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1.
Phys Rev Lett ; 102(18): 182001, 2009 May 08.
Article in English | MEDLINE | ID: mdl-19518860

ABSTRACT

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a hydrogen target. The polar and azimuthal angular distribution parameters have been extracted over the kinematic range 4.5

2.
Phys Rev Lett ; 100(6): 062301, 2008 Feb 15.
Article in English | MEDLINE | ID: mdl-18352463

ABSTRACT

We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, sigma(p+d-->Upsilon)/2sigma(p+p-->Upsilon), is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0

3.
Phys Rev Lett ; 99(8): 082301, 2007 Aug 24.
Article in English | MEDLINE | ID: mdl-17930942

ABSTRACT

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a deuterium target. The muon angular distributions in the dilepton rest frame have been measured over the kinematic range 4.5

Subject(s)
Mesons , Protons , Deuterium , Elementary Particle Interactions , Models, Theoretical , Motion , Nuclear Physics
4.
Phys Rev Lett ; 86(12): 2529-32, 2001 Mar 19.
Article in English | MEDLINE | ID: mdl-11289972

ABSTRACT

We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at square root of s = 38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state shows no polarization at small values of the fractional longitudinal momentum x(F) and transverse momentum p(T) but significant positive transverse production polarization for either p(T)>1.8 GeV/c or for x(F)>0.35. The Upsilon(2S+3S) (unresolved) states show a large transverse production polarization at all values of x(F) and p(T) measured. These observations challenge NRQCD calculations of the polarization expected in the hadronic production of bottomonium states.

5.
Phys Rev Lett ; 84(15): 3256-60, 2000 Apr 10.
Article in English | MEDLINE | ID: mdl-11019064

ABSTRACT

Measurements of the suppression of the yield per nucleon of J/psi and psi(') production for 800 GeV/ c protons incident on heavy nuclear targets, relative to light nuclear targets, have been made with very broad coverage in x(F) and p(T). The observed suppression is smallest at x(F) values of 0.25 and below, and increases at larger values of x(F). It is also strongest at small p(T). Substantial differences between psi(') and J/psi production are observed for the first time in p-A collisions. The suppression for psi(') production is stronger than that for J/psi for x(F) near zero, but becomes comparable to that for J/psi for x(F)>0.6.

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