Quelques aspects de la physique des collisions noyau–noyau à énergie ultra relativiste

1989 ◽  
Vol 67 (12) ◽  
pp. 1207-1218
Author(s):  
Claude Leroy
Keyword(s):  
Transverse Energy ◽  
Lattice Gauge Theory ◽  
Nuclear Research ◽  
Cosmic Ray ◽  
High Energy ◽  
European Organization ◽  
Lattice Gauge ◽  
200 Gev ◽  
Normal Nuclear Density ◽  
Order Of Magnitude

We discuss the results of the measurements of the energy flow and multiplicity for the collisions of 16O and 32S with a set of target nuclei at an incident energy of 60 and 200 GeV/nucleon and 200 GeV/nucleon, respectively. These measurements have been performed at the European Organization for Nuclear Research (CERN) super proton synchroton by NA-34/HELIOS (high energy lepton and ion spectrometer), NA-35, NA-36, NA-38, and WA-80 in various pseudorapidity regions. The measurements of the transverse energy (ET) distributions provide an understanding of the concept of the stopping power and the estimates of the energy density reached. The energy densities reached in these collisions (~ 5 GeV/fm3) are at least an order of magnitude larger than the normal nuclear density (0.15 GeV/fm3) and are also in the region of the critical value of ~ 2.5 GeV/fm3 obtained from lattice gauge theory. [Formula: see text], obtained by combining the transverse energy and the multiplicity measurements, is compared with earlier results reported in cosmic-ray studies. The pT spectra of the charged particles and photons produced in these collisions are compared with the corresponding spectra measured in proton–nucleus collisions. The present situation suggests the study of new observables.

scholarly journals Lattice gauge theory for condensed matter physics: ferromagnetic superconductivity as its example

2014 ◽  
Vol 28 (22) ◽  
pp. 1430012 ◽  
Author(s):  
Ikuo Ichinose ◽  
Tetsuo Matsui
Keyword(s):  
Gauge Theory ◽  
High Energy Physics ◽  
Lattice Gauge Theory ◽  
Condensed Matter ◽  
High Energy ◽  
Field Vector ◽  
Condensed Matter Physics ◽  
Ginzburg Landau ◽  
Topological Excitations ◽  
Lattice Gauge

Recent theoretical studies of various strongly-correlated systems in condensed matter physics reveal that the lattice gauge theory (LGT) developed in high-energy physics is quite a useful tool to understand physics of these systems. Knowledge of LGT is to become a necessary item even for condensed matter physicists. In the first part of this paper, we present a concise review of LGT for the reader who wants to understand its basics for the first time. For illustration, we choose the Abelian Higgs model, a typical and quite useful LGT, which is the lattice version of the Ginzburg–Landau model interacting with a U(1) gauge field (vector potential). In the second part, we present an account of the recent progress in the study of ferromagnetic superconductivity (SC) as an example of application of LGT to topics in condensed matter physics. As the ferromagnetism (FM) and SC are competing orders with each other, large fluctuations are expected to take place and therefore nonperturbative methods are required for theoretical investigation. After we introduce a LGT describing the FMSC, we study its phase diagram and topological excitations (vortices of Cooper pairs) by Monte Carlo simulations.

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

2001 ◽  
Vol 79 (4) ◽  
pp. 739-748
Author(s):  
F -H Liu
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Energy Distribution ◽  
Transverse Energy ◽  
High Energy ◽  
Nuclear Collision ◽  
200 Gev ◽  
Transverse Energy Distribution

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, and p–U collisions at 200 GeV/c. PACS Nos.: 13.85-t, 13.85Hd, 25.75-q

scholarly journals Ian Butterworth CBE. 3 December 1930—29 November 2013

2017 ◽  
Vol 64 ◽  
pp. 69-87
Author(s):  
Peter Dornan
Keyword(s):  
Particle Physics ◽  
Electronic Publishing ◽  
Bubble Chamber ◽  
Nuclear Research ◽  
Vice President ◽  
High Energy ◽  
European Organization ◽  
Special Person ◽  
Physics Department ◽  
The Web

Ian Butterworth was a major force in European particle physics from the start of the subject in the late fifties until leaving his post as the European Organization for Nuclear Research (CERN) research director in 1986 to become principal of Queen Mary College. Following his PhD at Manchester, he moved to Imperial College, where later he was head of both the high energy group and the physics department. His early research was dominated by bubble chamber analyses searching for resonant hadronic states, crucial for the establishment of the quark model. Investigating these resonances, using mass spectra and partial wave analyses, was his speciality. He had vision. He was one of the first to recognize the value of IT advances, the importance of networking and the vast potential of the Web. In 1990, at the age of 60, he had a stroke but less than a year later he was again active. His main interests became the effective use of the Web for electronic publishing and the advancement of a coherent European network strategy for education and research. Much of this was under the auspices of the Academia Europaea, of which he was vice president from 1997 to 2003. In his later years he retained a deep interest in European culture and gastronomy and continued to enjoy travelling around Europe. Ian was a special person, warm-hearted, lively and excellent company.

