Spectator Nucleons in Pb+Pb Collisions at 158 A$\cdot$GeV

H. Appelshäuser - et al.

doi:doi:10.1007/s100500050135

2022 Impact factor 2.7

Hadrons and Nuclei

Eur. Phys. J. A 2, 383-390

Spectator Nucleons in Pb+Pb Collisions at 158 A $\cdot$ GeV

H. Appelshäuser⁷ - J. Bächler⁵ - S.J. Bailey¹⁶ - L.S. Barnby³ - J. Bartke⁶ - R. A. Barton³ - H. Bia $\l$ kowska¹⁴ - C.O. Blyth³ - R. Bock⁷ - C. Bormann¹⁰ - F.P. Brady⁸ - R. Brockmann⁷ - N. Buncic^5,10 - P. Buncic^5,10 - H.L. Caines³ - D. Cebra⁸ - P. Chan¹⁶ - G.E. Cooper² - J.G. Cramer^16,13 - P.B. Cramer¹⁶ - P. Csato⁴ - J. Dunn⁸ - V. Eckardt¹³ - F. Eckhardt¹² - M.I. Ferguson⁵ - H.G. Fischer⁵ - D. Flierl¹⁰ - Z. Fodor⁴ - P. Foka¹⁰ - P. Freund¹³ - V. Friese¹² - M. Fuchs¹⁰ - F. Gabler¹⁰ - J. Gal⁴ - M. Gazdzicki¹⁰ - E. G $\l$ adysz⁶ - P. Gorodetsky^f - J. Grebieszkow¹⁵ - J. Günther¹⁰ - J.W. Harris¹⁷ - S. Hegyi⁴ - T. Henkel¹² - L.A. Hill³ - I. Huang^2,8 - H. Hümmler¹⁰ - G. Igo¹¹ - D. Irmscher^2,7 - P. Jacobs² - P.G. Jones³ - K. Kadija^18,13 - V.I. Kolesnikov⁹ - M. Kowalski⁶ - B. Lasiuk¹¹ - P. Lévai⁴ - A.I. Malakhov⁹ - S. Margetis² - C. Markert⁷ - G.L. Melkumov⁹ - A. Mock¹³ - J. Molnár⁴ - J.M. Nelson³ - G. Odyniec² - G. Palla⁴ - A.D. Panagiotou¹ - A. Petridis¹ - A. Piper¹² - R.J. Porter² - A.M. Poskanzer² - S. Poziombka¹⁰ - D.J. Prindle¹⁶ - F. Pühlhofer¹² - W. Rauch¹³ - J.G. Reid¹⁶ - R. Renfordt¹⁰ - W. Retyk¹⁵ - H.G. Ritter² - D. Röhrich¹⁰ - C. Roland⁷ - G. Roland¹⁰ - H. Rudolph^2,10 - A. Rybicki⁶ - I. Sakrejda² - A. Sandoval⁷ - H. Sann⁷ - A.Yu. Semenov⁹ - E. Schäfer¹³ - D. Schmischke¹⁰ - N. Schmitz¹³ - S. Schönfelder¹³ - P. Seyboth¹³ - J. Seyerlein¹³ - F. Sikler⁴ - E. Skrzypczak¹⁵ - G.T.A. Squier³ - R. Stock^5,10 - H. Ströbele¹⁰ - I. Szentpetery⁴ - J. Sziklai⁴ - M. Toy^2,11 - T.A. Trainor¹⁶ - S. Trentalange¹¹ - T. Ullrich¹⁷ - M. Vassiliou¹ - G. Vesztergombi⁴ - D. Vranic^7,18 - F. Wang² - D.D. Weerasundara¹⁶ - S. Wenig⁵ - S. White - C. Whitten¹¹ - T. Wienold² - L. Wood⁸ - T.A. Yates³ - J. Zimanyi⁴ - X.-Z. Zhu¹⁶ - R. Zybert³
NA49 Collaboration

¹ Department of Physics, University of Athens, Athens, Greece
² Lawrence Berkeley National Laboratory, University of California, Berkeley, USA
³ Birmingham University, Birmingham, England
⁴ KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary
⁵ CERN, Geneva, Switzerland
⁶ Institute of Nuclear Physics, Cracow, Poland
⁷ Gesellschaft für Schwerionenforschung (GSI), Darmstadt, Germany
⁸ University of California at Davis, Davis, USA
⁹ Joint Institute for Nuclear Research, Dubna, Russia
¹⁰ Fachbereich Physik der Universität, Frankfurt, Germany
¹¹ University of California at Los Angeles, Los Angeles, USA
¹² Fachbereich Physik der Universität, Marburg, Germany
¹³ Max-Planck-Institut für Physik, Munich, Germany
¹⁴ Institute for Nuclear Studies, Warsaw, Poland
¹⁵ Institute for Experimental Physics, University of Warsaw, Warsaw, Poland
¹⁶ Nuclear Physics Laboratory, University of Washington, Seattle, WA, USA
¹⁷ Yale University, New Haven, CT, USA
¹⁸ Rudjer Boskovic Institute, Zagreb, Croatia

Received: 16 February 1998 / Revised version: 30 March 1998 Communicated by V. Metag

Abstract
The composition of forward-going projectile spectator matter in fixed-target Pb+Pb collisions at 158 A $\cdot$ GeV at the CERN SPS has been studied as a function of centrality. The data were measured with the NA49 veto calorimeter. We observe that forward-going spectator matter in central collisions consists of 9 neutrons, 7 protons, and half a deuteron on average. At large impact parameters most spectator nucleons are bound in fragments. The relative resolution of the average impact parameter derived from the measurement of spectator neutrons is roughly 19% in the range from zero to half maximum impact parameters.

PACS
25.75.-qRelativistic heavy-ion collisions