G. Bencedi

A very high momentum particle identification detector

Abstract.A new detector concept has been investigated to extend the capabilities of heavy-ion collider experiments, represented here through the ALICE detector, in the high transverse momentum (pT region. The resulting Very High Momentum Particle Identification Detector (VHMPID) performs charged hadron identification on a track-by-track basis in the 5 GeV/c < p < 25 GeV/c momentum range and provides heavy-ion experiments with new opportunities to study parton-medium interactions at RHIC and LHC energies, where the creation of deconfined quark-gluon matter has been established. The detector is based on novel advances to the pressurized gaseous ring imaging Cherenkov (RICH) concept, which yield a very compact, high resolution addition to existing heavy-ion experiments. We conclude that in order for the device to yield statistically significant results not only for single particle measurements, but also for di-hadron and jet-tagged correlation studies, it has to cover contiguously up to 30% of a central barrel detector in radial direction. This will allow, for the first time, identified charged hadron measurements in jets. In this paper we summarize the physics motivations for such a device, as well as its conceptual design, layout, and integration into ALICE.

Inclusive photon production at forward rapidities in proton–proton collisions at √s = 0.9, 2.76 and 7 TeV - eScholarship

The multiplicity and pseudorapidity distributions of inclusive photons have been measured at forward rapidities (2.3 < η < 3.9) in proton–proton collisions at three center-of-mass energies, √ s = 0.9, 2.76 and 7 TeV using the ALICE detector. It is observed that the increase in the average photon multiplicity as a function of beam energy is compatible with both a logarithmic and a power-law dependence. The relative increase in average photon multiplicity produced in inelastic pp collisions at 2.76 and 7 TeV center-of-mass energies with respect to 0.9 TeV are 37.2 ± 0.3 % (stat) ± 8.8 % (sys) and 61.2 ± 0.3 % (stat) ± 7.6 % (sys), respectively. The photon multiplicity distributions for all center-of-mass energies are well described by negative binomial distributions. The multiplicity distributions are also presented in terms of KNO variables. The results are compared to model predictions, which are found in general to underestimate the data at large photon multiplicities, in particular at the highest center-of-mass energy. Limiting fragmentation behavior of photons has been explored with the data, but is not observed in the measured pseudorapidity range.

Monte Carlo Studies of Identified Two-particle Correlations in p-p and Pb-Pb Collisions

Azimuthal particle correlations have been extensively studied in the past at various collider energies in p-p, p-A, and A-A collisions. Hadron-correlation measurements in heavy-ion collisions have mainly focused on studies of collective (flow) effects at low-

New results on the multiplicity and centre-of-mass energy dependence of identified particle production in pp collisions with ALICE : arXiv

p_T

Identified Two-particle Correlations and Quantum Number Conservations in p-p and Pb-Pb Collisions at LHC Energies

and parton energy loss via jet quenching in the high-

Production of Σ (1385)±and Ξ (1530)0in p–Pb collisions at √sNN=5.02 TeV

p_T

Centrality dependence of ψ(2S) suppression in p-Pb collisions at √sNN= 5.02 TeV - eScholarship

regime. This was usually done without event-by-event particle identification. In this paper, we present two-particle correlations with identified trigger hadrons and identified associated hadrons at mid-rapidity in Monte Carlo generated events. The primary purpose of this study was to investigate the effect of quantum number conservation and the flavour balance during parton fragmentation and hadronization. The simulated p-p events were generated with PYTHIA 6.4 with the Perugia-0 tune at

Event-by-event mean pT fluctuations in pp and Pb–Pb collisions at the LHC - eScholarship

\sqrt{s}=7

Measurement of quarkonium production at forward rapidity in pp√s=7 TeV - eScholarship

TeV. HIJING was used to generate

VHMPID RICH prototype using pressurized C4F8O radiator gas and VUV photon detector

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