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Title: Pion production in p+C collisions at 158 GeV/c beam momentum

Abstract

The production of charged pions in minimum bias p+C collisions at 158 GeV/c beam momentum has been studied. A data sample of 377 000 inelastic events were obtained with NA49 detector at CERN SPS. The data cover large phase space ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in Feynman x. The comparison to the measurements in p+p collisions from the same detector allows for the extraction of the projectile and target contribution. The large phase space coverage offers for the first time detailed study of both longitudinal and transverse dependence of the projectile fragmentation in comparison with elementary collisions.

Authors:
 [1]
  1. Atomic Physics Department, Sofia University St. Kliment Ohridski, Sofia (Bulgaria)
Publication Date:
OSTI Identifier:
21057127
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 899; Journal Issue: 1; Conference: 6. international conference of the Balkan Physical Union, Istanbul (Turkey), 22-26 Aug 2006; Other Information: DOI: 10.1063/1.2733107; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA). NA49 Collaboration
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CARBON 12 TARGET; CERN SPS SYNCHROTRON; COMPARATIVE EVALUATIONS; GEV RANGE; INELASTIC SCATTERING; MULTIPARTICLE SPECTROMETERS; PARTICLE IDENTIFICATION; PARTICLE KINEMATICS; PARTICLE PRODUCTION; PHASE SPACE; PIONS; PROTON REACTIONS; PROTON-PROTON INTERACTIONS; TRANSVERSE MOMENTUM

Citation Formats

Makariev, M. Pion production in p+C collisions at 158 GeV/c beam momentum. United States: N. p., 2007. Web. doi:10.1063/1.2733107.
Makariev, M. Pion production in p+C collisions at 158 GeV/c beam momentum. United States. doi:10.1063/1.2733107.
Makariev, M. Mon . "Pion production in p+C collisions at 158 GeV/c beam momentum". United States. doi:10.1063/1.2733107.
@article{osti_21057127,
title = {Pion production in p+C collisions at 158 GeV/c beam momentum},
author = {Makariev, M.},
abstractNote = {The production of charged pions in minimum bias p+C collisions at 158 GeV/c beam momentum has been studied. A data sample of 377 000 inelastic events were obtained with NA49 detector at CERN SPS. The data cover large phase space ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in Feynman x. The comparison to the measurements in p+p collisions from the same detector allows for the extraction of the projectile and target contribution. The large phase space coverage offers for the first time detailed study of both longitudinal and transverse dependence of the projectile fragmentation in comparison with elementary collisions.},
doi = {10.1063/1.2733107},
journal = {AIP Conference Proceedings},
number = 1,
volume = 899,
place = {United States},
year = {Mon Apr 23 00:00:00 EDT 2007},
month = {Mon Apr 23 00:00:00 EDT 2007}
}
  • The slope of the invariant cross section of the process pp ..-->.. ..pi../sup +/ ..pi../sup -/+X varies near 1 GeV/c as a function of P/sub perpendicular/. If the slope is described by the sum of the two exponents, then the exponents must be equal to 12.3 +- 0.9 (GeV/c)/sup -1/ and 8.7 +- 0.6 (GeV/c)/sup -1/. The experimental values in the region P/sub perpendicular/>1 GeV/c are much higher than the values predicted by the QCD model (Ref. 1) and by the CIM model (Ref. 2) for inelastic collisions.
  • We have measured the momentum correlation of pion pairs produced in the collisions of 27.5 GeV/[ital c] protons in liquid hydrogen. By considering events for which all final state particles have been measured, we have succeeded in reducing backgrounds due to particle misidentification below 5% for [pi][sup +] and 1% for [pi][sup [minus]]. Our use of a precision magnetic spectrometer has provided an accurate determination of particle momenta and excellent acceptance for particle pairs with small relative momentum essential for correlations studies. A large data sample of fully reconstructed events (1[times]10[sup 6]) allows us to analyze the correlations for [pi][supmore » +][pi][sup +] and [pi][sup [minus]][pi][sup [minus]] pairs separately, and also as a function of the final state multiplicity. We find that the pion pair correlations scale 0.98 fm describes the data well. We do not find any indication of multiplicity dependence of the correlation scale for multiplicities from 6 to 14 final state particles.« less
  • Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at {radical}S{sub NN} = 17.4 GeV at midrapidity (2.3 {approx}< {eta}{sub lab} {approx}< 3.0) over the range 0.7 {approx}< p{sub 1} {approx}< 3.5 GeV/c. The spectra are compared to {pi}{sup 0} spectra measured in Pb+Pb collisions at {radical}S{sub NN} = 17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N{sub part} {approx}< 300), the yield of {pi}{sup 0}'s with {rho}{sub {Lambda}} {approx}> 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaled with the number of nucleon-nucleon collisions (N{sub coll}),more » while for central Pb+Pb collisions with N{sub part} {approx}> 350, the {pi}{sup 0} yield is suppressed.« less
  • Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at {radical}(s{sub NN})=17.4 GeV at midrapidity (2.3 < or approx. {eta}{sub lab} < or approx. 3.0) over the range 0.7 < or approx. p{sub T} < or approx. 3.5 GeV/c. The spectra are compared to {pi}{sup 0} spectra measured in Pb+Pb collisions at {radical}(s{sub NN})=17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N{sub part} < or approx. 300), the yield of {pi}{sup 0}'s with p{sub T} > or approx. 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaledmore » with the number of nucleon-nucleon collisions (N{sub coll}), while for central Pb+Pb collisions with N{sub part} > or approx. 350, the {pi}{sup 0} yield is suppressed.« less