Interplay of threshold resummation and hadron mass corrections in deep inelastic processes

Abstract

We discuss hadron mass corrections and threshold resummation for deep-inelastic scattering ℓN → ℓ ′ X and semi-inclusive annihilation e + e − → hX processes, and provide a prescription how to consistently combine these two corrections respecting all kinematic thresholds. We find an interesting interplay between threshold resummation and target mass corrections for deep-inelastic scattering at large values of Bjorken xB. In semi-inclusive annihilation, on the contrary, the two considered corrections are relevant in different kinematic regions and do not affect each other. A detailed analysis is nonetheless of interest in the light of recent high precision data from BaBar and Belle on pion and kaon production, with which we compare our calculations. For both deep inelastic scattering and single inclusive annihilation, the size of the combined corrections compared to the precision of world data is shown to be large. Therefore, we conclude that these theoretical corrections are relevant for global QCD fits in order to extract precise parton distributions at large Bjorken xB, and fragmentation functions over the whole kinematic range.

Strange quark suppression from a simultaneous Monte Carlo analysis of parton distributions and fragmentation functions

“…where z h ≡ p · p h /p · q is the light-cone fraction of the virtual photon's momentum carried by h. We use data on π ± [42] and K ± production [43] taken by the COM-PASS Collaboration on a deuterium target over the range 0.2 < z h < 0.8, with the low-z h cut chosen to exclude contributions from target fragmentation and the high-z h cut to avoid exclusive channels and complications from threshold resummation effects [44,45]. Lower energy SIDIS data from HERMES on hydrogen and deuterium [28,29,46] were also considered.…”

A determination of the fragmentation functions of pions, kaons, and protons with faithful uncertainties

“…While all-order resummation techniques have been developed both at small [70][71][72][73] and large z [74][75][76][77][78], their inclusion is beyond the scope of the present work. However, we note that the impact of small-and large-z unresummed logarithms is alleviated when higher-order corrections are included in the perturbative expansion of splitting and coefficient functions.…”

Effective field theory approach to open heavy flavor production in heavy-ion collisions

“…Including the off-diagonal contribution, we can now write the in-medium fragmentation function D H,med In this section we present numerical calculations for open heavy meson production in proton-proton collisions, pp → HX. We choose to work within the ZM-VFNS [73,74], in which one neglects all the heavy quark mass corrections in the partonic hard-scattering functions [75,76]. Thus, this approximation is justified for µ m c,b , where µ is the characteristic scale of the process and m c,b are the charm and bottom quark masses respectively.…”