Thomas Peitzmann

Publications (38)0 Total impact

• Article: Limits on the production of direct photons in 200 A GeV$^{32}$S + Au collisions

  R Albrecht, V G Antonenko, T C Awes, C Barlag, F Berger, M A Bloomer, C Blume, D L Bock, R K Böck, E M Bohne, [......], K Söderström, S P Sørensen, P Stankus, K Steffens, P Steinhäuser, E Stenlund, D Stüken, A Vinogradov, H Wegner, G R Young
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  ABSTRACT: A search for the production of direct photons in S+Au collisions at 200\cdotA~GeV has been carried out in the CERN-WA80 experiment. For central collisions the measured photon excess at each p_T, averaged over the range 0.5~GeV/c~ \leq p_T \leq 2.5~GeV/c, corresponded to 5.0\% of the total inclusive photon yield with a statistical error of \sigma_{\rm stat}=0.8\% and a systematic error of \sigma_{\rm syst}=5.8\%. Upper limits on the invariant yield for direct photon production at the 90\%~C.L. are presented. Possible implications for the dynamics of high-energy heavy-ion collisions are discussed.
• Source

  Available from: uni-wuppertal.de

  Article: A new monitoring system for the photon spectrometer LEDA in the WA98 experiment

  Thomas Peitzmann, C Barlag, C Blume, E M Bohne, D Bucher, A Claussen, R Glasow, N Heine, K. H. Kampert, R Santo, G. Schepers, H Schlagheck, M Schnittker, W Verhoeven
• Article: Intermittency and correlations in 200 GeV/nucleon S + S and S + Au collisions

  R Albrecht, A Antonenko, T C Awes, F Berger, M A Bloomer, D Bock, R K Böck, G Claesson, G Clewing, L Dragon, [......], R Santo, H R Schmidt, K Söderström, S P Sørensen, K Steffens, P Steinhäuser, E Stenlund, D Stüken, A Vinogradov, G R Young
• Article: Soft photon production in central 200 GeV/nucleon $^{32}S$ + Au collisions

  M. M. Aggarwal, Aris L S Angelis, V G Antonenko, T C Awes, S K Badyal, C Barlag, K B Bhalla, V S Bhatia, C Blume, D Bock, [......], A Ster, D Stüken, M D Trivedi, O Twenhöfel, N van Eijndhoven, E Van Heeringen, A Vinogradov, Y. P. Viyogi, He Xiao Chun, G R Young
• Article: Three-Pion Interferometry Results from Central Pb+Pb Collisions at 158 A GeV/c

  M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, [......], N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wyslouch, K Yagi, Y Yokota, G R Young
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  ABSTRACT: Three-particle correlations have been measured for identified negative pions from central 158 A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.
• Article: Central Pb+Pb Collisions at 158 A GeV/c Studied by $\pi^{-}\pi^{-}$ Interferometry

  M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, [......], N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wyslouch, K Yagi, Y Yokota, G R Young
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  ABSTRACT: Two-particle correlations have been measured for identified negative pionsfrom central 158 AGeV Pb+Pb collisions and fitted radii of about 7 fm in alldimensions have been obtained. A multi-dimensional study of the radii as afunction of kT is presented, including a full correction for the resolutioneffects of the apparatus. The cross term Rout-long of the standard fit in theLongitudinally CoMoving System (LCMS) and the vl parameter of the generalisedYano-Koonin fit are compatible with 0, suggesting that the source undergoes aboost invariant expansion. The shapes of the correlation functions in Qinv andQspace have been analyzed in detail. They are not Gaussian but betterrepresented by exponentials. As a consequence, fitting Gaussians to thesecorrelation functions may produce different radii depending on the acceptanceof the experimental setup used for the measurement.
• Article: Freeze-Out Parameters in Central 158 AGeV $^{208}Pb$ + $^{208}Pb$ Collisions

  M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, [......], N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wyslouch, K Yagi, Y Yokota, G R Young
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  ABSTRACT: Neutral pion production in central 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. The pi0 transverse mass spectrum has been analyzed in terms of a thermal model with hydrodynamic expansion. The high accuracy and large kinematic coverage of the measurement allow to limit previously noted ambiguities in the extracted freeze-out parameters. The results are shown to be sensitive to the shape of the velocity distribution at freeze-out.
• Article: Observation of Direct Photons in Central 158 A GeV $^{208}Pb+^{208}Pb$ Collisions

