Leading twist theory of nuclear shadowing: predictions for nuclear PDFs

Leading twist theory of nuclear shadowing

L. Frankfurt, V. Guzey and M. Strikman, arXiv:1106.2091 [hep-ph], accepted to Phys. Rept.
V. Guzey and M. Strikman, Phys. Lett. B 687, 167 (2010)
L. Frankfurt, V. Guzey and M. Strikman, Phys. Rev. D 71, 054001 (2005)
L. Frankfurt and M. Strikman, Eur. Phys. J. A 5, 293 (1999)

      Last updated: Sep 2011

Overview of the formalism

Predictions for nuclear PDFs

Predictions for impact parameter dependent nuclear PDFs

Nuclear diffractive PDFs





Back to V.Guzey at JLab

Predictions for nuclear parton distributions

The leading twist theory of nuclear shadowing enables one to predict the x, Q2, and impact parameter b dependence of sea quark and gluon parton distributions in nuclei [both at the next-to-leading (NLO) and leading orders (LO)]. The covered kinematic range is the following: 10-5 ≤ x ≤ 1, 4 ≤ Q2 ≤ 16,000 GeV2, and 0 ≤ b ≤ 5-10 fm (depending on the nucleus). For the summary of our formalism, see Overview of the formalism .
Fortran codes and required data files with grids for nuclear PDFs can be found in the end of this page.

As we mentioned in Overview of the formalism , the essential input our approach is the value of the rescattering cross section σsoftj which is needed to model the interaction with N ≥ 3 nucleons of the nucleus. We used two models for this cross section, models 1 and 2, which correspond to higher nuclear shadowing (FGS10_H) and lower nuclear shadowing (FGS10_L), respectively.

An example of our predictions is presented below, where we plot the ratio of the nuclear to nucleon PDFs, fj/A/(Afj/N), for Pb-208 as a function of x at two values of Q2, Q2=Q02=4 GeV2 and Q2=100 GeV2.
Shadowing for Pb-208 Shadowing for Pb-208 at Q2=100 GeV2
For convenience of the use, we performed the DGLAP evolution using our predictions for nuclear PDFs at the initial scale Q02=4 GeV2 to several values of Q2 between 4 and 16,000 GeV2 and tabulated our results as a two-dimensional grid in x and Q2. Using a simple Fortran code, one can interpolate between the grid points and thus obtain:
  • fj/A/(Afj/N) and F2A/(AF2N)
  • fj/A and F2A
at any desired x and Q2 in the interval 10-5 ≤ x ≤ 1 and 4 ≤ Q2 ≤ 16,000 GeV2. The tables below contain the data files with grids and the Fortran codes for the interpolation.

Table 1. NLO fj/A/(Afj/N) and F2A/(AF2N)

Nucleus FGS10_H (model 1) FGS10_L (model 2)
C-12 Fortran code LT2009_c12_model1.f
Grid QCDEvolution_c12proton_2009_model1.dat
Fortran code LT2009_c12_model2.f
Grid QCDEvolution_c12proton_2009_model2.dat
Ca-40 Fortran code LT2009_ca40_model1.f
Grid QCDEvolution_ca40proton_2009_model1.dat
Fortran code LT2009_ca40_mode12.f
Grid QCDEvolution_ca40proton_2009_model2.dat
Pd-110 Fortran code LT2009_pd110_model1.f
Grid QCDEvolution_pd110proton_2009_model1.dat
Fortran code LT2009_pd110_mode12.f
Grid QCDEvolution_pd110proton_2009_model2.dat
Pb-208Fortran code LT2009_pb208_model1.f
Grid QCDEvolution_pb208proton_2009_model1.dat
Fortran code LT2009_pb208_model2.f
Grid QCDEvolution_pb208proton_2009_model2.dat

 

Table 2. NLO fj/A and F2A

Nucleus FGS10_H (model 1) FGS10_L (model 2)
C-12 Fortran code LT2009_c12_absolute_model1.f
Grid QCDEvolution_c12_2009_model1.dat
Fortran code LT2009_c12_absolute_model2.f
Grid QCDEvolution_c12_2009_model2.dat
Ca-40 Fortran code LT2009_ca40_absolute_model1.f
Grid QCDEvolution_ca40_2009_model1.dat
Fortran code LT2009_ca40_absolute_mode12.f
Grid QCDEvolution_ca40_2009_model2.dat
Pd-110 Fortran code LT2009_pd110_absolute_model1.f
Grid QCDEvolution_pd110_2009_model1.dat
Fortran code LT2009_pd110_absolute_mode12.f
Grid QCDEvolution_pd110_2009_model2.dat
Pb-208Fortran code LT2009_pb208_absolute_model1.f
Grid QCDEvolution_pb208_2009_model1.dat
Fortran code LT2009_pb208_absolute_model2.f
Grid QCDEvolution_pb208_2009_model2.dat