438 research outputs found
Direct Photon Identification with Artificial Neural Network in the Photon Spectrometer PHOS
A neural network method is developed to discriminate direct photons from the
neutral pion background in the PHOS spectrometer of the ALICE experiment at the
LHC collider. The neural net has been trained to distinguish different classes
of events by analyzing the energy-profile tensor of a cluster in its eigen
vector coordinate system. Monte-Carlo simulations show that this method
diminishes by an order of magnitude the probability of -meson
misidentification as a photon with respect to the direct photon identification
efficiency in the energy range up to 120 GeV.Comment: 12 pages, TeX (or Latex, etc), https://edms.cern.ch/document/406291/
Test of an LED Monitoring System for the PHOS Spectrometer
Preprint submitted to Elsevier Print on 26th January 2000A prototype monitoring system for the Photon Spectrometer (PHOS) of the ALICE experiment at LHC is described in detail. The prototype consists of Control and Master modules. The first one is 8x8 matrix of Light Emitting Diodes coupled with stable generators of current pulses. The system provides an individual control for each of the 64 channels of PHOS prototype based on lead-tungstate crystals. A long term stability of order of 10-3 has been achieved in integral beam tests of the monitoring system and PHOS prototypes
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
Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment
We present a phenomenological model which describes the formation of a
Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and
at the LHC, and its decay to non-strange baryons and Strangelets. We describe
the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in
an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta <
7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations
for the response of the CASTOR calorimeter, and in particular to the traversal
of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR
Gamma-radiation as a Signature of Ultra Peripheral Ion Collisions at LHC energies
We study the peripheral ion collisions at LHC energies in which a nucleus is
excited to the discrete state and then emits -rays. Large nuclear
Lorenz factor allows to observe the high energy photons up to a few ten GeV and
in the region of angles of a few hundred micro-radians around the beam
direction. These photons can be used for tagging the events with particle
production in the central rapidity region in the ultra-peripheral collisions.
For that it is necessary to have an electromagnetic detector in front of the
zero degree calorimeter in the LHC experiments.Comment: 14 pages, 6 Postscript figure
- …