Unintegrated parton distributions and prompt photon hadroproduction
نویسنده
چکیده
We introduce a general expression which enables the parton distribution, unintegrated over the parton transverse momentum, to be obtained from the conventional parton densities. We use the formalism to study the effects of the transverse momentum qt of the incoming partonic system on the calculation of the transverse momentum spectra of prompt photons produced in high energy pp and pp̄ collisions. For the purposes of illustration, we use the double logarithm approximation. For large qt we calculate the effect directly from the perturbative formalism, whereas for small qt we bound the effect using two extreme hypotheses. In both qt domains we find that the shapes of the prompt photon spectra are not significantly modified, although the cross sections are enhanced.
منابع مشابه
Prompt photon hadroproduction at high energies in off-shell gluon-gluon fusion
The amplitude for production of a single photon associated with quark pair in the fusion of two off-shell gluons is calculated. The matrix element found is applied to the inclusive prompt photon hadroproduction at high energies in the framework of kT -factorization QCD approach. The total and differential cross sections are calculated in both central and forward pseudo-rapidity regions. The con...
متن کاملUnintegrated gluon distributions in a photon from the CCFM equation in the single loop approximation
The system of CCFM equations for unintegrated parton distributions in a photon is considered in the single loop approximation. We include quarks and non-singular parts of the splitting functions in the corresponding evolution equations. We solve the system of CCFM equations utilising the transverse coordinate representation which diagonalises these equations in the single loop approximation. Th...
متن کاملUnintegrated double parton distributions
We present the construction of unintegrated double parton distribution functions which include dependence on transverse momenta of partons. We extend the formulation which was used to obtain the single unintegrated parton distributions from the standard, integrated parton distribution functions. Starting from the homogeneous part of the evolution equations for the integrated double parton distr...
متن کاملUnintegrated generalised parton distributions
We show how the generalised (or skewed) parton distributions of the proton,H(x, ξ; k t , μ ), unintegrated over the partonic transverse momenta, can be calculated from the known conventional parton distributions, q(x, μ) and g(x, μ), for small values of the skewedness parameter ξ. We demonstrate the procedure by numerically evaluating the skewed unintegrated gluon. We also provide a simple appr...
متن کاملUnintegrated parton distributions and inclusive jet production at HERA
We describe how unintegrated parton distributions can be calculated from conventional integrated distributions. We extend and improve the ‘last-step’ evolution approach, and explain why doubly-unintegrated parton distributions are necessary. We generalise ktfactorisation to (z, kt)-factorisation. We apply the formalism to inclusive jet production in deep-inelastic scattering, mainly at leading ...
متن کامل