895 research outputs found
J/psi production as a function of charged-particle multiplicity in p-Pb collisions at root s(NN)=8.16 TeV
Inclusive J/psi yields and average transverse momenta in p-Pb collisions at a center-of-mass energy per nucleon pairs root s(NN) = 8.16 TeV are measured as a function of the charged-particle pseudorapidity density with ALICE. The J/psi mesons are reconstructed at forward (2.03<y(cms)Peer reviewe
Coherent photoproduction of rho(0) vector mesons in ultra-peripheral Pb-Pb collisions at root s(NN)=5.02 TeV
Cross sections for the coherent photoproduction of rho(0) vector mesons in ultra-peripheral Pb-Pb collisions at root s(NN) = 5.02 TeV are reported. The measurements, which rely on the pi(+)pi(-) decay channel, are presented in three regions of rapidity covering the range vertical bar y vertical bar <0.8. For each rapidity interval, cross sections are shown for different nuclear-breakup classes defined according to the presence of neutrons measured in the zero-degree calorimeters. The results are compared with predictions based on different models of nuclear shadowing. Finally, the observation of a coherently produced resonance-like structure with a mass around 1.7 GeV/c(2) and a width of about 140 MeV/c(2) is reported and compared with similar observations from other experiments.Peer reviewe
J/psi elliptic and triangular flow in Pb-Pb collisions at root s(NN)=5.02 TeV
The inclusive J/psi (v(2)) and triangular (v(3)) flow coefficients measured at forward rapidity (2.5 <y <4) and the v2 measured at midrapidity (vertical bar y vertical bar <0.9) in Pb-Pb collisions at root s(NN) = 5.02TeV using the ALICE detector at the LHC are reported. The entire Pb-Pb data sample collected during Run 2 is employed, amounting to an integrated luminosity of 750 mu b(-1) at forward rapidity and 93 mu b(-1) at midrapidity. The results are obtained using the scalar product method and are reported as a function of transverse momentum p(T) and collision centrality. At midrapidity, the J psi v(2) is in agreement with the forward rapidity measurement. The centrality averaged results indicate a positive J/psi v(3) with a significance of more than 5 sigma at forward rapidity in the p(T) range 2 <p(T) <5 GeV/c. The forward rapidity v(2), v(3), and v(3)/v(2) results at low and intermediate p(T) (p(T) <8 GeV/c) exhibit a mass hierarchy when compared to pions and D mesons, while converging into a species-independent curve at higher p(T). At low and intermediate p(T), the results could be interpreted in terms of a later thermalization of charm quarks compared to light quarks, while at high p(T), path-length dependent effects seem to dominate. The J/psi v(2) measurements are further compared to a microscopic transport model calculation. Using a simplified extension of the quark scaling approach involving both light and charm quark flow components, it is shown that the D-meson vn measurements can be described based on those for charged pions and J/flow.Peer reviewe
Elliptic and triangular flow of (anti)deuterons in Pb-Pb collisions root S-NN=5.02 TeV
The measurements of the (anti)deuteron elliptic flow (v(2)) and the first measurements of triangular flow (v(3)) in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision root S-NN = 5.02 TeV are presented. A mass ordering at low transverse momentum (p(T)) is observed when comparing these measurements with those of other identified hadrons, as expected from relativistic hydrodynamics. The measured (anti)deuteron v(2) lies between the predictions from the simple coalescence and blast-wave models, which provide a good description of the data only for more peripheral and for more central collisions, respectively. The mass number scaling, which is violated for v(2), is approximately valid for the (anti)deuterons v(3). The measured v(2) and v(3) are also compared with the predictions from a coalescence approach with phase-space distributions of nucleons generated by IEBE-VISHNU with AMPT initial conditions coupled with URQMD, and from a dynamical model based on relativistic hydrodynamics coupled to the hadronic afterburner SMASH. The model predictions are consistent with the data within the uncertainties in midcentral collisions, while a deviation is observed in the most central collisions.Peer reviewe
Measurement of isolated photon-hadron correlations in root S-NN=5.02 TeV pp and p-Pb collisions
This paper presents isolated photon-hadron correlations using pp and p-Pb data collected by the ALICE detector at the LHC. For photons with vertical bar eta vertical bar <0.67 and 12 <p(T) <40 GeV/c, the associated yield of charged particles in the range vertical bar eta vertical bar <0.80 and 0.5 <p(T) <10 GeV/c is presented. These momenta are much lower than previous measurements at the LHC. No significant difference between pp and p-Pb is observed, with PYTHIA 8.2 describing both data sets within uncertainties. This measurement constrains nuclear effects on the parton fragmentation in p-Pb collisions, and provides a benchmark for future studies of Pb-Pb collisions.Peer reviewe
Multiplicity dependence of pi, K, and p production in pp collisions at root s=13 TeV
