedom which is a property of the Quantum Chromo Dynamics (QCD). However, at high density and/or high temperature, they can be deconfined from nucleons. This phase is called the Quark Gluon Plasma (QGP). Hadron production measurements in proton-proton collisions at the Large Hadron Collider (LHC) energies can observe new phenomena which must be a frontier in the particle physics and allow validation of the predictive power of the QCD and can provide further constrains on pQCD theory for LHC energies. It is well known that the yield of high transvers momentum particles is suppressed in nucleus-nucleus collisions relative to that in proton-proton collisions. This effect is attributed to energy loss of parent partons or perhaps of hadrons after freeze-out. Since π 0 , η and...

Progress in high energy physics and nuclear safety : Proceedings of the NATO Advanced Research Workshop on Safe Nuclear Energy

CERN Document Server

Polański, Aleksander; Begun, Viktor

2009-01-01

The book contains recent results on the progress in high-energy physics, accelerator, detection and nuclear technologies, as well as nuclear safety in high-energy experimentation and in nuclear industry, covered by leading experts in the field. The forthcoming experiments at the Large Hadron Collider (LHC) at CERN and cosmic-ray experiments are highlighted. Most of the current high-energy experiments and their physical motivation are analyzed. Various nuclear energy safety aspects, including progress in the production of new radiation-resistant materials, new and safe nuclear reactor designs, such as the slowly-burning reactor, as well as the use of coal-nuclear symbiotic methods of energy production can be found in the book.

J/psi production and nuclear effects in p-Pb collisions at=5.02 TeV

Czech Academy of Sciences Publication Activity Database

Abelev, B.; Adam, J.; Adamová, Dagmar; Bielčík, J.; Bielčíková, Jana; Čepila, J.; Ferencei, Jozef; Křelina, M.; Křížek, Filip; Krus, M.; Kučera, Vít; Kushpil, Svetlana; Kushpil, Vasilij; Mareš, Jiří A.; Pachr, M.; Petráček, V.; Petráň, M.; Pospíšil, V.; Schulc, M.; Šmakal, R.; Špaček, M.; Šumbera, Michal; Vajzer, Michal; Wagner, V.; Zach, Č.; Závada, Petr

2014-01-01

Roč. 2014, č. 2 (2014), 073 ISSN 1029-8479 R&D Projects: GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : ALICE * heavy ion collisions * transverse momentum Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D) Impact factor: 6.111, year: 2014

Inclusive glueball production in high-energy p+p(p) collisions

CERN Document Server

Peng Hong An; He Zhen Min

2001-01-01

Using the factorizable character of amplitudes for the double diffractive process in the Landshoff-Nachtmann model (1987), we have discussed the inclusive glueball production in high-energy pp collisions via the fusion process of two non-perturbative gluons, and have compared it with the double diffractive alike process. We found that, as the c.m. energy E/sub CMS/ increases from 20 to 20 000 GeV, the cross sections of the latter process are about one to two orders larger than the former. Such an outcome could be explained from the hypothesis of duality between glueballs and pomeron. (7 refs).

A study of vorticity formation in high energy nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Becattini, F. [Universita di Firenze, Dipartimento di Fisica e Astronomia, Sesto F.no (Firenze) (Italy); INFN, Sezione di Firenze, Sesto F.no (Firenze) (Italy); Inghirami, G. [Universita di Firenze, Dipartimento di Fisica e Astronomia, Sesto F.no (Firenze) (Italy); Johann Wolfgang Goethe University, Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main (Germany); Rolando, V.; Pagliara, G. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); INFN, Sezione di Ferrara, Ferrara (Italy); Beraudo, A.; De Pace, A.; Nardi, M. [INFN, Sezione di Torino, Turin (Italy); Del Zanna, L. [Universita di Firenze, Dipartimento di Fisica e Astronomia, Sesto F.no (Firenze) (Italy); INFN, Sezione di Firenze, Sesto F.no (Firenze) (Italy); INAF, Osservatorio Astrofisico di Arcetri, Florence (Italy); Chandra, V. [Indian Institute of Technology Gandhinagar, Ahmedabad, Gujrat (India)

2015-09-15

We present a quantitative study of vorticity formation in peripheral ultrarelativistic heavy-ion collisions at √(s{sub NN}) = 200 GeV by using the ECHO-QGP numerical code, implementing relativistic dissipative hydrodynamics in the causal Israel-Stewart framework in 3 + 1 dimensions with an initial Bjorken flow profile. We consider different definitions of vorticity which are relevant in relativistic hydrodynamics. After demonstrating the excellent capabilities of our code, which proves to be able to reproduce Gubser flow up to 8 fm/c, we show that, with the initial conditions needed to reproduce the measured directed flow in peripheral collisions corresponding to an average impact parameter b = 11.6 fm and with the Bjorken flow profile for a viscous Quark Gluon Plasma with η/s = 0.1 fixed, a vorticity of the order of some 10{sup -2} c/fm can develop at freeze-out. The ensuing polarization of Λ baryons does not exceed 1.4 % at midrapidity. We show that the amount of developed directed flow is sensitive to both the initial angular momentum of the plasma and its viscosity. (orig.)

The picture of the nuclei disintegration mechanism - from hadron-nucleus and nucleus-nucleus collisions experimental investigations at high energies

International Nuclear Information System (INIS)

Strugalska-Gola, E.; Strugalski, Z.; Chmielowski, W.

1997-01-01

The mechanism of the nuclei disintegration process in collisions of high-energy hadrons with nuclei is revealed experimentally. The disintegration appears as a complicated nuclear process developing in time and space in intranuclear matter, consisting at least of three stages which last together about 10 -24 - 10 -17 s after the impact. At the first stage, which lasts about 10 -24 - 10 -22 s, fast nucleons are densely emitted and the target-nucleus is locally damaged. At the second stage, lasting about 10 -22 - 10 -1 7 s, the damaged and unstable residual target nucleus uses to evaporate light fragments - mainly nucleons, deuterons, tritons, α-particles. At the final stage, the residual target-nucleus uses to split sometimes into two or more nuclear fragments

Nuclear collisions at several tens of MeV per nucleus

International Nuclear Information System (INIS)

Randrup, J.

1979-10-01

Nuclear beams with energies of several tens of MeV per nucleon will soon be available at a number of research centers around the world. Such beams offer a tool for probing new aspects of nuclear structure and dynamics. As the energy is raised models and concepts developed for the relatively well studied lower energy domain will be pressed to their limits and are likely to grow obsolete as novel phenomena enter the scene. The theory of ordinary damped collisions is considered; the testing of such theories is one important aspect of the research with higher beam energies. Another is the search for truly novel phenomena, and some more speculative material on that aspect are given. 15 references

Nuclear collisions at several tens of MeV per nucleus

Energy Technology Data Exchange (ETDEWEB)

Randrup, J.

1979-10-01

Nuclear beams with energies of several tens of MeV per nucleon will soon be available at a number of research centers around the world. Such beams offer a tool for probing new aspects of nuclear structure and dynamics. As the energy is raised models and concepts developed for the relatively well studied lower energy domain will be pressed to their limits and are likely to grow obsolete as novel phenomena enter the scene. The theory of ordinary damped collisions is considered; the testing of such theories is one important aspect of the research with higher beam energies. Another is the search for truly novel phenomena, and some more speculative material on that aspect are given. 15 references.

Nuclear emulsion and high-energy physics

International Nuclear Information System (INIS)

Sun Hancheng; Zhang Donghai

2008-01-01

The history of the development of nuclear emulsion and its applications in high-energy physics, from the discovery of pion to the discovery of tau neutrino, are briefly reviewed in this paper. A new stage of development of nuclear-emulsion technique is discussed

A midrapidity source of intermediate mass fragments in highly central collisions of Au+Au at 150 A MeV

Energy Technology Data Exchange (ETDEWEB)

Alard, J P; Bastid, N; Crouau, M; Dupieux, P; Fraysse, L; Jorio, M; Montarou, G; Morel, P [Laboratoire de Physique Corpusculaire, 63 - Clermont-Ferrand (France); Basrak, Z; Caplar, R; Cindro, N; Hoelbling, S [Rudjer Boskovic Inst., Zagreb (Yugoslavia); Belayev, I M; Frolov, S; Korchagin, Y; Lebedev, A; Smolyankin, S; Zhilin, A V [Institute for Experimental and Theoretical Physics, Moscow (Russia); Bini, M; Olmi, A; Pasquali, G; Poggi, G; Taccetti, N [Florence Univ. (Italy); [INFN, Florence (Italy); Blaich, T [Mainz Univ. (Germany); Buta, A; Legrand, I; Moisa, D; Petrovici, M; Simion, V [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cerruti, C; Coffin, J P; Fintz, P; Guillaume, G; Houari, O; Jundt, F; Kuhn, C; Maguire, C; Rami, F; Tezkratt, R; Wagner, P [Centre de Recherches Nucleaires, 67 - Strasbourg (France); [Strasbourg Univ., 67 (France); Eroe, J; Fodor, Z; Kecskemeti, J; Koncz, P; Seres, Z [Central Research Inst. for Physics, Budapest (Hungary); Grigoriyan, Y; Manko, V; Mgebrishvili, G; Sadchikov, A; Vasiliev, M A [Kurchatov Inst. for Atomic Energy, Moscow (Russia); Herrmann, N; Pelte, D; Trzaska, M; Wienold, T [Heidelberg Univ. (Germany). Physikalisches Inst.; Kotte, R; Moesner, J; Neubert, W; Wohlfarth, D [Forschungszentrum Rossendorf (Germany); Matulewicz, T; Sikora, B; Wilhelmi, Z [Warsaw Univ. (Poland). Inst. of Experimental Physics; Bock, R; Fan, Z G; Freifelder, R; Gobbi, A; Hildenbrand, K D; Jeong, S C; Kraemer, M; Reisdorf, W; Schuell, D; Sodan, U; Teh, K; Wessels, J P; FOPI Collaboration at GSI

1992-02-01

Charged particles have been observed in collisions of Au on Au at incident energy of 150 A MeV using a high-granularity detector system covering approximatley the forward hemisphere in the center-of-mass system. Highly central collisions have been studied using a double selection criterion which combines large charged particle multiplicities with small transverse momentum directivities. In this class of events about one quarter of the total nuclear charge emerges as intermediate mass fragments with nuclear charges Z>2. These fragments are centred at midrapidity and are produced with large transverse velocities. (orig.).

A midrapidity source of intermediate mass fragments in highly central collisions of Au+Au at 150 A MeV

International Nuclear Information System (INIS)

Alard, J.P.; Bastid, N.; Crouau, M.; Dupieux, P.; Fraysse, L.; Jorio, M.; Montarou, G.; Morel, P.; Basrak, Z.; Caplar, R.; Cindro, N.; Hoelbling, S.; Belayev, I.M.; Frolov, S.; Korchagin, Y.; Lebedev, A.; Smolyankin, S.; Zhilin, A.V.; Bini, M.; Olmi, A.; Pasquali, G.; Poggi, G.; Taccetti, N.; Blaich, T.; Buta, A.; Legrand, I.; Moisa, D.; Petrovici, M.; Simion, V.; Cerruti, C.; Coffin, J.P.; Fintz, P.; Guillaume, G.; Houari, O.; Jundt, F.; Kuhn, C.; Maguire, C.; Rami, F.; Tezkratt, R.; Wagner, P.; Eroe, J.; Fodor, Z.; Kecskemeti, J.; Koncz, P.; Seres, Z.; Grigoriyan, Y.; Manko, V.; Mgebrishvili, G.; Sadchikov, A.; Vasiliev, M.A.; Herrmann, N.; Pelte, D.; Trzaska, M.; Wienold, T.; Matulewicz, T.; Sikora, B.; Wilhelmi, Z.; Bock, R.; Fan, Z.G.; Freifelder, R.; Gobbi, A.; Hildenbrand, K.D.; Jeong, S.C.; Kraemer, M.; Reisdorf, W.; Schuell, D.; Sodan, U.; Teh, K.; Wessels, J.P.

1992-02-01

Charged particles have been observed in collisions of Au on Au at incident energy of 150 A MeV using a high-granularity detector system covering approximatley the forward hemisphere in the center-of-mass system. Highly central collisions have been studied using a double selection criterion which combines large charged particle multiplicities with small transverse momentum directivities. In this class of events about one quarter of the total nuclear charge emerges as intermediate mass fragments with nuclear charges Z>2. These fragments are centred at midrapidity and are produced with large transverse velocities. (orig.)

Relation between hard photon production and impact parameter in heavy ion collisions at intermediate energies; Dependance de la production de photons durs avec le parametre d`impact dans les collisions entre ions lourds aux energies intermediaires

Energy Technology Data Exchange (ETDEWEB)

Martinez Garcia, G.

1994-06-01

Hard photons produced in heavy-ions collisions at intermediate energies have been used in order to study hot and compresses nuclear matter created in these collisions (at Ganil). It was found that Bremsstrahlung radiation emitted in np collisions is the main mechanism of hard-photon production for the whole range of impact parameter. Moreover, it was observed a substantial decrease of the hardness of hard-photon spectrum. The BUU model reproduces very well the experimental results, showing that the hardness of the spectrum reflects, mainly, nuclear-matter compression in the first stage of the collision. A new method was developed to measure the density of the nuclear matter created at the beginning of the collision. BUU results and some experimental evidences point out that a significant contribution of hard photons are produced in the last stage of the collision: thermal hard photons. These photons are sensitive to the density oscillation of nuclear matter. Its production cross-section will constitute a measurement of the compressibility of nuclear matter and its spectrum a measure of the temperature. (from author) 64 figs., 60 refs.

NMTC/JAM, Simulates High Energy Nuclear Reactions and Nuclear-Meson Transport Processes

International Nuclear Information System (INIS)

Furihata, Shiori

2002-01-01

1 - Description of program or function: NMTC/JAM is an upgraded version of the code system NMTC/JAERI97. NMTC/JAERI97 simulates high energy nuclear reactions and nucleon-meson transport processes. It implements an intra-nuclear cascade model taking account of the in-medium nuclear effects and the pre-equilibrium calculation model based on the exciton one. For treating the nucleon transport process, the nucleon-nucleus cross sections are revised to those derived by the systematics of Pearlstein. Moreover, the level density parameter derived by Ignatyuk is included as a new option for particle evaporation calculation. A geometry package based on the Combinatorial Geometry with multi-array system and the importance sampling technique is implemented in the code. Tally function is also employed for obtaining such physical quantities as neutron energy spectra, heat deposition and nuclide yield without editing a history file. The code can simulate both the primary spallation reaction and the secondary particle transport in the intermediate energy region from 20 MeV to 3.5 GeV by the use of the Monte Carlo technique. The code has been employed in combination with the neutron-photon transport codes available to the energy region below 20 MeV for neutronics calculation of accelerator-based subcritical reactors, analyses of thick target spallation experimented and so on. 2 - Methods: High energy nuclear reactions induced by incident high energy protons, neutrons and pions are simulated with the Monte Carlo Method by the intra-nuclear nucleon-nucleon reaction probabilities based on an intra-nuclear nucleon cascade model followed by the particle evaporation including high energy fission process. Jet-Aa Microscopic transport model (JAM) is employed to simulate high energy nuclear reactions in the energy range of GeV. All reaction channels are taken into account in the JAM calculation. An intra-nuclear cascade model (ISOBAR code) taking account of the in-medium nuclear effects

Inelastic scattering and endohedral complex formation in high-energy collisions of fullerenes with He

International Nuclear Information System (INIS)

Callahan, J.H.; Mowrey, R.C.; Ross, M.M.

