The Path to Proton Structure at One-Percent Accuracy

Ball, Richard D.; Carrazza, Stefano; Cruz-Martinez, Juan; Del Debbio, Luigi; Forte, Stefano; Giani, Tommaso; Iranipour, Shayan; Kassabov, Zahari; Latorre, Jose I.; Nocera, Emanuele R.; Pearson, Rosalyn L.; Rojo, Juan; Stegeman, Roy; Schwan, Christopher; Ubiali, Maria; Voisey, Cameron; Wilson, Michael

doi:10.48550/arxiv.2109.02653

Cited by 57 publications

(181 citation statements)

References 206 publications

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“…( 16) through ( 19), this appears to be possible only if the ratio ūp (x 2 )/ dp (x 2 ) at small x 2 and u p V (x 1 )/d p V (x 1 ) at large x 1 are positively correlated. We find this to be true at the EW scale for CT14 (and also for CT18, MSHT20 [41] and NNPDF4.0 [42]) as long as x 2 < 0.03, independently of…”

Section: Cms Datamentioning

confidence: 62%

Proton-PDF uncertainties in extracting nuclear PDFs from $W^\pm$ production in p+Pb collisions

Eskola,

Paakkinen,

Paukkunen

et al. 2022

Preprint

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We discuss the recent CMS Collaboration measurement of W ± 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 uncertainties on the nuclear PDF extraction is quantified by using a theoretical covariance-matrix method and Hessian PDF reweighting. We discuss different ways to mitigate these theoretical uncertainties, including self-normalization, forward-tobackward ratios and nuclear-modification ratios. It is found that none of these methods offer perfect cancellation of the free-proton PDFs but, with the present data uncertainties, the residual free-proton-PDF dependence has, conveniently for the global analyses, little effect on the extraction of the nuclear modifications. Based on a simple estimate of obtainable statistics at the LHC Run 3, we argue that this will change in the near future and it becomes more important to propagate the proton-PDF uncertainties accordingly. Using the obtained information on the correlations of the free-proton uncertainties, we also identify a new charge asymmetry ratio, where the cancellation of the proton-PDF uncertainties is found to be extremely good.

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Section: Cms Datamentioning

confidence: 62%

Proton-PDF uncertainties in extracting nuclear PDFs from $W^\pm$ production in p+Pb collisions

Eskola,

Paakkinen,

Paukkunen

et al. 2022

Preprint

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show abstract

“…This approach is conceptually more consistent, as it completely removes any residual nuclear effects from the proton baseline. Information loss on quark flavour separation for proton PDFs due to the removal of these datasets is partially compensated by the availability of additional measurements from proton-proton (pp) collisions [24], specifically concerning new weak gauge boson production data.…”

Section: Dataset Overviewmentioning

confidence: 99%

“…These measurements uniquely constrain quark flavour separation at intermediate and large x. Uncertainties due to nPDFs may inflate the overall free-proton PDF uncertainty by up to a factor of two at large x when properly taken into account [22][23][24]. More precise nPDFs can therefore lead to more precise free-proton PDFs.…”

Section: Introductionmentioning

confidence: 99%

NNNPDF3.0: Evidence for a modified partonic structure in heavy nuclei

Khalek¹,

Gauld²,

Giani³

et al. 2022

Preprint

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We present an updated determination of nuclear parton distributions (nPDFs) from a global NLO QCD analysis of hard processes in fixed-target lepton-nucleus and proton-nucleus together with collider protonnucleus experiments. In addition to neutral-and charged-current deep-inelastic and Drell-Yan measurements on nuclear targets, we consider the information provided by the production of electroweak gauge bosons, isolated photons, jet pairs, and charmed mesons in proton-lead collisions at the LHC across centre-ofmass energies of 5.02 TeV (Run I) and 8.16 TeV (Run II). For the first time in a global nPDF analysis, the constraints from these various processes are accounted for both in the nuclear PDFs and in the freeproton PDF baseline. The extensive dataset underlying the nNNPDF3.0 determination, combined with its model-independent parametrisation, reveals strong evidence for nuclear-induced modifications of the partonic structure of heavy nuclei, specifically for the small-x shadowing of gluons and sea quarks, as well as the large-x anti-shadowing of gluons. As a representative phenomenological application, we provide predictions for ultra-high-energy neutrino-nucleon cross-sections, relevant for data interpretation at neutrino observatories. Our results provide key input for ongoing and future experimental programs, from that of heavy-ion collisions in controlled collider environments to the study of high-energy astrophysical processes.

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“…Finally, we mention that the model hyperparameters E I,k and E II,k could eventually be determined by means of an automated hyper-optimisation procedure as proposed in, 42 hence further reducing the need for human-specific input in the whole procedure.…”

Section: B a Deep-learning Model For The Zero-loss Peakmentioning

confidence: 99%

Spatially-Resolved Band Gap and Dielectric Function in 2D Materials from Electron Energy Loss Spectroscopy

Brokkelkamp,

ter Hoeve,

Postmes

et al. 2022

Preprint

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The electronic properties of two-dimensional (2D) materials depend sensitively on the underlying atomic arrangement down to the monolayer level. Here we present a novel strategy for the determination of the bandgap and complex dielectric function in 2D materials achieving a spatial resolution down to a few nanometers. This approach is based on machine learning techniques developed in particle physics and makes possible the automated processing and interpretation of spectral images from electron energy

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The Path to Proton Structure at One-Percent Accuracy

Cited by 57 publications

References 206 publications

Proton-PDF uncertainties in extracting nuclear PDFs from $W^\pm$ production in p+Pb collisions

Proton-PDF uncertainties in extracting nuclear PDFs from $W^\pm$ production in p+Pb collisions

NNNPDF3.0: Evidence for a modified partonic structure in heavy nuclei

Spatially-Resolved Band Gap and Dielectric Function in 2D Materials from Electron Energy Loss Spectroscopy

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