scholarly journals Transverse Energy Density in High Energy Heavy Ion Collisions

2020 ◽  
Vol 240 ◽  
pp. 07006
Author(s):  
Kian Hwee Lim ◽  
Aik Hui Chan ◽  
Choo Hiap Oh
Keyword(s):  
Energy Density ◽  
Transverse Energy ◽  
Heavy Ion ◽  
High Energy ◽  
Atlas Collaboration ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Na35 Collaboration ◽  
200 Gev ◽  
Transverse Energy Distribution

A phenomenological model describing the transverse energy distribution (ET) of nuclear collisions is first studied in detail by fitting it on ET data for O-Pb collisions at √sNN = 200 GeV per nucleon obtained from the NA35 collaboration. Next, the model is used to fit the ET data for Pb-Pb collisions at LHC energies of √sNN = 2.76 TeV per nucleon obtained from the ATLAS collaboration. From the fits, we determine an upper bound for the energy density for Pb-Pb collisions at LHC energies of √sNN = 2.76 TeV per nucleon.

scholarly journals Successful transition of High-Energy Physics publications into Gold OA – review of two years of SCOAP3

2015 ◽  
Author(s):  
Alexander Kohls ◽  
Nina Karlstrøm
Keyword(s):  
Open Access ◽  
Particle Physics ◽  
High Energy Physics ◽  
Contact Point ◽  
Nuclear Research ◽  
High Energy ◽  
Open Access Publishing ◽  
European Organization ◽  
National Organizations ◽  
Energy Physics

See video of the presentation.During its first two years of operation SCOAP3 funded some 8,000 articles via the transformation of ten existing High-Energy Physics journals into Gold Open Access at no costs for authors. SCOAP3, the Sponsoring Consortium for Open Access Publishing in Particle Physics started in January 2014 after several years of preparation. The initiative is a collaboration of some 3,000 libraries, research institutions and funding agencies from 45 countries and IGOs and is hosted at CERN, the European Organization for Nuclear Research. Alexander Kohls, the Operations Manager of SCOAP3 will present a review of the first two years of SCOAP3. The specific business model of the initiative ensures a central management of relations with the publishers, and efficient and easy to administer APC payment process and article compliance validation using a dedicated global repository. The presentation will show how SCOAP3 performed in terms of operational efforts, APCs and benefits for the scientific community. The compliance of publishers with policies will be analyzed and all aspects will be reviewed in context of comparable Open Access initiatives in Europe and its potential to expand into other fields. Nina Karlstrøm will add the view of a National Contact Point and present benefits and challenges for national organizations within the SCOAP3 network using her organization CRIStin as an example.

scholarly journals The Askaryan Radio Array

2012 ◽  
Vol 8 (S288) ◽  
pp. 115-122
Author(s):  
Kara D. Hoffman
Keyword(s):  
Neutrino Flux ◽  
Austral Summer ◽  
Cosmic Ray ◽  
High Energy ◽  
Pierre Auger Observatory ◽  
Ultra High Energy ◽  
Performance Requirements ◽  
Transparent Media ◽  
Order Of Magnitude ◽  
Cosmic Ray Flux

AbstractUltra high energy cosmogenic neutrinos could be most efficiently detected in dense, radio frequency (RF) transparent media via the Askaryan effect. Building on the expertise gained by RICE, ANITA and IceCube's radio extension in the use of the Askaryan effect in cold Antarctic ice, we are currently developing an antenna array known as ARA (The Askaryan Radio Array) to be installed in boreholes extending 200 m below the surface of the ice near the geographic South Pole. The unprecedented scale of ARA, which will cover a fiducial area of ≈ 100 square kilometers, was chosen to ensure the detection of the flux of neutrinos suggested by the observation of a drop in high energy cosmic ray flux consistent with the GZK cutoff by HiRes and the Pierre Auger Observatory. Funding to develop the instrumentation and install the first prototypes has been granted, and the first components of ARA were installed during the austral summer of 2010–2011. Within 3 years of commencing operation, the full ARA will exceed the sensitivity of any other instrument in the 0.1-10 EeV energy range by an order of magnitude. The primary goal of the ARA array is to establish the absolute cosmogenic neutrino flux through a modest number of events. This information would frame the performance requirements needed to expand the array in the future to measure a larger number of neutrinos with greater angular precision in order to study their spectrum and origins.

