Heavy-flavor parton distributions without heavy-flavor matching prescriptions

Bertone, Valerio; Glazov, A.; Mitov, Alexander; Papanastasiou, Andrew S.; Ubiali, Maria

doi:10.1007/jhep04(2018)046

Cited by 20 publications

(21 citation statements)

References 117 publications

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“…In particular, it can be appreciated how the NNLO-accurate prediction starts to depart from the NNLL at large scales and large values of N , while in general, with the exception of the aforementioned spike, resummed computations show a better agreement with each other at large N . Increasing the initial scale µ 0 , reduces the differences between the resummed and truncated predictions, as it is expected and as it was studied in details in [92]. However the global pattern is unchanged.…”

Section: Impact Of Collinear Resummation and Resultssupporting

confidence: 52%

“…We conclude this section by discussing the dependence of truncated and resummed predictions on the initial scale µ 0 . The effect of changing the initial scale in the case of perturbatively generated bottom PDFs has been studied in details in [92]. It is interesting to compare the effects in the case of perturbative bottom fragmentation functions.…”

Section: Impact Of Collinear Resummation and Resultsmentioning

confidence: 99%

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A fragmentation-based study of heavy quark production

Ridolfi

Ubiali

Zaro

2020

J. High Energ. Phys.

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Processes involving heavy quarks are a crucial component of the LHC physics program, both by themselves and as backgrounds for Higgs physics and new physics searches. In this work, we critically reconsider the validity of the widely-adopted approximation in which heavy quarks are generated at the matrix-element level, with special emphasis on the impact of the collinear logarithms associated with final-state heavy quark and gluon splittings. Our study, based on a perturbative fragmentation-function approach, explicitly shows that neglecting the resummation of collinear logarithms may yield inaccurate predictions, in particular when observables exclusive in the heavy quark degrees of freedom are considered. Our findings motivate the use of schemes which encompass the resummation of final-state collinear logarithms.

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Section: Impact Of Collinear Resummation and Resultssupporting

confidence: 52%

Section: Impact Of Collinear Resummation and Resultsmentioning

confidence: 99%

A fragmentation-based study of heavy quark production

Ridolfi

Ubiali

Zaro

2020

J. High Energ. Phys.

Self Cite

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“…[16,17]. a matching prescription between FFNS and VFNS able to achieve this goal in a very simple fashion [19].…”

Section: Introductionmentioning

confidence: 99%

Impact of the heavy-quark matching scales in PDF fits

Bertone¹,

Britzger²,

Camarda³

et al. 2017

Eur. Phys. J. C

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We investigate the impact of displaced heavyquark matching scales in a global fit. The heavy-quark matching scale μ m determines at which energy scale μ the QCD theory transitions from N F to N F + 1 in the variable flavor number scheme (VFNS) for the evolution of the parton distribution functions (PDFs) and strong coupling α S (μ). We study the variation of the matching scales, and their impact on a global PDF fit of the combined HERA data. As the choice of the matching scale μ m effectively is a choice of scheme, this represents a theoretical uncertainty; ideally, we would like to see minimal dependence on this parameter. For the transition across the charm quark (from N F = 3 to 4), we find a large μ m = μ c dependence of the global fit χ 2 at NLO, but this is significantly reduced at NNLO. For the transition across the bottom quark (from N F = 4 to 5), we have a reduced μ m = μ b dependence of the χ 2 at both NLO and NNLO as compared to the charm. This feature is now implemented in xFitter 2.0.0, an open source QCD fit framework.

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“…Heavy flavour contributions to the diffractive DIS structure function Is is shown in literature that the correct treatments of heavy flavors have an important impact on the PDFs extracted from the global analysis due to the data available for heavy flavor structure functions, F h L (x, Q 2 , m 2 h ) with h = c, b and k = 2, L, as well as the heavy flavor contributions to the total inclusive structure functions at small values of momentum fraction x [4, [38][39][40]. There are several scheme available in literature where heavy quark production can be readily described.…”

Section: Cmentioning

confidence: 99%

Phenomenology of diffractive DIS in the framework of fracture functions and determination of diffractive parton distribution functions

Khanpour

2019

Phys. Rev. D

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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 collider, including the most recent H1 and ZUES combined inclusive diffractive cross section measurements. This extraction of diffractive PDFs, referred to as HK19-DPDF, is performed at next-to-leading (NLO) and next-to-next-to-leading (NNLO) in perturbative QCD. This new determination of diffractive PDFs is based on the fracture functions methodology, a QCD framework designed to provide a statistically sound representation of diffractive DIS processes. Heavy quark contributions to the diffractive DIS are considered within the framework of the FONLL general mass variable flavor number scheme (GM-VFNS) and the "Hessian approach" is used to determine the uncertainties of diffractive PDFs. We discuss the novel aspects of the approach used in the present analysis, namely an optimized and flexible parametrization of the diffractive PDFs as well as a strategy based on the fully factorization theorem for diffractive hard processes. We then present the diffractive PDFs, and discuss the fit quality and the stability upon variations of the kinematic cuts and the fitted data sets. We find that the systematic inclusion of higher-order QCD corrections could improves the description of the data. We compare the extracted sets of diffractive PDFs based on the fracture functions approach to other recent sets of diffractive PDFs, finding in general very good agreements.

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Heavy-flavor parton distributions without heavy-flavor matching prescriptions

Cited by 20 publications

References 117 publications

A fragmentation-based study of heavy quark production

A fragmentation-based study of heavy quark production

Impact of the heavy-quark matching scales in PDF fits

Phenomenology of diffractive DIS in the framework of fracture functions and determination of diffractive parton distribution functions

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