Equations for many-parton distributions in quantum chromodynamics

Staśto

2018

J. High Energ. Phys.

We present detailed numerical analysis of the unintegrated double gluon distribution which includes the dependence on the transverse momenta of partons. The unintegrated double gluon distribution was obtained following the Kimber-Martin-Ryskin method as a convolution of the perturbative gluon splitting function with the collinear integrated double gluon distribution and the Sudakov form factors. We analyze the dependence on the transverse momenta, longitudinal momentum fractions and hard scales. We find that the unintegrated gluon distribution factorizes into a product of two single unintegrated gluon distributions in the region of small values of x, provided the splitting contribution is included and the momentum sum rule is satisfied.

Section: Evolution Equations For the Double Gluon Distributionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the unintegrated double gluon distribution

Elias

Staśto

2018

J. High Energ. Phys.

“…Evolution equations for the DPDFs are known in the leading logarithmic approximation (LLA) in which large powers of (α s ln(Q 2 /Λ 2 )) n are resumed to all orders in n. They were derived in [1,2,5,6] for equal hard scales, Q 1 = Q 2 ≡ Q, and for the relative momentum q = 0,…”

Section: Evolution Equations For Dpdfsmentioning

confidence: 99%

“…The latter possibility as a starting point creates more problems than answers [10,15], despite its apparent attractiveness for phenomenological modeling of the DPDF dependence on this variable. The DPDFs obey QCD evolution equations known at present in the leading logarithmic approximation [1,2,5,6,45]. These are the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP)-type evolution equations with additional nonhomogeneous terms which describe splitting of a single parton into two partons.…”

Section: Introductionmentioning

confidence: 99%

Electroweak boson production in double parton scattering

Lewandowska

2014

Phys. Rev. D

We study the W + W − and Z 0 Z 0 electroweak boson production in double parton scattering using QCD evolution equations for double parton distributions. In particular, we analyze the impact of splitting terms in the evolution equations on the double parton scattering cross sections. Unlike the standard terms, the splitting terms are not suppressed for large values of the relative momentum of two partons in the double parton scattering. Thus, they play an important role which we discuss in detail for the single splitting contribution to the cross sections under the study.

“…The evolution equations for the DPDFs are only known for q = 0 in the leading logarithmic approximation [1][2][3][6][7][8]. The first discussion of the next-to-leading corrections can be found in [10].…”

Section: Evolution Equations For Dpdfsmentioning

confidence: 99%

How to impose initial conditions for QCD evolution of double parton distributions?

Lewandowska

2014

Phys. Rev. D

Double parton distribution functions are used in the QCD description of double parton scattering. The double parton distributions evolve with hard scales through QCD evolution equations which obey nontrivial momentum and valence quark number sum rules. We describe an attempt to construct initial conditions for the evolution equations which exactly fulfill these sum rules and discuss its shortcomings. We also discuss the factorization of the double parton distributions into a product of two single parton distribution functions at small values of the parton momentum fractions.