T.Peitzmann Status of the ALICE Project NIKHEF annual scientific meeting Thomas Peitzmann Universiteit Utrecht

T.Peitzmann The Quark-Gluon-Plasma QCD ground state –color charge of quarks and gluons is confined –chiral symmetry spontaneously broken pressure or heat leads to overlap of hadrons –intuitive in bag model new state of matter: –color charges can move between hadrons –deconfinement: quark-gluon-plasma –restoration of chiral symmetry

T.Peitzmann The QCD Phase Diagram SPS –QGP probably reached –dominated by transition and hadron gas –theoretically extremely difficult RHIC and LHC –dominated by QGP –theoretically simpler »coupling  s small »thermodynamical “limit” »baryon. chem. potential  b = 0 –new physical observables »heavy quarks »jets

T.Peitzmann People (NIKHEF and Utrecht University) PhD –M. van LeeuwenNA49 »strangeness and charm yields –E. van der PijllWA98 »direct photons –P. de RijkeNA57 »omega production –E. SchillingsNA57 »lambda polarisation –A. SokolovALICE »SSD module tests staff –M. Botje –N. van Eijndhoven –R. Kamermans –P. Kuijer –G.-J. Nooren –T. Peitzmann –R. Snellings

T.Peitzmann SPS: Reaping The Harvest Example 1: WA98 (E. van der Pijll) –study of direct photon production »signal of hot initial state in heavy ion collisions »very difficult: small signal with high background –direct photon signal observed in WA98 –development of new analysis method –extension of analysis to lower transverse momenta »even more difficult! Example 2: NA57 (E. Schillings, P. de Rijke) –  polarisation (E. Schillings, see talk) »small polarisation at mid-rapidity –  production (P. de Rijke) »understanding the systematic errors alignment, efficiencies, …

T.Peitzmann transverse mass spectra of different hadron species well described by thermalized source measures freeze-out conditions –hadronic interactions stop –similar temperatures for all SPS energies –high average expansion velocity Hydrodynamical Model Fits To NA49 Data M. van Leeuwen

T.Peitzmann RHIC: Joining The -Party exciting data from first beam times at RHIC the most important physics activity in present day heavy ion physics is happening at RHIC STAR one of the major players –substantial contribution to be built up! see talk by R. Snellings central Au+Au collision at  s NN =200GeV in the STAR TPC STAR

T.Peitzmann LHC: Preparations for ALICE hardware contribution: silicon strip detector –design and prototyping well under way physics simulation –efforts being started

T.Peitzmann Hardware Contributions DetectorDetector FE moduleFE module EndcapEndcap FEROMFEROM DAQDAQ Alice Inner Tracking System ADC racks outside magnet 5mm 50 cm 25 m 200 m CF supportCF support CoolingCooling

T.Peitzmann Status Of Technical Work preseries of double sided strip detectors –delivered (Canberra, SINTEF, ITC) –tested (IRES, Trieste) ladder spaceframes –delivered (St. Petersburg) ASICs for endcap –design ready (NIKHEF/UU) readout chain using prototype ASICs –first test (NIKHEF/UU) testequipment for ASICs and hybrids –operational (NIKHEF/UU) ladder assembly robot –near to completion (NIKHEF/UU) first silicon strip detector module –NIKHEF/UU + IRES design –manufactured at IRES by Ukraine people –to be tested at NIKHEF/UU

T.Peitzmann Tests Of SSD With Infrared Laser laser wavelength chosen to optimize penetration depth –close to band gap energy –20-30% light absorbed –nearly uniform density of ionization properties adequate for detector tests –beam spot ≈ 30 µm »larger than for particle, but small compared to strip pitch –precision of positioning ≈ 1.5 µm A. Sokolov

T.Peitzmann 2-Dimensional Map Of Collected Charge strip structure visible –aspect ratio distorted »y-axis compressed by factor 15 »true angle: 35 mrad setup used for –dead strip search –relative calibration –measurement of charge sharing

T.Peitzmann Charge Sharing Around Dead Strip

T.Peitzmann ALICE Physics Studies (Simulation) work on the Physics Performance Report for ALICE pA physics –important link pp - pA - AA –nuclear modifications –no thermalization/phase transition further simulation studies foreseen –prepare analysis framework for future data taking (pp, pA and AA) full tracking with ITS and TPC example: impact parameter vs. charged multiplicity –HIJING simulations

T.Peitzmann Summary physics analysis from SPS experiments –very fruitful! participation in STAR –major activity in heavy ion group gearing up for ALICE –hardware contribution well under way –increase effort on physics simulations