The ALICE experiment at the LHC

A free-energy function is constructed, which couples strain and magnetic moments in ferromagnetic shape memory alloys. The associated Gibbs function is used to calculate time-dependent transition probabilities between martensite variants in a magnetic field under applied stress. By keeping track of the variant fractions, the evolution of strain and magnetization is determined. The simulation model is built in a finite element program for structural analysis, in order to simulate magnetic field-dependent strain and magnetization characteristics of a test actuator. The influence of material parameters and sample geometry is discussed.     

The ALICE experiment at the LHC

After a general introduction on the Quark Gluon Plasma and a short overview of the experimental results obtained so far with heavy-ion collisions at the SPS and at the RHIC, the physics goals of the ALICE experiment at the LHC are presented. The text was submitted by the author in English.     

Jet measurements by ALICE at LHC

Jets are collimated sprays of particles originating from fragmentation of high energy partons produced in a hard collision. They are an important diagnostic tool in studies of the Quark Gluon Plasma (QGP). The modification of the jet fragmentation pattern and its structure is a signature for the influence of hot and dense matter on the parton fragmentation process. Jet measurements in proton-proton collisions provide a baseline for similar measurements in heavy-ion collisions, while studies in proton-nucleus system allow to estimate cold nuclear matter effects. Here we present jet studies in different colliding systems (p–p, p–Pb, Pb–Pb) performed by the ALICE collaboration at LHC energies. Results on jet spectra, cross sections, nuclear modification factors, jet structure and other kinematic observables will be presented.     

Jet physics at the LHC with ALICE

In central Pb-Pb collisions at the LHC, jet rates are expected to be high at energies at which ALICE can reconstruct jets over the background of the underlying event. This will open the possibility to quantify the effect of partonic energy loss through medium induced gluon radiation, jet quenching, by detailed measurement of the modification of the longitudinal and transverse structure of identified jets. In order to obtain probes sensitive to the properties of the QCD medium, it is mandatory to measure the high- parton fragments together with the low- particles from the radiated gluons. Hence, the excellent charged particle tracking capabilities of ALICE combined with the proposed electromagnetic calorimeter for ALICE, EMCAL, represent an ideal tool for jet quenching studies at the LHC. Electronic Supplementary Material Supplementary material is available for this article at PACS: 25.75.Nq, 24.85. + p, 13.87.-a     

ALICE perspectives for the study of charm and beauty energy loss at the LHC

At LHC energy, heavy quarks will be abundantly produced and the design of the ALICE detector will allow us to study their production using several channels. The expected heavy-quark in-medium energy loss in nucleus-nucleus collisions at the LHC is calculated within a model, that is compared to the available heavy-quark quenching measurements at RHIC. The nuclear modification factors and heavy-to-light ratios of charm and beauty mesons are considered. The capability of the ALICE experiment for addressing this phenomenology is discussed. PACS 25.75.-q; 14.65.Dw; 13.25.Ft     

High pt and photon physics with ALICE at LHC

ALICE,A Large Ion Collider Experiment,is dedicated to study the QCD matter at extreme high temperature and density to understand the Quark Gluon Plasma （QGP） and phase transition.High-transversemomentum photons and neutral mesons from the initial hard scattering of partons can be measured with ALICE calorimeters,PHOS （PHOton Spectrometer） and EMCAL （ElectroMagnetic CALorimeter）.Combing the additional central tracking detectors,the γ-jet and π 0-jet measurements thus can be accessed.These measurements offer us a sensitive tomography probe of the hot-dense medium generated in the heavy ion collisions.In this paper,high p T and photon physics is discussed and the ALICE calorimeters capabilities of high-transverse-momentum neutral mesons and γ-jet measurements are presented.     

High pt and photon physics with ALICE at LHC

ALICE,A Large Ion Collider Experiment,is dedicated to study the QCD matter at extreme high temperature and density to understand the Quark Gluon Plasma (QGP) and phase transition.High-transversemomentum photons and neutral mesons from the initial hard scattering of partons can be measured with ALICE calorimeters,PHOS (PHOton Spectrometer) and EMCAL (ElectroMagnetic CALorimeter).Combing the additional central tracking detectors,the γ-jet and π 0-jet measurements thus can be accessed.These measurements offer us a sensitive tomography probe of the hot-dense medium generated in the heavy ion collisions.In this paper,high p T and photon physics is discussed and the ALICE calorimeters capabilities of high-transverse-momentum neutral mesons and γ-jet measurements are presented.     

Proton-proton physics with the ALICE muon spectrometer at the LHC

ALICE, the dedicated heavy-ion experiment at the LHC, has also an important proton-proton physics program. The ALICE muon spectrometer will be presented and the corresponding physics analysis will be reviewed. A particular emphasis will be placed on heavy-flavor measurement. (for the ALICE Collaboration) The text was submitted by the author in English.     