  M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, [......], N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wysouch, K Yagi, Y Yokota, G R Young
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  ABSTRACT: A measurement of direct photon production in 208Pb + 208Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central collisions is extracted as a function of transverse momentum in the interval 0.5 < p_T < 4 GeV/c. A significant direct photon signal, compared to statistical and systematical errors, is seen at p_T > 1.5 GeV/c. The results constitute the first observation of direct photons in ultrarelativistic heavy-ion collisions which could be significant for diagnosis of quark gluon plasma formation.
• Article: Scaling of Particle and Transverse Energy Production in 208Pb+208Pb collisions at 158 A GeV

  M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, [......], N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wyslouch, K Yagi, Y Yokota, G R Young
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  ABSTRACT: Transverse energy, charged particle, and photon pseudorapidity distributions have been studied as a function of the number of participants (N_{part}) and the number of binary nucleon-nucleon collisions (N_{coll}) in 158 A GeV Pb+Pb collisions over a wide impact parameter range. A scaling of the transverse energy and charged particle pseudorapidity density at midrapidity as N_{part}^{1.08} and N_{coll}^{0.83} is observed. This faster than linear scaling with N_{part} indicates a violation of the naive Wounded Nucleon Model.
• Source

  Available from: Mikhail Ippolitov

  Article: Electromagnetic probes of hot and dense nuclear matter

  K. H. Kampert, T C Awes, C Barlag, F Berger, M A Bloomer, C Blume, D Bock, R K Böck, E M Bohne, D Bucher, [......], H R Schmidt, K Söderström, S P Sørensen, K Steffens, P Steinhäuser, E Stenlund, D Stüken, A Vinogradov, H Wegner, G R Young
• Source

  Available from: Mikhail Ippolitov

  Article: Single photon and neutral meson production in nuclear collisions at 200 AGeV

  K. H. Kampert, R Albrecht, T C Awes, F Berger, M A Bloomer, D Bock, G Clewing, R Debbe, L Dragon, A Eklund, [......], R Santo, H R Schmidt, S P Sørensen, K Steffens, P Steinhäuser, E Stenlund, D Stüken, A Vinogradov, H Wegner, G R Young
• Article: Collective flow in Pb + Pb collisions at the CERN-SPS

  S Nishimura, M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, [......], W.H. van Heeringen, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wyslouch, K Yagi, Y Yokota, G R Young
• Source

  Available from: Mikhail Ippolitov

  Article: Direct Photon Production in 158 A GeV $^{208}Pb+^{208}Pb$ collisions

  M. M. Aggarwal, A Agnihotri, Z. Ahammed, Aris L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, [......], N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wysouch, K Yagi, Y Yokota, G R Young
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  ABSTRACT: A measurement of direct photon production in 208Pb + 208Pb collisions at 158 A GeV has been carried out in the CERN WA98 experiment. The invariant yield or upper limit of direct photons as a function of transverse momentum in the interval 0.5 < p_T < 4 GeV/c is presented. A significant direct photon excess is observed at p_T > 1.5 GeV/c in central collisions. The results are compared to proton-induced results and to theoretical predictions. Implications for the dynamics of high-energy heavy-ion collisions are discussed.
• Article: Prototype tests for the ALICE TRD

  A. Andronic, H Appelshäuser, C Blume, P. Braun-Munzinger, V. Catanescu, M Ciobanu, H W Daues, A Devismes, C Finck, N. Herrmann, [......], R Santo, R. Schulze, S N Sedykh, R S Simon, J J Stachel, H Stelzer, J. P. Wessels, O. Winkelmann, B. Windelband, C Xu
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  ABSTRACT: A Transition Radiation Detector (TRD) has been designed to improve the electron identification and trigger capability of the ALICE experiment at the Large Hadron Collider (LHC) at CERN. We present results from tests of a prototype of the TRD concerning pion rejection for different methods of analysis over a momentum range from 0.7 to 2 GeV/c. We investigate the performance of different radiator types, composed of foils, fibres and foams.
• Source

  Available from: Hans Herbert Gutbrod

  Article: Effective source sizes of low rapidity soft particle emission

  Thomas Peitzmann, R Albrecht, T C Awes, P Beckmann, F Berger, M A Bloomer, C Blume, D Bock, G Claesson, G Clewing, [......], B Roters, S Saini, R Santo, H R Schmidt, S P Sørensen, K Steffens, P Steinhäuser, E Stenlund, D Stüken, G R Young
• Source

