scholarly journals An open-source machine learning framework for global analyses of parton distributions

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
◽  
Richard D. Ball ◽  
Stefano Carrazza ◽  
Juan Cruz-Martinez ◽  
Luigi Del Debbio ◽  
...  
Keyword(s):  
Open Source ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
The Public ◽  
Learning Framework ◽  
Extensive Documentation ◽  
Subsequent Determination ◽  
Code Base ◽  
Theoretical Predictions

AbstractWe present the software framework underlying the NNPDF4.0 global determination of parton distribution functions (PDFs). The code is released under an open source licence and is accompanied by extensive documentation and examples. The code base is composed by a PDF fitting package, tools to handle experimental data and to efficiently compare it to theoretical predictions, and a versatile analysis framework. In addition to ensuring the reproducibility of the NNPDF4.0 (and subsequent) determination, the public release of the NNPDF fitting framework enables a number of phenomenological applications and the production of PDF fits under user-defined data and theory assumptions.

scholarly journals Delineating the Polarized and Unpolarized Parton Structure of the Nucleon

2015 ◽  
Vol 37 ◽  
pp. 1560053
Author(s):  
Pedro Jimenez-Delgado
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Distribution Analysis ◽  
Coupling Constant ◽  
Parton Distribution Functions ◽  
Careful Treatment ◽  
Future Data ◽  
The Impact

Reports on our latest extractions of parton distribution functions of the nucleon are given. First an overview of the recent JR14 upgrade of our unpolarized PDFs, including NNLO determinations of the strong coupling constant and a discussion of the role of the input scale in parton distribution analysis. In the second part of the talk recent results on the determination of spin-dependent PDFs from the JAM collaboration are reported, including a careful treatment of hadronic and nuclear corrections, as well as reports on the impact of present and future data in our understanding of the spin of the nucleon.

scholarly journals Study of the Drell-Yan process with the pair-production of polarized tau leptons in collisions of polarized proton beams

2019 ◽  
Vol 222 ◽  
pp. 03021
Author(s):  
A. Aleshko ◽  
E. Boos ◽  
V. Bunichev
Keyword(s):  
Parton Distribution ◽  
Polarization State ◽  
Distribution Functions ◽  
Hadronic Decay ◽  
New Method ◽  
Tau Leptons ◽  
Parton Distribution Functions ◽  
Accuracy Of Measurements ◽  
Polarized Proton

The new method for studying polarized parton distribution functions via the Drell-Yan process with tau production is proposed. The hadronic decay of tau to single charged pi-meson and neutrino is utilised for determination of the polarization state of the tau-lepton. The key feature of our approach is that we do not sum over the polarizations states of tau, but preserve this information through energies ofpions produced in corresponding decays. The new method in addition to existing ones should improve the accuracy of measurements of polarized structure functions of hadrons. In the current work, the feasibility of such an approach is assessed through numerical simulations.

scholarly journals αs from global fits of parton distribution functions

2016 ◽  
Vol 31 (25) ◽  
pp. 1630023 ◽  
Author(s):  
S. Alekhin ◽  
J. Blümlein ◽  
S.-O. Moch
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Scattering Data ◽  
Hard Scattering ◽  
Coupling Constant ◽  
Parton Distribution Functions ◽  
The Status

The status of the determination of the strong coupling constant [Formula: see text] from deep-inelastic scattering and related hard scattering data is reviewed.

H1 INCLUSIVE CROSS-SECTION MEASUREMENTS AND AN EXTRACTION OF PARTON DISTRIBUTION FUNCTIONS

2005 ◽  
Vol 20 (21) ◽  
pp. 1557-1571
Author(s):  
BURKARD REISERT
Keyword(s):  
Cross Section ◽  
Parton Distribution ◽  
Inclusive Cross Section ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Single Experiment ◽  
Parton Distributions ◽  
The Standard Model ◽  
Qcd Analysis

An extraction of the parton distributions of the proton by a next-to-leading order QCD fit in the framework of the Standard Model is presented. The fit implements a novel decomposition of the quark species into up- and down-type quark distributions, which is the key to enable a determination of flavor separated parton distributions from a single experiment. The fit is performed on the inclusive unpolarized neutral and charged current cross-section measurements by the H1 collaboration at HERA. The discussion of uncertainties of parton distribution functions is based upon but extends the QCD analysis published together with the H1 data.

scholarly journals NNLO compatibility between pQCD theory and phenomenology in determination of the b-quark pole and MS¯ running masses

2020 ◽  
Vol 35 (30) ◽  
pp. 2050253
Author(s):  
A. Vafaee ◽  
K. Javidan
Keyword(s):  
Mass Formula ◽  
Distribution Functions ◽  
Pole Mass ◽  
Parton Distribution Functions ◽  
Quantum Chromo Dynamics ◽  
The Standard Model ◽  
Uncertainty Band ◽  
Perturbative Quantum ◽  
B Quark

This contribution attempts to determine the [Formula: see text]-quark pole mass [Formula: see text] and [Formula: see text] running mass [Formula: see text] with two different approaches at the next-to-next-to-leading order (NNLO) corrections. At the first approach, we derive a relation between the [Formula: see text]-quark pole mass [Formula: see text] and its [Formula: see text] running mass [Formula: see text] at the NNLO corrections based on the perturbative Quantum Chromo Dynamics (pQCD) predictions. At the second approach, we extract numerical values of the [Formula: see text]-quark pole and [Formula: see text] running masses based on the NNLO phenomenology of H1 and ZEUS Collaborations combined beauty vertex production experimental data. Then we discuss about the compatibility between the pQCD theory results and phenomenology approach in determination of the [Formula: see text]-quark pole and [Formula: see text] running masses at the NNLO corrections. Also, we investigate the role and influence of the [Formula: see text]-quark mass as an extra degree of freedom added to the input parameters of the Standard Model Lagrangian, on the improvement of the uncertainty band of the proton parton distribution functions (PDFs) and particularly on the gluon distribution.

scholarly journals Are PDFs still consistent with Tevatron data?

2018 ◽  
Vol 172 ◽  
pp. 03008 ◽  
Author(s):  
Zack Sullivan
Keyword(s):  
Excellent Agreement ◽  
Top Quark ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Single Top ◽  
Theoretical Predictions ◽  
Top Quark Production ◽  
Quark Production ◽  
Active Data

As active data taking has moved to the LHC at CERN, more and more LHC data have been included into fits of parton distribution functions. An anomaly has arisen where formerly excellent agreement between theoretical predictions and experiment in single-top-quark production at the Tevatron is no longer quite as good. Is this indicative of a deeper issue?

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