Meritxell Bach

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We report on the first measurement of the triangular v3, quadrangular v4, and pentagonal v5 charged particle flow in Pb-Pb collisions at sqrt(s(NN)) = 2.76  TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides(More)
Measurements of cross sections of inelastic and diffractive processes in proton–proton collisions at LHC energies were carried out with the ALICE detector. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudora-pidity distributions: for single diffraction (diffractive mass
This paper is a joint effort between several institutions that propose a new evaluation method for segmentation techniques using mul-timodal information. We propose new similarity measures based on the location and the intensity values of the misclassified voxels and also based on the connectivity and the boundaries of the segmented data and we show how the(More)
Differential cross sections of charged particles in inelastic pp collisions as a function of p T have been measured at √ s = 0.9, 2.76 and 7 TeV at the LHC. The p T spectra are compared to NLO-pQCD calculations. Though the differential cross section for an individual √ s cannot be described by NLO-pQCD, the relative increase of cross section with √ s is in(More)
The directed flow of charged particles at midrapidity is measured in Pb-Pb collisions at √(s(NN))=2.76 TeV relative to the collision symmetry plane defined by the spectator nucleons. A negative slope of the rapidity-odd directed flow component with approximately 3 times smaller magnitude than found at the highest RHIC energy is observed. This suggests a(More)
The ALICE measurement of K(S)(0) and Λ production at midrapidity in Pb-Pb collisions at √(s(NN))=2.76 TeV is presented. The transverse momentum (p(T)) spectra are shown for several collision centrality intervals and in the p(T) range from 0.4 GeV/c (0.6 GeV/c for Λ) to 12 GeV/c. The p(T) dependence of the Λ/K(S)(0) ratios exhibits maxima in the vicinity of(More)
Finding particle trajectories is usually the most time consuming part of modern experiments in high energy physics. In many present experiments with high track densities and complicated event topologies a Kalman filter based track fit is used already at this combinatorial part of the event reconstruction. Therefore speed of the track fitting algorithm(More)
The measurement of primary π ± , K ± , p and p production at mid-rapidity (|y| < 0.5) in proton–proton collisions at √ s = 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ioni-sation energy-loss and time-of-flight information, the ring-imaging(More)
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. Quarko-nia are reconstructed in the dimuon-decay channel and the signal yields are(More)
The ALICE Collaboration at the LHC has measured the J/ψ and ψ photoproduction at mid-rapidity in ultra-peripheral Pb–Pb collisions at √ s NN = 2.76 TeV. The charmonium is identified via its leptonic decay for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of(More)