1992-01-01

Since the original postulation of its icosahedral structure by Smalley and Kroto in 1985, C 60 (also known as buckminsterfullerene) has fascinated investigators in a variety of fields. With the publication of a synthetic method for the bulk production of C 60 , there has been an explosion of research interest in this molecule. A number of intriguing experimental results have been published, including work in the area of mass spectrometry. For example, at a workshop at the 1991 ASMS meeting, Schwartz and coworkers reported a remarkable result. They showed that high energy collisions of C 60 + with He resulted not only in the expected formation of collision-induced dissociation (CID) products such as C 56 + and C 58 + (C 2 loss is the main fragmentation pathway for C 60 ), but also in the formation of products such as C 56 + + 4 and C 58 + + 4. Careful experiments with He showed that the products were C 56 He + and C 58 He + , most likely formed by the uptake of He by C 60 + during the collision. Subsequent experiments in this laboratory were able to directly observe the C 60 He + product, the product ion shifts in kinetic energy by an amount equal to the center-of-mass collision energy, consistent with kinematic arguments. C 60 He + was also observed by the Gross group and the Schwarz group. Gross and coworkers also showed that inelastic scattering processes can be observed in the collision spectrum. More recently, the Anderson group has studied reverse processes, in which ions such as He + , Li + , and C + undergo collisions with C 60 and are taken up in the collision

Study of heavy ions collision at SIS energies with the detector FOPI; Etude des collisions d'ions lourds aux energies de SIS avec le detecteur FOPI

Energy Technology Data Exchange (ETDEWEB)

Bastid, N

1999-09-23

The present work has been carried out in the framework of experiments performed with the FOPI detector at the SIS/ESR accelerator facility of GSI-Darmstadt. It is devoted to the study of central and semi-central heavy ion collisions at beam energies ranging from 100 MeV to 2 GeV per nucleon. We present first generalities on relativistic heavy ion collisions then the FOPI detector with a special attention to the FOPI Inner Wall constructed by the Clermont-Ferrand group. The main results of the FOPI collaboration obtained with light and intermediate mass fragments and kaons are presented. A systematic study of the different forms of collection motion of nuclear matter, radial flow in very central reactions, sideward flow and squeeze-out in semi-central collisions, is performed. Further exciting possibilities concerning production and propagation of strangeness at SIS energies will be offered soon with the upgrade of the FOPI detector. The FOPI data have introduced constraints on parameters of theoretical models. Important progress concerning the knowledge of the properties of nuclear matter, the dynamics of the collisions and in-medium effects have been achieved. (author)

Quantum mechanical theory of positron production in heavy ion collisions with nuclear contact

International Nuclear Information System (INIS)

Heinz, U.

1986-01-01

The interplay between atomic and nuclear interactions in heavy ion collisions with nuclear contact is studied. The general theoretical description is outlined and analyzed in a number of different limits (semiclassical approximation, DWBA, fully quantal description). The two most important physical mechanisms for generating atomic-nuclear interference, i.e., energy conservation and the introduction of additional phase shifts by nuclear reactions, are extracted. The resulting typical coupling matrix elements are analyzed for their relative importance in atomic and nuclear excitations. The description of nuclear influence on atomic excitations in terms of a classical time delay caused by nuclear reactions is reviewed, and its relationship to the underlying quantal character of the nuclear reaction is discussed. The theory is applied to spontaneous positron emission in supercritical heavy-ion collisions (Z/sub tot/ ≥ 173). It is shown that nuclear contact can lead to line structures in the positron energy spectra if the probability distribution for nuclear delay times caused by the contact has contributions for T ≥ 10 -19 sec. We explicitly evaluate a model where a pocket in the internuclear potential near the touching configuration leads to formation of nuclear molecules, and predict a resonance-like excitation function for the positron peak. 25 refs., 7 figs

arXiv Isothermal compressibility of hadronic matter formed in relativistic nuclear collisions

CERN Document Server

Mukherjee, Maitreyee; Chatterjee, Arghya; Chatterjee, Sandeep; Adhya, Souvik Priyam; Thakur, Sanchari; Nayak, Tapan K.

We present the first estimates of isothermal compressibility (\\kT) of hadronic matter formed in relativistic nuclear collisions (\\sNN=7.7~GeV to 2.76~TeV) using experimentally observed quantities. \\kT~is related to the fluctuation in particle multiplicity, temperature and volume of the system formed in the collisions. Multiplicity fluctuations are obtained from the event-by-event distributions of charged particle multiplicities in narrow centrality bins. The dynamical components of the fluctuations are extracted by removing the contributions to the fluctuations from the number of participating nucleons. From the available experimental data, a constant value of \\kT~has been observed as a function of collision energy. The results are compared with calculations from UrQMD, AMPT and EPOS event generators, and estimations of \\kT~are made for Pb-Pb collisions at the CERN Large Hadron Collider. A hadron resonance gas (HRG) model has been used to calculate \\kT~as a function of collision energy. Our results show a dec...

High energy nucleus-nucleus collisions at CERN: Signatures, physical observables and experimental results

International Nuclear Information System (INIS)

Harris, J.W.

1988-02-01

Experimental results on high energy nucleus-nucleus collisions have become available with the recent experiments at CERN utilizing 200 GeV/n oxygen and sulfur beams. Physics motivations for these experiments are presented: a description of predicted signatures for possible formation of a quark-gluon plasma and physical observables that are expected to provide important information for understanding the dynamics of these collisions. A presentation will be made of some of the first experimental results to emerge from this new field. 28 refs., 9 figs

Collective flow in central Ca + Ca and Nb + Nb collisions

International Nuclear Information System (INIS)

Fai, G.; Csernai, L.P.; Kapusta, J.I.

1986-01-01

Questions related to the entropy, equation of state and collective flow of nuclear matter are important to the authors understanding of high energy nuclear collisions. Completion of the analysis of exclusive measurements on central Ca + Ca and Nb + Nb collisions triggered renewed interest in these problems. In order to address the results of exclusive measurements, however, the complex multifragment final states of high energy nuclear collisions need to be incorporated in a theoretical description. The microcanonical event generator model provides statistically generated complete events that can be compared to the exclusive data on an event-by-event basis. To describe the disassembly of hot nuclear matter the model uses an approximate scheme in which the available final states are populated according to their microcanonical weight in phase space. This statistical description is front-ended with simple geometric ideas to divide the collision system into subsystems and with a prescription to share energy and momentum among the subsystems. Any physical quantity of interest is in principle calculable in the model if sufficient statistics is accumulated

Quantum chromodynamics at high energy, theory and phenomenology at hadron colliders; Chromodynamique quantique a haute energie, theorie et phenomenologie appliquee aux collisions de hadrons

Energy Technology Data Exchange (ETDEWEB)

Marquet, C

2006-09-15

When probing small distances inside a hadron, one can resolve its partonic constituents: quarks and gluons that obey the laws of perturbative Quantum Chromodynamics (QCD). This substructure reveals itself in hadronic collisions characterized by a large momentum transfer: in such collisions, a hadron acts like a collection of partons whose interactions can be described in QCD. In a collision at moderate energy, a hadron looks dilute and the partons interact incoherently. As the collision energy increases, the parton density inside the hadron grows. Eventually, at some energy much bigger than the momentum transfer, one enters the saturation regime of QCD: the gluon density has become so large that collective effects are important. We introduce a formalism suitable to study hadronic collisions in the high-energy limit in QCD, and the transition to the saturation regime. In this framework, we derive known results that are needed to present our personal contributions and we compute different cross-sections in the context of hard diffraction and particle production. We study the transition to the saturation regime as given by the Balitsky-Kovchegov equation. In particular we derive properties of its solutions.We apply our results to deep inelastic scattering and show that, in the energy range of the HERA collider, the predictions of high-energy QCD are in good agreement with the data. We also consider jet production in hadronic collisions and discuss the possibility to test saturation at the Large Hadron Collider. (author)

Evidence of final-state suppression of high-p{_ T} hadrons in Au + Au collisions using d + Au measurements at RHIC

Science.gov (United States)

Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.; Zhang, J.

Transverse momentum spectra of charged hadrons with pT 2 GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-pT yields. These measurements suggest a large energy loss of the high-pT particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions. PACS: 25.75.-q

Global Λ hyperon polarization in nuclear collisions

Science.gov (United States)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; de La Barca Sánchez, M. Calderón; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; de Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.

2017-08-01

The extreme energy densities generated by ultra-relativistic collisions between heavy atomic nuclei produce a state of matter that behaves surprisingly like a fluid, with exceptionally high temperature and low viscosity. Non-central collisions have angular momenta of the order of 1,000ћ, and the resulting fluid may have a strong vortical structure that must be understood to describe the fluid properly. The vortical structure is also of particular interest because the restoration of fundamental symmetries of quantum chromodynamics is expected to produce novel physical effects in the presence of strong vorticity. However, no experimental indications of fluid vorticity in heavy ion collisions have yet been found. Since vorticity represents a local rotational structure of the fluid, spin-orbit coupling can lead to preferential orientation of particle spins along the direction of rotation. Here we present measurements of an alignment between the global angular momentum of a non-central collision and the spin of emitted particles (in this case the collision occurs between gold nuclei and produces Λ baryons), revealing that the fluid produced in heavy ion collisions is the most vortical system so far observed. (At high energies, this fluid is a quark-gluon plasma.) We find that Λ and hyperons show a positive polarization of the order of a few per cent, consistent with some hydrodynamic predictions. (A hyperon is a particle composed of three quarks, at least one of which is a strange quark; the remainder are up and down quarks, found in protons and neutrons.) A previous measurement that reported a null result, that is, zero polarization, at higher collision energies is seen to be consistent with the trend of our observations, though with larger statistical uncertainties. These data provide experimental access to the vortical structure of the nearly ideal liquid created in a heavy ion collision and should prove valuable in the development of hydrodynamic models that

Breakup of spectator residues in relativistic nuclear collisions

International Nuclear Information System (INIS)

Warwick, A.I.; Wieman, H.H.; Gutbrod, H.H.

1983-01-01

Low energy nuclear fragments (12 4 He, and 20 Ne projectiles are measured to yield information on the breakup of the target nucleus. We discuss the shapes of the fragment energy spectra across this broad range of fragment mass and pick out the fission component by its binary breakup. Multiplicities of coincident fast charged particles are presented as a measure of the degree of violence of the initial stage of the collision. Angular distributions of light fragments (8< or =Z< or =11) give the average velocities imparted to the residue in central collisions, and these values are compared to the results of cascade calculations. Measurements of slow fragment multiplicities from central events reveal a many-fragment final state. In the light of this finding we develop a simple calculation of the Coulomb features of the observed spectra. The applicability of a statistical breakup model is discussed

Low-energy particle production and residual nuclei production from high-energy hadron-nucleus collisions

International Nuclear Information System (INIS)

Alsmiller, F.S.; Alsmiller, R.G. Jr.; Hermann, O.W.

1987-01-01

The high-energy hadron-nucleus collision model, EVENTQ, has been modified to include a calculation of the excitation and kinetic energy of the residual compound nucleus. The specific purpose of the modification is to make it possible to use the model in the high-energy radiation transport code, HETC, which, in conjunction with MORSE, is used to transport the low energy particles. It is assumed that the nucleons in the nucleus move in a one-dimensional potential well and have the momentum distribution of a degenerate Fermi gas. The low energy particles produced by the deexcitation of the residual compound nucleus, and the final residual nucleus, are determined from an evaporation model. Comparisons of multiplicities and residual nuclei distributions with experimental data are given. The ''grey'' particles, i.e., charged particles with 0.25 < β < 0.7, are in good agreement with experimental data but the residual nuclei distributions are not. 12 refs., 3 figs

Measurement of the nuclear modification factor for high-$p_\\mathrm{T}$ charged hadrons in p+Pb collisions with the ATLAS detector

CERN Document Server

Balek, Petr; The ATLAS collaboration

2016-01-01

The charged hadron spectra in p+Pb and pp collisions at $\\sqrt{s}=5.02$TeV are measured with the ATLAS experiment at the LHC. The measurements are performed with p+Pb data recorded in 2013 with an integrated luminosity of 25nb${}^{-1}$ and pp data recorded in 2015 with an integrated luminosity of 28pb${}^{-1}$. The p+Pb results are directly compared to pp spectra, as a ratio scaled by the number of binary nucleon-nucleon collisions, the nuclear modification factor $R_\\mathrm{pPb}$. The study of $R_\\mathrm{pPb}$ allows a detailed comparison of the collision systems in different centrality intervals and up to high transverse momentum. It is shown that the nuclear modification factor does not have any significant deviation from unity in the high transverse momentum region.

Hard Pomeron-odderon interference effects in the production of π+π- pairs in high energy γγ collisions at the LHC

International Nuclear Information System (INIS)

Pire, B.; Schwennsen, F.; Szymanowski, L.; Wallon, S.

2008-01-01

We estimate the production of two meson pairs in high energy photon-photon collisions produced in ultraperipheral collisions at LHC. We show that the study of charge asymmetries may reveal the existence of the perturbative Odderon and discuss the concrete event rates expected at the LHC. Sizable rates and asymmetries are expected in the case of proton-proton collisions and medium values of γγ energies √(s γγ )≅20 GeV. Proton-proton collisions will benefit from a high rate due to a large effective γγ luminosity and ion-ion collisions with a somewhat lower rate from the possibility to trigger on ultraperipheral collisions and a reduced background from strong interactions.

Interference between vibration-to-translation and vibration-to-vibration energy transfer modes in diatomic molecules at high collision energies

International Nuclear Information System (INIS)

Shin, H.K.

1983-01-01

An explicit time dependent approach for simultaneous VT and VV energy transfer in diatom--diatom collisions is explored using the exponential form of ladder operators in the solution of the Schroedinger equation of motion. The collision of two hydrogen molecules is chosen to illustrate the extent of interference between VT and VV modes among various vibrational states. While vibrational energy transfer processes of nominally VT type can be treated with pure VT mode at low collision energies, the intermode coupling is found to be very important at collision energies of several hω. The occurrence of the coupling appears to be nearly universal in vibrational transitions at such energies. Exceptions to the coupling have been discussed

High energy nuclear physics

International Nuclear Information System (INIS)

Meyer, J.

1988-01-01

The 1988 progress report of the High Energy Nuclear Physics laboratory (Polytechnic School, France), is presented. The Laboratory research program is focused on the fundamental physics of interactions, on the new techniques for the acceleration of charged particles and on the nuclei double beta decay. The experiments are performed on the following topics: the measurement of the π 0 inclusive production and the photons production in very high energy nuclei-nuclei interactions and the nucleon stability. Concerning the experiments under construction, a new detector for LEP, the study and simulation of the hadronic showers in a calorimeter and the H1 experiment (HERA), are described. The future research programs and the published papers are listed [fr

Advanced Detectors for Nuclear, High Energy and Astroparticle Physics

CERN Document Server

Das, Supriya; Ghosh, Sanjay

2018-01-01

The book presents high-quality papers presented at a national conference on ‘Advanced Detectors for Nuclear, High Energy and Astroparticle Physics’. The conference was organized to commemorate 100 years of Bose Institute. The book is based on the theme of the conference and provides a clear picture of basics and advancement of detectors for nuclear physics, high-energy physics and astroparticle physics together. The topics covered in the book include detectors for accelerator-based high energy physics; detectors for non-accelerator particle physics; nuclear physics detectors; detection techniques in astroparticle physics and dark matter; and applications and simulations. The book will be a good reference for researchers and industrial personnel working in the area of nuclear and astroparticle physics.

LOCAL COLLISION SIMULATION OF AN SC WALL USING ENERGY ABSORBING STEEL

Directory of Open Access Journals (Sweden)

CHUL-HUN CHUNG

2013-08-01

Full Text Available This study evaluates the local damage of a turbine in an auxiliary building of a nuclear power plant due to an external impact by using the LS-DYNA finite element program. The wall of the auxiliary building is SC structure and the material of the SC wall plate is high manganese steel, which has superior ductility and energy absorbance compared to the ordinary steel used for other SC wall plates. The effects of the material of the wall, collision speed, and angle on the magnitude of the local damage were evaluated by local collision analysis. The analysis revealed that the SC wall made of manganese steel had significantly less damage than the SC wall made of ordinary steel. In conclusion, an SC wall made of manganese steel can have higher effective resistance than an SC wall made of ordinary steel against the local collision of an airplane engine or against a turbine impact.

Local Collision Simulation of an SC Wall Using Energy Absorbing Steel

Energy Technology Data Exchange (ETDEWEB)

Chung, Chulhun; Choi, Hyun; Park, Jaegyun [Dankook Univ., Yongin (Korea, Republic of)

2013-08-15

This study evaluates the local damage of a turbine in an auxiliary building of a nuclear power plant due to an external impact by using the LS-DYNA finite element program. The wall of the auxiliary building is SC structure and the material of the SC wall plate is high manganese steel, which has superior ductility and energy absorbance compared to the ordinary steel used for other SC wall plates. The effects of the material of the wall, collision speed, and angle on the magnitude of the local damage were evaluated by local collision analysis. The analysis revealed that the SC wall made of manganese steel had significantly less damage than the SC wall made of ordinary steel. In conclusion, an SC wall made of manganese steel can have higher effective resistance than an SC wall made of ordinary steel against the local collision of an airplane engine or against a turbine impact.

