Search results for "Rapidity"
showing 10 items of 810 documents
ϒ production and nuclear modification at forward rapidity in Pb–Pb collisions at sNN=5.02TeV
2021
Abstract The production of ϒ mesons in Pb–Pb collisions at a centre-of-mass energy per nucleon pair s NN = 5.02 TeV is measured with the muon spectrometer of the ALICE detector at the LHC. The yields as well as the nuclear modification factors are determined in the forward rapidity region 2.5 y 4.0 , as a function of rapidity, transverse momentum and collision centrality. The results show that the production of the ϒ ( 1S ) meson is suppressed by a factor of about three with respect to the production in proton–proton collisions. For the first time, a significant signal for the ϒ ( 2S ) meson is observed at forward rapidity, indicating a suppression stronger by about a factor 2–3 with respec…
Inclusive heavy-flavour production at central and forward rapidity in Xe–Xe collisions at TeV
2021
The first measurements of the production of muons and electrons from heavy-flavour hadron decays in Xe–Xe collisions at sNN=5.44 TeV, using the ALICE detector at the LHC, are reported. The measurement of the nuclear modification factor RAA is performed as a function of transverse momentum pT in several centrality classes at forward rapidity (2.5<y<4) and midrapidity (|y|<0.8) for muons and electrons from heavy-flavour hadron decays, respectively. A suppression by a factor up to about 2.5 compared to the binary-scaled pp reference is observed in central collisions at both central and forward rapidities. The RAA of muons from heavy-flavour hadron decays is compared to previous measur…
Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead–lead collisions at sNN=2.76 TeV with the ATLAS d…
2012
The ATLAS experiment at the LHC has measured the centrality dependence of charged particle pseudorapidity distributions over vertical bar eta vertical bar < 2 in lead-lead collisions at a nucleo ...
Measurement of the azimuthal anisotropy for charged particle production insNN=2.76TeV lead-lead collisions with the ATLAS detector
2012
Differential measurements of charged particle azimuthal anisotropy are presented for lead-lead collisions at root sNN = 2.76 TeV with the ATLAS detector at the LHC, based on an integrated luminosity of approximately 8 mu b(-1). This anisotropy is characterized via a Fourier expansion of the distribution of charged particles in azimuthal angle relative to the reaction plane, with the coefficients v(n) denoting the magnitude of the anisotropy. Significant v(2)-v(6) values are obtained as a function of transverse momentum (0.5 = 3 are found to vary weakly with both eta and centrality, and their p(T) dependencies are found to follow an approximate scaling relation, v(n)(1/n)(p(T)) proportional …
Initial Conditions in the One-Fluid Hydrodynamical Description of Ultrarelativistic Nuclear Collisions
1997
We present a phenomenological model for the initial conditions needed in a one-fluid hydrodynamical description of ultrarelativistic nuclear collisions at CERN--SPS. The basic ingredient is the parametrization of the baryon stopping, i.e. the rapidity distribution, as a function of the thickness of the nuclei. We apply the model to S + S and Pb + Pb collisions and find after hydrodynamical evolution reasonable agreement with the data.
From quark-gluon plasma to hadron spectra
2001
Results on initial transverse energy production based on NLO perturbative QCD calculation with final state saturation of produced minijets are used to fix the initial energy density of produced matter. Assuming rapid thermalization, this provides the initial conditions for a hydrodynamic description of the expansion of final matter. Given a prescription of the the decoupling of particles from the thermal system to free particles, final transverse spectra of hadrons and integrated quantities like multiplicity and transverse energy can be calculated in the central rapidity region. Results are reported and compared with measurements.
Transverse-momentum dependence of theJ/ψnuclear modification ind+Au collisions atsNN=200GeV
2013
We present measured J/psi production rates in d + Au collisions at root s(NN) = 200 GeV over broad ranges of transverse momentum (p(T) = 0-14 GeV/c) and rapidity (-2.2 1) for p(T) > 2 GeV/c. The observed enhancement at negative rapidity has implications for the interpretation of the observed modification in heavy-ion collisions at high p(T). DOI: 10.1103/PhysRevC.87.034904
Studies ofWboson plus jets production inpp¯collisions ats=1.96 TeV
2013
We present a comprehensive analysis of inclusive W(-> ev) + n-jet (n >= 1, 2, 3, 4) production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Tevatron collider using a 3.7 fb(-1) data set collected by the D0 detector. Differential cross sections are presented as a function of the jet rapidities (y), lepton transverse momentum (P-T) and pseudorapidity (eta), the scalar sum of the transverse energies of the W boson and all jets (H-T), leading dijet P-T and invariant mass, dijet rapidity separations for a variety of jet pairings for P-T-ordered and angular-ordered jets, dijet opening angle, dijet azimuthal angular separations for P-T-ordered and angular-ordered j…
The rapidity structure of Mach cones and other large angle correlations in heavy-ion collisions
2006
The pattern of angular correlations of hadrons with a (semi-)hard trigger hadron in heavy-ion collisions has attracted considerable interest. In particular, unexpected large angle structures on the away side (opposite to the trigger) have been found. Several explanations have been brought forward, among them Mach shockwaves and Cherenkov radiation. Most of these scenarios are characterized by radial symmetry around the parton axis, thus angular correlations also determine the rapidity dependence of the correlation. If the observed correlations are remnants of an away side parton after interaction with the medium created in the collision, pQCD allows to calculate the distribution $P(y)$ of t…
Multi-strange baryon production in p Pb collisions at sNN=5.02 TeV
2016
The multi-strange baryon yields in Pb--Pb collisions have been shown to exhibit an enhancement relative to pp reactions. In this work, $\Xi$ and $\Omega$ production rates have been measured with the ALICE experiment as a function of transverse momentum, ${p_{\rm T}}$, in p-Pb collisions at a centre-of-mass energy of ${\sqrt{s_{\rm NN}}}$ = 5.02 TeV. The results cover the kinematic ranges 0.6 GeV/$c<{p_{\rm T}} <$7.2 GeV/$c$ and 0.8 GeV/$c<{p_{\rm T}}<$ 5 GeV/$c$, for $\Xi$ and $\Omega$ respectively, in the common rapidity interval -0.5 $<{y_{\rm CMS}}<$ 0. Multi-strange baryons have been identified by reconstructing their weak decays into charged particles. The ${p_{\rm T}}$ spectra are ana…