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We present NNPDFpol2.0, a new set of collinear helicity parton distribution functions (PDFs) of the proton based on legacy measurements of structure functions in inclusive neutral-current longitudinally polarised deep-inelastic scattering…

An important limitation in current fits of parton distribution functions (PDFs) is that PDF uncertainties do not include any source of theoretical uncertainty. Here we present a general method for incorporating theoretical uncertainties…

High Energy Physics - Phenomenology · Physics 2018-10-05 R. L. Pearson , C. Voisey

Parton distribution functions play a pivotal role in hadron collider phenomenology. They are non-perturbative quantities extracted from fits to available data, and their scale dependence is dictated by the DGLAP evolution equations. In this…

High Energy Physics - Phenomenology · Physics 2024-08-08 Salvador A. Ochoa-Oregon , David F. Rentería-Estrada , Roger J. Hernández-Pinto , German F. R. Sborlini , Pia Zurita

Transverse and longitudinal electroweak gauge boson parton distribution functions (PDFs) are computed in terms of deep-inelastic scattering structure functions, following the recently developed method to determine the photon PDF. The…

High Energy Physics - Phenomenology · Physics 2018-05-18 Bartosz Fornal , Aneesh V. Manohar , Wouter J. Waalewijn

We propose an analysis method for the leading-twist operator product expansion based lattice QCD determinations of the valence parton distribution function (PDF). In the first step, we determine the confidence-intervals of the leading-twist…

High Energy Physics - Lattice · Physics 2021-10-08 Nikhil Karthik , Raza Sabbir Sufian

We present a new regression model for the determination of parton distribution functions (PDF) using techniques inspired from deep learning projects. In the context of the NNPDF methodology, we implement a new efficient computing framework…

High Energy Physics - Phenomenology · Physics 2019-09-04 Stefano Carrazza , Juan Cruz-Martinez

We develop in more detail our reweighting method for incorporating new datasets in parton fits based on a Monte Carlo representation of PDFs. After revisiting the derivation of the reweighting formula, we show how to construct an unweighted…

A precise knowledge of the quark and gluon structure of the proton, encoded by the parton distribution functions (PDFs), is of paramount importance for the interpretation of high-energy processes at present and future lepton-hadron and…

We investigate the behavior of spin-dependent parton distribution functions (PDFs) at large parton momentum fractions x in the context of global QCD analysis. We explore the constraints from existing deep-inelastic scattering data, and from…

High Energy Physics - Phenomenology · Physics 2015-06-19 P. Jimenez-Delgado , H. Avakian , W. Melnitchouk

A new parametrization for the parton distribution functions with a higher flexibility in the small-$x$ region is presented. It has been implemented in the xFitter open-source PDF fitting tool, and compared to the default xFitter…

High Energy Physics - Phenomenology · Physics 2019-06-26 Francesco Giuli , Marco Bonvini

We apply a classical mathematical problem, the moment problem, with its related mathematical achievements, to the study of the parton distribution function (PDF) in hadron physics, and propose a strategy to sieve the moments of the PDF by…

High Energy Physics - Phenomenology · Physics 2023-10-27 Xiaobin Wang , Minghui Ding , Lei Chang

We determine the pion parton distribution functions (PDFs) from its light-front wave functions, obtained using the holographic Schr\"odinger equation of light-front chiral QCD combined with the 't Hooft equation in (1+1)-dimensional QCD at…

High Energy Physics - Phenomenology · Physics 2026-05-15 Jiangshan Lan , Satvir Kaur , Chandan Mondal

We discuss the recent CMS Collaboration measurement of $W^\pm$ boson production in p+Pb collisions at 8.16 TeV in terms of the constraining power on nuclear parton distribution functions (PDFs). The impact of the free-proton PDF…

High Energy Physics - Phenomenology · Physics 2022-04-13 Kari J. Eskola , Petja Paakkinen , Hannu Paukkunen , Carlos A. Salgado

Although protons are baryons with an overall vanishing lepton number, they possess a non-trivial leptonic content arising from quantum fluctuations which can be described by lepton parton distribution functions (PDFs) of the proton. These…

High Energy Physics - Phenomenology · Physics 2025-01-27 Leandro Da Rold , Anibal D. Medina , Subhojit Roy , Carlos E. M. Wagner

The photon parton distribution function (PDF) of the proton is crucial for precise comparisons of LHC cross sections with theoretical predictions. However, it was previously affected by very large uncertainties of around ${\cal O}(100\%)$…

High Energy Physics - Phenomenology · Physics 2024-08-26 Aneesh Manohar , Paolo Nason , Gavin Salam , Giulia Zanderighi

We study the potential of the LHCb 13 TeV single $W^{\pm}$ and $Z$ boson pseudo-data for constraining the parton distribution functions (PDFs) of the proton. As an example, we demonstrate the sensitivity of the LHCb 13 TeV data, collected…

High Energy Physics - Phenomenology · Physics 2021-01-26 Qilin Deng , Qundong Han , Hang Yin , Sayipjamal Dulat , Tie-Jiun Hou , C. -P. Yuan

We investigate the parton distribution function (PDF) uncertainty in the measurement of the effective weak mixing angle $\sin^2\theta_{\text{eff}}^{\ell}$ at the CERN Large Hadron Collider (LHC). The PDF-induced uncertainty is large in the…

High Energy Physics - Experiment · Physics 2021-05-26 Yao Fu , Siqi Yang , Minghui Liu , Liang Han , Tie-Jiun Hou , Carl Schmidt , Chen Wang , C. -P. Yuan

The parton distribution functions (PDFs) of the proton play a role in determining the lineshape of $Z$ and $W$ bosons produced at the LHC. In particular, the mode of the gauge boson virtuality is shifted with respect to the pole due to the…

High Energy Physics - Experiment · Physics 2020-04-27 Valerio Bertacchi , Lorenzo Bianchini , Elisabetta Manca , Gigi Rolandi , Suvankar Roy Chowdhury

In this contribution we present a status report on the recent progress towards an analysis of nuclear parton distribution functions (nPDFs) using the NNPDF methodology. We discuss how the NNPDF fitting approach can be extended to account…

High Energy Physics - Phenomenology · Physics 2018-11-15 Rabah Abdul Khalek , Jacob J. Ethier , Juan Rojo

A new QCD analysis for nuclear parton distribution functions (nPDFs) at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) is presented. The framework of the analysis, including the form of the parameterization as well as…

High Energy Physics - Phenomenology · Physics 2019-08-15 Marina Walt , Ilkka Helenius , Werner Vogelsang