Particle production in high energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

Stock, R.

1985-05-01

Recent data on the production of pions and strange particles at the Bevalac and Synchrophasotron accelerators are reviewed, covering pion spectra and multiplicity distributions, Λ, K + and K - yields and spectra, and Λ polarization. Emphasis is placed on recent progress in determining the equation of state of compressed fireball nuclear matter from the observed pion yield in central collisions. Further, the information derived from apparent spectral temperatures is critically examined, along with a discussion of thermal and chemical equilibrium attainment in the reactions, as revealed by particle spectra and yields. (orig.)

Toward the Limits of Matter: Ultra-relativistic nuclear collisions at CERN

CERN Document Server

Schukraft, Jurgen

2015-01-01

Strongly interacting matter as described by the thermodynamics of QCD undergoes a phase transition, from a low temperature hadronic medium to a high temperature quark-gluon plasma state. In the early universe this transition occurred during the early microsecond era. It can be investigated in the laboratory, in collisions of nuclei at relativistic energy, which create "fireballs" of sufficient energy density to cross the QCD Phase boundary. We describe 3 decades of work at CERN, devoted to the study of the QCD plasma and the phase transition. From modest beginnings at the SPS, ultra-relativistic heavy ion physics has evolved today into a central pillar of contemporary nuclear physics and forms a significant part of the LHC program.

Inelastic collisions of medium energy atomic elements. Qualitative model of energy losses during collisions

International Nuclear Information System (INIS)

Pustovit, A.N.

2006-01-01

A new approach to the theoretical description of energy losses of atomic particle of medium energy during their interaction with the substance is proposed. The corner-stone of this approach is the supposition that all of the collision processes have inelastic nature during particle movement through the substance, while the calculation of the atomic particles braking is based on the law of their dispersion and the laws of energy and momentum conservation at the inelastic collisions. It is shown that inelastic atomic collision there are three dispersion zones for the only potential interaction with different laws, which characterize energy losses. The application conditions of this approach are determined [ru

Searching for squeezed particle-antiparticle correlations in high-energy heavy-ion collisions

International Nuclear Information System (INIS)

Padula, Sandra S.; Socolowski, O. Jr.

2010-01-01

Squeezed correlations of particle-antiparticle pairs were predicted to exist if the hadron masses were modified in the hot and dense medium formed in high-energy heavy-ion collisions. Although well-established theoretically, they have not yet been observed experimentally. We suggest here a clear method to search for such a signal by analyzing the squeezed correlation functions in terms of measurable quantities. We illustrate this suggestion for simulated φφ pairs at the Relativistic Heavy Ion Collider (RHIC) energies.

QCD and the space-time evolution of high energy e+e-, p anti p, and heavy ion collisions

International Nuclear Information System (INIS)

Bjorken, J.D.

1982-06-01

We begin with a discussion of e + e - annihilation into hadrons, a process blessed with well-known elements of simplicity. We consider the opposite extreme of highly relativistic nucleus-nucleus collisions. Here a space-time description has its own elements of simplicity, elements which might conceivably be applicable in hadron-hadron collisions. We also address the more immediate issues of how these ideas relate to present-day observations, especially high-energy hadron-hadron collisions. 40 references

Exclusive observables from a statistical simulation of energetic nuclear collisions

International Nuclear Information System (INIS)

Fai, G.

1983-01-01

Exclusive observables are calculated in the framework of a statistical model for medium-energy nuclear collisions. The collision system is divided into a few (participant/spectator) sources, that are assumed to disassemble independently. Sufficiently excited sources explode into pions, nucleons, and composite, possibly particle unstable, nuclei. The different final states compete according to their microcanonical weight. Less excited sources, and the unstable explosion products, deexcite via light-particle evaporation. The model has been implemented as a Monte Carlo computer code that is sufficiently efficient to permit generation of large event samples. Some illustrative applications are discussed. (author)

ψ' and J/ψ suppression in high-energy nucleon-nucleus and nucleus-nucleus collisions

International Nuclear Information System (INIS)

Wong, Cheuk-Yin.

1995-01-01

The observed features of ψ' to J/ψ suppression in pA and nucleus-nucleus collisions can be explained in terms of a two-component absorption model. For the hard component of the absorption due to the interaction of the produced c bar c systems with baryons at high relative energies, the absorption cross sections are insensitive to the radii of the c bar c systems, as described by the Additive Quark Model. For the soft component due to the low energy c bar c interactions with soft particles produced by other baryon-baryon collisions, the absorption cross sections are greater for ψ' than for J/ψ, because the breakup threshold for ψ' is much smaller than for ψ

TCP (truncated compound Poisson) process for multiplicity distributions in high energy collisions

International Nuclear Information System (INIS)

Srivastave, P.P.

1990-01-01

On using the Poisson distribution truncated at zero for intermediate cluster decay in a compound Poisson process, the authors obtain TCP distribution which describes quite well the multiplicity distributions in high energy collisions. A detailed comparison is made between TCP and NB for UA5 data. The reduced moments up to the fifth agree very well with the observed ones. The TCP curves are narrower than NB at high multiplicity tail, look narrower at very high energy and develop shoulders and oscillations which become increasingly pronounced as the energy grows. At lower energies the distributions, of the data for fixed intervals of rapidity for UA5 data and for the data (at low energy) for e + e - annihilation and pion-proton, proton-proton and muon-proton scattering. A discussion of compound Poisson distribution, expression of reduced moments and Poisson transforms are also given. The TCP curves and curves of the reduced moments for different values of the parameters are also presented

Do nuclear collisions create a locally equilibrated quark-gluon plasma?

Energy Technology Data Exchange (ETDEWEB)

Romatschke, P. [University of Colorado at Boulder, Department of Physics, 390 UCB, Boulder, CO (United States); University of Colorado, Center for Theory of Quantum Matter, Boulder, CO (United States)

2017-01-15

Experimental results on azimuthal correlations in high energy nuclear collisions (nucleus-nucleus, proton-nucleus, and proton-proton) seem to be well described by viscous hydrodynamics. It is often argued that this agreement implies either local thermal equilibrium or at least local isotropy. In this note, I present arguments why this is not the case. Neither local near-equilibrium nor near-isotropy are required in order for hydrodynamics to offer a successful and accurate description of experimental results. However, I predict the breakdown of hydrodynamics at momenta of order seven times the temperature, corresponding to a smallest possible QCD liquid drop size of 0.15 fm. (orig.)

Production of high-pt jets in hadron-nucleus collisions

International Nuclear Information System (INIS)

Stewart, C.; Zieminski, A.; Blessing, S.; Crittenden, R.; Draper, P.; Dzierba, A.; Heinz, R.; Krider, J.; Marshall, T.; Martin, J.; Sambamurti, A.; Smith, P.; Sulanke, T.; Gomez, R.; Dauwe, L.; Haggerty, H.; Malamud, E.; Nikolic, M.; Hagopian, S.; Abrams, R.; Ares, J.; Goldberg, H.; Halliwell, C.; Margulies, S.; McLeod, D.; Salminen, A.; Solomon, J.; Wu, G.; Ellsworth, R.; Goodman, J.; Gupta, S.; Yodh, G.; Watts, T.; Abramov, V.; Antipov, Y.; Baldin, B.; Denisov, S.; Glebov, V.; Gorin, Y.; Kryshkin, V.; Petrukhin, A.; Polovnikov, S.; Sulyaev, R.

1990-01-01

We present results on the production of jets and ''jetlike'' clusters in 800-GeV/c proton-nucleus (pA) collisions. Events with high values of transverse energy in the central kinematic region were selected for nuclear targets of H, Be, C, Cu, and Pb. A jet-finding algorithm was used in analyzing the data. The A dependence of the jet and dijet cross sections was parametrized as A α . The values of α for events with ''jetlike'' cluster pairs found by the algorithm without any additional kinematic cuts reach a plateau of approximately 1.5 at dijet transverse energies >11 GeV. The collimation of observed ''jetlike'' clusters decreases with A, and the fragmentation is softer for heavier target nuclei. However, nuclear effects become less pronounced with the increasing cluster or cluster-pair transverse energy. We argue that the observed nuclear enhancement for the production of ''jetlike'' clusters is due to underlying event or/and soft-scattering contributions to the heavy-nuclei data. We show that the nuclear enhancement becomes consistent with a value of α within 0.10 from unity once the data are corrected for the underlying event or kinematic cuts enhancing clear jet structure are applied

Evolution of pressures and correlations in the glasma produced in high energy nuclear collisions

Science.gov (United States)

Ruggieri, M.; Liu, J. H.; Oliva, L.; Peng, G. X.; Greco, V.

2018-04-01

We consider the SU(2) glasma with Gaussian fluctuations and study its evolution by means of classical Yang-Mills equations solved numerically on a lattice. Neglecting in this first study the longitudinal expansion, we follow the evolution of the pressures of the system and compute the effect of the fluctuations in the early stage up to t ≈2 fm /c , that is the time range in which the glasma is relevant for high energy collisions. We measure the ratio of the longitudinal over the transverse pressure, PL/PT, and we find that unless the fluctuations carry a substantial amount of the energy density at the initial time, they do not change significantly the evolution of PL/PT in the early stage and that the system remains quite anisotropic. We also measure the longitudinal fields correlators both in the transverse plane and along the longitudinal direction: while at initial time fields appear to be anticorrelated in the transverse plane, this anticorrelation disappears in the very early stage, and the correlation length in the transverse plane increases. On the other hand, we find a dependence of the gauge invariant correlator on the longitudinal coordinate, which we interpret as a partial loss of correlation induced by the dynamics that we dub the gauge invariant string breaking. We finally study the effect of fluctuations on the longitudinal correlations: we find that string breaking is accelerated by the fluctuations and waiting for a sufficiently long time fluctuations lead to the complete breaking of the color strings.

Finite escape fraction for ultrahigh energy collisions around Kerr

Indian Academy of Sciences (India)

We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location = M around the Kerr naked singularity if ...

Finite escape fraction for ultrahigh energy collisions around Kerr ...

Indian Academy of Sciences (India)

Abstract. We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location r = M around the Kerr naked ...

Multiple scattering in the nuclear rearrangement reactions at medium energy

International Nuclear Information System (INIS)

Tekou, A.

1980-09-01

It is shown that the multiple scattering mechanism is very important in the transfer of the large momenta involved in the nuclear rearrangement reactions at medium energy. In contrast to the usual belief, the reaction cross-section is not very sensitive to the high momenta components of the nuclear wave function. The multiple scattering mechanism is especially important in 4 He(p,d) 3 He reaction around 800 MeV. Here the collisions involving two nucleons of the target nucleus are dominant. The triple collisions contribution is also important. The four collision contribution is negligible in the forward direction and sizeable at large angles. Thus, using the K.M.T. approach in DWBA calculations, the second order term of the optical potential must be included. So, is it not well established that the second term of the K.M.T. optical potential is important for the proton elastic scattering on light nuclei. (author)

Scaling of anisotropy flows in intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Ma, Y.G.; Yan, T.Z.; Cai, X.Z.; Chen, J.G.; Fang, D.Q.; Guo, W.; Liu, G.H.; Ma, C.W.; Ma, E.J.; Shen, W.Q.; Shi, Y.; Su, Q.M.; Tian, W.D.; Wang, H.W.; Wang, K.

2007-01-01

Anisotropic flows (v 1 , v 2 and v 4 ) of light nuclear clusters are studied by a nucleonic transport model in intermediate energy heavy ion collisions. The number-of-nucleon scalings of the directed flow (v 1 ) and elliptic flow (v 2 ) are demonstrated for light nuclear clusters. Moreover, the ratios of v 4 /v 2 2 of nuclear clusters show a constant value of 1/2 regardless of the transverse momentum. The above phenomena can be understood by the coalescence mechanism in nucleonic level and are worthy to be explored in experiments

Closing in on parton energy loss with charged particle spectra in Xe-Xe and Pb-Pb collisions with ALICE

CERN Multimedia

CERN. Geneva

2018-01-01

For comparison, a pp reference at the collision energy of 5.44 TeV is obtained by interpolating between existing pp measurements at 5.02 and 7 TeV.  The nuclear modification factor in Xe-Xe collisions is compared to Pb-Pb collisions at 5.02 TeV and 2.76 TeV, showing remarkable similarity at pT > 10 GeV/c. The comparison of the measured nuclear mod...

In-medium and isospin effects on eta production in heavy-ion collisions near threshold energies

Energy Technology Data Exchange (ETDEWEB)

Chen, Jie; Chen, Peng-Hui [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Feng, Zhao-Qing; Wang, Jian-Song [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Niu, Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Henan Normal University, Institute of Particle and Nuclear Physics, Xinxiang (China); Guo, Ya-Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

2017-06-15

The dynamics of η meson produced in heavy-ion collisions has been investigated within the Lanzhou quantum molecular dynamics model (LQMD). The in-medium corrections have been considered in the model, in which an attractive η-nucleon potential is implemented. The impacts of the η optical potential and the nuclear symmetry energy on the η dynamics are investigated. It is found that the total yields are slightly influenced by the potential and weakly depend on the symmetry energy. However, the structure of the kinetic spectra is related to the optical potential and the stiffness of symmetry energy. The attractive potential leads to the reduction of high-momentum (kinetic energy) η production, i.e., the spectra of momentum and transverse mass distributions, increasing the reabsorption process by surrounding nucleons, and favoring the in-plane eta emissions. The reabsorption process in η-nucleon collisions plays a significant role on the η dynamics. (orig.)

Microscopic description of low-energy nuclear collisions: review and perspective

International Nuclear Information System (INIS)

Bonche, Paul

2000-01-01

The primary goal of this lecture is a review of the microscopic approaches to nuclear reactions. Semi-phenomenological theories will not be discussed. First the Time-Dependent Hartree-Fock formalism is recalled. The effective nucleon-nucleon interactions used in TDHF calculations are discussed. Applications to collisions are presented in different approximation scheme, one-dimensional dynamics, approximate three-dimensional ones.... Finally two microscopic extensions beyond mean-field are reviewed: the variational principal of Balian and Veneroni and the implementation of residual two-body interactions in the Time-Dependent Density Matrix (TDDM) and the Extended Time-Dependent Hartree-Fock schemes (ET-DHF). (author)

Nuclear compression effects on pion production in nuclear collisions

International Nuclear Information System (INIS)

Sano, M.; Gyulassy, M.; Wakai, M.; Kitazoe, Y.

1984-11-01

The pion multiplicity produced in nuclear collisions between 0.2 and 2 AGeV is calculated assuming shock formation. We also correct the procedure of extracting the nuclear equation of state as proposed by Stock et al. The nuclear equation of state would have to be extremely stiff for this model to reproduce the observed multiplicities. The assumptions of this model are critically analyzed. (author)

Spin transport in intermediate-energy heavy-ion collisions as a probe of in-medium spin–orbit interactions

Energy Technology Data Exchange (ETDEWEB)

Xia, Yin [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xu, Jun, E-mail: xujun@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Bao-An [Department of Physics and Astronomy, Texas A& M University-Commerce, Commerce, TX 75429-3011 (United States); Department of Applied Physics, Xi' an Jiao Tong University, Xi' an 710049 (China); Shen, Wen-Qing [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2016-11-15

The spin up-down splitting of collective flows in intermediate-energy heavy-ion collisions as a result of the nuclear spin–orbit interaction is investigated within a spin- and isospin-dependent Boltzmann–Uehling–Uhlenbeck transport model SIBUU12. Using a Skyrme-type spin–orbit coupling quadratic in momentum, we found that the spin splittings of the directed flow and elliptic flow are largest in peripheral Au+Au collisions at beam energies of about 100–200 MeV/nucleon, and the effect is considerable even in smaller systems especially for nucleons with high transverse momenta. The collective flows of light clusters of different spin states are also investigated using an improved dynamical coalescence model with spin. Our study can be important in understanding the properties of in-medium nuclear spin–orbit interactions once the spin-dependent observables proposed in this work can be measured.

Free-parameterless model of high energy particle collisions with atomic nuclei

International Nuclear Information System (INIS)

Strugalski, Z.

