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The goal of this study is to determine a set of diffractive parton distribution function (diffractive PDFs) from a QCD analysis of all available and up-to-date diffractive deep inelastic scattering (diffractive DIS) data sets from HERA $ep$…

High Energy Physics - Phenomenology · Physics 2019-04-02 Hamzeh Khanpour

We develop a methodology for the construction of a Hessian representation of Monte Carlo sets of parton distributions, based on the use of a subset of the Monte Carlo PDF replicas as an unbiased linear basis, and of a genetic algorithm for…

High Energy Physics - Phenomenology · Physics 2015-09-02 Stefano Carrazza , Stefano Forte , Zahari Kassabov , Jose Ignacio Latorre , Juan Rojo

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…

We present a next-to-leading order (NLO) global DGLAP analysis of nuclear parton distribution functions (nPDFs) and their uncertainties. Carrying out an NLO nPDF analysis for the first time with three different types of experimental input…

High Energy Physics - Phenomenology · Physics 2009-04-22 K. J. Eskola , H. Paukkunen , C. A. Salgado

We review the current status of spin-averaged and spin-dependent parton distribution functions (PDFs) of the nucleon. After presenting the formalism used to fit PDFs in modern global data analyses, we discuss constraints placed on the PDFs…

High Energy Physics - Phenomenology · Physics 2015-06-16 P. Jimenez-Delgado , W. Melnitchouk , J. F. Owens

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

Global QCD analyses of nuclear parton distribution functions (nPDFs) have traditionally relied on the Hessian method for uncertainty estimation. However, the inherent Gaussian approximation and reliance on local curvature often prove…

High Energy Physics - Phenomenology · Physics 2026-03-16 N. Derakhshanian , P. Risse , T. Jezo , M. Klasen , K. Kovarik , A. Kusina

At large values of $x$ the parton distribution functions (PDFs) of the proton are poorly constrained and there are considerable variations between different global fits. Data at such high $x$ have already been published by the ZEUS…

High Energy Physics - Experiment · Physics 2021-07-14 Ritu Aggarwal

In this article we obtain a new set of nuclear parton distribution functions (nuclear PDFs) at next-to-leading order and next-to-next-to-leading order accuracy in perturbative QCD. The common nuclear deep-inelastic scattering (DIS) data…

High Energy Physics - Phenomenology · Physics 2021-08-17 Hamzeh Khanpour , Maryam Soleymaninia , S. Atashbar Tehrani , Hubert Spiesberger , Vadim Guzey

The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering experimental results. It enables us to improve the description…

High Energy Physics - Phenomenology · Physics 2017-04-05 Jacques Soffer , Claude Bourrely

The current analysis aims to present the results of a QCD analysis of diffractive parton distribution functions (diffractive PDFs) at next-to-leading order (NLO) accuracy in perturbative QCD. In this new determination of diffractive PDFs,…

High Energy Physics - Phenomenology · Physics 2019-09-20 Atefeh Maktoubian , Hossein Mehraban , Hamzeh Khanpour , Muhammad Goharipour

We examine the sources of parton distribution errors in the $W$ mass measurement, and point out shortcomings in the existing literature. Optimistic assumptions about strategies to reduce the error by normalizing to $Z$ observables are…

High Energy Physics - Phenomenology · Physics 2015-08-26 Seth Quackenbush , Zack Sullivan

This paper presents a novel approach for propagating uncertainties in dynamical systems building on high-order Taylor expansions of the flow and moment-generating functions (MGFs). Unlike prior methods that focus on Gaussian distributions,…

Space Physics · Physics 2025-04-08 Giacomo Acciarini , Nicola Baresi , David Lloyd , Dario Izzo

We present the first lattice results on isovector unpolarized and longitudinally polarized parton distribution functions (PDFs) at physical pion mass. The PDFs are obtained using the large-momentum effective field theory (LaMET) framework…

High Energy Physics - Lattice · Physics 2018-09-12 Huey-Wen Lin , Jiunn-Wei Chen , Tomomi Ishikawa , Jian-Hui Zhang

We study an influence of precise data on uncertainty of polarized parton distribution functions. This analysis includes the SLAC-E155 proton target data which are precise measurements. Polarized PDF uncertainties are estimated by using the…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Hirai

In this paper, conventional Global QCD analysis is generalized to produce parton distributions optimized for use with event generators at the LHC. This optimization is accomplished by combining the constraints due to existing…

High Energy Physics - Phenomenology · Physics 2015-03-13 Hung-Liang Lai , Joey Huston , Stephen Mrenna , Pavel Nadolsky , Daniel Stump , Wu-Ki Tung , C. -P. Yuan

We report global analysis results of experimental data for nuclear structure-function ratios F_2^A/F_2^{A'} and proton-nucleus Drell-Yan cross-section ratios sigma_{DY}^{pA}/sigma_{DY}^{pA'} in order to determine optimum parton distribution…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Hirai , S. Kumano , T. -H. Nagai

We study the uncertainties of quantum mechanical observables, quantified by the standard deviation (square root of variance) in Haar-distributed random pure states. We derive analytically the probability density functions (PDFs) of the…

Quantum Physics · Physics 2022-07-22 Lin Zhang , Jinping Huang , Jiamei Wang , Shao-Ming Fei

Accurate Standard Model predictions of proton-proton collisions are essential for interpreting the current and forthcoming experimental measurements from high-energy colliders. The quest for physics beyond the Standard Model is in fact…

High Energy Physics - Phenomenology · Physics 2025-04-09 Giacomo Magni

We present NNPDF3.0, the first set of parton distribution functions (PDFs) determined with a methodology validated by a closure test. NNPDF3.0 uses a global dataset including HERA-II deep-inelastic inclusive cross-sections, the combined…

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