This paper presents the measurements of pi(+/-), K-+/-, p and (p) over bar transverse momentum (p(T)) spectra as a function of charged-particle multiplicity density in proton-proton (pp) collisions at root s = 13 TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-ofmass energy dependence of light-flavour particle production. The measurements reported here cover a pT range from 0.1 to 20 GeV/c and are done in the rapidity interval | y| <0.5. The p(T)-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at v s = 7 TeV, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the pT-integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multi-strange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.Peer reviewe
Higher harmonic non-linear flow modes of charged hadrons in Pb-Pb collisions at root s(NN)=5.02 TeV
Anisotropic flow coefficients, nu(n), non-linear flow mode coefficients, chi(n,mk), and correlations among different symmetry planes, rho(n,mk) are measured in Pb-Pb collisions at root s(NN) = 5.02TeV. Results obtained with multi-particle correlations are reported for the transverse momentum interval 0.2 <p(T) <5.0 GeV/c within the pseudorapidity interval 0.4 <vertical bar eta vertical bar <0.8 as a function of collision centrality. The nu(n) coefficients and chi(n,mk) and rho(n,mk) are presented up to the ninth and seventh harmonic order, respectively. Calculations suggest that the correlations measured in different symmetry planes and the non-linear flow mode coefficients are dependent on the shear and bulk viscosity to entropy ratios of the medium created in heavy-ion collisions. The comparison between these measurements and those at lower energies and calculations from hydrodynamic models places strong constraints on the initial conditions and transport properties of the system.Peer reviewe
Measurement of nuclear effects on Ï(2S) production in p-Pb collisions at sNNââââ = 8.16 TeV
Inclusive psi(2S) production is measured in p-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair root s(NN) = 8.16 TeV, using the ALICE detector at the CERN LHC. The production of psi(2S) is studied at forward (2.03<y(cms)Peer reviewe
What kinds of value motives guide people in their moral attitudes? The role of personal and prescriptive values at the culture level and individual level
Opinions about moralized issues are arguably one of the most difficult issues in interpersonal dialogues given that they can result in intolerance and prejudicial behavior toward those with divergent moral beliefs. Recent research has shown that moral attitudes vary not only depending on the individual's characteristics but also as a function of culture. Individuals from individualistic-oriented cultures exhibit more lenient judgments toward moralized issues than those from collectivistic-oriented cultures. What is unclear to date is what kinds of cultural value motives underlie these attitudesAre they driven only by intrinsic value motives (personal values) or also by extrinsic value motives (prescriptive values in the form of societal expectations about what should be valued)? The cultural press to conform is arguably stronger if moral attitudes are predicted by the latter. Participants from eight countries (N = 1,456) responded to a questionnaire containing a modified version of the Schwartz Value Survey assessing personal and prescriptive values. The results showed that personal value ratings of openness-to-change versus conservation at the culture and individual levels were predictive of individuals' moral attitudes consistent with previous findings. Prescriptive value ratings of openness-to-change versus conservation also predicted individuals' moral attitudes, but only at the aggregated culture level. This suggests that the prescriptive values concept is a truly group-level phenomenon and that attitudes toward moralized issues are guided by cultural values with normative qualities. We discuss the implications for intercultural contact situations.info:eu-repo/semantics/acceptedVersio
Constraining the Chiral Magnetic Effect with charge-dependent azimuthal correlations in Pb-Pb collisions at root s(NN)=2.76 and 5.02 TeV
Systematic studies of charge-dependent two- and three-particle correlations in Pb-Pb collisions at root s(NN) = 2.76 and 5.02 TeV used to probe the Chiral Magnetic Effect (CME) are presented. These measurements are performed for charged particles in the pseudorapidity (eta) and transverse momentum (p(T)) ranges |eta| and gamma(1, - 3) = . The results are used to estimate the contribution of background effects, associated with local charge conservation coupled to anisotropic flow modulations, to measurements of the CME. A blast-wave parametrisation that incorporates local charge conservation tuned to reproduce the centrality dependent background effects is not able to fully describe the measured gamma(1,1). Finally, the charge and centrality dependence of mixed-harmonics three-particle correlations, of the form gamma(1, 2) = , which are insensitive to the CME signal, verify again that background contributions dominate the measurement of gamma(1,1).Peer reviewe
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