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We present the MCscales approach for incorporating scale uncertainties in parton distribution functions (PDFs). The new methodology builds on the Monte Carlo sampling for propagating experimental uncertainties into the PDF space that…

High Energy Physics - Phenomenology · Physics 2023-03-27 Zahari Kassabov , Maria Ubiali , Cameron Voisey

We present new sets of nuclear parton distribution functions (nPDFs) at next-to-leading order and next-to-next-to-leading order in perturbative QCD. Our analyses are based on deeply inelastic scattering data with charged-lepton and neutrino…

High Energy Physics - Phenomenology · Physics 2022-06-09 Ilkka Helenius , Marina Walt , Werner Vogelsang

Precision determinations of Standard Model (SM) Electro-Weak (EW) parameters at the Large Hadron Collider (LHC) are dominated by uncertainties due to Parton Distribution Functions (PDFs). Reweighting and profiling techniques are routinely…

High Energy Physics - Phenomenology · Physics 2021-05-26 Juri Fiaschi , Francesco Giuli , Francesco Hautmann , Stefano Moretti

Double parton distribution functions (dPDFs), measurable in hadron-hadron collisions and encoding information on how partons inside a proton are correlated among each other, could represent a new tool to explore the three dimensional…

High Energy Physics - Phenomenology · Physics 2017-04-03 Matteo Rinaldi , Sergio Scopetta , Vicente Vento , Marco Traini , Federico Alberto Ceccopieri

We review the next generation global PDF sets: NNPDF3.0, MMHT14 and CT14. We describe the global datasets, particularly the new data from LHC Run 1, recent developments in QCD theory and PDF methodology, improvements in combination and…

High Energy Physics - Phenomenology · Physics 2016-04-20 Richard D. Ball

A new and simple statistical approach is performed to calculate the parton distribution functions (PDFs) of the nucleon in terms of light-front kinematic variables. We do not put in any extra arbitrary parameter or corrected term by hand,…

High Energy Physics - Phenomenology · Physics 2009-03-12 Yunhua Zhang , Lijing Shao , Bo-Qiang Ma

Global perturbative QCD analyses, based on large data sets from e-p and hadron collider experiments, provide tight constraints on the parton distribution function (PDF) in the proton. The extension of these analyses to nuclear parton…

High Energy Physics - Phenomenology · Physics 2011-04-07 Paloma Quiroga-Arias , José Guilherme Milhano , Urs Achim Wiedemann

The LHC has recently released precise measurements of the transverse momentum distribution of the Z-boson that provide a unique constraint on the structure of the proton. Theoretical developments now allow the prediction of these…

High Energy Physics - Phenomenology · Physics 2017-09-13 Radja Boughezal , Alberto Guffanti , Frank Petriello , Maria Ubiali

In this article we present a review of the structure of the proton and the current status of our knowledge of the parton distribution functions (PDFs). The lepton-nucleon scattering experiments which provide the main constraints in PDF…

High Energy Physics - Experiment · Physics 2013-03-20 Emmanuelle Perez , Eram Rizvi

We illustrate how electron Parton Distribution Functions (PDFs) with next-to-leading collinear logarithmic accuracy must be employed in the context of perturbative predictions for high-energy $e^+e^-$-collision processes. In particular, we…

High Energy Physics - Phenomenology · Physics 2022-09-23 V. Bertone , M. Cacciari , S. Frixione , G. Stagnitto , M. Zaro , X. Zhao

We show that the parton distribution functions (PDF) described by the statistical model have very interesting physical properties which help to understand the structure of partons. The role of the quark helicity components is emphasized as…

High Energy Physics - Phenomenology · Physics 2015-09-28 Claude Bourrely

We reexamine the dominant contribution of parton distribution function (PDF) uncertainties to the W mass measurement, and determine their contribution is +-39(30) MeV when running the Large Hadron Collider at 7(13) TeV. We find that…

High Energy Physics - Phenomenology · Physics 2015-08-19 Zack Sullivan , Seth Quackenbush

Determinations of the proton's collinear parton distribution functions (PDFs) are emerging with growing precision due to increased experimental activity at facilities like the Large Hadron Collider. While this copious information is…

High Energy Physics - Phenomenology · Physics 2019-01-24 Bo-Ting Wang , T. J. Hobbs , Sean Doyle , Jun Gao , Tie-Jiun Hou , Pavel M. Nadolsky , Fredrick I. Olness

The choice of data that enters a global QCD analysis can have a substantial impact on the resulting parton distributions and their predictions for collider observables. One of the main reasons for this has to do with the possible presence…

High Energy Physics - Phenomenology · Physics 2014-09-11 Juan Rojo

Modern analysis on parton distribution functions (PDFs) requires calculations of the log-likelihood functions from thousands of experimental data points, and scans of multi-dimensional parameter space with tens of degrees of freedom. In…

High Energy Physics - Phenomenology · Physics 2022-08-24 DianYu Liu , ChuanLe Sun , Jun Gao

Reliable knowledge of parton distribution functions is crucial for many searches for new physics signals in the next generation of experiments. Presently, there remain a number of open questions regarding the PDF's and their uncertainties.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Fredrick Olness

We present a set of parton distribution functions (PDFs), based on the NNPDF2.3 set, which includes a photon PDF, and QED contributions to parton evolution. We describe the implementation of the combined QCD+QED evolution in the NNPDF…

We present an analysis of parton distribution functions (PDFs) of the proton using Markov Chain Monte Carlo (MCMC) methods. The MCMC approach naturally implements Bayes' theorem and thus provides a means to directly sample the underlying…

High Energy Physics - Phenomenology · Physics 2026-03-31 Peter Risse , Nasim Derakhshanian , Tomas Jezo , Karol Kovarik , Aleksander Kusina

We provide an analysis of the x-dependence of the bare unpolarized, helicity and transversity iso-vector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The x-dependence of the…

Parton distribution functions (PDFs) at large $x$ are challenging to extract from experimental data, yet they are essential for understanding hadron structure and searching for new physics beyond the Standard Model. Within the framework of…

High Energy Physics - Phenomenology · Physics 2025-03-03 Xiangdong Ji , Yizhuang Liu , Yushan Su , Rui Zhang