The STAR-RICH detector extends the particle identification capapbilities of the STAR experiment for charged hadrons at mid-rapidity. This detector represents the first use of a proximity-focusing CsI-based RICH detector in a collider experiment. It provides identification of pions and kaons up to 3 GeV/c and protons up to 5 GeV/c. The characteristics and performance of the device in the inaugural RHIC run are described.
The construction of a new detector is proposed to extend the capabilities of ALICE in the high transverse momentum (pT) region. This Very High Momentum Particle Identification Detector (VHMPID) performs charged hadron identification on a track-by-tra
ck basis in the 5 GeV/c < p < 25 GeV/c momentum range and provides ALICE with new opportunities to study parton-medium interactions at LHC energies. The VHMPID covers up to 30% of the ALICE central barrel and presents sufficient acceptance for triggered- and tagged-jet studies, allowing for the first time identified charged hadron measurements in jets. This Letter of Intent summarizes the physics motivations for such a detector as well as its layout and integration into ALICE.
We derive a new method to improve the statistics of identified particles at high transverse momentum (pt) using online-triggered events by the Barrel Electro-Magnetic-Calorimeter (BEMC) detector. The BEMC is used to select hadronic interaction and en
ergy deposit from showers created by charged hadrons ($pi^{pm},K^{pm}$ and $p$($bar{p}$)) in the BEMC. With this trigger, the statistics of the high pt particles are significantly enhanced by about a factor of 100 with selection efficiency up to 20%. In addition, resonant states ($rho^0$, $K^{star}$) and weak-decay V0 (Ks and La(aLa)) can be constructed by selecting the BEMC-trigger hadron as one of its daughters. We also show that the trigger efficiency can be obtained reliably in simulation and data-driven approaches.
We present two-particle $p_{rm t}$ correlations as a function of event centrality for Au+Au collisions at $sqrt{s_{rm NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV at the Relativistic Heavy Ion Collider using the STAR detector. These resul
ts are compared to previous measurements from CERES at the Super Proton Synchrotron and from ALICE at the Large Hadron Collider. The data are compared with UrQMD model calculations and with a model based on a Boltzmann-Langevin approach incorporating effects from thermalization. The relative dynamical correlations for Au+Au collisions at $sqrt{s_{rm NN}}$ = 200 GeV show a power law dependence on the number of participant nucleons and agree with the results for Pb+Pb collisions at $sqrt{s_{rm NN}} = 2.76~ {rm TeV}$ from ALICE. As the collision energy is lowered from $sqrt{s_{rm NN}}$ = 200 GeV to 7.7 GeV, the centrality dependence of the relative dynamical correlations departs from the power law behavior observed at the higher collision energies. In central collisions, the relative dynamical correlations increase with collision energy up to $sqrt{s_{rm NN}}$ = 200 GeV in contrast to previous measurements that showed little dependence on the collision energy.
The ALICE experiment studies nucleus-nucleus collisions at the LHC in order to investigate the properties of QCD matter at extreme energy densities. The measurement of open charm and open beauty production allows one to probe the mechanisms of heavy-
quark propagation, energy loss and hadronization in the hot and dense medium formed in high-energy nucleus-nucleus collisions. In particular, in-medium energy loss is predicted to be different for massless partons (light quarks and gluons) and heavy quarks at moderate momentum. The ALICE apparatus allows us to measure open heavy-flavour particles in several decay channels and with a wide phase-space coverage. We present the results on the nuclear modification factors for heavy-flavour particle production in Pb-Pb collisions at sqrtsNN=2.76 TeV. Using proton-proton and lead-lead collision samples at sqrts=2.76 and 7 TeV and at sqrtsNN=2.76 TeV, respectively, nuclear modification factors R_AA(pT) were measured for D mesons at central rapidity (via displaced decay vertex reconstruction), and for electrons and muons from heavy-flavour decays, at central and forward rapidity, respectively. A large suppression is observed, by a factor 2.5-4 in central Pb--Pb collisions with respect to the pp reference, in the high-pT region, indicating a strong in-medium energy loss of heavy quarks.
Details concerning the design, fabrication and performance of STAR Photon Multiplicity Detector (PMD) are presented. The PMD will cover the forward region, within the pseudorapidity range 2.3--3.5, behind the forward time projection chamber. It will
measure the spatial distribution of photons in order to study collective flow, fluctuation and chiral symmetry restoration.
STAR-RICH Collaboration: A. Braem
,D. Cozza
,M. Davenport
.
(2002)
.
"Identification of High $rm p_{perp}$ Particles with the STAR-RICH Detector"
.
James C. Dunlop
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