Unpolarized Dihadron Fragmentation Functions in Nonlocal Chiral Quark Model

Abstract

We have calculated the unpolarized dihadron fragmentation functions (uDiFFs) of pions and kaons using the nonlocal chiral-quark model (NLChQM) and evolved our results to the transferred momentum scale Q 2 =4GeV 2 by the QCD evolution equations. These uDiFFs have also been computed in the Nambu-Jona-Lasinio-jet (NJL-jet) model for the sake of comparison. We find that there is substantial difference between the results of these two models. Furthermore, the DiFFs of u → π + π − and g → π + π − at Q 2 = 109 GeV 2 in these two models are presented in comparison with the parametrizations fitted by the Monte Carlo event generator JETSET.

Parton fragmentation functions

“…This observation is in line with the output from the PYTHIA event generator and the general philosophy of [135]. An independent study of the unpolarized DiFF D h 1 h 2 /q 1 in the Nambu-Jona-Lasinio model was reported in [551]. The results do not agree with the earlier calculation in Ref.…”

“…In the same work also a nonlocal chiral quark model was used. The numerical results from these two models were found to differ significantly [551]. We also mention that very recently the unpolarized gluon FF D h/g 1 was studied in the Nambu-Jona-Lasinio model [552].…”

“…Dedicated studies of TMD FFs can be found in [564,544,565], including a discussion on how model-independent constraints such as the Schäfer-Teryaev sum rule [138,137] can be satisfied in such a picture. Related calculations on DiFFs can be found in [549,550,566,551]. The general aim of such studies is to get a quantitative description of FFs which contains as few parameters as possible by computing single-hadron emission based on a Lagrange density.…”

Empirical estimate of the unpolarized dihadron fragmentation functions

“…(4). The dashed lines represent the result the nonlocal chiral quark model [39]. The dotted lines represent the result of the NLJ model [39].…”

“…The dashed lines represent the result the nonlocal chiral quark model [39]. The dotted lines represent the result of the NLJ model [39]. These figures are differentiated from their corresponding z 1 values.…”