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Tomasz Pietrycki

Publications and source records attributed to Tomasz Pietrycki.

5 recordsLinked to original sources
arXiv2008

Inclusive photon production and photon-jet correlations in hadronic collisions

We compare results of $k_t$-factorization approach and next-to-leading order collinear-factorization approach for photon-jet correlations in $pp$ and $p \bar p$ collisions at RHIC, Tevatron and LHC energies. We discuss correlations in azimuthal angle between photon and jet as well as correlations in two-dimensional space of photon and jet transverse momenta. Different unintegrated gluon/parton distributions are used in the $k_t$-factorization approach. The results depend on UGDF/UPDF used. The collinear NLO $2 \to 3$ contributions dominate over $k_t$-factorization cross section at small relative azimuthal angles as well as for asymmetric transverse momentum configurations.

hep-ph↗
arXiv2007

Dijet and photon-jet correlations in proton-proton collisions at RHIC

We discuss correlations in azimuthal angle as well as correlations in two-dimensional space of transverse momenta of two jets as well as photon and jet. Some $k_t$-factorization subprocesses are included for the first time in the literature. Different unintegrated gluon/parton distributions are used in the $k_t$-factorization approach. The results depend on UGDF/UPDF used. The collinear NLO $2 \to 3$ contributions dominate over $k_t$-factorization cross section at small relative azimuthal angles as well as for asymmetric transverse momentum configurations.

nucl-th↗
arXiv2007

Photon-jet correlations in $pp$ and $p \bar p$ collisions

We compare results of the $k_t$-factorization approach and the next-to-leading order collinear-factorization approach for photon-jet correlations in $pp$ and $p \bar p$ collisions at RHIC and Tevatron energies. We discuss correlations in the azimuthal angle as well as in the two-dimensional space of transverse momentum of photon and jet. Different unintegrated parton distributions (UPDF) are included in the $k_t$-factorization approach. The results depend on UPDFs used. The standard collinear approach gives cross section comparable to the $k_t$-factorization approach. For correlations of the photon and any jet the NLO contributions dominate at relatively small azimuthal angles as well as for asymmetric transverse momenta. For correlations of the photon with the leading jet (the one having the biggest transverse momentum) the NLO approach gives zero contribution at $ϕ_{-} < π/2$ which opens a possibility to study higher-order terms and/or UPDFs in this region.

hep-ph↗
arXiv2006

Direct Photon Production in $pp$ and $p \bar p$ Collisions at High Energies

The invariant cross sections for direct photon production in hadron-hadron collisions are calculated for several initial energies (SPS, ISR, S$p \bar p$S, RHIC, Tevatron, LHC) including initial parton transverse momenta within the formalism of unintegrated parton distributions (UPDF). Kwieciński UPDFs provide very good description of all world data, especially at SPS and ISR energies. Inclusion of the QCD evolution effects and especially their effect on initial parton transverse momenta allowed to solve the long-standing problem of understanding the low energy and low transverse momentum data.

hep-ph↗
arXiv2005

Resolved photon and multi-component model for $γ^*$p and $γ^* γ^*$ scattering at high energies

We generalize our previous model for $γ^* p$ scattering to $γγ$ scattering. In the latter case the number of components naturally grows. When using the model parameters from our previous $γ^* p$ analysis the model cross section for $γγ$ scattering is larger than the corresponding LEP2 experimental data by more than a factor of two. However, performing a new simultaneous fit to $γ^* p$ and $γγ$ total cross section we can find an optimal set of parameters to describe both processes. We propose new measures of factorization breaking for $γ^* γ^*$ collisions and present results for our new model.

hep-ph↗