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Electroweak corrections to hadron collider processes become relevant at the level of precision reached by present-day LHC experiments. We provide a preliminary discussion of the impact of electroweak corrections to parton distributions,…

High Energy Physics - Phenomenology · Physics 2013-11-12 Stefano Carrazza

We review the current status of Parton Distribution Function (PDF) determinations for unpolarized and longitudinally polarized protons and for unpolarized nuclei, which are probed by high-energy hadronic scattering in perturbative Quantum…

High Energy Physics - Phenomenology · Physics 2020-02-18 Jacob J. Ethier , Emanuele R. Nocera

A determination of Parton Distribution Functions (PDFs) from a global fit to a dataset including measurements from the LHC has been performed. The determinations have been carried out according to the NNPDF methodology, leading to a fit…

High Energy Physics - Phenomenology · Physics 2014-11-04 Nathan Hartland

We show how the photon input parton distribution function (PDF) may be calculated with good accuracy, and used in an extended DGLAP global parton analysis in which the photon is treated as an additional point-like parton. The uncertainty of…

High Energy Physics - Phenomenology · Physics 2015-06-19 A. D. Martin , M. G. Ryskin

Building upon the most recent CT18 global fit, we present a new calculation of the photon content of the proton based on an application of the LUX formalism. In this work, we explore two principal variations of the LUX ansatz. In one…

High Energy Physics - Phenomenology · Physics 2023-02-14 Keping Xie , T. J. Hobbs , Tie-Jiun Hou , Carl Schmidt , Mengshi Yan , C. -P. Yuan

In the last decade, and even more so in the last few years, our knowledge of the internal structure of the proton has become more accurate and precise thanks to the large amount of data available and developments in theory and methodology.…

High Energy Physics - Phenomenology · Physics 2026-02-09 Thomas Cridge , Juan Cruz Martinez , Joey Huston

We present the MSHT20qed_an3lo parton distribution functions (PDFs). These result from the first global PDF analysis to combine QED and approximate N${}^3$LO (aN${}^3$LO) QCD corrections in the theoretical calculation of the PDF evolution…

High Energy Physics - Phenomenology · Physics 2024-07-31 T. Cridge , L. A. Harland-Lang , R. S. Thorne

The parton distribution functions (PDFs) of the proton, a necessary input to almost all theory predictions for hadron colliders, are reviewed in this document. An introduction to the PDF determination by global analyses of the main PDF…

High Energy Physics - Phenomenology · Physics 2019-08-14 Ringaile Placakyte

By working in QED, we obtain the electron, positron, and photon Parton Distribution Functions (PDFs) of the unpolarised electron at the next-to-leading logarithmic accuracy. The PDFs account for all of the universal effects of initial-state…

High Energy Physics - Phenomenology · Physics 2022-07-26 V. Bertone , M. Cacciari , S. Frixione , G. Stagnitto

The unprecedented precision of experimental measurements at the Large Hadron Collider (LHC) and the increased statistics that will be reached in the High-Luminosity phase of the LHC (HL-LHC) are pushing the phenomenology community to a new…

High Energy Physics - Phenomenology · Physics 2024-04-15 Maria Ubiali

The description of the structure of proton is fundamental in order to describe the standard model processes at the LHC as well as for the searching of New Physics. Quantum fluctuations imply the presence of photons and leptons inside the…

High Energy Physics - Phenomenology · Physics 2023-05-10 Victor P. Goncalves , Daniel E. Martins

We introduce a generalized definition of parton distribution functions (PDFs) for a more consistent all-order treatment of power corrections. We present a new set of modified DGLAP evolution equations for nuclear PDFs, and show that the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Zhong-Bo Kang , Jian-Wei Qiu

We compute the Parton Distribution Functions (PDFs) of the unpolarised muon for the leptons, the photon, the light quarks, and the gluon. We discuss in detail the issues stemming from the necessity of evaluating the strong coupling constant…

High Energy Physics - Phenomenology · Physics 2023-12-14 Stefano Frixione , Giovanni Stagnitto

The electron, positron, and photon Parton Distribution Functions (PDFs) of the unpolarised electron have recently been computed at the next-to-leading logarithmic accuracy in QED, by adopting the $\overline{\rm MS}$ factorisation scheme. We…

High Energy Physics - Phenomenology · Physics 2021-12-22 Stefano Frixione

Recently, two photon PDF sets based on implementations of the LUX ansatz into the CT18 global analysis were released. In CT18lux, the photon PDF is calculated directly using the LUX master formula for all scales, $\mu$. In an alternative…

High Energy Physics - Phenomenology · Physics 2021-07-30 Keping Xie , T. J. Hobbs , Tie-Jiun Hou , Carl Schmidt , Mengshi Yan , C. -P. Yuan

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 discuss the effect of QED corrections in the evolution of polarized parton distributions. We solve the corresponding evolution equations exactly to ${\cal O}(\alpha )$ and ${\cal O}(\alpha_s^2)$ in Mellin $N$-space, extending the…

High Energy Physics - Phenomenology · Physics 2024-10-30 Daniel de Florian , Lucas Palma Conte

The parton distribution functions (PDFs) which characterize the structure of the proton are currently one of the dominant sources of uncertainty in the predictions for most processes measured at the Large Hadron Collider (LHC). Here we…

It has become apparent in recent years that it is important, notably for a range of physics studies at the Large Hadron Collider, to have accurate knowledge on the distribution of photons in the proton. We show how the photon parton…

High Energy Physics - Phenomenology · Physics 2016-12-19 Aneesh Manohar , Paolo Nason , Gavin P. Salam , Giulia Zanderighi

We calculate the electron structure functions, aka parton distribution functions (PDFs), to NNLO in QED. The calculation is based on the definition of the PDFs in terms of operator matrix elements in soft collinear effective theory (SCET)…

High Energy Physics - Phenomenology · Physics 2025-12-01 Maximilian Stahlhofen