High-mass dimuon production inp¯Nandπ−N interactions at 125 GeV/c

Abstract

We have studied muon pairs with an invariant mass between 4 and 9 Gev/c2 produced in PN and a -N interactions at an incident momentum of 125 GeV/c. The experiment was performed at Fermilab using a tungsten target and a special beam enriched to contain 18% antiprotons. We compare differential distributions as functions of the dimuon invariant mass, Feynman x, transverse momentum, and decay angles of the dimuon to the predictions of the Drell-Yan model including QCD corrections. Quark structure functions for the j7 and n are extracted. Comparisons of the antiproton data to the Drell-Yan model are significant because the cross sections depend principally on the valence-quark structure functions which are accurately determined by deep-inelastic scattering measurements. The measured absolute cross section (integrated over positive Feynman x and all transverse momenta) is 0.106+0.005+0.008 nb/nucleon for the p,V interaction and 0.107+0.003+0.009 nb/nucleon for the n -N interaction, where the quoted errors are statistical and systematic, respectively. Normalization ( K ) factors that are required to bring the naive Drell-Yan and first-order QCD predictions into agreement with the measurements are extracted, and the uncertainties involved in such comparisons are examined.

Limits on transverse momentum dependent evolution from semi-inclusive deep inelastic scattering at moderateQ

“…Ideally, to see an effect, a comparison should be done with both experiments performed at exactly the same values of x 1 , x 2 and Q to avoid mixing dependence on the species of the TMD PDF with variations in kinematics. At present, the closest we can find to such a comparison in existing data is for proton-Tungsten [37] and antiproton-Tungsten [38] production of Drell-Yan pairs with overlapping bins in Q and x F . The transverse momentum distributions, normalized to the same values in the lowest P 2 T bins, are shown in Fig.…”

“…One may consider, for instance, the difference between valence and sea quark TMD PDFs. Chiral quark soliton models [30][31][32][33] suggest that the transverse momentum width of sea quarks in a proton [37] and [38], respectively and have been normalized to the same value at the lowest P 2 T . The data from [37] use a beam energy of 400 GeV (27.4 GeV center-of-mass energy) while the data from [38] have a beam energy of 125 GeV (15.4 GeV center-of-mass energy).…”

A microscopic calculation of secondary Drell-Yan production in heavy ion collisions

“…The dimuon spectrum produced in π − + W reactions, at p lab = 125 GeV/c, as measured by the E537 experiment [36], is presented in Fig. 4 for a central and a forward x F bin.…”

“…Notice that the K factor to be applied to these calculations is 2 for GRV LO 92 and 1.5 to GRV LO 94. We show our leading order calculations with data from experiment FNAL-537 [36]. We use a K factor of 2 for these pion induced reactions.…”

The dilepton-production cross section in principal value resummation

“…This Fermilab experiment [18] involved collisions of an antiproton beam with a tungsten (W) target at √ s = 15.4 GeV. Again, dimuon production events which fell in the positive…”