arXiv subjects

Maryam Soleymaninia

Publications and source records attributed to Maryam Soleymaninia.

24 records · Page 2Linked to original sources

arXiv2019

Determination of contributions from residual light charged hadrons to inclusive charged hadrons from $e^+e^-$ annihilation data

In this paper, we present an extraction of the contribution from the "{\it residual}" light charged hadrons to the inclusive unidentified light charged hadron fragmentation functions (FFs) at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. Considering the contributions from charged pion, kaon and (anti)proton FFs from recent {\tt NNFF1.0} analysis of charged hadron FFs, we determine the small but efficient {\it residual} charged hadron FFs from QCD analysis of all available single inclusive unidentified charged hadron data sets in electron-positron ($e^+ e^-$) annihilations. The zero-mass variable flavor number scheme (ZM-VFNS) has been applied to account the heavy flavor contributions. The obtained optimum set of {\it residual} charged hadron FFs is accompanied by the well-known Hessian technique to assess the uncertainties in the extraction of these new sets of FFs. It is shown that the {\it residual} contributions of charged hadron FFs have very important impact on the inclusive charged hadron FFs and substantially on the quality and the reliability of the QCD fit. Furthermore, this study shows that the {\it residual} contributions become also sizable for the case of heavy quark FFs as well as for the $c$- and $b$-tagged cross sections.

hep-ph↗

arXiv2019

$B$-hadron fragmentation functions at next-to-next-to-leading order from global analysis of $e^+e^-$ annihilation data

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 (NNLO) in the $\overline{\mathrm{MS}}$ factorization scheme with five massless quark flavors. They are determined by fitting all available experimental data of inclusive single $B$-hadron production in $e^+e^-$ 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.

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arXiv2019

Impact of unidentified light charged hadron data on the determination of pion fragmentation functions

In this paper a new comprehensive analysis of parton-to-pion fragmentation functions (FFs) is performed for the first time by including all experimental data sets on single inclusive pion as well as unidentified light charged hadron production in electron-positron ($e^+e^-$) 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 perturabative QCD. It is shown that the determination of pion FFs using simultaneously the data sets from pion and unidentified light charged hadron productions leads to the reduction of all pion FFs uncertainties especially for the case of strange quark and gluon FFs by significant factors. In this study, we have quantified the constraints that these data sets could impose on the extracted pion FFs. Our results also illustrate the significant improvement in the precision of FFs fits achievable by inclusion of higher order corrections. The improvements on both FFs uncertainties as well as fit quality have been clearly discussed.

hep-ph↗

arXiv2018

First global QCD analysis of charged hadron fragmentation functions and their uncertainties at next-to-next-to-leading order

In this paper, we present ${\tt SGK18}$ FFs, a first global QCD analysis of parton-to-{\it unidentified} charged hadrons fragmentation functions (FFs) at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. This analysis is based on single-inclusive charged hadron production in electron-positron ($e^-e^+$) annihilation. The uncertainties in the extraction of ${\tt SGK18}$ FFs as well as the corresponding observables are estimated using the "Hessian" technique. We study the quality of the {\tt SGK18} FFs determined in this analysis by comparing with the recent results in literature. We also show how {\tt 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 {\tt 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.

hep-ph↗

arXiv2018

First determination of $D^{*+}$-meson fragmentation functions and their uncertainties at next-to-next-to-leading order

We present, for the first time, a set of next-to-next-to-leading order (NNLO) fragmentation functions (FFs) describing the production of charmed-meson $D^{*+}$ from partons. Exploiting the universality and scaling violations of FFs, we extract the NLO and NNLO FFs through a global fit to all relevant data sets from single-inclusive $e^+e^-$ annihilation. The uncertainties for the resulting FFs as well as the corresponding observables are estimated using the Hessian approach. We evaluate the quality of the {\tt SKM18} FFs determined in this analysis by comparing with the recent results in literature and show how they describe the available data for single-inclusive $D^{*+}$-meson production in electron-positron annihilation. As a practical application, we apply the extracted FFs to make our theoretical predictions for the scaled-energy distributions of $D^{*+}$-mesons inclusively produced in top quark decays. We explore the implications of {\tt SKM18} for LHC phenomenology and show that our findings of this study can be introduced as a channel to indirect search for top-quark properties.

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arXiv2013

QCD analysis of polarized DIS and the SIDIS asymmetry world data and light sea-quark decomposition

The results of our new QCD analysis of helicity parton distributions of the nucleon at full next-to-leading order (NLO) accuracy in the fixed-flavor number scheme will be presented. Performing a combined QCD fit on the global sets of latest inclusive and the semi-inclusive polarized deep inelastic scattering data, we are able to extract new polarized parton distribution functions (PPDFs) at the input scale $Q_{0}^2=1$ GeV$^2$. Particulary, we have calculated PPDFs considering light sea-quark decomposition and the results are compared with the experimental data and the most precise theoretical models obtained by recent analyses. The latest COMPASS2010 SIDIS data, which were not available for the previous analyses, are employed in the current analysis and the effect of COMPASS SIDIS data is studied in detail. Also the uncertainties of PPDFs are determined using the standard Hessian technique.

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