Phys. Rev. Lett.
98,
252001
(2007)
[5 pages]
Production of Mesons and Baryons at High Rapidity and High pT in Proton-Proton Collisions at √s=200 GeV
I. Arsene et al. BRAHMS Collaboration
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I. Arsene10, I. G. Bearden5, D. Beavis1, S. Bekele9, C. Besliu8, B. Budick4, H. Bøggild5, C. Chasman1, C. H. Christensen5, H. H. Dalsgaard5, R. Debbe1, J. J. Gaardhøje5, K. Hagel6, H. Ito1, A. Jipa8, E. B. Johnson9, C. E. Jørgensen5, R. Karabowicz3, N. Katrynska3, E. J. Kim9, T. M. Larsen10, J. H. Lee1, S. Lindal10, G. Løvhøiden10, Z. Majka3, M. Murray9, J. Natowitz6, B. S. Nielsen5, C. Nygaard5, R. Płaneta3, F. Rami2, F. Renault5, C. Ristea5, O. Ristea8, D. Röhrich7, B. H. Samset10, S. J. Sanders9, R. A. Scheetz1, P. Staszel3, T. S. Tveter10, F. Videbæk1, R. Wada6, Z. Yin7, H. Yang7, and I. S. Zgura11 (BRAHMS Collaboration)
1Brookhaven National Laboratory, Upton, New York 11973, USA 2Institut Pluridisciplinaire Hubert Curien and Université Louis Pasteur, Strasbourg France 3Smoluchkowski Institute of Physics, Jagiellonian University, Krakow, Poland 4New York University, New York 10003, USA 5Niels Bohr Institute, Blegdamsvej 17, University of Copenhagen, Copenhagen 2100, Denmark 6Texas A&M University, College Station, Texas 17843, USA 7Department of Physics Technology, University of Bergen, Bergen, Norway 8University of Bucharest, Bucharest, Romania 9University of Kansas, Lawerence, Kansas 66049, USA 10Department of Physics, University of Oslo, Oslo, Norway 11Institute for Space Science, Bucharest, Romania
Received 22 January 2007; published 21 June 2007
We present particle spectra for charged hadrons π±, K±, p, and p̅ from pp collisions at √s=200 GeV measured for the first time at forward rapidities (2.95 and 3.3). The kinematics of these measurements are skewed in a way that probes the small momentum fraction in one of the protons and large fractions in the other. Large proton to pion ratios are observed at values of transverse momentum that extend up to 4 GeV/c, where protons have momenta up to 35 GeV. Next-to-leading order perturbative QCD calculations describe the production of pions and kaons well at these rapidities, but fail to account for the large proton yields and small p̅ /p ratios.
© 2007 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.98.252001
DOI:
10.1103/PhysRevLett.98.252001
PACS:
13.85.Ni, 13.85.Hd, 13.87.Fh, 25.75.Dw
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