NNLO charmed-meson fragmentation functions and their uncertainties in the presence of meson mass corrections

Maral Salajegheh,Maryam Soleymaninia,S Mohammad Moosavi Nejad,Hamzeh Khanpour,S Atashbar Tehrani

doi:10.1140/epjc/s10052-019-7521-x

Abstract

The main aim of this paper is to present new sets of non-perturbative fragmentation functions (FFs) for D^0 and D^+ mesons at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) in the overline{mathrm {MS}} factorization scheme with five massless quark flavors. This new determination of FFs is based on the QCD fit to the OPAL experimental data for hadron production in the electron-positron single-inclusive annihilation (SIA). We discuss in detail the novel aspects of the methodology used in our analysis and the validity of obtained FFs by comparing with previous works in literature which have been carried out up to NLO accuracy. We will also incorporate the effect of charmed meson mass corrections into our QCD analysis and discuss the improvements upon inclusion of these effects. The uncertainties in the extracted FFs as well as in the corresponding observables are estimated using the “Hessian” approach. For a typical application, we use our new FFs to make theoretical predictions for the energy distributions of charmed mesons inclusively produced through the decay of unpolarized top quarks, to be measured at the CERN LHC. As a result of this analysis, suggestions are discussed for possible future studies on the current topic to consider any theory improvements and other available experimental observables.

Highlights

Introduction[14] have applied the massless scheme or zero-mass variable-flavor-number scheme (ZM-VFNS) where heavy quarks are treated as any other massless parton
At first, the numerical results obtained for the (c, b) → D0/D+ fragmentation functions (FFs) through the perturbative QCD analysis are reported at the initial scale μ0
A new determination of nonperturbative FFs for D0 and D+ mesons are presented at next-to-leading order (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) in perturbative QCD considering the hadron mass effects

Summary

Introduction

[14] have applied the massless scheme or zero-mass variable-flavor-number scheme (ZM-VFNS) where heavy quarks are treated as any other massless parton This scheme can be applied to the open production of heavy flavors, such as D and B hadrons, provided the hard energy scale characteristic for the production process is sufficiently larger than the heavy-flavors mass. In the present analysis, using the ZM-VFN scheme we focus on the hadronization of charm- and bottom-quarks into D0 and D+ mesons and provide the first QCD analysis of (c, b) → (D0, D+) FFs at NNLO accuracy in perturbative QCD. As an application of our analysis, we apply the extracted FFs to make our theoretical predictions for the energy distribution of charmed mesons produced through the top quark decays.

Objectives

Results

Conclusion