1,647 research outputs found
Heavy flavour Langevin diffusion with the chromo-electromagnetic field fluctuations in the quark-gluon plasma
The chromo-electromagnetic field is produced due to the motion of partons in
a quark-gluon plasma created by relativistic heavy-ion collisions. The
fluctuations in the produced chromo-electromagnetic field are important, since
they cause heavy quarks to gain energy in the low velocity limit. We study the
effect of such fluctuations on heavy quark diffusion in quark-gluon plasma
within the framework of Langevin dynamics under the background matter described
by the ()-dimensional relativistic viscous hydrodynamics. Theoretical
calculations of the nuclear modification factor () of heavy mesons (
and mesons), with the effect of these fluctuations, are compared with
experimental measurements in collisions at GeV by
the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC) and
collisions at and TeV by the ALICE and
CMS experiments at the CERN Large Hadron Collider (LHC). We find a significant
effect of these fluctuations in describing the the measured of and
mesons in both RHIC and LHC energies
A Proof-of-principle for Time-Of-Flight Positron Emission Tomography Imaging
Time-Of-Flight (TOF) is a noble technique that is used in Positron Emission
Tomography (PET) imaging worldwide. The scintillator based imaging system that
is being used around the world for TOF-PET is very expensive. Multi-gap
Resistive Plate Chambers (MRPCs) are gaseous detectors which are easy to
fabricate, inexpensive and have excellent position and timing resolution. They
can be used as a suitable alternative to highly expensive scintillators. For
the sole purpose of TOF-PET, a pair of 18 cm 18 cm, 5 gap, glass-based
MRPC modules have been fabricated. Our main aim was to determine the shift in
the position of the source (Na-22) with these fabricated MRPCs. In this
document, the details of the experimental results will be presented
Measurement of quarkonium production at forward rapidity in pp collisions at √s=7 TeV
The inclusive production cross sections at forward rapidity of J/ψ , ψ(2S) , Υ (1S) and Υ (2S) are measured in pp collisions at s√=7 TeV with the ALICE detector at the LHC. The analysis is based on a data sample corresponding to an integrated luminosity of 1.35 pb‾¹ . Quarkonia are reconstructed in the dimuon-decay channel and the signal yields are evaluated by fitting the μ+μ− invariant mass distributions. The differential production cross sections are measured as a function of the transverse momentum pT and rapidity y , over the ranges 0<pT<20 GeV/c for J/ψ , 0<pT<12 GeV/c for all other resonances and for \(2.5 . The measured cross sections integrated over pT and y , and assuming unpolarized quarkonia, are: σJ/ψ=6.69±0.04±0.63 μ b, σψ(2S)=1.13±0.07±0.19 μ b, σΥ(1S)=54.2±5.0±6.7 nb and σΥ(2S)=18.4±3.7±2.9 nb, where the first uncertainty is statistical and the second one is systematic. The results are compared to measurements performed by other LHC experiments and to theoretical models
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