Updating and optimizing error parton distribution function sets in the Hessian approach

Schmidt, C.; Pumplin, Jon; Yuan, C. P.

doi:10.1103/physrevd.98.094005

Cited by 64 publications

(80 citation statements)

References 51 publications

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“…For calculating the uncertainties of the TMD FFs, we follow our previous analyses and use the standard "Hessian" method [44][45][46][47][48] with ∆χ 2 = 1 at 68% confidence level (CL). Further details can be found in Refs.…”

Section: Fitting Methodology and Sk19 Tmd Ffs Parametrizationmentioning

confidence: 99%

Transverse momentum dependent of charged pion, kaon, and proton/antiproton fragmentation functions from e+e− annihilation process

Soleymaninia

Khanpour

2019

Phys. Rev. D

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The main aim of this paper is a new determination of transverse momentum dependence of unpolarized fragmentation function (TMD FFs) in single inclusive hadron production in electron-positron annihilation (SIA) processes. Motivated by the need for a reliable and consistent determination of TMD FFs, we use the most recent TMD production cross sections of charged pions (π ± ), kaons (K ± ) and protons/antiprotons (p/p) measured in inclusive e + e − collisions by Belle Collaboration. These datasets are the first identified light charged hadron measurements which depend on the transverse momentum in SIA process. In this analysis, referred to as SK19 TMD FFs, the common Gaussian distribution is used for the P hT dependent of the cross section. The uncertainties in the extraction of SK19 TMD FFs are estimated using the standard "Hessian" technique. We study the quality of the TMD FFs determined in this analysis by comparing with the available recent Belle cross sections measurement. For all hadron species, we found a very good agreement between this particular set of experimental data and the corresponding theory calculations over a relatively wide range of transverse momentum P hT . As a result of this study, suggestions were identified for possible future research considering the theory improvements and other available experimental observables.

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Section: Fitting Methodology and Sk19 Tmd Ffs Parametrizationmentioning

confidence: 99%

Transverse momentum dependent of charged pion, kaon, and proton/antiproton fragmentation functions from e+e− annihilation process

Soleymaninia

Khanpour

2019

Phys. Rev. D

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“…The error bands represent the uncertainty estimation coming from the experimental errors. It is also worth noticing here that for calculating of uncertainty bands for our diffractive PDFs and all theoretical predictions we use the standard "Hessian" error propagation [51][52][53][54][55][56] with ∆χ 2 = 1. For the case of predictions including HT effects, the related theoretical uncertainties are also included.…”

Section: Results Of the Diffractive Pdfs Analysismentioning

confidence: 99%

Role of higher twist effects in diffractive DIS and determination of diffractive parton distribution functions

et al. 2019

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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, we use all available and up-to-date diffractive deep inelastic scattering (diffractive DIS) datasets from H1 and ZEUS Collaborations at HERA including the most recent H1/ZEUS combined measurements. In this analysis, we consider the heavy quark contributions to the diffractive DIS in the so-called framework of FONLL general mass variable flavor number scheme (GM-VFNS). The uncertainties on the diffractive PDFs are calculated using the standard "Hessian error propagation" which served to provide a more realistic estimate of the uncertainties. This analysis are enriched, for the first time, by including the nonperturbative higher twist (HT) effects in the calculation of diffractive DIS cross sections which are particularly important at large-x and low Q 2 regions. Then, the stability and reliability of the extracted diffractive PDFs are investigated upon inclusion of HT effects. We discuss the novel aspects of the approach used in this QCD fit, namely, optimized and flexible parameterizations of diffractive PDFs, the inclusion of HT effects, and considering the recent H1/ZEUS combined dataset. Finally, we present the extracted diffractive PDFs with and without the presence of HT effects, and discuss the fit quality and the stability upon variations of the kinematic cuts and the fitted datasets. We show that the inclusion of HT effects in diffractive DIS can improve the description of the data which leads, in general, to a very good agreement between data and theory predictions. CONTENTS

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“…Quantifying the impact of new experimental data into a Hessian PDF set such as PDF4LHC15 100 can be efficiently carried out by means of the Hessian Profiling technique [44,45]. This approach is based on the minimization of the following figure of merit:…”

Section: The Hessian Profiling Methodsmentioning

confidence: 99%

“…Subsequently, we quantify the constraints of the HL-LHC pseudo-data on the PDF4LHC15 100 set [40][41][42][43] by means of the Hessian Profiling method [44] (see also [45]). We have chosen the PDF4LHC15 set since it broadly represents the state-of-the-art understanding of the proton structure.…”

Section: Introductionmentioning

confidence: 99%

Towards ultimate parton distributions at the high-luminosity LHC

et al. 2018

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Since its start of data taking, the LHC has provided an impressive wealth of information on the quark and gluon structure of the proton. Indeed, modern global analyses of parton distribution functions (PDFs) include a wide range of LHC measurements of processes such as the production of jets, electroweak gauge bosons, and top quark pairs. In this work, we assess the ultimate constraining power of LHC data on the PDFs that can be expected from the complete dataset, in particular after the High-Luminosity (HL) phase, starting in around 2025. The huge statistics of the HL-LHC, delivering to ATLAS and CMS and to LHCb, will lead to an extension of the kinematic coverage of PDF-sensitive measurements as well as to an improvement in their statistical and systematic uncertainties. Here we generate HL-LHC pseudo-data for different projections of the experimental uncertainties, and then quantify the resulting constraints on the PDF4LHC15 set by means of the Hessian profiling method. We find that HL-LHC measurements can reduce PDF uncertainties by up to a factor of 2 to 4 in comparison to state-of-the-art fits, leading to few-percent uncertainties for important observables such as the Higgs boson transverse momentum distribution via gluon-fusion. Our results illustrate the significant improvement in the precision of PDF fits achievable from hadron collider data alone, and motivate the continuation of the ongoing successful program of PDF-sensitive measurements by the LHC collaborations.

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Updating and optimizing error parton distribution function sets in the Hessian approach

Cited by 64 publications

References 51 publications

Transverse momentum dependent of charged pion, kaon, and proton/antiproton fragmentation functions from e+e− annihilation process

Transverse momentum dependent of charged pion, kaon, and proton/antiproton fragmentation functions from e+e− annihilation process

Role of higher twist effects in diffractive DIS and determination of diffractive parton distribution functions

Towards ultimate parton distributions at the high-luminosity LHC

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