LHC能区ALICE实验及其PHOS触发选判

综述了CERN/LHC能区的大型重离子碰撞实验(ALICE)的现状, 并对ALICE实验中的光子谱仪(PHOS)的触发选判机制进行了模拟研究.     

Investigations of the new generation pixel detectors for ALICE experiment at LHC

We present the results from testing Monolithic Active Pixel Sensors of the detector ALPIDE (ALICE Pixel Detector). The purpose of these tests was to measure the pixel threshold and noise distributions in each of the four sectors of the detector, as well as the analysis of the hit maps produced by different radioactive sources.     

Measuring beauty production in Pb-Pb collisions at the LHC via single electrons in ALICE

We present the expected ALICE performance for the measurement of the p _t-differential cross section of electrons from beauty decays in central Pb-Pb collisions at the LHC. for the ALICE Collaboration Presented in the Poster Session “Future Experiments and Facilities” at the 18th International Conference “Quark Matter 2005”, Budapest, Hungary, 4–9 August 2005.     

Multiple charm production at the LHC energy

Cross sections for J/ψ mesons produced in association with open charm and two charmed hadrons from different $c\bar c$ pairs under LHC conditions are predicted theoretically. The respective processes are considered both in single and in double parton interactions. Particular attention is given to kinematical limits of the LHCb detector, and a comparison with the most recent experimental data is performed for them.     

Multiplicity fluctuation and correlation of mesons and baryons in ultra-relativistic heavy-ion collisions at the LHC

We study the multiplicity fluctuation and correlation of identified mesons and baryons formed at hadronization by the quark combination mechanism in the context of ultra-relativistic heavy-ion collisions. Based on the statistical method of free quark combination, we derive the two-hadron multiplicity correlations, including meson-meson and meson-baryon correlations, and take the effects of quark number fluctuation at hadronization into account by a Taylor expansion method. After including the decay contributions, we calculate the dynamical fluctuation observable ν_(dyn) for Kπ, pπ and Kp pairs and discuss what underlying physics can be obtained by comparing with data from Pb-Pb collisions at sNN~(1/2)=2.76 Te V and simulations from the HIJING and AMPT event generators.     

Low mass dielectrons at LHC energy

We study the thermal production of low mass dielectrons in central nucleus-nucleus collisions at LHC energy. We assume initial quark-gluon plasma production, followed by a first order quark-hadron phase transition and subsequent hadronization; the expansion of the system is described by Bjorken's hydrodynamical model. In the quark-gluon plasma, we include both the basisq annihilation process and lowest order QED and QCD corrections. In the hadronic phase, we consider pion annihilation as well as pion scattering with virtual bremsstrahlung leading to dielectron production. Our results are then compared to dielectron rates from ⁰ and Dalitz decays. We conclude that it will be rather difficult to disentangle the quark-gluon plasma contributions from competing dielectron production processes.     

ALICE FIT Data Processing and Performance during LHC Run 3

Physics of Atomic Nuclei - During the upcoming Run 3 and Run 4 at the LHC the upgraded ALICE (A Large Ion Collider Experiment) will operate at a significantly higher luminosity and will collect two...     

Generators of nuclear collisions at the LHC energy

Current versions of the most popular generators of ultrarelativistic heavy-ion collisions are used to simulate central (b<3 fm) Pb + Pb collisions at the LHC energy, $\sqrt s = 6A$ TeV. The charged-particle density predicted by the generators for the mid-rapidity range, dN _ch/dη, varies in a wide range, from about 2000 to about 6000. Moreover, even for a given generator, it depends strongly on model parameters and can vary from 10 to 100%.     

High energy Cherenkov gluons at RHIC and LHC

The collective effect of emission by the forward moving partons of high energy Cherenkov gluons in nucleus-nucleus collisions at RHIC and LHC energies is considered. It can reveal itself as peaks in the pseudorapidity distribution of jets at midrapidities, or as a ring-like structure of individual events in event-by-event analysis. The pseudorapidity distribution of centers of dense isolated groups of particles in the HIJING model is determined. It can be considered as the background for Cherenkov gluons. If peaks above this background are found in experiments, they indicate new collective effects. In memory of E.L. Feinberg     

Measurement of(di)muons from heavy flavour decay in p-p collisions at 14 TeV with ALICE at the LHC

We present the performance of the ALICE muon spectrometer for measuring the charm and beauty inclusive pt differential production cross sections via single muons and unlike-sign dimuons in proton-proton collisions at(√s) = 14 TeV.