First determination of D *+ -meson fragmentation functions and their uncertainties at next-to-next-to-leading order (original) (raw)
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2019
The main aim of this paper is to present new sets of non-perturbative fragmentation functions (FFs) for D 0 and D + mesons at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. This new determination of FFs is based on the QCD fit to the OPAL experimental data for hadroproduction in the electron-positron single-inclusive annihilation (SIA). We discuss in details the novel aspects of the methodology used in our analysis and the validity of obtained FFs by comparing with previous works in literature which have been done up to NLO accuracy. We will also incorporate the effects of charmed meson mass corrections into our QCD analysis and discuss the improvements upon inclusion of these effects. The uncertainties of extracted FFs as well as SIA cross sections are estimated employing the "Hessian approach". For a typical application, we use the extracted FFs to make theoretical predictions for the scaled-energy distributions of charmed mesons inclusively produced in top quark decays.
Physical Review D, 2019
We present nonperturbative fragmentation functions (FFs) for bottom-flavored (B) hadrons both at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order in the MS factorization scheme with five massless quark flavors. They are determined by fitting all available experimental data of inclusive single B-hadron production in e þ e − annihilation, from the ALEPH, DELPHI, and OPAL collaborations at CERN LEP1 and the SLD collaboration at SLAC SLC. The uncertainties in these FFs as well as in the corresponding observables are estimated using the Hessian approach. We perform comparisons with available NLO sets of B-hadron FFs. We apply our new FFs to generate theoretical predictions for the energy distribution of B hadrons produced through the decay of unpolarized or polarized top quarks, to be measured at the CERN LHC.
Determination of Ds+ meson fragmentation functions through two different approaches
Physical Review D, 2019
The hadronization mechanism is described by the fragmentation functions (FFs) which are universal and process-independent quantities. They can be generally determined theoretically or phenomenologically. In the phenomenological approach which is based on the data analysis, we present the FFs of D þ s both at leading-order (LO) and next-to-leading order (NLO) and, for the first time, at next-to-next-to-leading order in the minimal subtraction factorization scheme with five massless quarks. These functions are determined by fitting all available experimental data of inclusive single D þ s-meson production in electron-positron annihilation, from the OPAL Collaboration at CERN LEP1. We shall also estimate the uncertainties in these FFs as well as in the corresponding observables. In the theoretical approach, we apply the perturbative FFs formalism based on the Suzuki's model and present our analytical results at LO and NLO perturbative QCD framework. For the first time, a comparison between both approaches will be presented in this work. We also apply our new FFs to generate theoretical predictions for the energy distribution of D þ s mesons produced through the decay of unpolarized top quarks, to be measured at the CERN LHC.
Physical Review D, 2019
In this paper, we present SGK18 FFs, a first global QCD analysis of parton-to-unidentified charged hadrons fragmentation functions (FFs) at next-to-next-to-leading order (NNLO) accuracy in per-turbative QCD. This analysis is based on single-inclusive charged hadron production in electron-positron (e − e +) annihilation. The uncertainties in the extraction of SGK18 FFs as well as the corresponding observables are estimated using the " Hessian " technique. We study the quality of the SGK18 FFs determined in this analysis by comparing with the recent results in literature. We also show how SGK18 FFs results describe the available data for single-inclusive unidentified charged hadron production in e − e + annihilation. We demonstrate that the theoretical uncertainties due to the variation of the renormalization and factorization scales improve when NNLO QCD corrections are considered. We find that the resulting SGK18 FFs are in good agreement with all data analyzed and the inclusion of NNLO corrections tends to improve the data description with somewhat smaller uncertainty.
Physical Review D, 2019
In this paper a new comprehensive analysis of parton-to-pion fragmentation functions (FFs) is performed for the first time by including all experimental datasets on single inclusive pion as well as unidentified light charged hadron production in electron-positron (e þ e −) annihilation. We determine the pion FFs along with their uncertainties using the standard "Hessian" technique at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) in perturbative QCD. It is shown that the determination of pion FFs using simultaneously the datasets from pion and unidentified light charged hadron production leads to the reduction of all pion FF uncertainties, especially for the case of strange quark and gluon FFs by significant factors. In this study, we have quantified the constraints that these datasets could impose on the extracted pion FFs. Our results also illustrate the significant improvement in the precision of FFs fits achievable by the inclusion of higher-order corrections. The improvements on FF uncertainties as well as fit quality have been clearly discussed.
Parton-to-kaon fragmentation revisited
Physical Review D, 2017
We revisit the global QCD analysis of parton-to-kaon fragmentation functions at next-to-leading order accuracy using the latest experimental information on single-inclusive kaon production in electron-positron annihilation, lepton-nucleon deep-inelastic scattering, and proton-proton collisions. An excellent description of all data sets is achieved, and the remaining uncertainties in parton-tokaon fragmentation functions are estimated and discussed based on the Hessian method. Extensive comparisons to the results from our previous global analysis are made.
Physical Review D, 2013
We present new functional form of pion and kaon fragmentation functions up to next-to-leading order obtained through a global fit to single-inclusive electron-positron annihilation data and also employ, the semi-inclusive deep inelastic scattering asymmetry data from HERMES and COMPASS to determine FFs. In this analysis we consider the impression of semi-inclusive deep inelastic scattering asymmetry data on the fragmentation functions, where the produced hadrons of different electric charge are identified. We break symmetry assumption between quark and anti-quark fragmentation functions for favored partons by using the asymmetry data. The results of our analysis are in good agreement with electron-positron annihilation data and also with all the semi-inclusive deep inelastic scattering asymmetry data. Also we apply the obtained fragmentation functions to predict the scaled-energy distribution of π + /K + inclusively produced in top-quark decays at nextto-leading order using the zero-mass variable-flavor-number scheme exploiting the universality and scaling violations of fragmentation functions.
Charmed-meson fragmentation functions with finite-mass corrections
Nuclear Physics B, 2008
We elaborate the inclusive production of single heavy-flavored hadrons in e + e − annihilation at next-to-leading order in the general-mass variable-flavor-number scheme. In this framework, we determine non-perturbative fragmentation functions for D 0 , D + , and D * + mesons by fitting experimental data from the Belle, CLEO, ALEPH, and OPAL Collaborations, taking dominant electroweak corrections due to photonic initial-state radiation into account. We assess the significance of finite-mass effects through comparisons with a similar analysis in the zero-mass variable-flavor-number scheme. Under Belle and CLEO experimental conditions, charmed-hadron mass effects on the phase space turn out to be appreciable, while charm-quark mass effects on the partonic matrix elements are less important.
Parton-to-pion fragmentation reloaded
Physical Review D, 2015
We present a new, comprehensive global analysis of parton-to-pion fragmentation functions at next-to-leading order accuracy in QCD. The obtained results are based on the latest experimental information on single-inclusive pion production in electron-positron annihilation, lepton-nucleon deep-inelastic scattering, and proton-proton collisions. An excellent description of all data sets is achieved, and the remaining uncertainties in parton-to-pion fragmentation functions are estimated based on the Hessian method. Extensive comparisons to the results from our previous global analysis are performed.