R. de Rooij

Alignment of the ALICE inner tracking system with cosmic-ray tracks

ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 mu m in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10(5) charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 μm in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton– proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 105 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.

J/ψ Production as a Function of Charged Particle Multiplicity in pp Collisions at s√=7 TeV

The ALICE Collaboration reports the measurement of the relative J/psi yield as a function of charged particle pseudorapidity density dN(ch)/d eta in pp collisions at root s = 7 TeV at the LHC. J/psi particles are detected for p(t) > 0, in the rapidity interval vertical bar y vertical bar 0. In the highest multiplicity interval with (dN(ch)/d eta)(bin)) = 24.1, corresponding to four times the minimum bias multiplicity density, an enhancement relative to the minimum bias J/psi yield by a factor of about 5 at 2.5 < y <4 (8 at vertical bar y vertical bar < 0.9) is observed

Centrality dependence of charged particle production at large transverse momentum in Pb–Pb collisions at √sNN =2.76 TeV

The inclusive transverse momentum (

Transverse Momentum Distribution and Nuclear Modification Factor of Charged Particles in p+Pb Collisions at √sNN=5.02 TeV

p_{\rm T}

Charmonium and e+e-pair photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at √sNN = 2.76 Tev

) distributions of primary charged particles are measured in the pseudo-rapidity range

Charge-dependent azimuthal correlations in Pb–Pb collisions at √sNN = 2.76 TeV

|\eta|<0.8

J/ψ Polarization in pp Collisions at √s=7 TeV

as a function of event centrality in Pb-Pb collisions at

Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

\sqrt{s_{\rm{NN}}}=2.76

Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76 TeV

TeV with ALICE at the LHC. The data are presented in the

Pseudorapidity Density of Charged Particles in p+Pb Collisions at √sNN=5.02 TeV

p_{\rm T}