1982-01-01

In result of studies, it has been discovered that: a) Intensive emission of fast nucleons of kinetic energy from 20 to 400 MeV proceeds independently of the pion production process; b) The particle production in hadron-nucleon collisions is mediated by intermediate objects produced first in a 2 → 2 type endoergic reaction and decaying after lifetime tausub(g) > or approximately 10 - 22 s into commonly known resonances and particles; c) Inside of massive enough atomic nuclei quasi-onedimensional cascades of the intermediate objects can develop; d) A definite simple connection exists between the characteristics of the secondaries appearing in hadron-nucleus collision events and corresponding hadron-nucleon collision events, the target-nucleus size and the nucleon density distribution in it. The yield of the hadron-nucleus collisions is described in a convincing manner in terms of the hadron-nucleon collision data by means of simple formulas

Study of Particle Production and Nuclear Fragmentation in Relativistic Heavy-Ion Collisions in Nuclear Emulsions

CERN Multimedia

2002-01-01

% EMU11 \\\\ \\\\ We propose to use nuclear emulsions for the study of nuclear collisions of $^{207}$Pb, $^{197}$Au, and any other heavy-ion beams when they are available. We have, in the past, used $^{32}$S at 200A~GeV and $^{16}$O at 200A and 60A~GeV from CERN (Experiment EMU08) and at present the analysis is going on with $^{28}$Si beam from BNL at 14.5A~GeV. It will be important to compare the previous and the present investigations with the new $^{207}$Pb beam at 60-160A~GeV. We want to measure in nuclear emulsion, on an event by event basis, shower particle multiplicity, pseudorapidity density and density fluctuations of charged particles, charge multiplicity and angular distributions of projectile fragments, production and interaction cross-sections of heavily ionizing particles emitted from the target fragmentation. Special emphasis will be placed on the analysis of events produced in the central collisions which are selected on the basis of low energy fragments emitted from the target excitation. It woul...

Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

International Nuclear Information System (INIS)

Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

2005-01-01

The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

Relativistic nuclear collisions: theory

International Nuclear Information System (INIS)

Gyulassy, M.

1980-07-01

Some of the recent theoretical developments in relativistic (0.5 to 2.0-GeV/nucleon) nuclear collisions are reviewed. The statistical model, hydrodynamic model, classical equation of motion calculations, billiard ball dynamics, and intranuclear cascade models are discussed in detail. Inclusive proton and pion spectra are analyzed for a variety of reactions. Particular attention is focused on how the complex interplay of the basic reaction mechanism hinders attempts to deduce the nuclear matter equation of state from data. 102 references, 19 figures

Hadron-nucleon inelastic collision mean free path in nuclear matter

International Nuclear Information System (INIS)

Strugalski, Z.

1980-01-01

Characteristics of atomic nuclei, used as targets in high energy hadron-nucleus collision experiments, are defined on the basis of the data on the nuclei sizes and radial nucleon density distributions in nuclei. Average mean free path for inelastic hadron-nucleon collisions in nuclei is estimated using existing experimental data on the pion-xenon nucleus collisions and the connection of it with the cross-section for hadron-nucleon elementary inelastic collisions is discussed

Proceedings of the third specialists` meeting on high energy nuclear data

Energy Technology Data Exchange (ETDEWEB)

Fukahori, Tokio [ed.

1998-11-01

This report is the Proceedings of the Third Specialists` Meeting on High Energy Nuclear Data. The meeting was held on March 30-31, 1998, at the Tokai Research Establishment of Japan Atomic Energy Research Institute with the participation of forty-odd specialists, who were the evaluators, theorists, experimentalists and users of high energy nuclear data including the members of the Japanese Nuclear Data Committee. The need of the high energy nuclear data up to a few Gev has been stressed in the meeting for many applications, such as spallation neutron sources for radioactive waste treatment, accelerator shielding design, medical isotope production, radiation therapy, the effects of space radiation on astronauts and their equipments, and the cosmic history of meteorites and other galactic substances. Since the Second Specialists` Meeting in 1995, such an evaluation activity in Japan has been grown and the results are accumulated. Foreign activities of high energy nuclear data evaluation are also being increased. According to the above situation, with the view point of reviewing and validating an evaluated high energy nuclear data file, project of high energy nuclear data file production, differential and integral experiments, status of evaluation and reviewing methods, processing and transport calculation methods, benchmark tests, international trends, etc. were discussed. The 16 of the presented papers are indexed individually. (J.P.N.)

Energy from nuclear fission an introduction

CERN Document Server

De Sanctis, Enzo; Ripani, Marco

2016-01-01

This book provides an overview on nuclear physics and energy production from nuclear fission. It serves as a readable and reliable source of information for anyone who wants to have a well-balanced opinion about exploitation of nuclear fission in power plants. The text is divided into two parts; the first covers the basics of nuclear forces and properties of nuclei, nuclear collisions, nuclear stability, radioactivity, and provides a detailed discussion of nuclear fission and relevant topics in its application to energy production. The second part covers the basic technical aspects of nuclear fission reactors, nuclear fuel cycle and resources, safety, safeguards, and radioactive waste management. The book also contains a discussion of the biological effects of nuclear radiation and of radiation protection, and a summary of the ten most relevant nuclear accidents. The book is suitable for undergraduates in physics, nuclear engineering and other science subjects. However, the mathematics is kept at a level that...

Early time evolution of high-energy heavy-ion collisions

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [Cyclotron Institute and Department of Physics, Texas A and M University, College Station, TX 77843 (United States); RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2007-08-15

We solve the Yang-Mills equations in the framework of the McLerran-Venugopalan model for small times {tau} after a collision of two nuclei. An analytic expansion around {tau} = 0 leads to explicit results for the field strength and the energy-momentum tensor of the gluon field at early times. We then discuss constraints for the energy density, pressure and flow of the plasma phase that emerges after thermalization of the gluon field.

Multifragmentation in intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Jacak, B.V.; Britt, H.C.; Claesson, G.

1986-01-01

There has been considerable recent interest in the production of intermediate mass fragments (A > 4) in intermediate and high energy nucleus-nucleus collisions. The mechanism for production of these fragments is not well understood and has been described by models employing a variety of assumptions. Some examples are: disassembly of a system in thermal equilibrium into nucleons and nuclear fragments, liquid-vapor phase transitions in nuclear matter, final state coalescence of nucleons and dynamical correlations between nucleons at breakup. Previous studies of fragment production, with one exception, have been single particle inclusive measurements; the observed fragment mass (or charge) distributions can be described by all of the models above. To gain insight into the fragment production mechanism, the authors used the GSI/LBL Plastic Ball detector system to get full azimuthal coverage for intermediate mass fragments in the forward hemisphere in the center of mass system while measuring all the light particles in each event. The authors studied the systems 200 MeV/nucleon Au + Au and Au + Fe

Nuclear de-excitation processes following medium energy heavy ion collisions

International Nuclear Information System (INIS)

Blann, M.

1986-09-01

As heavy ion reaction studies have progressed from beam energies below 10 MeV/nucleon to higher energies, many non-equilibrium reaction phenomena have been observed. Among these are nucleon emission with velocities in excess of the beam velocity, incomplete momentum transfer to evaporation residue and fission-like fragments, γ-rays with energies in excess of 100 MeV, and π 0 production when beam energies are below the threshold for production by the nucleon-nucleon collision mechanism. Additionally, prefission neutrons have been observed in excess of numbers expected from equilibrium models. A few of the approaches which have been applied to these phenomena are as follows: Intranuclear cascade: two body collisions are assumed to mediate the equilibration. The geometry and momentum space is followed semiclassically. The approach has many successes though it may suffer in a few applications is not following holes; TDHF considers one body processes only; in the energy regime of interest, two body processes are important so that this may not be a viable approach; Boltzmann-Uehling-Uhlenbeck or Vlasov-Uehling-Uhlenbeck (BUU/VUU) equations combine both one body and two body dynamics. The spatial and momentum evolution of the reactions are followed in a mean field. These should be the Cadillacs of the models. They are computationally tedious, and sometimes significant approximations are made in order to achieve computational tract ability; models of collective deceleration. A very simple model approach is discussed to interpret these phenomena, the Boltzmann master equation (BME). The hybrid model was the first to be applied to the question of heavy ion precompound decay, and the BME second. 26 refs., 5 figs., 2 tabs

[Intermediate/high energy nuclear physics

International Nuclear Information System (INIS)

1989-01-01

We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. The effort in quantum field theory provides theoretical results to test or replace assumed ingredients of the QCM. By the explicit example of a scalar field theory in 2D we have solved the long-standing problem of how to treat the dynamics of the vacuum in light-front quantization. We now propose to solve the same problem for simple Fermion field theories in 2D such as the Gross-Neveu model. We propose in subsequent years to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We have completed our analysis of the SLAC E101 and E133 experiments on Deuterium to elucidate the degree to which a six-quark cluster contribution is admissable in the Bjorken x > 1 data. We have completed our development of a parameterized thermal liquid drop model for light nuclei. In addition we have completed a set of predictions for the formation of a ''nuclear stratosphere'' in nuclei created by intermediate energy heavy ion interactions. These results motivate a new investigation of the temperature dependence of the ion-ion potential with particular emphasis on the thermal dependence of the barrier height and radius. We have also shown that a consistent treatment of relativistic effects is important for a theoretical description of the elastic magnetic form factor of 17 O. 85 refs

The Theory of High Energy Collision Processes - Final Report DOE/ER/40158-1

Energy Technology Data Exchange (ETDEWEB)

Wu, Tai, T.

2011-09-15

In 1984, DOE awarded Harvard University a new Grant DE-FG02-84ER40158 to continue their support of Tai Tsun Wu as Principal Investigator of research on the theory of high energy collision processes. This Grant was renewed and remained active continuously from June 1, 1984 through November 30, 2007. Topics of interest during the 23-year duration of this Grant include: the theory and phenomenology of collision and production processes at ever higher energies; helicity methods of QED and QCD; neutrino oscillations and masses; Yang-Mills gauge theory; Beamstrahlung; Fermi pseudopotentials; magnetic monopoles and dyons; cosmology; classical confinement; mass relations; Bose-Einstein condensation; and large-momentum-transfer scattering processes. This Final Report describes the research carried out on Grant DE-FG02-84ER40158 for the period June 1, 1984 through November 30, 2007. Two books resulted from this project and a total of 125 publications.

Towards high-density matter with relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Nagamiya, Shoji.

1990-04-01

Recent progress in nucleus-nucleus collisions at BNL and CERN suggests a hint that the formation of high-density nuclear matter could be possible with relativistic heavy-ion beams. What is the maximum density that can be achieved by heavy-ion collisions? Are there data which show evidence or hints on the formation of high density matter? Why is the research of high-density interesting? How about the future possibilities on this subject? These points are discussed. (author)

Investigation of the Direct Charge Transfer in Low Energy D2+ + H Collisions using Merged-Beams Technique

Science.gov (United States)

Romano, S. L.; Guillen, C. I.; Andrianarijaona, V. M.; Havener, C. C.

2011-10-01

The hydrogen - hydrogen (deuterium) molecular ion is the most fundamental ion-molecule two-electron system. Charge transfer (CT) for H2+ on H, which is one of the possible reaction paths for the (H-H2)+ system, is of special interest because of its contribution to H2 formation in the early universe, its exoergicity, and rich collision dynamics. Due to technical difficulty in making an atomic H target, the direct experimental investigations of CT for H2+ on H are sparse and generally limited to higher collision energies. The measurements of the absolute cross section of different CT paths for H2+ on H over a large range of collision energy are needed to benchmark theoretical calculations, especially the ones at low energies. The rate coefficient of CT at low energy is not known but may be comparable to other reaction rate coefficients in cold plasmas with H, H+, H2+, and H3+ as constituents. For instance, CT for H2+ on H and the following H3+ formation reaction H2+ + H2 → H + H3+ are clearly rate interdependent although it was always assumed that every ionization of H2 will lead to the formation of H3+. CT proceeds through dynamically coupled electronic, vibrational and rotational degrees of freedom. One can depict three paths, electronic CT, CT with nuclear substitution, and CT with dissociation. Electronic CT and CT with nuclear substitution in the H2+ on H collisions are not distinguishable by any quantum theory. Here we use the isotopic system (D2+ - H) to measure without ambiguity the electronic CT cross section by observing the H+ products. Using the ion-atom merged-beam apparatus at Oak Ridge National Laboratory, the absolute direct CT cross sections for D2+ + H from keV/u to meV/u collision energies have been measured. The molecular ions are extracted from an Electron-Cyclotron Resonance (ECR) ion source with a vibrational state distribution which is most likely determined by Frank-Condon transitions between ground state D2 and D2+. A ground-state H beam

Nuclear fragmentation energy and momentum transfer distributions in relativistic heavy-ion collisions

Science.gov (United States)

Khandelwal, Govind S.; Khan, Ferdous

1989-01-01

An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

Production and decay of exotic fermions in high energy collisions

International Nuclear Information System (INIS)

Queiroz Filho, Pedro Pacheco de

1995-05-01

In this work, we investigate the production and decay of exotic fermions predicted by some extensions of the standard model. We select for our study the more popular models: vector singlet, vector doublet and Fermion Mirror-Fermion. We want to establish the differences between these models and also in relation to the Standard Model. We make investigations by Monte Carlo simulations, to study the phenomenology of the particles expected in these models, particularly the exotic fermions. These studies were done for electron-proton collisions at DESY HERA energies. We considered the investigation of exotic quark production, electron-positron collisions in LEP II and NLC energies in order to study the production of exotic leptons, and virtual exotic lepton contribution in the specific process e + e - → ιν-bar ι W + . (author)

Anisotropy of dilepton emission from nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Bratkovskaya, E.L.; Teryaev, O.V. [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Bogolubov Lab. of Theoretical Physics; Toneev, V.D. [Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory]|[Joint Inst. for Nuclear Research, Dubna (Russian Federation). Bogolubov Lab. of Theoretical Physics

1994-11-07

Attention is paid to studying the angular characteristics of e{sup +}e{sup {minus}} pairs created in collisions with nuclear targets at intermediate and relativistic energies. Arising due to general spin and angular momentum constraints, the dilepton anisotropy seems to be quite sensitive to the contribution of different sources and may be used for disentangling these sources (or models) as well as an additional signature of a possible chiral symmetry restoration and phase transition of hadrons into the quark-gluon plasma. An anisotropy estimate for some dilepton sources is given and its relevance to the problems mentioned is discussed.

Anisotropy of dilepton emission from nuclear collisions

International Nuclear Information System (INIS)

Bratkovskaya, E.L.; Teryaev, O.V.; Toneev, V.D.; Joint Inst. for Nuclear Research, Dubna

1994-01-01

Attention is paid to studying the angular characteristics of e + e - pairs created in collisions with nuclear targets at intermediate and relativistic energies. Arising due to general spin and angular momentum constraints, the dilepton anisotropy seems to be quite sensitive to the contribution of different sources and may be used for disentangling these sources (or models) as well as an additional signature of a possible chiral symmetry restoration and phase transition of hadrons into the quark-gluon plasma. An anisotropy estimate for some dilepton sources is given and its relevance to the problems mentioned is discussed

Biological effectiveness of high-energy protons - Target fragmentation

International Nuclear Information System (INIS)

Cucinotta, F.A.; Katz, R.; Wilson, J.W.; Townsend, L.W.; Shinn, J.; Hajnal, F.

