Revisiting the D-meson hadroproduction in general-mass variable flavour number scheme

Helenius, Ilkka; Paukkunen, Hannu

doi:10.1007/jhep05(2018)196

Cited by 80 publications

(106 citation statements)

References 77 publications

(146 reference statements)

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“…The value ∆ = 1 is the default value [1], resulting in k 2 T ∼ 3 GeV 2 for √ s = 7 TeV. Note that it is necessary to use a code such as the exclusive HVQMNR calculation because the QQ pair quantities are calculable in such an approach while only single inclusive quark distributions are available with the FONLL [24] and generalized mass -variable flavor number approaches [25,26]. For further details on the determination of ǫ P and the sensitivity of the QQ results to the magnitude of k 2 T , see Ref.…”

Section: Model Descriptionmentioning

confidence: 99%

bb¯ kinematic correlations in cold nuclear matter

Vogt

2020

Phys. Rev. C

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Background: The LHCb Collaboration has studied a number of kinematic correlations between B-hadron pairs through their subsequent decays to J/ψ pairs at 7 and 8 TeV for four minimum values of the J/ψ pT . Purpose: In this work, these measurements are compared to calculations of bb pairs and their hadronization and inclusive decays to J/ψJ/ψ are compared to the same observables. Potential cold matter effects on the bb pair observables are discussed to determine which are most likely to provide insights about the system and why. Methods: The calculations, employing the exclusive HVQMNR code, assume the same intrinsic kT -broadening and fragmentation as in Ref. [1]. The pair distributions presented by LHCb are calculated in this approach, both for the parent bb and the J/ψJ/ψ pairs produced in their decay. The sensitivity of the results to the intrinsic kT broadening is shown. The theoretical uncertainties due to the b quark mass and scale variations on both the initial bb pairs and the resulting J/ψ pairs are also shown. Possible effects due to the presence of the nucleus are studied by increasing the size of the kT broadening and modification of the fragmentation parameter. Results: Good agreement with the LHCb data is found for all observables. The parent bb distributions are more sensitive to the kT broadening than are the final-state J/ψ pairs. Conclusions: Next-to-leading order calculations with kT broadening, as in Ref.[1], can describe all correlated observables. Multiple measurements of correlated observables are sensitive to different nuclear effects which can help distinguish between them.

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Section: Model Descriptionmentioning

confidence: 99%

bb¯ kinematic correlations in cold nuclear matter

Vogt

2020

Phys. Rev. C

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“…The GM-VFNS "master formula" for D-meson production at fixed rapidity Y and transverse momentum P T is (see Refs. [9,10] for details), Here, f h i (x 1 , µ 2 fact ) denote the PDFs at factorization scale µ 2 fact , D k→D 0 (z, µ 2 frag ) are the parton-tomeson fragmentation functions (FFs) at fragmentation scale µ 2 frag , and dσ i j→k are the partonic Wilson coefficients which also depend on the renormalization scale µ 2 ren and charm-quark mass m. Towards small P T , the coefficient functions behave as in the FFNS, but at the high-P T limit the zero-mass MS expressions are recovered. The fragmentation variable z is not unique due to the finite masses of the charm quark and the D meson.…”

Section: D-meson Production In Gm-vfnsmentioning

confidence: 99%

“…As is well known, the GM-VFNS entails a scheme dependence related to the exact way the mass dependence of the contributions initiated by heavy quarks and those in which a light quark or gluon fragments into a D meson, is treated. In our work, we have adopted the so-called SACOT-m T scheme [10], in which the scheme-dependent contributions retain the kinematics of the heavy-quark pair production, but the Wilson coefficients are massless. In…”

Section: D-meson Production In Gm-vfnsmentioning

confidence: 99%

“…However, the theoretical treatment of D-meson production is not fully established, and the used approaches vary from the fixed flavour-number scheme (FFNS) [4] to FONLL [5], to FFNS combined with parton showers [6], and to matrix-element fitting [7]. In the work summarized here [8], we have used the general-mass variable-flavour-number scheme (GM-VFNS) approach [9,10].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Constraints for nuclear PDFs from the LHCb D-meson data

Paukkunen¹,

Eskola²,

Helenius³

et al. 2019

Proceedings of XXVII International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS2019)

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We quantify the impact of LHCb D-meson measurements at √ s = 5 TeV on the EPPS16 and nCTEQ15 nuclear PDFs. In our study, the theoretical description of D-meson production is based on the recently developed SACOT-m T variant of the general-mass variable-flavour-number formalism, and the impact on PDFs is estimated via reweighting methods. We pay special attention on the theoretical uncertainties known to us, and are led to exclude the p T < 3 GeV region from our main analysis. The LHCb data can be accommodated well within EPPS16 and nCTEQ15, and the data provide stringent constraints on the gluons in the shadowing/antishadowing regions.No evidence of non-linear effects beyond standard DGLAP evolution is found even if the full kinematic region down to zero p T is considered.

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“…FFNS calculation in conjunction with PDFs defined in variable flavour-number schemes (the commonly used general-purpose PDFs) may be too restrictive, and in this sense calculations within the framework of general-mass variable-flavour-number scheme (GM-VFNS) would be more natural. Here, we will discuss our novel implementation of the GM-VFNS, the so-called SACOT-m T scheme [6].…”

Section: Introductionmentioning

confidence: 99%

Hadroproduction of open heavy flavour for PDF analyses

Paukkunen

Helenius

2019

Proceedings of XXVII International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS2019)

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Due to the large masses of the charm and bottom quarks, their production cross sections are calculable within the perturbative QCD. This makes the heavy-quark mesons important observables in high-energy collisions of protons and nuclei. However, the available calculations for heavyflavored-meson hadroproduction have been somewhat problematic in reliably describing the cross sections across the full kinematic range from zero to very high p T . This has put some question marks on the robustness of LHC heavy-flavored-meson measurements in studying the partonic structure of the colliding hadrons and nuclei. Here, we introduce SACOT-m T -a novel scheme for open heavy-flavour hadroproduction within the general-mass variable-flavour-number formalism that solves this problem. The introduced scheme is an analogue of the SACOT-χ scheme often used for deeply-inelastic scattering in global analyses of PDFs.

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Revisiting the D-meson hadroproduction in general-mass variable flavour number scheme

Cited by 80 publications

References 77 publications

bb¯ kinematic correlations in cold nuclear matter

bb¯ kinematic correlations in cold nuclear matter

Constraints for nuclear PDFs from the LHCb D-meson data

Hadroproduction of open heavy flavour for PDF analyses

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