2,037 research outputs found
Physics with the ALICE experiment
ALICE experiment at LHC collects data in pp collisions at =0.9,
2.76 and 7 TeV and in PbPb collisions at 2.76 TeV. Highlights of the detector
performance and an overview of experimental results measured with ALICE in pp
and AA collisions are presented in this paper. Physics with proton-proton
collisions is focused on hadron spectroscopy at low and moderate .
Measurements with lead-lead collisions are shown in comparison with those in pp
collisions, and the properties of hot quark matter are discussed.Comment: Presented at the Conference of the Nuclear Physics Division of the
Russian Academy of Science, 11-25.11.2011, ITEP, Moscow. 16 pages, 14 figure
CASTOR: Centauro and Strange Object Research in nucleus-nucleus collisions at LHC
We describe the CASTOR detector designed to probe the very forward,
baryon-rich rapidity region in nucleus-nucleus collisions at the LHC. We
present a phenomenological model describing the formation of a QGP fireball in
a high baryochemical potential environment, and its subsequent decay into
baryons and strangelets. The model explains Centauros and the long-penetrating
component and makes predictions for the LHC.
Simulations of Centauro-type events were done. To study the response of the
apparatus to new effects different exotic species (DCC, Centauros, strangelets
etc.) were passed through the deep calorimeter. The energy deposition pattern
in the calorimeter appears to be a new clear signature of the QGP.Comment: Talk given by E. Gladysz-Dziadus for the CASTOR group, Intern.
Workshop on Nuclear Theory, 10-15 June, 2002, Bulgaria, Rila Mountains, 15
pages, 14 figure
Metal-insulator transition and magnetism in correlated band insulator: FeSi and FeCoSi
The LDA+DMFT (local density approximation combined with dynamical mean-field
theory) computation scheme has been used to study spectral and magnetic
properties of FeSi and FeCoSi. Having compared different models
we conclude that a correlated band insulator scenario in contrast to Kondo
insulator model agrees with FeSi band structure as well as experimental data.
Coulomb correlation effects lead to band narrowing of the states near the Fermi
level with mass renormalization parameter in agreement with the
results of angle-resolved photoemission spectroscopy (ARPES). Temperature
dependence of spectral functions and magnetic susceptibility calculated in DMFT
reproduces transition from nonmagnetic semiconductor to metal with local
magnetic moments observed experimentally. Cobalt doping leads to ferromagnetism
that has itinerant nature and can be successfully described by LDA+DMFT method.Comment: 10 pages, 15 figure
The Physics of Ultraperipheral Collisions at the LHC
We discuss the physics of large impact parameter interactions at the LHC:
ultraperipheral collisions (UPCs). The dominant processes in UPCs are
photon-nucleon (nucleus) interactions. The current LHC detector configurations
can explore small hard phenomena with nuclei and nucleons at photon-nucleon
center-of-mass energies above 1 TeV, extending the range of HERA by a
factor of ten. In particular, it will be possible to probe diffractive and
inclusive parton densities in nuclei using several processes. The interaction
of small dipoles with protons and nuclei can be investigated in elastic and
quasi-elastic and production as well as in high
production accompanied by a rapidity gap. Several of these phenomena
provide clean signatures of the onset of the new high gluon density QCD regime.