1991-01-01

High-energy protons traversing tissue produce local sources of high-linear-energy-transfer ions through nuclear fragmentation. The contribution of these target fragments to the biological effectiveness of high-energy protons using the cellular track model is examined. The effects of secondary ions are treated in terms of the production collision density using energy-dependent parameters from a high-energy fragmentation model. Calculations for mammalian cell cultures show that at high dose, at which intertrack effects become important, protons deliver damage similar to that produced by gamma rays, and with fragmentation the relative biological effectiveness (RBE) of protons increases moderately from unity. At low dose, where sublethal damage is unimportant, the contribution from target fragments dominates, causing the proton effectiveness to be very different from that of gamma rays with a strongly fluence-dependent RBE. At high energies, the nuclear fragmentation cross sections become independent of energy. This leads to a plateau in the proton single-particle-action cross section, below 1 keV/micron, since the target fragments dominate. 29 refs

Studies in High Energy Heavy Ion Nuclear Physics

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, Gerald W. [Univ. of Texas, Austin, TX (United States); Markert, Christina [Univ. of Texas, Austin, TX (United States)

2016-09-01

This close-out report covers the period 1994 - 2015 for DOE grant DE-FG02-94ER40845 with the University of Texas at Austin. The research was concerned with studies of the strong nuclear force and properties of nuclear matter under extreme conditions of temperature and density which far exceed that in atomic nuclei. Such extreme conditions are briefly created (for about 10 trillionths of a trillionth of a second) during head-on collisions of large atomic nuclei (e.g. gold) colliding at speeds very close to the speed-of-light. The collisions produce thousands of subatomic particles, many of which are detected in our experiment called STAR at the Relativistic Heavy-Ion Collider at the Brookhaven National Lab in New York. The goal of our research is to learn how the strong nuclear force and its fundamental particles (quarks and gluons) behave in extreme conditions similar to that of the early Universe when it was about 1 micro-second old, and in the cores of very dense neutron stars. To learn anything new about the matter which exists for such a very short amount of time requires carefully designed probes. In our research we focused on two such probes, one being short-lived resonance particles and the other using correlations between pairs of the detected particles. Resonances are short-lived particles created in the collision, which interact with the surrounding matter, and which break apart, or "decay" into more stable particles which survive long enough to be seen in our detectors. The dependence of resonance properties on the conditions in the collision system permit tests of theoretical models and improve our understanding. Dynamical interactions in the matter also leave imprints on the final, outgoing particle distributions measured in the experiment. In particular, angular correlations between pairs of particles can be related to the fundamental strong force as it behaves in the hot, dense matter. Studying correlations as a function of experimentally controlled

Studies in High Energy Heavy Ion Nuclear Physics

International Nuclear Information System (INIS)

Hoffmann, Gerald W.; Markert, Christina

2016-01-01

This close-out report covers the period 1994 - 2015 for DOE grant DE-FG02-94ER40845 with the University of Texas at Austin. The research was concerned with studies of the strong nuclear force and properties of nuclear matter under extreme conditions of temperature and density which far exceed that in atomic nuclei. Such extreme conditions are briefly created (for about 10 trillionths of a trillionth of a second) during head-on collisions of large atomic nuclei (e.g. gold) colliding at speeds very close to the speed-of-light. The collisions produce thousands of subatomic particles, many of which are detected in our experiment called STAR at the Relativistic Heavy-Ion Collider at the Brookhaven National Lab in New York. The goal of our research is to learn how the strong nuclear force and its fundamental particles (quarks and gluons) behave in extreme conditions similar to that of the early Universe when it was about 1 micro-second old, and in the cores of very dense neutron stars. To learn anything new about the matter which exists for such a very short amount of time requires carefully designed probes. In our research we focused on two such probes, one being short-lived resonance particles and the other using correlations between pairs of the detected particles. Resonances are short-lived particles created in the collision, which interact with the surrounding matter, and which break apart, or 'decay' into more stable particles which survive long enough to be seen in our detectors. The dependence of resonance properties on the conditions in the collision system permit tests of theoretical models and improve our understanding. Dynamical interactions in the matter also leave imprints on the final, outgoing particle distributions measured in the experiment. In particular, angular correlations between pairs of particles can be related to the fundamental strong force as it behaves in the hot, dense matter. Studying correlations as a function of experimentally controlled

Annual report of the Institute of Nuclear Physics of the Universite de Paris-Sud (Orsay)

International Nuclear Information System (INIS)

1988-01-01

Experimental and theoretical research in nuclear physics is described. Experimental work includes ground states and low energy excited states; high excitation energy nuclear states; heavy ion collision phenomena; intermediate energy nuclear physics; radiochemistry; and interdisciplinary studies of atomic physics and ion interactions. Theoretical studies include few-nucleon systems; properties of nuclear matter; nuclear collisions; nuclear physics at intermediate energies; effective Lagrangians and quark models; high energy hadronic physics; superstrings; high spins, and gravity; astrophysics; statistical physics and chaotic systems; relativistic quantum mechanics; and mathematical physics [fr

Past and present of nuclear matter

International Nuclear Information System (INIS)

Ritter, H.G.

1994-05-01

The subject of nuclear matter is interesting for many fields of physics ranging from condensed matter to lattice QCD. Knowing its properties is important for our understanding of neutron stars, supernovae and cosmology. Experimentally, we have the most precise information on ground state nuclear matter from the mass formula and from the systematics of monopole vibrations. This gives us the ground state density, binding energy and the compression modulus k at ground state density. However, those methods can not be extended towards the regime we are most interested in, the regime of high density and high temperature. Additional information can be obtained from the observation of neutron stars and of supernova explosions. In both cases information is limited by the rare events that nature provides for us. High energy heavy ion collisions, on the other hand, allow us to perform controlled experiments in the laboratory. For a very short period in time we can create a system that lets us study nuclear matter properties. Density and temperature of the system depend on the mass of the colliding nuclei, on their energy and on the impact parameter. The system created in nuclear collisions has at best about 200 constituents not even close to infinite nuclear matter, and it lasts only for collision times of ∼ 10 -22 sec, not an ideal condition for establishing any kind of equilibrium. Extended size and thermal and chemical equilibrium, however, axe a priori conditions of nuclear matter. As a consequence we need realistic models that describe the collision dynamics and non-equilibrium effects in order to relate experimental observables to properties of nuclear matter. The study of high energy nuclear collisions started at the Bevalac. I will try to summarize the results from the Bevalac studies, the highlights of the continuing program, and extension to higher energies without claiming to be complete

Discussion of electron capture theories for ion-atom collisions at high energies

Energy Technology Data Exchange (ETDEWEB)

Miraglia, J E [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina); Piacentini, R D [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivarola, R D [Rosario Univ. Nacional (Argentina). Dept. de Fisica; Salin, A [Bordeaux-1 Univ., 33 - Talence (France)

1981-03-14

Different theories of charge exchange processes in ion-atom collisions at high energies for the H/sup +/-H system are considered. Large discrepancies are found in the differential cross sections obtained from the various models. The validity of Dettmann's peaking approximation is analysed by comparison with exact values for the first- and second-order Oppenheimer-Brinkman-Kramers (OBK 1 and OBK 2) theories. It is also shown that for energies up to a few MeV the OBK 2 differential cross sections are higher than the corresponding OBK 1 ones. Total cross sections in the OBK 2 approximation are given.

Theory of e+e/sup /minus// collisions at very high energy

International Nuclear Information System (INIS)

Peskin, M.E.

1988-04-01

In these lectures, the array of new phenomena are reviewed which might be discovered in electron-positron reactions conducted at energies well above the Z/degree/. Before beginning a discussion of what new phenomena we might find, or how we might uncover them, the question is addressed of why such a program of research is important. The question of what we should be looking for, and what discoveries will be the most illuminating, as we search for the next layer of fundamental physics is argued. With this background, we can then discuss in some considerable detail the contributions that the study of electron-positron collisions at high energy can make in this search

The theory of relativistic heavy ion collisions. [Annual] progress report, [July 1, 1993--June 30, 1994

International Nuclear Information System (INIS)

Shuryak, E.

1994-07-01

For clarity of presentation, we have divided the topics of interest into the following main topics which are discussed in this report: the dynamics of nuclear collisions at very high energies (RHIC and LHC); electromagnetic probes; the dynamics of nuclear collisions at AGS energies; and non-perturbative QCD and the physics of the phase transition

Abstracts of contributed papers. Sixth international conference on high-energy physics and nuclear structure, Santa Fe and Los Alamos, NM, June 9--14, 1975

International Nuclear Information System (INIS)

Mischke, R.; Hargrove, C.; Hoffman, C.

1975-08-01

Abstracts of contributed papers are assembled under the following headings (number denotes the number of abstracts in the section): pi p and pi d interactions (10); π nucleus theory (33); intermediate isobar calculations (8); π-nucleus interactions (25); stopping muons (44); exotic atoms and condensed nuclear states (28); nucleus-nucleus interactions (31); nuclear structure and hypernuclei (7); nucleon-nucleon interactions (24); e- and γ-nucleus interactions (29); weak interactions (17); high energy collisions (13); heavy ions (22); instrumentation (8). (SDF)

Seventh international seminar on ion-atom collisions (ISIAC VII): summary

International Nuclear Information System (INIS)

1981-01-01

The scientific program was structured into eight symposia representing seven important research areas. The subject matter was expanded to include ion-molecule collisions as one of the eight symposia. The symposia were: (1) collisions involving strong binding phenomena and nuclear effects; (2) low-energy, high charge state collisions; (3) Rydberg states; (4) an Open Session; (5) ion-molecule collisions; (6) laser applications to atomic and molecular collisions; (7) collision spectroscopy; and (8) polarization, alignment and correlation

Nuclear reactions induced by high-energy alpha particles

Science.gov (United States)

Shen, B. S. P.

1974-01-01

Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

Interplay of short-range correlations and nuclear symmetry energy in hard-photon production from heavy-ion reactions at Fermi energies

Science.gov (United States)

Yong, Gao-Chan; Li, Bao-An

2017-12-01

Within an isospin- and momentum-dependent transport model for nuclear reactions at intermediate energies, we investigate the interplay of the nucleon-nucleon short-range correlations (SRCs) and nuclear symmetry energy Esym(ρ ) on hard-photon spectra in collisions of several Ca isotopes on 112Sn and 124Sn targets at a beam energy of 45 MeV/nucleon. It is found that over the whole spectra of hard photons studied, effects of the SRCs overwhelm those owing to the Esym(ρ ) . The energetic photons come mostly from the high-momentum tails (HMTs) of single-nucleon momentum distributions in the target and projectile. Within the neutron-proton dominance model of SRCs based on the consideration that the tensor force acts mostly in the isosinglet and spin-triplet nucleon-nucleon interaction channel, there are equal numbers of neutrons and protons, thus a zero isospin asymmetry in the HMTs. Therefore, experimental measurements of the energetic photons from heavy-ion collisions at Fermi energies have the great potential to help us better understand the nature of SRCs without any appreciable influence by the uncertain Esym(ρ ) . These measurements will be complementary to but also have some advantages over the ongoing and planned experiments using hadronic messengers from reactions induced by high-energy electrons or protons. Because the underlying physics of SRCs and Esym(ρ ) are closely correlated, a better understanding of the SRCs will, in turn, help constrain the nuclear symmetry energy more precisely in a broad density range.

Universality, maximum radiation, and absorption in high-energy collisions of black holes with spin.

Science.gov (United States)

Sperhake, Ulrich; Berti, Emanuele; Cardoso, Vitor; Pretorius, Frans

2013-07-26

We explore the impact of black hole spins on the dynamics of high-energy black hole collisions. We report results from numerical simulations with γ factors up to 2.49 and dimensionless spin parameter χ=+0.85, +0.6, 0, -0.6, -0.85. We find that the scattering threshold becomes independent of spin at large center-of-mass energies, confirming previous conjectures that structure does not matter in ultrarelativistic collisions. It has further been argued that in this limit all of the kinetic energy of the system may be radiated by fine tuning the impact parameter to threshold. On the contrary, we find that only about 60% of the kinetic energy is radiated for γ=2.49. By monitoring apparent horizons before and after scattering events we show that the "missing energy" is absorbed by the individual black holes in the encounter, and moreover the individual black-hole spins change significantly. We support this conclusion with perturbative calculations. An extrapolation of our results to the limit γ→∞ suggests that about half of the center-of-mass energy of the system can be emitted in gravitational radiation, while the rest must be converted into rest-mass and spin energy.

Energy-Aware RFID Anti-Collision Protocol.

Science.gov (United States)

Arjona, Laura; Simon, Hugo Landaluce; Ruiz, Asier Perallos

2018-06-11

The growing interest in mobile devices is transforming wireless identification technologies. Mobile and battery-powered Radio Frequency Identification (RFID) readers, such as hand readers and smart phones, are are becoming increasingly attractive. These RFID readers require energy-efficient anti-collision protocols to minimize the tag collisions and to expand the reader's battery life. Furthermore, there is an increasing interest in RFID sensor networks with a growing number of RFID sensor tags. Thus, RFID application developers must be mindful of tag anti-collision protocols. Energy-efficient protocols involve a low reader energy consumption per tag. This work presents a thorough study of the reader energy consumption per tag and analyzes the main factor that affects this metric: the frame size update strategy. Using the conclusion of this analysis, the anti-collision protocol Energy-Aware Slotted Aloha (EASA) is presented to decrease the energy consumption per tag. The frame size update strategy of EASA is configured to minimize the energy consumption per tag. As a result, EASA presents an energy-aware frame. The performance of the proposed protocol is evaluated and compared with several state of the art Aloha-based anti-collision protocols based on the current RFID standard. Simulation results show that EASA, with an average of 15 mJ consumed per tag identified, achieves a 6% average improvement in the energy consumption per tag in relation to the strategies of the comparison.

Differences in high $p_{t}$ meson production between CERN SPS and RHIC heavy ion collisions

CERN Document Server

Papp, G; Barnafoldi, G G; Yi Zhang; Fái, G; Papp, Gabor; Levai, Peter; Barnafoldi, Gergely G.; Zhang, Yi; Fai, George

2001-01-01

In this talk we present a perturbative QCD improved parton model calculation for light meson production in high energy heavy ion collisions. In order to describe the experimental data properly, one needs to augment the standard pQCD model by the transverse momentum distribution of partons ("intrinsic k/sub T/"). Proton-nucleus data indicate the presence of nuclear shadowing and multi-scattering effects. Further corrections are needed in nucleus-nucleus collisions to explain the observed reduction of the cross section. We introduce the idea of proton dissociation and compare our calculations with the SPS and RHIC experimental data. (18 refs).

The nuclear response and the imaginary potential for nucleus-nucleus collisions

International Nuclear Information System (INIS)

Phatak, S.C.; Sinha, B.

1983-01-01

The Fermi-gas model is used in this paper to study the nucleus-nucleus collision. The field produced by one of the nuclei is considered to act on nucleons in the other nucleus, which is treated as a Fermi gas of radius R. The imaginary part of the (non-local) nucleus-nucleus potential is then computed by evaluating the energy-conserving second-order term in which the intermediate states are particle-hole excitations produced in the Fermi gas. The equivalent local potential, obtained by using the Perey-Saxon method, is compared with phenomenological imaginary potentials. Later it is shown that, in the limit of small range of non-locality, the imaginary potential can be related to the nuclear response function. With this, one can write the nuclear friction coefficient that is used in phenomenological analyses of heavy-ion collisions in terms of the imaginary potential. (orig.)

QCD in high-energy proton-proton and proton-antiproton collisions

International Nuclear Information System (INIS)

Baier, R.

1985-01-01

The experimental and theoretical investigation of nucleon-nucleon collisions at high energies allows to explore the structure of the nucleon by large momentum transfer (deep-inelastic) processes. In these lectures the structure of the nucleon from momentum scales Q > 1 GeV/c ( -16 cm) is discussed. In the first lecture the basic concepts of the parton model and of perturbative quantum chromodynamics (QCD) are introduced, and applied to deep inelastic lepton-nucleon scattering. The following lectures cover large transverse momentum, psub(T), hadronic processes, massive dilepton production and production of prompt real photons at large psub(T). The present status of the theoretical understanding of these processes is summarized. (Auth.)

Hydrogen energy based on nuclear energy

International Nuclear Information System (INIS)

2002-06-01

A concept to produce hydrogen of an energy carrier using nuclear energy was proposed since 1970s, and a number of process based on thermochemical method has been investigated after petroleum shock. As this method is used high temperature based on nuclear reactors, these researches are mainly carried out as a part of application of high temperature reactors, which has been carried out at an aim of the high temperature reactor application in the Japan Atomic Energy Research Institute. On October, 2000, the 'First International Conference for Information Exchange on Hydrogen Production based on Nuclear Energy' was held by auspice of OECD/NEA, where hydrogen energy at energy view in the 21st Century, technology on hydrogen production using nuclear energy, and so on, were published. This commentary was summarized surveys and researches on hydrogen production using nuclear energy carried out by the Nuclear Hydrogen Research Group established on January, 2001 for one year. They contains, views on energy and hydrogen/nuclear energy, hydrogen production using nuclear energy and already finished researches, methods of hydrogen production using nuclear energy and their present conditions, concepts on production plants of nuclear hydrogen, resources on nuclear hydrogen production and effect on global environment, requests from market and acceptability of society, and its future process. (G.K.)

