Abstract
We present the transverse momentum ( pT) spectra for identified charged pions, protons and anti-protons from p + p and d + Au collisions at sqrt(sNN) = 200 GeV. The spectra are measured around midrapidity ( | y | < 0.5) over the range of 0.3 < pT < 10 GeV / c with particle identification from the ionization energy loss and its relativistic rise in the time projection chamber and time-of-flight in STAR. The charged pion and proton + anti-proton spectra at high pT in p + p and d + Au collisions are in good agreement with a phenomenological model (EPOS) and with next-to-leading order perturbative quantum chromodynamic (NLO pQCD) calculations with a specific fragmentation scheme and factorization scale. We found that all proton, anti-proton and charged pion spectra in p + p collisions follow xT-scaling for the momentum range where particle production is dominated by hard processes ( pT ≳ 2 GeV / c). The nuclear modification factor around midrapidity is found to be greater than unity for charged pions and to be even larger for protons at 2 < pT < 5 GeV / c.
Original language | English |
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Pages (from-to) | 161-169 |
Number of pages | 9 |
Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
Volume | 637 |
Issue number | 3 |
DOIs | |
State | Published - Jun 8 2006 |
Bibliographical note
Funding Information:We would like to thank Simon Albino, Stefan Kretzer and Werner Vogelsang for providing us the NLO pQCD results, Klaus Werner for the EPOS results and J. Raufeisen for useful discussions. We thank the RHIC Operations Group and RCF at BNL, and the NERSC Center at LBNL for their support. This work was supported in part by the HENP Divisions of the Office of Science of the US DOE; the US NSF; the BMBF of Germany; IN2P3, RA, RPL, and EMN of France; EPSRC of the United Kingdom; FAPESP of Brazil; the Russian Ministry of Science and Technology; the Ministry of Education and the NNSFC of China; IRP and GA of the Czech Republic, FOM of the Netherlands, DAE, DST, and CSIR of the Government of India; Swiss NSF; the Polish State Committee for Scientific Research; STAA of Slovakia, and the Korea Sci. & Eng. Foundation.
Funding
We would like to thank Simon Albino, Stefan Kretzer and Werner Vogelsang for providing us the NLO pQCD results, Klaus Werner for the EPOS results and J. Raufeisen for useful discussions. We thank the RHIC Operations Group and RCF at BNL, and the NERSC Center at LBNL for their support. This work was supported in part by the HENP Divisions of the Office of Science of the US DOE; the US NSF; the BMBF of Germany; IN2P3, RA, RPL, and EMN of France; EPSRC of the United Kingdom; FAPESP of Brazil; the Russian Ministry of Science and Technology; the Ministry of Education and the NNSFC of China; IRP and GA of the Czech Republic, FOM of the Netherlands, DAE, DST, and CSIR of the Government of India; Swiss NSF; the Polish State Committee for Scientific Research; STAA of Slovakia, and the Korea Sci. & Eng. Foundation.
Funders | Funder number |
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EMN | |
Office of Science of the US DOE | |
Russian Ministry of Science and Technology | |
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | |
Engineering and Physical Sciences Research Council | |
Department of Science and Technology, Ministry of Science and Technology, India | |
Council of Scientific and Industrial Research, India | |
Government of India, Department of Atomic Energy | |
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung | |
Fundação de Amparo à Pesquisa do Estado de São Paulo | |
National Natural Science Foundation of China (NSFC) | |
Bundesministerium für Bildung und Forschung | IN2P3 |
Bundesministerium für Bildung und Forschung | |
Ministry of Education China | |
Komitet Badań Naukowych |
Keywords
- Cronin effect and x-scaling
- Fragmentation function
- Particle production
- Perturbative quantum chromodynamics
ASJC Scopus subject areas
- Nuclear and High Energy Physics