skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: RESULTS FROM PP AT 62.4 AND 200 GeV WITH THE BRAHMS EXPERIMENTATION.

Abstract

Measurements of elementary pp collisions are essential for understanding heavy ion collisions. R.esu1ts for pp collisions at 200 and 62.4 GeV are presented. At both energies NLO pQCD describes pion production well. The measured pion transverse single spin asymmetries are very large at 62.4 GeV and are reasonably well described by models relying on pQCD at transverse momenta larger than 1 GeV/c.

Authors:
;  [1]
  1. (
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
910364
Report Number(s):
BNL-78044-2007-CP
R&D Project: 08861; KB-02-01-021; TRN: US0704165
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Conference
Resource Relation:
Conference: WINTER WORKSHOP ON NUCLEAR DYNAMICS; BIG SKY MONTANA; 20070211 through 20070218
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 74 ATOMIC AND MOLECULAR PHYSICS; HEAVY IONS; PIONS; PRODUCTION; SPIN; QUANTUM CHROMODYNAMICS

Citation Formats

VIDEBAEK,F., and BRAHMS EXPERIMENTATION). RESULTS FROM PP AT 62.4 AND 200 GeV WITH THE BRAHMS EXPERIMENTATION.. United States: N. p., 2007. Web.
VIDEBAEK,F., & BRAHMS EXPERIMENTATION). RESULTS FROM PP AT 62.4 AND 200 GeV WITH THE BRAHMS EXPERIMENTATION.. United States.
VIDEBAEK,F., and BRAHMS EXPERIMENTATION). Sun . "RESULTS FROM PP AT 62.4 AND 200 GeV WITH THE BRAHMS EXPERIMENTATION.". United States. doi:. https://www.osti.gov/servlets/purl/910364.
@article{osti_910364,
title = {RESULTS FROM PP AT 62.4 AND 200 GeV WITH THE BRAHMS EXPERIMENTATION.},
author = {VIDEBAEK,F. and BRAHMS EXPERIMENTATION)},
abstractNote = {Measurements of elementary pp collisions are essential for understanding heavy ion collisions. R.esu1ts for pp collisions at 200 and 62.4 GeV are presented. At both energies NLO pQCD describes pion production well. The measured pion transverse single spin asymmetries are very large at 62.4 GeV and are reasonably well described by models relying on pQCD at transverse momenta larger than 1 GeV/c.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Feb 11 00:00:00 EST 2007},
month = {Sun Feb 11 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Measurements of x{sub F}-dependent single spin asymmetries of identified charged hadrons, {pi}{sup {+-}}, K{sup {+-}}, p, and {bar p}, from transversely polarized proton collisions at {radical}s = 200 and 62.4 GeV at RHIC are presented. The energy and flavor dependent asymmetry measurements bring new insight into the fundamental mechanisms of transverse spin asymmetries and Quantum Chromodynamical description of hadronic structure.
  • Based on results obtained with event generators we have launched the core-corona model. It describes in a simplified way but quite successfully the centrality dependence of multiplicity and of identified particles observed in heavy-ion reactions at beam energies between {radical}s = 17 and 200 GeV. Also the centrality dependence of the elliptic flow, {upsilon}{sub 2}, for all charged and identified particles could be explained in this model. Here we extend this analysis and study the centrality dependence of single-particle spectra of K{sup -} and p-bar measured by the PHENIX, STAR, and BRAHMS Collaborations. We find that also for these particlesmore » the analysis of the spectra in the core-corona model suffers from differences in the data published by the different experimental groups, notably for the pp collisions. As for protons and K{sup +}, for each experience the data agree well with the prediction of the core-corona model but the values of the two necessary parameters depend on the experiments. We show as well that the average momentum as a function of the centrality depends in a very sensitive way on the particle species and may be quite different for particles which have about the same mass. Therefore the idea to interpret this centrality dependence as a consequence of a collective expansion of the system, as done in blast way fits, may be premature.« less
  • A primary goal of the STAR spin physics program is measuring the polarized gluon distribution function, {delta}g(x), accessible through the double longitudinal spin asymmetry, A{sub LL}. The STAR detector is uniquely suited for measuring A{sub LL} in a number of different final-state channels, such as inclusive jet and pion production, in polarized pp collisions. We present preliminary A{sub LL} results from RHIC run 6 for neutral pion production at mid-rapidity. These A{sub LL} measurements allow for discrimination among a number of different next-to-leading order (NLO) perturbative Quantum Chromodynamics (pQCD) predictions and provide meaningful constraints on {delta}g(x)
  • The STAR experiment at RHIC measures the longitudinal double-spin asymmetry A{sub LL} for a variety of final states in collisions of longitudinally polarized protons to constrain the polarized gluon distribution in the proton. Asymmetries for mid-rapidity charged pion production benefit from large cross-sections and the excellent tracking and particle identification capabilities of the STAR Time Projection Chamber. This contribution presents a measurement of the ratio of cross sections for inclusive {pi}{sup -} and {pi}{sup +} production using data collected in 2005, as well as a new measurement of A{sub LL} for charged pions opposite a jet obtained from the 2006more » RHIC run.« less
  • Preliminary results on invariant cross section for inclusive ..pi../sup 0/ production, eta/..pi../sup 0/ production ratio and direct photon to ..pi../sup 0/ production ratio in anti pp collisions at ..sqrt..s = 24.3 GeV in the transverse momentum range 2.5 < p/sub T/ < 5 GeV/c are presented. These results are from data collected in an initial run of the UA6 experiment in the fall of 1984 with an integrated luminosity of 4.10/sup 34/ cm/sup -2/.