K0S and Λ production in Pb-Pb collisions at sNN−−−−√=2.76 TeV

The ALICE measurement of K0S and Λ production at midrapidity in Pb-Pb collisions at sNN−−−√=2.76  TeV is presented. The transverse momentum (pT) spectra are shown for several collision centrality intervals and in the pT range from 0.4  GeV/c (0.6  GeV/c for Λ) to 12  GeV/c. The pT dependence of the Λ/K0S ratios exhibits maxima in the vicinity of 3  GeV/c, and the positions of the maxima shift towards higher pT with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate pT is not observed in pp interactions at s√=0.9  TeV and at s√=7  TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured pT spectra above 2  GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of pT, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the pT dependence of the Λ/K0S ratio

Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe

Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at root(NN)-N-S=2.76 TeV

Peer reviewe

phi-Meson production at forward rapidity in p-Pb collisions at root s(NN)=5.02 TeV and in pp collisions at root s=2.76 TeV

The first study of phi-meson production in p-Pb collisions at forward and backward rapidity, at a nucleonnucleon centre-of-mass energy root s(NN)= 5.02 TeV, has been performed with the ALICE apparatus at the LHC. The phi-mesons have been identified in the dimuon decay channel in the transverse momentum (p(T)) range 1 <p(T) <7GeV/c, both in the p-going (2.03 <y <3.53) and the Pb-going (-4.46 <y <-2.96) directions - where ystands for the rapidity in the nucleon-nucleon centre-of-mass - the integrated luminosity amounting to 5.01 +/- 0.19nb(-1) and 5.81 +/- 0.20nb(-1), respectively, for the two data samples. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward-backward ratio for f-meson production is measured for 2.96Peer reviewe

Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb-Pb collisions at root s(NN)=2.76TeV

The elliptic flow, v(2), of muons from heavy-flavour hadron decays at forward rapidity (2.5 <y <4) is measured in Pb-Pb collisions at root s(NN)= 2.76TeVwith the ALICE detector at the LHC. The scalar product, two- and four-particle Q cumulants and Lee-Yang zeros methods are used. The dependence of the v(2) of muons from heavy-flavour hadron decays on the collision centrality, in the range 0-40%, and on transverse momentum, p(T), is studied in the interval 3 <p(T)<10 GeV/c. A positive v(2) is observed with the scalar product and two-particle Q cumulants in semi-central collisions (10-20% and 20-40% centrality classes) for the p(T) interval from 3 to about 5GeV/c with a significance larger than 3 sigma, based on the combination of statistical and systematic uncertainties. The v(2) magnitude tends to decrease towards more central collisions and with increasing pT. It becomes compatible with zero in the interval 6 <p(T)<10 GeV/c. The results are compared to models describing the interaction of heavy quarks and open heavy-flavour hadrons with the high-density medium formed in high-energy heavy-ion collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.Peer reviewe

Centrality dependence of the nuclear modification factor of charged pions, kaons, and protons in Pb-Pb collisions at root s(NN)=2.76 TeV

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Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density rho(mu) > 5.9 m(-2). Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 10(16) eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. The development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.Peer reviewe

Prevalence and patterns of hypertension in Peruvian Andean Hispanics: the PREVENCION study

Cardiovascular disease is emerging as a leading cause of morbidity and mortality in Latin America. Population-based data regarding the prevalence of hypertension and hypertension subtypes in Andean Hispanic populations are scarce. The authors performed a population-based study that included 1878 Peruvian Andean adults to determine: (1) the prevalence, awareness, and control of hypertension and (2) the relative frequency of hypertension subtypes (systolic vs. diastolic). The prevalence of hypertension was 15.7% (95% confidence interval [CI], 14.0%-17.4%), did not differ by gender, and increased steeply with age, particularly in women. Awareness, treatment, and control rates were 47.9%, 39.5%, and 14%, respectively. Diastolic blood pressure increased until age 50 years and reached a plateau thereafter, whereas mean arterial pressure continued to increase with age even after age 50 years. Furthermore, in sharp contrast with the United States population, the predominant type of hypertension was systodiastolic (41.7%; 95% CI, 35.1%-48.5%). Isolated systolic hypertension accounted for only 29.3% of cases (95% CI, 23.9%-35.4%) and was responsible for a minority of cases in all age groups before age 70 years. Hypertension subtypes in this Andean population seem to differ significantly from those present in the United States population, with a much larger proportion of systodiastolic and diastolic hypertension even with advanced age. These differences result from interactions between hemodynamic and structural factors, and further studies aimed at characterizing their genetic and environmental determinants and implications in end-organ damage and prognosis in this population may contribute to understanding the pathophysiology of hypertension