The LHC is in the kinematic range where nonlinear effects are several times
larger than at HERA. Two-photon processes in UPCs are also studied. In
addition, while UPCs play a role in limiting the maximum beam luminosity, they
can also be used a luminosity monitor by measuring mutual electromagnetic
dissociation of the beam nuclei. We also review similar studies at HERA and
RHIC as well as describe the potential use of the LHC detectors for UPC
measurements.Comment: 229 Pages, 121 figure
Photon Physics in Heavy Ion Collisions at the LHC
Various pion and photon production mechanisms in high-energy nuclear
collisions at RHIC and LHC are discussed. Comparison with RHIC data is done
whenever possible. The prospect of using electromagnetic probes to characterize
quark-gluon plasma formation is assessed.Comment: Writeup of the working group "Photon Physics" for the CERN Yellow
Report on "Hard Probes in Heavy Ion Collisions at the LHC", 134 pages. One
figure added in chapter 5 (comparison with PHENIX data). Some figures and
correponding text corrected in chapter 6 (off-chemical equilibrium thermal
photon rates). Some figures modified in chapter 7 (off-chemical equilibrium
photon rates) and comparison with PHENIX data adde
Model of Centauro and strangelet production in heavy ion collisions
We discuss the phenomenological model of Centauro event production in
relativistic nucleus-nucleus collisions. This model makes quantitative
predictions for kinematic observables, baryon number and mass of the Centauro
fireball and its decay products. Centauros decay mainly to nucleons, strange
hyperons and possibly strangelets. Simulations of Centauro events for the
CASTOR detector in Pb-Pb collisions at LHC energies are performed. The
signatures of these events are discussed in detail.Comment: 19 pages, LaTeX+revtex4, 14 eps-figures and 3 table
Structure of facial pain at ambulatory dental reception
The article describes the structure of facial pain at an outpatient surgical dental appointment. The treatment of young women with muscle pain is predominant.В статье описана структура лицевой боли на амбулаторном хирургическом стоматологическом приеме. Преобладает обращение лиц женского пола молодого возраста, имеющих чаще мышечную боль
CASTOR detector: model, objectives and simulated performance
We present a phenomenological model describing the formation and evolution of a Centauro fireball in the baryon-rich region in nucleus-nucleus interactions in the upper atmosphere and at the LHC. The small particle multiplicity and imbalance of electromagnetic and hadronic content characterizing a Centauro event and also the strongly penetrating particles (assumed to be strangelets) frequently accompanying them can be naturally explained. We describe the CASTOR calorimeter, a subdetector of the ALICE experiment dedicated to the search for Centauro in the very forward, baryon-rich region of central Pb+Pb collisions at the LHC. The basic characteristics and simulated performance of the calorimeter are presented
Metal-Insulator Transitions and Magnetism in Correlated Band Insulators: FeSi and Fe1-x CoxSi
The LDA+DMFT (local density approximation combined with dynamical mean-field theory) computation scheme has been used to study spectral and magnetic properties of FeSi and Fe1-x Cox Si. Having compared different models, we conclude that a correlated band insulator scenario in contrast to Kondo insulator model agrees well with FeSi band structure and experimental data. Coulomb correlation effects lead to band narrowing of the states near the Fermi level with mass renormalization parameter m *≈.2 in agreement with the results of angle-resolved photoemission spectroscopy. Temperature dependence of spectral functions and magnetic susceptibility calculated in DMFT reproduces transition from nonmagnetic semiconductor to metal with local magnetic moments observed experimentally. Cobalt doping leads to ferromagnetism that has itinerant nature and can be successfully described by the LDA+DMFT method. © 2010 The American Physical Society.The hospitality of the Institute of Theoretical Physics of Hamburg University (Grant No. SFB 668) and the Institute of Theoretical Physics of ETH-Zurich is gratefully acknowledged. We would like to thank T. M. Rice, M. Sigrist, A. Läuchli, Y. Yamashita, D. van der Marel, and I. Solovyev for helpful discussions, and Y. O. Kvashnin for his assistance with Wannier function analysis. This work is supported by the grant program of President of Russian Federation under Grant No. MK-1162.2009.2, by the scientific program “Development of scientific potential of universities” under Grant No. N 2.1.1/779, by the scientific program of the Russian Federal Agency of Science and Innovation under Grant No. N 02.740.11.0217, President of Russian Federation fund for support for scientific schools under Grants No. NSH 1941.2008.2, No. RFFI 07-02-00041, and No. RFFI-09-02-00431a, grants of the Ural Division of the Russian Academy of Sciences N7 and N28. The calculations were performed on the computer cluster of “University Center of Parallel Computing” of USTU-UPI
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