Glauber gluons in pion-induced Drell-Yan processes revisited

Abstract

We reanalyze the anomalous angular distribution of lepton pairs produced in a pion-induced Drell-Yan process by taking into account the Glauber gluon effect in the $k_T$ factorization theorem. Compared to the previous study, we adopt the realistic parton distribution functions (PDFs) for a proton from the CTEQ and for a pion from the xFitter, include the QCD evolutions of the strong coupling and the PDFs, and integrate the differential cross section over the kinematic regions for the NA10, E615 and COMPASS experiments. These improvements then allow rigorous confrontations of theoretical results with the data. It is shown that the lepton angular distribution and the violation of the Lam-Tung relation measured in all the above experiments can be well accommodated with a single Glauber phase. We illustrate the Glauber effect in the geometric picture for a Drell-Yan process, and its distinction from the conventional Boer-Mulders mechanism. The observables are pointed out, which can be used to discriminate the two proposals, when data become more precise.

12 pages, 7 figures, discussion on rotational-invariant observables and more references added, journal version

References in corpus (17)

• 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
• Model-independent constraints on the shape parameters of dilepton angular distributions
• Angular distribution of leptons from the decay of massive vector bosons
• Glauber gluons in spectator amplitudes for $B\to \pi M$ decays
• Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes
• On the $\pi$ and $K$ as $q\bar{q}$ Bound States and Approximate Nambu-Goldstone Bosons
• Transverse-momentum-dependent wave functions with Glauber gluons in $B\to \pi \pi$, $\rho \rho$ decays
• Rotation-invariant observables as Density Matrix invariants
• Dependencies of Lepton Angular Distribution Coefficients on the Transverse Momentum and Rapidity of$Z$ Bosons Produced in $pp$ Collisions at LHC
• Glauber gluons in annihilation amplitudes for heavy meson decays