Nuclear parton densities and their uncertainties at the next-to-leading order

Abstract

Considering the nuclear reactions which involve specific features at certain regions of the x-Bjorken variable which was first observed by the EMC group, we indicate that the parton distributions in nuclei are not simply as the parton densities in nucleons. In addition to the most commonly analyzed data sets for deep-inelastic scattering of charged leptons off nuclei, we also analyze the Drell-Yan dilepton production. We investigate parametrizations of nuclear parton distributions at the next-to-leading order (NLO) of α s . Finally, optimum nuclear structure functions are determined by a χ 2 analysis of experimental data for the nuclear structure function F A 2 /F A 2 and Drell-Yan cross-section ratios. The related uncertainties are estimated by the Hessian method. Our results are in good agreement with the available experimental data and better than the results of some other fitting parametrization methods.

EMC effect in the next-to-leading order approximation based on the Laplace transformation

“…Furthermore, we extract the analytical solutions for the nuclear structure function F A 2 (x, Q 2 ) as the sum of a flavor singlet F S 2 (x, Q 2 ), gluon F g 2 (x, Q 2 ), and a flavor non-singlet F NS 2 (x, Q 2 ). The obtained results indicate an excellent agreement with the DIS data as well as those obtained by other methods such as the fit to F A ′ 2 /F A 2 structure function ratio performed by the AT12 model [23].…”

“…7 and they have been compared with the results from the DIS data in nuclear reactions NMC [45] as well as EMC [46], E139 [44] and E665 [47] collaborations. The corresponding results for the EMC effect in 40 Ca structure function in Laplace s-space and Mellin moment space [23] at Q 2 = 4 GeV 2 have been presented inn Fig. 8 and compared with the results from DIS data in nuclear reactions by NMC [43] and EMC [48], E139 [44], and E665 [47] Collaborations.…”

“…In order to be able to do the required calculations for iron (Fe), calcium (Ca), carbon (C), helium (He) and deuterium (D) nuclei, we need the relevant weight functions which are presented in the following relations in which the effects of shadowing, anti-shadowing, fermi motion and the EMC regions are included [23]:…”

“…3, the parton distribution functions inside 56 F e nucleus at Q 2 0 = 2 GeV 2 are presented. compared with the AT12 model [23] and DIS data of NMC [43] and E139 [44] Collaborations.…”

“…Finally, the non-singlet contribution for three active (light) flavours is given by compared with the AT12 model [23] and DIS data of NMC [45], EMC [46], E139 [44] and E665 [47] Collaborations. compared with the AT12 model [23] and DIS data of BCDMS [49], E140 [50], E139 [44] and finally E87 [51] Collaborations. where C (1) q (s) and C Explicit expressions for the corresponding Wilson coefficients functions are as follow [19]:…”