Glauber gluons in pion-induced Drell-Yan processes

Abstract

We point out that the existence of Glauber gluons in the $k_T$ factorization theorem can account for the violation of the Lam-Tung relation, namely, the anomalous lepton angular distribution, observed in pion-induced Drell-Yan processes. Radiations, that balance the lepton-pair transverse momentum, cause the responsible spin-transverse-momentum correlation in the Glauber-gluon background. It is argued that the Glauber effect is significant in the pion due to its unique role of being a Nambu-Goldstone boson and a $q\bar{q}$ bound state simultaneously. This mechanism is compared to other resolutions in the literature by means of vacuum effects and Boer-Mulders functions. We propose to discriminate the above resolutions by measuring the $p\bar{p}$ Drell-Yan process at GSI and J-PARC.

power counting of Glauber divergences added; more references included

References in corpus (10)

• k_T factorization is violated in production of high-transverse-momentum particles in hadron-hadron collisions
• Branching ratios and direct CP asymmetries in $D\to PP$ decays
• Measurement of Angular Distributions of Drell-Yan Dimuons in p + d Interaction at 800 GeV/c
• First Measurement of the Angular Coefficients of Drell-Yan $e^{+}{e}^{-}$ pairs in the Z Mass Region from $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV
• Measurement of Angular Distributions of Drell-Yan Dimuons in $p+p$ Interactions at 800 GeV/c
• Implication of the B -> rho rho data on the B -> pi pi puzzle
• Azimuthal asymmetries in unpolarized Drell-Yan processes and the Boer-Mulders distributions of antiquarks
• Transverse momentum dependence of the angular distribution of the Drell-Yan process
• Angular distribution of leptons from the decay of massive vector bosons
• On the $\pi$ and $K$ as $q\bar{q}$ Bound States and Approximate Nambu-Goldstone Bosons

Cited by in corpus (7)

• Pion TMDs in light-front constituent approach, and Boer-Mulders effect in the pion-induced Drell-Yan process
• Interpretation of Angular Distributions of $Z$-boson Production at Colliders
• Glauber gluons in spectator amplitudes for $B\to \pi M$ decays
• The pionic Drell-Yan process: a brief survey
• Investigation of pionic contribution in the lepton and anti-lepton production cross section in p-Cu and p-Pt collision
• Glauber gluons in pion-induced Drell-Yan processes revisited
• Nucleon partonic spin structure to be explored by the unpolarized Drell-Yan program of COMPASS experiment at CERN