  Available from: Hans Herbert Gutbrod

  Article: Bose-Einstein correlations of soft pions in ultrarelativistic nucleus-nucleus collisions

  T C Awes, M A Bloomer, C Blume, D Bock, R K Böck, D Bucher, G Clewing, S I A Garpman, R Glasow, Hans Åke Gustafsson, [......], B Roters, S Saini, R Santo, H R Schmidt, S P Sørensen, K Steffens, P Steinhäuser, E Stenlund, D Stüken, G R Young
• Article: A new VME-based high voltage power supply for large photomultiplier systems

  S Neumaier, H H Gutbrod, T Hubbeling, B W Kolb, M L Purschke, M S Ippolitov, V I Man'ko, G Mgebrishvili, A Nijanin, Yu Sibiryak, A A Tsvetkov, A Vinogradov, C Barlag, C Blume, E M Bohne, D Bucher, A Claussen, Thomas Peitzmann, G Shepers, H Schlagheck
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  ABSTRACT: We describe a new high voltage power supply, developed for the leadglass calorimeter of the WA98 experiment at CERN. The high voltage is produced for each of the 10 080 photomultiplier tubes of the detector individually, by the same number of active bases with on-board Greinacher voltage multipliers. The full VME-based HV controller system, which addresses each base via bus cables once per second, is miniaturized and fits into a single VME crate. The main advantages of this approach are the low heat dissipation, the considerably reduced amount of cabling and cost, as well as the high stability and low noise of the system.
• Article: Azimuthal Anisotropy of Photon and Charged Particle Emission in Pb+Pb Collisions at 158 A GeV/c

  M. M. Aggarwal, Z. Ahammed, A L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, S K Badyal, [......], L Tykarski, E C Van den Pijll, N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi, A S Vodopyanov, S Vörös, B Wysouch, G R Young
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  ABSTRACT: The azimuthal distributions of photons and charged particles with respect to the event plane are investigated as a function of centrality in Pb + Pb collisions at 158 A GeV/c in the WA98 experiment at the CERN SPS. The anisotropy of the azimuthal distributions is characterized using a Fourier analysis. For both the photon and charged particle distributions the first two Fourier coefficients are observed to decrease with increasing centrality. The observed anisotropies of the photon distributions compare well with the expectations from the charged particle measurements for all centralities.
• Article: Centrality and Transverse Momentum Dependence of Collective Flow in 158 A GeV Pb+Pb Collisions Measured via Inclusive Photons

  M. M. Aggarwal, Z. Ahammed, A L S Angelis, V G Antonenko, V Arefev, V A Astakhov, V Avdeichikov, T C Awes, P V K S Baba, S K Badyal, [......], E Stenlund, M. Sumbera, T Svensson, A A Tsvetkov, L Tykarski, E C Van den Pijll, N van Eijndhoven, G J van Nieuwenhuizen, A Vinogradov, Y. P. Viyogi
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  ABSTRACT: Directed and elliptic flow of inclusive photons near mid-rapidity in $158 $A GeV Pb+Pb collisions has been studied. The data have been obtained with the photon spectrometer LEDA of the WA98 experiment at the CERN SPS. The flow strength has been measured for various centralities as a function of $p_T$ and rapidity over $0.18 < p_T < 1.5 \mathrm{GeV}/c$ and $2.3 < y < 2.9$. The angular anisotropy has been studied relative to an event plane obtained in the target fragmentation region that shows the elliptic flow to be in-plane. The elliptic flow has also been studied using two-particle correlations and shown to give similar results. A small directed flow component is observed. Both the directed and elliptic flow strengths increase with $p_T$. The photon flow results are used to estimate the corresponding neutral pion flow.
• Article: Photon and neutral meson production in 158 AGeV208Pb+Pb collisions

  Thomas Peitzmann, M. Aggarwal, A. Agnihotri, A.L.S. Angelis, V. Antonenko, V. Arefiev, V. Astakhov, V. Avdeitchikov, T.C. Awes, S.K. Badyal, [......], W.H.v. Heeringen, G.J.v. Nieuwenhuizen, A. Vinogradov, Y.P. Viyogi, A. Vodopianov, M.A. Vos, B. Wyslouch, K. Yagi, Y. Yokota, G.R. Young
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  ABSTRACT: First results from the WA98 experiment on 33 TeV 208Pb ion reactions with various targets measured at the CERN SPS are presented. Data on transverse energy production and particle multiplicity are discussed. Special emphasis is laid on photon and neutral meson production.
  Nuclear Physics A.