First identified particle studies at the CERN-LHC with the ALICE experiment Pano

First identified particle studies at the CERN-LHC with the ALICE experiment Pano www.phwiki.com

First identified particle studies at the CERN-LHC with the ALICE experiment Pano

Sawyers, Gloria, Founder & Publisher has reference to this Academic Journal, PHwiki organized this Journal First identified particle studies at the CERN-LHC with the ALICE experiment Panos Christakogloua,b as long as the ALICE Collaboration 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki a NIKHEF b Utrecht University Outline The ALICE experiment at LHC Experimental setup PID design per as long as mance Commissioning of the PID detectors Results from the ITS Results from the TPC Results from the TOF First physics measurements Identified particle spectra Baryon number transport Conclusion 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Experimental setup 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki

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PID in ALICE PID as long as hadrons in the central barrel ( < 0.9) ITS: Excellent (3) separation from ~50 MeV/c as long as TPC: from 200 MeV/c, from 300 MeV/c TOF: K up to 2.5 GeV/c, p up to 3.5 GeV/c HMPID: intermediate to high momenta Photons with the dedicated spectrometer (PHOS) Electrons in the central barrel: ITS + TPC as long as low momentum TRD from P ~ 1GeV/c (beauty measurements feasible even @1GeV/c!) Muons reconstructed in the as long as ward region (muon arm: -4 < < -2.4) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki ITS commissioning 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Design goals Optimal resolution as long as primary vertex in addition to track impact parameter Minimize distance of innermost layer from beam axis ( 3.9 cm) in addition to material budget Maximum occupancy (central PbPb) < few % dE/dx in as long as mation in the 4 outermost layers as long as particle ID in 1/2 region Installed in 2007. Successfully commissioned during the cosmics runs in 2008 in addition to 2009. ITS alignment 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki First order alignment with cosmics using the SPD trigger Coincidence between top outer SPD layer in addition to bottom outer SPD layer (rate: 0.18 Hz) ITS calibration in addition to PID (SDD + SSD) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Charge distribution measured on all the SDD modules ~95% of the detector included in the readout during data taking Charge distribution measured on all the SSD modules 90% of the detector active in 2009 <1.5% bad strips S/N ~40 dE/dx resolution ~ 13% Main TPC characteristics Cylindrical in shape, with an active volume that has an inner radius of about 85 cm, an outer radius of about 250 cm, in addition to an overall length along the beam direction of 500 cm (largest TPC ever built) Cylindrical field cage filled with ~90 m3 of Ne/CO2/N2 gas mixture (90:10:5) Drift time of ~90 s Many (>90) 3D points (+dE/dx) per track Since August 2009 more than 750 million events (cosmics, krypton, in addition to laser) recorded, with in addition to without B-field. First round of calibrations (dE/dx, momentum, alignment, gain) completed be as long as e collisions. TPC commissioning 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki J. Alme et al. (ALICE TPC), arXiv:1001.1950 (subm. to NIM) TPC particle identification

TOF 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki 18 sectors, 2 covering in < 0.9 Granularity: 2.5x3.5 cm2 at 3.7 m from the primary vertex; Resolution at present 130 ps (calibration only from cosmic rays) Analysis details 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Analysis of the p+p events collected during the first LHC run in December Accepted events: 250K Hadron spectra – , , p 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Subtract measured signal (dE/dx or tof) from the expected one as long as each pt bin Yields extracted from a fit with a convolution of three Gaussians Compare results with a simple 3 cut ITS TPC TOF Hadron spectra - , , p (cont). 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki ITS points to be added: new reconstruction pass based on the latest calibration constants (SDD) Excellent agreement between TPC in addition to TOF in the overlap regions: max. difference of 6% K± from Kinks 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki - kinks M. Spyropoulou-Stassinaki, P. Ganoti, A. Belogianni, F. Roukoutakis Preliminary results in good agreement with the K± spectra obtained from the dE/dx in addition to TOF PID Baryon number transport – Motivation 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Who is the carrier of the baryon number Valence quarks: G.C. Rossi in addition to G. Veneziano, Nucl. Phys B123 (1977) 507. Gluonic field: B.Z. Kopeliovich in addition to B. Zakharov, Z. Phys. C43 (1989) 241. Different approaches based on theory: QGSM considers the baryon as a bound quark-diquark state. BN transport implies breaking the diquark pair. Gluonic mechanism aka String Junction (SJ). BN transport implies the stopping of the SJ. LHC’s large rapidity gap between the incoming protons (yp = ±9.6) will give us the opportunity to distinguish between the different models. Baryon number transport – Experimental results 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Proton excess at mid-rapidity can be attributed to the BN transport from the beam at RHIC energies No sign of any rapidity or pt dependence PYTHIA systematically overestimates the proton ratio HIJING-B describes the experimental data Initially reported an asymmetry of ~8% as long as y ~ 7. Results never published due to large systematic uncertainties caused by the high beam-gas rate. Results reported at the DIS2008 are compatible with an asymmetry as long as s ~0 Baryon number transport – Corrections (I) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Apply corrections that don’t cancel out in the ratio: Absorption Cross section in transport codes Secondaries (mainly protons) Baryon number transport – Corrections (II) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Baryon number transport – Corrections (III) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Fit the dca distributions of primary antiprotons which are background free. Use the same function in addition to fit the primary protons scaled by the ratio (free parameter). Fit the dca distributions of secondaries (protons coming from the interaction of particles with the material). Use the same fitting functions to fit the dca distributions from real data. Baryon number transport – Results (I) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Fully corrected ratio: stat. error – lines, syst. error – shaded are around data points Preliminary results show no sign of any rapidity or pt dependence. Experimental points are compared with different model predictions that include variation of BN transport mechanisms: HIJING-B clearly underestimates the y dependence, whereas it predicts a decrease of the ratio with increasing pt not seen in p+p collisions. QGSM’s (only y in as long as mation) version with aSJ 0 is systematically below the data points The different PYTHIA tunes describe the data well. Baryon number transport – Results (II) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Mid-rapidity ratio as long as ALICE extracted by fitting the y dependence plot at y < 0.5. Preliminary results show still a small excess of baryons over antibaryons (asymmetry of ~1.9%) at s = 900 GeV/c. ALICE is up in addition to running!!! 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki THANK YOU FOR YOUR ATTENTION BACKUP 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Strangeness (Ks0) 26.03.2010 Panos.Christakoglou@cern.ch - XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Sawyers, Gloria Black Living Founder & Publisher www.phwiki.com

Strangeness () 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki Cascades () 26.03.2010 Panos.Christakoglou@cern.ch – XXVIII Workshop on Recent Advances in Particle Physics in addition to Cosmology,Thessaloniki

Sawyers, Gloria Founder & Publisher

Sawyers, Gloria is from United States and they belong to Black Living and they are from  Chula Vista, United States got related to this Particular Journal. and Sawyers, Gloria deal with the subjects like Black Interest; Women’s Interest

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