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We discuss different approaches to photon isolation in fixed-order calculations and present a new next-to-next-to-leading order (NNLO) QCD calculation of $R_{13/8}^\gamma$, the ratio of the inclusive isolated photon cross section at 8 TeV…

High Energy Physics - Phenomenology · Physics 2019-05-22 X. Chen , T. Gehrmann , N. Glover , M. Höfer , A. Huss

Measurements of inclusive and direct photon production at mid-rapidity in pp collisions at $\sqrt{s}=2.76$ and 8 TeV are presented by the ALICE experiment at the LHC. The results are reported in transverse momentum ranges of $0.4<p_{T}<10$…

Nuclear Experiment · Physics 2019-11-11 ALICE Collaboration

Measurements of the deep-inelastic scattering (DIS) of leptons and nucleons, $e+p\to e+X$, allow the extraction of Parton Distribution Functions (PDFs) which describe the longitudinal momentum carried by the quarks, anti-quarks and gluons…

High Energy Physics - Phenomenology · Physics 2014-11-20 Laurent Schoeffel

The phenomenology of Standard Model and New Physics at hadron colliders depends critically on results from global QCD analysis for parton distribution functions (PDFs). The accuracy of the standard next-to-leading-order (NLO) global…

High Energy Physics - Phenomenology · Physics 2009-11-11 J. Huston , J. Pumplin , D. Stump , W. K. Tung

We calculate the nuclear dependence of direct photon production in hadron-nucleus collisions. In terms of a multiple scattering picture, we factorize the cross section for direct photon production into calculable short-distance partonic…

High Energy Physics - Phenomenology · Physics 2014-11-17 Xiaofeng Guo , Jianwei Qiu

Fragmentation functions (FFs) are essential non-perturbative QCD inputs for predicting hadron production cross sections in high energy scatterings. In this study, we present a joint determination of FFs for light charged hadrons through a…

High Energy Physics - Phenomenology · Physics 2024-12-20 Jun Gao , ChongYang Liu , XiaoMin Shen , Hongxi Xing , Yuxiang Zhao

The photon PDF of the proton is needed for precision comparisons of LHC cross sections with theoretical predictions. In a recent paper, we showed how the photon PDF could be determined in terms of the electromagnetic proton structure…

High Energy Physics - Phenomenology · Physics 2018-01-17 Aneesh V. Manohar , Paolo Nason , Gavin P. Salam , Giulia Zanderighi

We complete our earlier study of the "direct" part of the cross section and spin asymmetry for the photoproduction process $\gamma N\rightarrow h X$ by analysing the "resolved" contribution, for which the photon couples like a hadron…

High Energy Physics - Phenomenology · Physics 2017-11-01 Claudia Uebler , Andreas Schäfer , Werner Vogelsang

We present a study of high-$p_T$ photon and pion production in hadronic interactions, focusing on a comparison of the yields with expectations from next-to-leading order perturbative QCD (NLO pQCD). We examine the impact of phenomenological…

High Energy Physics - Phenomenology · Physics 2009-10-31 Marek Zielinski

We present numerical studies of the leading non-linear corrections to the DGLAP evolution equations of parton distribution functions (PDFs) resulting from gluon recombination, which reduce the pace of evolution at small momentum fractions…

High Energy Physics - Phenomenology · Physics 2024-06-21 Pit Duwentäster , Vadim Guzey , Ilkka Helenius , Hannu Paukkunen

Top-quark pair production at the LHC is directly sensitive to the gluon PDF at large x. While total cross-section data is already included in several PDF determinations, differential distributions are not, because the corresponding NNLO…

High Energy Physics - Phenomenology · Physics 2017-04-26 Michał Czakon , Nathan P. Hartland , Alexander Mitov , Emanuele R. Nocera , Juan Rojo

Non-perturbative QCD effects from Parton Distribution Functions (PDFs) may be constrained by using high-statistics Large Hadron Collider (LHC) data. Drell-Yan (DY) measurements in the Charged Current (CC) case provide one of the primary…

The complete details of our calculation of the NLO QCD corrections to heavy flavor photo- and hadroproduction with longitudinally polarized initial states are presented. The main motivation for investigating these processes is the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ingo Bojak

In the framework of the kt-factorization approach, the production of prompt photons in association with a heavy (charm or beauty) quarks at high energies is studied. The consideration is based on the O(\alpha \alpha_s^2) off-shell…

High Energy Physics - Phenomenology · Physics 2013-02-11 A. V. Lipatov , M. A. Malyshev , N. P. Zotov

We propose a simple and model-independent procedure to account for the impact of the nuclear modification of the gluon density as encoded in nuclear collinear PDF sets on two-to-two partonic hard processes in proton-nucleus collisions. This…

High Energy Physics - Phenomenology · Physics 2016-12-30 Jean-Philippe Lansberg , Hua-Sheng Shao

We determine the parton distribution functions (PDFs) in a next-to-next-to-leading order (NNLO) QCD-analysis of the inclusive neutral-current deep-inelastic-scattering (DIS) world data combined with the neutri{-}no-nucleon DIS di-muon data…

High Energy Physics - Phenomenology · Physics 2010-05-25 S. Alekhin , J. Blümlein , S. Klein , S. Moch

Charm production in charged-current neutrino-nucleus deep-inelastic scattering (DIS), measured through dimuon final states, remains an important constraint of strangeness in global analyses of parton distribution functions (PDFs). This…

High Energy Physics - Phenomenology · Physics 2026-03-11 Ilkka Helenius , Hannu Paukkunen , Sami Yrjänheikki

We propose a method which allows the inclusion of exclusive heavy vector-meson production data at low $x$ in future global parton analyses. As an example we perform a study within xFitter to determine the gluon parton distribution function…

High Energy Physics - Phenomenology · Physics 2025-01-29 C. A. Flett , A. D. Martin , M. G. Ryskin , T. Teubner

We compare the cross section for exclusive $J/\psi$ photoproduction calculated at NLO in the collinear factorization approach with HERA and LHCb data. Using the optimum scale formalism together with the subtraction of the low $k_t<Q_0$…

High Energy Physics - Phenomenology · Physics 2020-05-20 Chris A. Flett , Stephen P. Jones , Alan D. Martin , Misha G. Ryskin , Thomas Teubner

The computation of the NLO QCD corrections to the cross sections for W+W- gamma and ZZgamma production in hadronic collisions is presented. We consider the case of a real photon in the final state, but include full leptonic decays of the W…

High Energy Physics - Phenomenology · Physics 2014-11-20 G. Bozzi , F. Campanario , V. Hankele , D. Zeppenfeld