3,330 research outputs found
Electron identification performance with ALICE TRD prototypes
We present the electron/pion identification performance measured with
prototypes for ALICE TRD. Measured spectra of energy deposit of pions and
electrons as well as their average values are presented and compared to
calculations. Various radiators are investigated over the momentum range of 1
to 6 GeV/c. The time signature of TR is exploited in a bidimensional likelihood
mothod.Comment: Presented at the conference "TRDs for the 3rd millenium", Bari,
Italy, Sept. 4-7 2003. To appear in Nucl.Instrum.Meth. A. (4 pages, 6
figures
Experimental results and phenomenology of quarkonium production in relativistic nuclear collisions
An overview of recent measurements of quarkonium production in
nucleus-nucleus collisions and their understanding in theoretical models is
given.Comment: 8 pages, 7 figures; writeup of a plenary talk at Quark Matter 2014;
v2: final version (as published), with some rephrasing of tex
Elucidating the multiplicity dependence of J/ production in proton-proton collisions with PYTHIA8
A study of prompt and non-prompt J/ production as a function of
charged-particle multiplicity in inelastic proton--proton (pp) collisions at a
centre-of-mass energy of = 13 TeV based on calculations using the
PYTHIA8 Monte Carlo is reported. Recent experimental data shows an intriguing
stronger-than-linear increase of the self-normalized J/ yield with
multiplicity; several models, based on initial or final state effects, have
been able to describe the observed behaviour. In this paper, the microscopic
reasons for this behaviour, like the role of multiple parton interactions,
colour reconnections and auto-correlations are investigated. It is observed
that the stronger-than-linear increase and the transverse momentum () dependence, contrary to what is predicted by the other available models,
can be attributed to auto-correlation effects only. In absence of
auto-correlation effects, the increase of the yield of J/ with
multiplicity -- and in general for all hard processes -- is weaker than linear
for multiplicities exceeding about three times the mean multiplicity. The
possibility of disentangling auto-correlation effects from other physical
phenomena by measuring the charged-particle multiplicity in different
pseudo-rapidity and azimuthal regions relative to the J/ direction is
investigated. In this regard, it is suggested to extend the experimental
measurements of J/ production as a function of the charged-particle
multiplicity by determining the multiplicity in several azimuthal regions and
in particular in the Transverse region with respect to the direction of the
J/ meson.Comment: 12 pages, 14 figures: accepted by EPJ
The horn, the hadron mass spectrum and the QCD phase diagram - the statistical model of hadron production in central nucleus-nucleus collisions
We present the status of the description of hadron production in central
nucleus-nucleus collisions within the statistical model . The recent inclusion
of very high-mass resonances and the sigma meson leads to an improved
description of the data, in particular the energy dependence of the K+/pi+
ratio at SPS energies (``the horn''). The connection to the QCD phase diagram
is discussed.Comment: 4 pages, 3 figures; presented at the Nucleus-Nucleus 2009 conference,
Beijing, Aug. 200
The charm of hot matter - charmonium and open charm measurements in Pb--Pb collisions with ALICE at the LHC
We present selected results obtained by the ALICE Collaboration concerning
charmed hadron and quarkonium production in Pb--Pb collisions at the LHC.Comment: 10 pages, 10 figures; proceedings of the International Workshop on
Discovery at the LHC, Kruger Gate, dec. 201
An overview of the experimental study of quark-gluon matter in high-energy nucleus-nucleus collisions
An overview is given on the experimental study of quark-gluon matter produced
in relativistic nucleus-nucleus collisions, with emphasis on recent
measurements at the Large Hadron Collider.Comment: 31 pages, 20 figures; invited review in Int. J. Mod. Phys. A; based
on an overview talk at the Lepton-Photon 2013 conferenc
Quarkonium production in ultra-relativistic nuclear collisions: suppression vs. enhancement
After a brief review of the various scenarios for quarkonium production in
ultra-relativistic nucleus-nucleus collisions we focus on the ingredients and
assumptions underlying the statistical hadronization model. We then confront
model predictions for J/ phase space distributions with the most recent
data from the RHIC accelerator. Analysis of the rapidity dependence of the
J/ nuclear modification factor yields first evidence for the production
of J/ mesons at the phase boundary. We conclude with predictions for
charmonium production at the LHC.Comment: 8 pages, 6 figures, invited paper, Quark Matter 2006 conference,
Shanghai, submitted to J. Phys.
Z0 Boson Measurement with the ALICE Central Barrel in pp collisions at 14 TeV
The possibility to detect the Z0 in the ALICE central barrel is studied via
the electronic decay channel Z0->e+e-. The signal and the background are
simulated with the leading order event generator PYTHIA 6. The total
cross-sections are taken from NLO calculations. Based on test beam data, the
electron identification performance of the Transition Radiation Detector is
extrapolated to high momenta. The expected yields for minimum-bias pp
collisions at 14 TeV are presented. An isolation cut on the single electron,
together with a minimum transverse momentum cut, allows to obtain a clear
signal. The expected background is of the order of 1 % with the main
contribution coming from misidentified pions from jets.Comment: 4 pages, 3 figures, QM2008 proceeding
The statistical model in Pb-Pb collisions at the LHC
We briefly review the predictions of the thermal model for hadron production
in comparison to latest data from RHIC and extrapolate the calculations to LHC
energy. Our main emphasis is to confront the model predictions with the
recently released data from ALICE at the LHC. This comparison reveals an
apparent anomaly for protons and anti-protons which we discuss briefly. We also
demonstrate that our statistical hadronization predictions for J/
production agree very well with the most recent LHC data, lending support to
the picture in which there is complete charmonium melting in the quark-gluon
plasma (QGP) followed by statistical generation of J/ mesons at the phase
boundary.Comment: 4 pages, 3 figures, proceedings of QM201
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