Jets in d (p )-A collisions: Color transparency or energy conservation

Science.gov (United States)

Kordell, Michael; Majumder, Abhijit

2018-05-01

The production of jets, and high momentum hadrons from jets, produced in deuteron-Au (d -Au) collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and proton-Pb (p -Pb) collisions at the CERN Large Hadron Collider (LHC) are studied as a function of centrality, a measure of the impact parameter of the collision. A modified version of the event generator pythia, widely used to simulate p -p collisions, is used in conjunction with a nuclear Monte Carlo event generator which simulates the locations of the nucleons within a large nucleus. We demonstrate how events with a hard jet may be simulated, in such a way that the parton distribution function of the projectile is "frozen" during its interaction with the extended nucleus. Using our approach, we demonstrate that the puzzling enhancement seen in peripheral events at RHIC and the LHC, as well as the suppression seen in central events at the LHC, are possibly due to mis-binning of central and semicentral events, containing a jet, as peripheral events. This occurs due to the suppression of soft particle production away from the jet, caused by the depletion of energy available in a nucleon of the deuteron (in d -Au at RHIC) or in the proton (in p -Pb at LHC), after the production of a hard jet. We conclude that partonic correlations built out of simple energy conservation are responsible for such an effect, though these are sampled at the hard scale of jet production and, as such, represent smaller states.

Measurement of transverse energy at midrapidity in Pb-Pb collisions at root s(NN)=2.76 TeV

Czech Academy of Sciences Publication Activity Database

Adam, J.; Adamová, Dagmar; Bielčík, J.; Bielčíková, Jana; Brož, M.; Čepila, J.; Contreras, J. G.; Eyyubova, G.; Ferencei, Jozef; Horák, D.; Křížek, Filip; Kučera, Vít; Mareš, Jiří A.; Petráček, V.; Pospíšil, Jan; Schulc, M.; Špaček, M.; Šumbera, Michal; Vaňát, Tomáš; Závada, Petr

2016-01-01

Roč. 94, č. 3 (2016), s. 034903 ISSN 2469-9985 R&D Projects: GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : ALICE collaboration * heavy ion collisions * electromagnetic calorimeters Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D) Impact factor: 3.820, year: 2016

On the angular distribution of spectator nucleons in high-energy collisions with deuterium nuclei

International Nuclear Information System (INIS)

Bartke, J.

1975-01-01

Angular distributions of spectator nucleons in collisions of high-energy particles with deuterium nuclei are discussed in the framework of the impulse model. Comparison with experimental data shows that predictions following from this simple theoretical model are verified by experiment. Some general remarks on the study of angular distributions of spectator nucleons are given. (author)

Multiple nucleon transfer in damped nuclear collisions. [Lectures, mass charge, and linear and angular momentum transport

Energy Technology Data Exchange (ETDEWEB)

Randrup, J.

1979-07-01

This lecture discusses a theory for the transport of mass, charge, linear, and angular momentum and energy in damped nuclear collisions, as induced by multiple transfer of individual nucleons. 11 references.

Heavy flavour production at CMS in heavy ion collisions

CERN Document Server

Nguyen, Matthew

2015-01-01

We review recent results relating to beauty production in heavy-ion collisions, in both the closed and open heavy flavor sectors, from the CMS experiment at the LHC. The sequential suppression of the ° states in PbPb collisions is thought to be evidence of the dissociation of quarkonia bound states in deconfined matter. Data from pPb collisions demonstrate that while cold nuclear effects appear to be subdominant in minimum bias collisions, there exists a non-trivial dependence on collision multiplicity that remains to be understood. The suppression of high p T particles in heavy-ion collisions, relative to the expectation from pp collisions, is typically interpreted in terms of energy loss of hard scattered parton in the dense nuclear medium. The flavor dependence of the energy loss may be accessed via measurements of b hadrons and b-tagged jets. Measurement of B mesons, via non-prompt J = y , at relatively low p T indicate a smaller suppression factor than D meson or inclusive charged hadrons. Data on b jet...

Theory of low energy collisions; Theorie des collisions a basse energie

Energy Technology Data Exchange (ETDEWEB)

Sparenberg, J.M. [Universite Libre de Bruxelles, Bruxelles (Belgium)

2007-07-01

The basic notions of low-energy quantum scattering theory are introduced (cross sections, phase shifts, resonances,... ), in particular for positively-charged particles, in view of nuclear physics applications. An introduction to the reaction-matrix (or R-matrix) method is then proposed, as a tool to both solve the Schroedinger equation describing collisions and fit experimental data phenomenologically. Most results are established without proof but with a particular emphasis on their intuitive understanding and their possible analogs in classical mechanics. Several choices are made consequently: (i) the text starts with a detailed reminder of classical scattering theory, (ii) the concepts are first introduced in ideal theoretical cases before going to the more complicated formalism allowing the description of realistic experimental situations, (iii) a single example is used throughout nearly the whole text, (iv) all concepts are established for the elastic scattering of spinless particles, with only a brief mention of their multichannel generalization at the end of the text. (author)

Nuclear modification factor for J/ψ production in nucleus-nucleus collisions

International Nuclear Information System (INIS)

Xu Xiaoming; Zhou Jie

2011-01-01

The STAR Collaboration has offered an eminent nuclear modification factor of J/ψ at high p T and midrapidity produced in Cu-Cu collisions at √ s NN= 200 GeV. Recalling a prediction, we can understand that the feature of high-p T nuclear modification factor is related to cc produced by 2 → 1 and 2 → 2 partonic processes in deconfined matter, particularly in the prethermal stage and to the recombination of c and c-bar. The nuclear modification factor at high p T is sensitive to the earliest form of deconfined matter that does not have a temperature.(authors)

Energy dependence of J/ψ production in Au + Au collisions at √{sNN} = 39 , 62.4 and 200GeV

Science.gov (United States)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fujita, J.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, T.; Huang, X.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, Y.; Li, X.; Li, W.; Li, C.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, Y.; Liu, H.; Liu, F.; Liu, P.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, X.; Sun, Y.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

2017-08-01

The inclusive J / ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (| y | < 1.0) in Au + Au collisions at √{sNN} = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J / ψ production, with respect to the production in p + p scaled by the number of binary nucleon-nucleon collisions, is observed in central Au + Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J / ψ production due to the color screening effect and J / ψ regeneration from recombination of uncorrelated charm-anticharm quark pairs.

On Descriptions of Particle Transverse Momentum Spectra in High Energy Collisions

Directory of Open Access Journals (Sweden)

Fu-Hu Liu

2014-01-01

is obtained that, at a given set of parameters, the standard distributions show a narrower shape than their Tsallis forms which result in wide and/or multicomponent spectra with the Tsallis distribution in between. A comparison among the temperatures obtained from the distributions is made with a possible relation to the Boltzmann temperature. An example of the angular distributions of projectile fragments in nuclear collisions is given.

1-3 Nuclear In-medium Effects of Strange Particles in Proton-nucleus Collisions

Institute of Scientific and Technical Information of China (English)

Feng; Zhaoqing[1

2014-01-01

Extraction of the in-medium properties of strange particles from heavy-ion collisions is very complicated, since he nuclear density varies in the evolution of nucleus-nucleus collisions. To avoid the uncertainties of the baryon ensities during the stage of strange particle production, one can investigate proton-nucleus collisions where the uclear density is definite around the saturation density. Dynamics of strange particles produced in the protoninduced uclear the reactions near the threshold energies has been investigated within the Lanzhou quantum olecular dynamics (LQMD) transport model. The in-medium modifications on particle production in densenuclear matter are considered through the corrections to the elementary cross sections via the effective mass and he mean-field potentials[1].

High-Energy Compton Scattering Light Sources

CERN Document Server

Hartemann, Fred V; Barty, C; Crane, John; Gibson, David J; Hartouni, E P; Tremaine, Aaron M

2005-01-01

No monochromatic, high-brightness, tunable light sources currently exist above 100 keV. Important applications that would benefit from such new hard x-ray sources include: nuclear resonance fluorescence spectroscopy, time-resolved positron annihilation spectroscopy, and MeV flash radiography. The peak brightness of Compton scattering light sources is derived for head-on collisions and found to scale with the electron beam brightness and the drive laser pulse energy. This gamma 2

Measurement of the nuclear modification factor for high-$p_\\mathrm{T}$ charged hadrons in pPb collisions with the ATLAS detector

CERN Document Server

Balek, Petr; The ATLAS collaboration

2016-01-01

The charged hadron spectra in p+Pb and pp collisions at $\\sqrt{s}=5.02$TeV are measured with the ATLAS experiment at the LHC. The measurements are performed with p+Pb data recorded in 2013 with an integrated luminosity of 25nb${}^{-1}$ and pp data recorded in 2015 with an integrated luminosity of 25pb${}^{-1}$. The p+Pb results are directly compared to pp spectra, as a ratio scaled by the number of binary nucleon-nucleon collisions, the nuclear modification factor $R\\mathrm{pPb}$. It allows for a detailed comparison of the collision systems in different centrality intervals and up to high transverse momentum.

Seven principle of highly effective Nuclear Energy Programs

International Nuclear Information System (INIS)

Ferguson, Ch.D.; Reed, Ph.D.

2010-01-01

This paper presents seven principles that demand consideration for any country using a nuclear power program or wanting to acquire such a program. These principles are assessing the overall energy system, determining effective use of financial resources for energy development, ensuring high safety standards, implementing best security practices, preventing the spread of nuclear weapons, managing radioactive waste in a safe and secure manner, and enacting a legal framework that encompasses the other principle areas. The paper applies management methods that underscore development of strong independent national capabilities integrated within an interdependent international system. The paper discusses the individual responsibilities of states in all seven principles and offers recommendations for how states can benefit from greater international cooperation in nuclear energy development

Comparison of models of high energy heavy ion collision

International Nuclear Information System (INIS)

Gyulassy, M.

1977-01-01

Some of the main theoretical developments on heavy ion collisions at energies (0.1 to 2.0) GeV/nuc are reviewed. The fireball, firestreak, hydrodynamic (1-fluid, 2-fluids), ''row on row'', hard sphere and intranuclear cascades, and classical equations of motion models are discussed in detail. Results are compared to each other and to measured Ne + U → p + X reactions

Generalized z-scaling in proton-proton collisions at high energies

International Nuclear Information System (INIS)

Zborovsky, I.; Tokarev, M.

2006-01-01

New generalization of z-scaling in inclusive particle production is proposed. The scaling variable z is a fractal measure which depends on kinematical characteristics of the underlying subprocess expressed in terms of the momentum fractions x 1 and x 2 of the incoming protons. In the generalized approach, the x 1 and x 2 are functions of the momentum fractions y a and y b of the scattered and recoil constituents carried out by the inclusive particle and recoil object, respectively. The scaling function ψ(z) for charged and identified hadrons produced in proton-proton collisions is constructed. The fractal dimensions and heat capacity of the produced medium entering definition of the z are established to obtain energy, angular and multiplicity independence of the ψ(z). The scheme allows unique description of data on inclusive cross sections of charged particles, pions, kaons, antiprotons, and lambdas at high energies. The obtained results are of interest to use z-scaling as a tool for searching for new physics phenomena of particle production in high transverse momentum and high multiplicity region at the proton-proton colliders RHIC and LHC

Axial spatial distribution focusing: improving MALDI-TOF/RTOF mass spectrometric performance for high-energy collision-induced dissociation of biomolecules.

Science.gov (United States)

Belgacem, O; Pittenauer, E; Openshaw, M E; Hart, P J; Bowdler, A; Allmaier, G

2016-02-15

For the last two decades, curved field reflectron technology has been used in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometers, assisting in the generation of post-source-decay (PSD) or collision-induced dissociation (CID) without decelerating precursor ions, producing true high-energy CID spectra. The result was the generation of product ion mass spectra with product ions typical of high-energy (10 keV and beyond) collision processes. The disadvantage of this approach was the lack of resolution in CID spectra resulting from the excess laser energy deposition used to generate those MS/MS spectra. The work presented in this study overcomes this limitation and includes comprehensive examples of high-energy and high-resolution CID MALDI-MS/MS spectra of biomolecules. The devices used in this study are TOF/RTOF instruments equipped with a high-vacuum MALDI ion source. High-resolution and high-energy CID spectra result from the use of axial spatial distribution focusing (ASDF) in combination with curved field reflectron technology. A CID spectrum of the P14 R1 peptide exhibits product ion resolution in excess of 10,000 (FWHM) but at the same time yields typical high-energy product ions such as w- and [y-2]-type ion series. High-energy CID spectra of lipids, exemplified by a glycerophospholipid and triglyceride, demonstrate C-C backbone fragmentation elucidating the presence of a hydroxyl group in addition to double-bond positioning. A complex high mannose carbohydrate (Man)8 (GlcNAc)2 was also studied at 20 keV collision energy and revealed further high-energy product ions with very high resolution, allowing unambiguous detection and characterization of cross-ring cleavage-related ions. This is the first comprehensive study using a MALDI-TOF/RTOF instrument equipped with a curved field reflectron and an ASDF device prior to the reflectron. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley

Effects of the in-medium nucleon-nucleon cross section on collective flow and nuclear stopping in heavy-ion collisions in the Fermi-energy domain

Science.gov (United States)

Li, Pengcheng; Wang, Yongjia; Li, Qingfeng; Guo, Chenchen; Zhang, Hongfei

2018-04-01

With the newly updated version of the ultrarelativistic quantum molecular dynamics (UrQMD) model, a systematic investigation of the effects of in-medium nucleon-nucleon (NN ) elastic cross section on the collective flow and the stopping observables in 197Au+197Au collisions at beam energies from 40 to 150 MeV/nucleon is performed. Simulations with the medium correction factors F =σNN in -medium/σNN free=0.2 ,0.3 ,0.5 and the one obtained with the FU3FP1 parametrization which depends on both the density and the momentum are compared to the FOPI and INDRA experimental data. It is found that, to best fit the experimental data of the slope of the directed flow and the elliptic flow at midrapidity as well as the nuclear stopping, the correction factors of F =0.2 and 0.5 are required for reactions at beam energies of 40 and 150 MeV/nucleon, respectively. Whereas calculations with the FU3FP1 parametrization can simultaneously reproduce these experimental data reasonably well. And, the observed increasing nuclear stopping with increasing beam energy in experimental data can also be reproduced by using the FU3FP1 parametrization, whereas the calculated stopping power in Au + Au collisions with beam energies from 40 to 150 MeV /nucleon almost remains constant when taking F equal to a fixed value.

Very-high-energy nuclear physics

International Nuclear Information System (INIS)

Frankel, S.

1983-06-01

In 1980 we carried out an extensive series of experiments on alpha-alpha collisions in the ISR. The purpose of the experiment was to discover something new for example, to search for some evidence of new correlated behaviour, and, in particular, to search for the existence of the formation of a quark-gluon plasma. The reason for this hope lay in the fact that the ISR experiments were to be carried out at ultrarelativistic energies of 1000 GeV/c in the alpha cm. This is a region where it is known that the mean pion multiplicities are very large and it is possible to sample events with event multiplicities of at least 200. Another important feature was the fact that remarkable spectrometers existed at the ISR to make definitive studies of the whole event structure. The apparatus of the AFS had the capability of detecting 50 charged particles in an apparatus covering 85% of the total solid angle. The momentum of each particle could be measured with high accuracy and protons, kaons, pions and their antiparticles could be identified, along with neutral lambdas and kaons. The ability to handle large multiplicities was important in the study of violent collisions. To describe the results of these experiments we shall list below the titles of papers published, in press, or in preparation which will have been completed by the end of this fiscal year, commenting on the results and their significance

Collisions of low-energy multicharged ions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Crandall, D.H.

1981-01-01

Experimental measurements of cross sections for collisions of multiply charged ions with atoms at the lowest attainable collision energies are reported. Emphasis is on electron capture from hydrogen atoms by multiply charged ions at energies below 1 keV/amu. The principal effort is the development of a merged-ion-atom-beams apparatus for studies down to 1 eV/amu relative energy

Multiparticle Production in Particle and Nuclear Collisions. I

Science.gov (United States)

Kanki, T.; Kinoshita, K.; Sumiyoshi, H.; Takagi, F.