scholarly journals The measurements of light high-energy ions in NINA-2 experiment

2007 ◽  
Vol 25 (9) ◽  
pp. 2029-2036 ◽  
Author(s):  
A. Leonov ◽  
M. Cyamukungu ◽  
J. Cabrera ◽  
P. Leleux ◽  
Gh. Grégoire ◽  
...  
Keyword(s):  
High Performance ◽  
Cosmic Ray ◽  
High Energy ◽  
Space Mission ◽  
Data Sets ◽  
Energetic Ions ◽  
Radiation Damages ◽  
Light Ions ◽  
Order Of Magnitude ◽  
Low Altitude

Abstract. The flux of energetic light ions at low altitude is both an important input and output for self-consistent calculations of albedo particles resulting from the interaction of trapped and cosmic ray particles, with the upper atmosphere. In addition, data on the flux of light ions are needed to evaluate radiation damages on space-borne instruments and on space mission crews. In spite of that, sources of data on the flux of energetic ions at LEO are roughly limited to the AP-8 model, CREME/CREME96 codes and the SAMPEX, NOAA/TIROS satellites. The existing and operational European SAC-C/ICARE and PROBA-1/SREM instruments could also be potential sources for proton data at LEO. Although AP-8 and SAMPEX/PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes and they do not contain helium fluxes. Therefore, improved light ion radiation models are still needed. In this paper we present a procedure to identify and measure the energy of ions that are not stopped in the NINA-2 instrument. Moreover, problems related to particles that cross the instrument in the opposite direction are addressed and shown to be a possible cause of particle misidentification. Measuring fluxes of low abundance elements like energetic helium ions requires a good characterisation of all possible sources of backgrounds in the detector. Hints to determine the several contributions to the background are presented herein and may be applied to extract an order of magnitude of energetic ions fluxes from existing data sets, while waiting for dedicated high performance instruments.

STUDY OF HIGH ENERGY DENSITIES OVER EXTENDED NUCLEAR VOLUMES VIA NUCLEUS–NUCLEUS COLLISIONS AT THE CERN SPS

1992 ◽  
Vol 07 (12) ◽  
pp. 2635-2659 ◽  
Author(s):  
FRANÇOIS LAMARCHE ◽  
CLAUDE LEROY
Keyword(s):  
Energy Density ◽  
Transverse Energy ◽  
Gluon Plasma ◽  
High Energy ◽  
Maximum Energy ◽  
Proton Synchrotron ◽  
Flow Measurements ◽  
Super Proton Synchrotron ◽  
200 Gev ◽  
Very High Energy

Nucleus–nucleus collisions at very high energy are believed to create the conditions for the existence of a new state of matter, the so-called quark–gluon plasma. This possibility depends on the magnitude of the energy density really achieved during the collisions. Estimates of the energy density are model dependent and have been attempted according to various approaches: fire-ball model and Bjorken model. The understanding of the transverse energy flow measurements and of the stopping power helps to define a proper way to estimate the energy density beyond naive approaches. A space- and time-averaged energy density is shown to be a more reliable probe for the QGP search than is a naive estimate of the maximum energy density. The computation is performed within the framework of hydrodynamics. The data considered in this paper were obtained by experiments performed to study nucleus–nucleus collisions at the CERN Super Proton Synchrotron (CERN-SPS). The incident nuclei were accelerated at energies of 60 and 200 GeV/nucleon.

scholarly journals Trotter errors in digital adiabatic quantum simulation of quantum ℤ2 lattice gauge theory

2020 ◽  
Vol 34 (30) ◽  
pp. 2050292
Author(s):  
Xiaopeng Cui ◽  
Yu Shi
Keyword(s):  
Gauge Theory ◽  
Lattice Gauge Theory ◽  
Coupling Parameter ◽  
Quantum Simulation ◽  
Evolution Operators ◽  
Quantum Simulations ◽  
Lattice Gauge ◽  
Experimental Implementation ◽  
Order Of Magnitude ◽  
Symmetric Decomposition

Trotter decomposition is the basis of the digital quantum simulation. Asymmetric and symmetric decompositions are used in our GPU demonstration of the digital adiabatic quantum simulations of (2[Formula: see text]+[Formula: see text]1)-dimensional quantum [Formula: see text] lattice gauge theory. The actual errors in Trotter decompositions are investigated as functions of the coupling parameter and the number of Trotter substeps in each step of the variation of coupling parameter. The relative error of energy is shown to be equal to the Trotter error usually defined in terms of the evolution operators. They are much smaller than the order-of-magnitude estimation. The error in the symmetric decomposition is much smaller than that in the asymmetric decomposition. The features of the Trotter errors obtained here are useful in the experimental implementation of digital quantum simulation and its numerical demonstration.

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