The dominant phenomenon in high-energy particle and nuclear collisions is multiple production of hadrons. This had attracted may physicists in 1950's, the period of the first remarkable development of particle physics. Multiparticle production was already observed in cosmic-ray experiments and expected to be explained as a natural consequence of the strong Yukawa interaction. Statistical and hydrodynamical models were then proposed by Fermi, Landau and others. These theories are still surviving even today as a prototype of modern ``fire-ball'' models. After twenty years, a golden age came in this field of physics. It was closely related to the rapid development of accelerator facilities, especially, the invention of colliding-beam machines which yield high enough center-of-mass energies for studying reactions with high multiplicity. Abundant data on final states of multiparticle production have been accumulated mainly by measuring inclusive cross sections and multiplicity distributions. In super high-energy bar{p}p collisions at CERN S pmacr pS Collider, we confirmed the increasing total cross section and found violations of many scaling laws which seemed to be valid at lower energies. This suggests a fundamental complexity of the multiparticle phenomena and offers new materials for further development of theoretical investigations. In the same period, studies of constituent (quark-gluon) structure of hadrons had also been develped. Nowadays, pysicists believe that the quantum chromodynamics (QCD) is the fundamental law of the hadronic world. Multiparticle dynamics should also be described by QCD. We have known that the hard-jet phenomena are well explained by the perturbative QCD. On the other hand, the soft processes are considered to be non-perturbative phenomena which have not yet been solved, and related to the mechanism of the color confinement and formation of strings or color-flux tubes. Multiparticle production would offer useful information on this

Multiparticle Production in Particle and Nuclear Collisions. II

Science.gov (United States)

Kanki, T.; Kinoshita, K.; Sumiyoshi, H.; Takagi, F.

The dominant phenomenon in high-energy particle and nuclear collisions is multiple production of hadrons. This had attracted may physicists in 1950's, the period of the first remarkable development of particle physics. Multiparticle production was already observed in cosmic-ray experiments and expected to be explained as a natural consequence of the strong Yukawa interaction. Statistical and hydrodynamical models were then proposed by Fermi, Landau and others. These theories are still surviving even today as a prototype of modern ``fire-ball'' models. After twenty years, a golden age came in this field of physics. It was closely related to the rapid development of accelerator facilities, especially, the invention of colliding-beam machines which yield high enough center-of-mass energies for studying reactions with high multiplicity. Abundant data on final states of multiparticle production have been accumulated mainly by measuring inclusive cross sections and multiplicity distributions. In super high-energy bar{p}p collisions at CERN S pmacr pS Collider, we confirmed the increasing total cross section and found violations of many scaling laws which seemed to be valid at lower energies. This suggests a fundamental complexity of the multiparticle phenomena and offers new materials for further development of theoretical investigations. In the same period, studies of constituent (quark-gluon) structure of hadrons had also been develped. Nowadays, pysicists believe that the quantum chromodynamics (QCD) is the fundamental law of the hadronic world. Multiparticle dynamics should also be described by QCD. We have known that the hard-jet phenomena are well explained by the perturbative QCD. On the other hand, the soft processes are considered to be non-perturbative phenomena which have not yet been solved, and related to the mechanism of the color confinement and formation of strings or color-flux tubes. Multiparticle production would offer useful information on this

Constraints on the high-density nuclear equation of state from the phenomenology of compact stars and heavy-ion collisions

International Nuclear Information System (INIS)

Klaehn, T.; Blaschke, D.; Typel, S.; Dalen, E. N. E. van; Faessler, A.; Fuchs, C.; Gaitanos, T.; Wolter, H. H.; Grigorian, H.; Ho, A.; Weber, F.; Kolomeitsev, E. E.; Miller, M. C.; Roepke, G.; Truemper, J.; Voskresensky, D. N.

2006-01-01

A new scheme for testing nuclear matter equations of state (EoSs) at high densities using constraints from neutron star (NS) phenomenology and a flow data analysis of heavy-ion collisions is suggested. An acceptable EoS shall not allow the direct Urca process to occur in NSs with masses below 1.5M · , and also shall not contradict flow and kaon production data of heavy-ion collisions. Compact star constraints include the mass measurements of 2.1±0.2M · (1σ level) for PSR J0751+1807 and of 2.0±0.1M · from the innermost stable circular orbit for 4U 1636-536, the baryon mass--gravitational mass relationships from Pulsar B in J0737-3039 and the mass-radius relationships from quasiperiodic brightness oscillations in 4U 0614+09 and from the thermal emission of RX J1856-3754. This scheme is applied to a set of relativistic EoSs which are constrained otherwise from nuclear matter saturation properties. We demonstrate on the given examples that the test scheme due to the quality of the newly emerging astrophysical data leads to useful selection criteria for the high-density behavior of nuclear EoSs

CMBE v05-Implementation of a toy-model for chaos analysis of relativistic nuclear collisions at the present BNL energies

Science.gov (United States)

Grossu, I. V.; Felea, D.; Jipa, Al.; Besliu, C.; Stan, E.; Ristea, O.; Ristea, C.; Calin, M.; Esanu, T.; Bordeianu, C.; Tuturas, N.

2014-11-01

In this paper we present a new version of Chaos Many-Body Engine (CMBE) Grossu et al. (2014) [1]. Inspired by the Mean Free Path concept, we implemented a new parameter, namely the ;Mean Free Time;, which is defined as the mean time between one particle's creation and its stimulated decay. This new parameter should be understood as an effect of the nuclear environment and, as opposed to the particle lifetime, it has the advantage of not being affected by the relativistic dilation. In [2] we presented a toy-model for chaos analysis of relativistic nuclear collisions at 4.5 A GeV/c (the SKM 200 collaboration). In this work, we extended our model to 200 A GeV (the maximum BNL energy).

Direct processes in ion-atom collisions at intermediate and high energies

International Nuclear Information System (INIS)

Rodriguez Chariarse, V.D.

1990-01-01

This thesis deals with direct processes induced by Zp charge ion impact on one or two electron atoms and ions at intermediate energies. At a first step, a one-dimensional collision model is used in order to prove the different theoretical methods available to study collisions at such energy range, such as: perturbative and related variational principles, and distorted wave methods. The best description of both, symmetric and asymmetric collision type, is achieved by the distorted wave methods, particularly the ones using the exact impulsive wave function. As a next step, the appropriate formulations of the wave functions employed in the one-dimensional model to describe the real 3-dimensional Coulomb interaction case are examined by using the Eikonal and impulse hypothesis. In this way, the VPS and Eikonal wave functions are reviewed, and furtherly, the Eikonal form of the extended impulse wave function is derived. The Eikonal impulse approximation (EIA) is introduced. This is a distorted wave method using the Eikonal and extended impulse wave functions. The choice of the EIA prior version, i.e., the one using extended impulse wave function in the final channel for excitation is widely discussed and justified. (Author) [es

Dynamical and statistical aspects in nucleus-nucleus collisions around the Fermi energy

Energy Technology Data Exchange (ETDEWEB)

Tamain, B.; Bocage, F.; Bougault, R.; Brou, R. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Assenard, M. [Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees; Auger, G.; Benlliure, J. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Bacri, C.O.; Borderie, B. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Bisquer, E. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire] [and others

1997-12-31

Nucleus-nucleus collisions at low incident energy are mainly governed by statistical dissipative processes, fusion and deep inelastic reactions being the most important ones. Conversely, in the relativistic energy regime, dynamical effects play a dominant role and one should apply a participant-spectator picture in order to understand the data. In between, the intermediate energy region is a transition one in which it is necessary to disentangle dynamics from statistical effects. Moreover, the Fermi energy region corresponds to available energies comparable with nuclear binding energies and one may except to observe phase transition effects. Experiments performed recently with 4{pi} devices have given quite new data and a much better insight into involved mechanisms and hot nuclear matter properties. INDRA data related to reaction mechanisms and multifragmentation are presented. (author) 53 refs.

Dynamical and statistical aspects in nucleus-nucleus collisions around the Fermi energy

International Nuclear Information System (INIS)

Tamain, B.; Bocage, F.; Bougault, R.; Brou, R.; Bacri, C.O.; Borderie, B.; Bisquer, E.

1997-01-01

Nucleus-nucleus collisions at low incident energy are mainly governed by statistical dissipative processes, fusion and deep inelastic reactions being the most important ones. Conversely, in the relativistic energy regime, dynamical effects play a dominant role and one should apply a participant-spectator picture in order to understand the data. In between, the intermediate energy region is a transition one in which it is necessary to disentangle dynamics from statistical effects. Moreover, the Fermi energy region corresponds to available energies comparable with nuclear binding energies and one may except to observe phase transition effects. Experiments performed recently with 4π devices have given quite new data and a much better insight into involved mechanisms and hot nuclear matter properties. INDRA data related to reaction mechanisms and multifragmentation are presented. (author)

Theoretical studies in medium-energy nuclear and hadronic physics

International Nuclear Information System (INIS)

Horowitz, C.J.; Macfarlane, M.H.; Matsui, T.; Serot, B.D.

1993-01-01

A proposal for theoretical nuclear physics research is made for the period April 1, 1993 through March 31, 1996. Research is proposed in the following areas: relativistic many-body theory of nuclei and nuclear matter, quasifree electroweak scattering and strange quarks in nuclei, dynamical effects in (e,e'p) scattering at large momentum transfer, investigating the nucleon's parton sea with polarized leptoproduction, physics of ultrarelativistic nucleus endash nucleus collisions, QCD sum rules and hadronic properties, non-relativistic models of nuclear reactions, and spin and color correlations in a quark-exchange model of nuclear matter. Highlights of recent research, vitae of principal investigators, and lists of publications and invited talks are also given. Recent research dealt primarily with medium-energy nuclear physics, relativistic theories of nuclei and the nuclear response, the nuclear equation of state under extreme conditions, the dynamics of the quark endash gluon plasma in relativistic heavy-ion collisions, and theories of the nucleon endash nucleon force

High education and nuclear energy

International Nuclear Information System (INIS)

Ghitescu, Petre; Prisecaru, Ilie; Stefanescu, Petre

1998-01-01

The Faculty of Energy of the University 'Politecnica' in Bucharest is the only faculty in Romania in the field of nuclear energy education. With an experience of more than 29 years, the Faculty of Energy offers the major 'Nuclear Power Plants', which students graduate after a 5-year education as engineers in the Nuclear Power Plant major. Among the principal objectives of the development and reshape of the Romanian education system was mentioned the upgrading of organizational forms by introducing the transfer credit system, and starting in the fall '97 by accrediting Radioprotection and Nuclear Safety Master education. As a result of co-operation and assistance offered by TEMPUS-SENECA program, the new major is shaped and endowed with a modern curriculum harmonized with UE and IAEA requirements and a modern and performing laboratory. This way the Romanian higher education offers a fully correct and concordant structure with UE countries education. (authors)

Inclusive jet production in ultrarelativistic proton-nucleus collisions

CERN Document Server

Perepelitsa, Dennis

High-$p_\\mathrm{T}$ processes in proton- and deuteron-nucleus collisions at TeV energies are the best presently available way to study the partonic structure of the nucleus in a high-density regime. Jet production over a wide range of phase space can significantly constrain the current knowledge of nuclear parton distribution functions (nPDFs), which are substantially less well understood than the corresponding PDFs in protons and which have only recently begun to be treated in a spatially-dependent way. An accurate knowledge of nPDFs is crucial for a definitive control of perturbative processes in a cold nuclear environment, since high-$p_\\mathrm{T}$ probes are used to quantitatively investigate the hot QCD matter created in ultrarelativistic nucleus-nucleus collisions. Furthermore, jets from low Bjorken-$x$ partons can probe the transition from the dilute to saturated nuclear regimes. Jet production is investigated in $d$+Au collisions at $\\sqrt{s} = 200$ GeV with the PHENIX detector at the Relativistic Hea...

Studies of fluctuation processes in nuclear collisions

International Nuclear Information System (INIS)

Ayik, S.

1991-02-01

This report summarizes the progress on grant No. DE-FG05-89ER40530 during the period April 15, 1990 to February 15, 1991. Our studies of heavy-ion collisions in the framework of ''a stochastic one-body transport model'' has progress in several directions. We developed a method for obtaining approximate numerical solutions of the transport-equation in semi-classical limit, i.e., Boltzmann-Langevin equation, and tested the method in realistic cases of heavy-ion collisions at energies below 100 MeV per nucleon. Some results of the numerical simulations for a head-on collision of 12 C + 12 C system is included in this report. Work has also continued on studying the stochastic one-body transport model in a quantal representation, which provides a microscopic basis for a consistent description of dissipation and fluctuation properties of large amplitude collective nuclear motion. The previous derivation of the stochastic one-body transport model was presented within the density matrix formalisam. We generalized this treatment and proposed an alternative derivation of the model by employing the Green's function approach within the real-time path formalism of Keldish. One manuscript has been submitted to Nucl. Phys. A for publication. Two other manuscripts are in preparation for publication. Several seminars and contributed talks were presented at various meeting

Energy dependence of J/ψ production in Au+Au collisions at sNN=39,62.4 and 200GeV

Directory of Open Access Journals (Sweden)

L. Adamczyk

2017-08-01

Full Text Available The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (|y|<1.0 in Au+Au collisions at sNN = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J/ψ production, with respect to the production in p+p scaled by the number of binary nucleon–nucleon collisions, is observed in central Au+Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J/ψ production due to the color screening effect and J/ψ regeneration from recombination of uncorrelated charm–anticharm quark pairs.

Removal of nonorthogonality in the Born theory used for study of electron capture in high energy ion-atom collisions

International Nuclear Information System (INIS)

Kimura, M.

1989-01-01

We show the complete removal of the nonorthogonality of wave functions between initial and final states in the Born theory. Hence, this treatment offers more realistic electron capture cross sections in high energy ion-atom collisions. Representative results for resonant electron capture in H + + H collision are discussed in conjunction with other perturbative results. 10 refs., 1 fig

Cosmological Hubble constant and nuclear Hubble constant

International Nuclear Information System (INIS)

Horbuniev, Amelia; Besliu, Calin; Jipa, Alexandru

2005-01-01

The evolution of the Universe after the Big Bang and the evolution of the dense and highly excited nuclear matter formed by relativistic nuclear collisions are investigated and compared. Values of the Hubble constants for cosmological and nuclear processes are obtained. For nucleus-nucleus collisions at high energies the nuclear Hubble constant is obtained in the frame of different models involving the hydrodynamic flow of the nuclear matter. Significant difference in the values of the two Hubble constant - cosmological and nuclear - is observed

Development of a fragment detector system for the study of peripheral collisions at high beam energies

International Nuclear Information System (INIS)

Spies, H.

1992-06-01

In the framework of the experimental program at the accelerator facilities SIS/ESR of the Society for Heavy-Ion research in Darmstadt one of the essential research aims of the LAND collaboration is the study of high-lying collective states after electromagnetic excitation in heavy-ion collisions at nearly relativistic beam energies. By the exchange of virtual photons with high energy giant resonances are excited with high probabilities. The main decay channel of giant resonances in heavy nuclei is the emission of neutrons as well as below the particle threshold the emission of γ radiation. For the study of these states a detector system was developed, which makes the kinematically complete measurement of all reaction partners possible. For the determination of the neutron energy serves the Large Area Neutron Detector LAND, a time-of-flight spectrometer for high-energetic neutrons. For the measurement of the γ radiation emitted by the excited projectile the target is surrounded by an array of 48 BaF 2 crystals. A radiation detector system consisting of 6 single detectors and further 5 help detectors allows together with the magnetic spectrometer ALADIN the identification of the heavy projectile fragments by charge, momentum, and mass. Four position-sensitive plastic scintillators serve for the measurement of the trajectory of the projectile respectively the projectile fragments in front and behind the deviating magnet. Additionally with these detectors the velocity is measured. For the determination of the nuclear charge of the projectile fragments serve a multiple-ionization chamber and a Cherenkov detector. In this thesis the development and taking into operation of the LAND radiation detector system is described. (orig./HSI) [de

Jets in heavy ion collisions

International Nuclear Information System (INIS)

Nattrass, Christine

2017-01-01

High energy collisions of heavy nuclei permit the study of nuclear matter at temperatures and energy densities so high that the fundamental theory for strong interactions, QCD, predicts a phase transition to a plasma of quarks and gluons. This matter, called a Quark Gluon Plasma (QGP), has been studied experimentally for the last decade and has been observed to be a strongly interacting liquid with a low viscosity. High energy partons created early in the collision interact with the QGP and provide unique probes of its properties. Hard partons fragment into collimated sprays of particles called jets and have been studied through measurements of single particles, correlations between particles, and measurements of fully reconstructed jets. These measurements demonstrate partonic energy loss in the QGP and constrain the QGP’s properties. Measurements of the jet structure give insight into the mechanism of this energy loss. The information we have learned from studies of jets and challenges for the field will be reviewed. (paper)

Correlations between high momentum particles in proton-proton collisions at high energies

International Nuclear Information System (INIS)

Bobbink, G.J.

1981-01-01

This thesis describes an experiment performed at the CERN Intersecting Storage Rings. The experiment studies the reaction p+p→h 1 +h 2 +X at two centre-of-mass energies, √s=44.7 GeV and √s=62.3 GeV. Two of the outgoing particles (h 1 and h 2 ) are detected in opposite c.m.s. hemispheres at small polar angles with respect to the direction of two incident protons. The remaining particles produced (X) are not detected. The hadrons hsub(i) are identified mesons (π + , π - , K + , K - ) or baryons (p, Λ) with relatively large longitudinal psub(L) and small transverse momentum psub(T). The aim of the experiment is twofold. The first aim is to study whether the momentum distributions of the fast particles hsub(i) are correlated and thereby to constrain the possible interaction mechanisms responsible for the production of high psub(L), low psub(T) particles. The second aim is to establish to what extent the production of pions and kaons in inclusive proton-proton collisions (e.g. p+p→π+X, X=all other particles) resembles the production of pions and kaons in diffractive proton-proton collisions (e.g. p+p→p+π+X, in which the final-state proton has a momentum close to its maximum possible value). (Auth.)

Laboratory for Nuclear Science. High Energy Physics Program

Energy Technology Data Exchange (ETDEWEB)

Milner, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2014-07-30

High energy and nuclear physics research at MIT is conducted within the Laboratory for Nuclear Science (LNS). Almost half of the faculty in the MIT Physics Department carry out research in LNS at the theoretical and experimental frontiers of subatomic physics. Since 2004, the U.S. Department of Energy has funded the high energy physics research program through grant DE-FG02-05ER41360 (other grants and cooperative agreements provided decades of support prior to 2004). The Director of LNS serves as PI. The grant supports the research of four groups within LNS as “tasks” within the umbrella grant. Brief descriptions of each group are given here. A more detailed report from each task follows in later sections. Although grant DE-FG02-05ER41360 has ended, DOE continues to fund LNS high energy physics research through five separate grants (a research grant for each of the four groups, as well as a grant for AMS Operations). We are pleased to continue this longstanding partnership.

Monotonous braking of high energy hadrons in nuclear matter

International Nuclear Information System (INIS)

Strugalski, Z.

1979-01-01

Propagation of high energy hadrons in nuclear matter is discussed. The possibility of the existence of the monotonous energy losses of hadrons in nuclear matter is considered. In favour of this hypothesis experimental facts such as pion-nucleus interactions (proton emission spectra, proton multiplicity distributions in these interactions) and other data are presented. The investigated phenomenon in the framework of the hypothesis is characterized in more detail

Covariance analysis of symmetry energy observables from heavy ion collision

Directory of Open Access Journals (Sweden)

Yingxun Zhang

2015-10-01

Full Text Available Using covariance analysis, we quantify the correlations between the interaction parameters in a transport model and the observables commonly used to extract information of the Equation of State of Asymmetric Nuclear Matter in experiments. By simulating 124Sn + 124Sn, 124Sn + 112Sn and 112Sn + 112Sn reactions at beam energies of 50 and 120 MeV per nucleon, we have identified that the nucleon effective mass splitting is most strongly correlated to the neutrons and protons yield ratios with high kinetic energy from central collisions especially at high incident energy. The best observable to determine the slope of the symmetry energy, L, at saturation density is the isospin diffusion observable even though the correlation is not very strong (∼0.7. Similar magnitude of correlation but opposite in sign exists for isospin diffusion and nucleon isoscalar effective mass. At 120 MeV/u, the effective mass splitting and the isoscalar effective mass also have opposite correlation for the double n/p and isoscaling p/p yield ratios. By combining data and simulations at different beam energies, it should be possible to place constraints on the slope of symmetry energy (L and effective mass splitting with reasonable uncertainties.

X-ray emission in slow highly charged ion-surface collisions

International Nuclear Information System (INIS)

Watanabe, H; Abe, T; Fujita, Y; Sun, J; Takahashi, S; Tona, M; Yoshiyasu, N; Nakamura, N; Sakurai, M; Yamada, C; Ohtani, S

2007-01-01

X-rays emitted in the collisions of highly charged ions with a surface have been measured to investigate dissipation schemes of their potential energies. While 8.1% of the potential energy was dissipated in the collisions of He-like I ions with a W surface, 29.1% has been dissipated in the case of He-like Bi ions. The x-ray emissions play significant roles in the dissipation of the potential energies in the interaction of highly charged heavy ions with the surface

Probing medium-induced jet splitting and energy loss in heavy-ion collisions

Science.gov (United States)

Chang, Ning-Bo; Cao, Shanshan; Qin, Guang-You

2018-06-01

The nuclear modification of jet splitting in relativistic heavy-ion collisions at RHIC and the LHC energies is studied based on the higher twist formalism. Assuming coherent energy loss for the two splitted subjets, a non-monotonic jet energy dependence is found for the nuclear modification of jet splitting function: strongest modification at intermediate jet energies whereas weaker modification for larger or smaller jet energies. Combined with the smaller size and lower density of the QGP medium at RHIC than at the LHC, this helps to understand the groomed jet measurements from CMS and STAR Collaborations: strong modification of the momentum sharing zg distribution at the LHC and no obvious modification of zg distribution at RHIC. In addition, the observed nuclear modification pattern of the groomed jet zg distribution cannot be explained solely by independent energy loss of the two subjets. Our result may be tested in future measurements of groomed jets with lower jet energies at the LHC and larger jet energies at RHIC, for different angular separations between the two subjets.

Baseline measures for net-proton distributions in high energy heavy-ion collisions

International Nuclear Information System (INIS)

Netrakanti, P.K.; Mishra, D.K.; Mohanty, A.K.; Mohanty, B.

2014-01-01

The STAR experiment at the Relativistic Heavy-Ion Collider facility has reported results for the cumulants and their ratios from the net-proton distributions upto the fourth order cumulants at various collision energies. These measurements were carried to look for the signatures of the possible critical point (CP) in the phase diagram for a system undertaking strong interactions. The results show an intriguing dependence of the cumulant ratios C 3 /C 2 and C 4 /C 2 as a function of beam energy. The beam energy dependence appears to be non-monotonic in nature. However the experiment also reports that the energy dependence is observed to be consistent with expectation from an approach based on the independent production of proton and anti-protons in the collisions. In this paper we emphasize the need to have a proper baseline for appropriate interpretation of the cumulant measurements and argue that the comparison to independent production approach needs to be done with extreme caution

New aspects of high energy heavy-ion transfer reactions

International Nuclear Information System (INIS)

Scott, D.K.

1975-03-01

New aspects of heavy ion reactions at incident energies in the region of 10 MeV/nucleon are discussed with an emphasis on the peripheral nature of the collisions, which leads to simplicities in the differential cross sections. The distortion of the peripheral distribution through the interference of direct and multistep processes is used to illustrate aspects of high energy reactions unique to heavy ions. The simplicities of the distributions for reactions on lighter nuclei are exploited to give new information about nuclear structure from direct and compound reactions at high energy. (16 figures, 32 references) (U.S.)

ATTILA (All Type Target Independent Lund Algorithm) for nuclear collisions at ≅ 200 AGeV

International Nuclear Information System (INIS)

Gyulassy, M.; Lawrence Berkeley Lab., CA

1987-08-01

The Lund string model, Fritiof, is applied in the form of a Monte-Carlo event generator, ATTILA, to nuclear collisions in the 200 AGeV range. We study how uncertainties at the pp level amplify at the AB level and compare preliminary CERN data on multiplicity, transverse energy, and veto energy distributions to this linear extrapolation scheme from pp to AB dynamics. (orig.)

Production of pi(0) and eta mesons up to high transverse momentum in pp collisions at 2.76 TeV

Czech Academy of Sciences Publication Activity Database

Acharya, S.; Adamová, Dagmar; Bielčík, J.; Bielčíková, Jana; Brož, M.; Contreras, J. G.; Ferencei, Jozef; Hladký, Jan; Horák, D.; Křížek, Filip; Kučera, Vít; Kushpil, Svetlana; Lavička, R.; Mareš, Jiří A.; Petráček, V.; Pospíšil, Jan; Šumbera, Michal; Vaňát, Tomáš; Závada, Petr

2017-01-01

Roč. 77, č. 5 (2017), č. článku 339. ISSN 1434-6044 R&D Projects: GA MŠk(CZ) LG15052 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : ALICE collaboration * heavy ion collisions * LHC Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D) OBOR OECD: Nuclear physics; Particles and field physics (FZU-D) Impact factor: 5.331, year: 2016

Multiple collision effects on the antiproton production by high energy proton (100 GeV - 1000 GeV)

International Nuclear Information System (INIS)

Takahashi, Hiroshi; Powell, J.

1987-01-01

Antiproton production rates which take into account multiple collision are calculated using a simple model. Methods to reduce capture of the produced antiprotons by the target are discussed, including geometry of target and the use of a high intensity laser. Antiproton production increases substantially above 150 GeV proton incident energy. The yield increases almost linearly with incident energy, alleviating space charge problems in the high current accelerator that produces large amounts of antiprotons

Collective processes in heavy-ion collisions with atomic nuclei. Dissipation of energy and angular momentum

International Nuclear Information System (INIS)

Kuzminski, J.

1980-01-01

The collective processes in collision of heavy-ions with atomic nuclei are discussed. Measured data on the S+Ti collision at Esub(LAB)=105, 130 and 144 MeV have been analysed in terms of a ''fission-like'' processes which seem to be a special case of deep inelastic collisions whose total available kinetic energy is completely dissipated. Applying transport theory it was possible to introduce a ''clock'' for measuring the time scale of nuclear processes in collision of heavy-ions by measuring the FWHM of mass distribution of emitted reaction products. Experimental data on continuum gamma spectra from Cu+Au collision at Esub(LAB)=400 MeV are presented and the angular momentum dissipation in this reaction is discussed. (author)

Global Lambda hyperon polarization in nuclear collisions

Czech Academy of Sciences Publication Activity Database

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Bielčík, J.; Bielčíková, Jana; Chaloupka, P.; Federič, Pavol; Federičová, P.; Harlenderová, A.; Kocmánek, Martin; Kvapil, J.; Lidrych, J.; Rusňák, Jan; Rusňáková, O.; Šaur, Miroslav; Šimko, Miroslav; Šumbera, Michal; Trzeciak, B. A.

2017-01-01

Roč. 548, č. 7665 (2017), č. článku 23004. ISSN 0028-0836 R&D Projects: GA MŠk LG15001; GA MŠk LM2015054 Institutional support: RVO:61389005 Keywords : STAR collaboration * heavy ion collisions * vorticity Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 40.137, year: 2016

A hadron-nucleus collision event generator for simulations at intermediate energies

CERN Document Server

Ackerstaff, K; Bollmann, R

2002-01-01

Several available codes for hadronic event generation and shower simulation are discussed and their predictions are compared to experimental data in order to obtain a satisfactory description of hadronic processes in Monte Carlo studies of detector systems for medium energy experiments. The most reasonable description is found for the intra-nuclear-cascade (INC) model of Bertini which employs microscopic description of the INC, taking into account elastic and inelastic pion-nucleon and nucleon-nucleon scattering. The isobar model of Sternheimer and Lindenbaum is used to simulate the inelastic elementary collisions inside the nucleus via formation and decay of the DELTA sub 3 sub 3 -resonance which, however, limits the model at higher energies. To overcome this limitation, the INC model has been extended by using the resonance model of the HADRIN code, considering all resonances in elementary collisions contributing more than 2% to the total cross-section up to kinetic energies of 5 GeV. In addition, angular d...

Inner shell ionization accompanying nuclear collisions

International Nuclear Information System (INIS)

Sujkowski, Z.

1987-01-01

Selected phenomena leading to inner shell ionization and being of relevance for nuclear physics are discussed. The selection emphasizes the K-shell ionization induced in head-on collisions by fast light and medium-heavy ions. Cross-sections are reviewed. Effects of multiple inner shell ionization on the K X-ray spectra are illustrated with recent results. Implications for nuclear experiments are noted. Use of atomic observables as clocks for proton induced nuclear reactions is reviewed. Prospects for H.I. reactions are discussed. Preliminary experimental results on the direct K-shell ionization accompanying H.I. fusion reactions are presented. The post-collisional K-shell ionization due to internal conversion of γ-rays is discussed as the dominating contribution to the ionization for residues of dissipative nuclear reactions with Z > 40. Systematics of the corresponding K X-ray multiplicities are presented for rotational nuclei. These multiplicity values can be used for determining cross-sections for e.g. incomplete fusion reactions. Examples of such applications are given. Also discussed is the use of target K X-rays for normalization purposes and of the post-collisional, residue K X-rays in the studies of high spin phenomena. 96 references, 35 figures, 3 tables

Hydrodynamic evolution and jet energy loss in Cu + Cu collisions

International Nuclear Information System (INIS)

Schenke, Bjoern; Jeon, Sangyong; Gale, Charles

2011-01-01

We present results from a hybrid description of Cu + Cu collisions using (3 + 1)-dimensional hydrodynamics (music) for the bulk evolution and a Monte Carlo simulation (martini) for the evolution of high-momentum partons in the hydrodynamical background. We explore the limits of this description by going to small system sizes and determine the dependence on different fractions of wounded nucleon and binary collisions scaling of the initial energy density. We find that Cu + Cu collisions are well described by the hybrid description at least up to 20% central collisions.

ARRONAX, a high-energy and high-intensity cyclotron for nuclear medicine

International Nuclear Information System (INIS)

Haddad, Ferid; Guertin, Arnaud; Michel, Nathalie; Ferrer, Ludovic; Carlier, Thomas; Barbet, Jacques; Chatal, Jean-Francois

2008-01-01

This study was aimed at establishing a list of radionuclides of interest for nuclear medicine that can be produced in a high-intensity and high-energy cyclotron. We have considered both therapeutic and positron emission tomography radionuclides that can be produced using a high-energy and a high-intensity cyclotron such as ARRONAX, which will be operating in Nantes (France) by the end of 2008. Novel radionuclides or radionuclides of current limited availability have been selected according to the following criteria: emission of positrons, low-energy beta or alpha particles, stable or short half-life daughters, half-life between 3 h and 10 days or generator-produced, favourable dosimetry, production from stable isotopes with reasonable cross sections. Three radionuclides appear well suited to targeted radionuclide therapy using beta ( 67 Cu, 47 Sc) or alpha ( 211 At) particles. Positron emitters allowing dosimetry studies prior to radionuclide therapy ( 64 Cu, 124 I, 44 Sc), or that can be generator-produced ( 82 Rb, 68 Ga) or providing the opportunity of a new imaging modality ( 44 Sc) are considered to have a great interest at short term whereas 86 Y, 52 Fe, 55 Co, 76 Br or 89 Zr are considered to have a potential interest at middle term. Several radionuclides not currently used in routine nuclear medicine or not available in sufficient amount for clinical research have been selected for future production. High-energy, high-intensity cyclotrons are necessary to produce some of the selected radionuclides and make possible future clinical developments in nuclear medicine. Associated with appropriate carriers, these radionuclides will respond to a maximum of unmet clinical needs. (orig.) 5

Neck instabilities in deep inelastic collisions at medium energies

International Nuclear Information System (INIS)

Colonna, M.; Guarnera, A.; Istituto Nazionale di Fisica Nucleare, Catania; Catania Univ.; Di Toro, M.; Latora, V.; Smerzi, A.; Catania Univ.; Jiquan, Z.; Catania Univ.; Lanzhou Univ., GS

1994-01-01

A novel reaction mechanism for semi-peripheral heavy ion collisions is discussed due to new features of the nuclear dynamics in the overlapping region. In a very selected beam energy range, between 40 and 70 Me/u, we see the onset of new neck instabilities coupled to an increasing amount of dynamical fluctuations. Expected consequences are a possibility of intermediate mass fragment emission form the neck region and large variances in the projectile-like and target-like observables. (authors). 11 refs., 3 figs

Towards relativistic heavy ion collisions 'by small steps towards the stars'

International Nuclear Information System (INIS)

Scott, D.K.

1980-01-01

Current attempts to search for the exotic processes occurring in relativistic heavy ion collisions are reviewed under the headings; peripheral collisions (peripheral collisions as a function of energy, new features at intermediate energies, ground state correlations, microscopic aspects), central collisions (low energy perspective, time scales in heavy ion collisions, spatial, temporal localization and the onset of the nuclear fireball, models of particle emission in central relativistic collisions, the heart of the matter, multiplicity selection, the emission of composite particles), a search for the exotic (the limits of temperature and pressure, temporal and spatial limits, the limits of nuclear matter and nuclei,). 229 references. (U.K.)