18 research outputs found
First global QCD analysis of charged hadron fragmentation functions and their uncertainties at next-to-next-to-leading order
In this paper, we present 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 () annihilation. The uncertainties in the extraction
of 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
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.Comment: 17 pages, 6 figures and 3 Table
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 () 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.Comment: 34 pages, 9 figures and 3 table
A global QCD analysis of diffractive parton distribution function considering higher twist corrections within the xFitter framework
We present {\tt SKMHS22}, a new set of diffractive parton distribution
functions (PDFs) and their uncertainties at next-to-leading-order accuracy in
perturbative QCD within the {\tt xFitter} framework. We describe all available
diffractive DIS data sets from HERA and the most recent high-precision H1/ZEUS
combined measurements considering three different scenarios. First, we extract
the diffractive PDFs considering the standard twist-2 contribution. Then, we
include the twist-4 correction from the longitudinal virtual photons. Finally,
the contribution of subleading Reggeon exchange to the structure-function
is also examined. For the contribution of heavy flavors, we utilize the
Thorne-Roberts general mass variable number scheme. We show that for those
corrections, in particular, the twist-4 contribution allows to include the
high- region and leads to a better description of the diffractive DIS
data sets. We find that the inclusion of the subleading Reggeon exchange
significantly improves the description of the diffractive DIS cross-section
measurements. The resulting sets are in good agreement with all diffractive DIS
data analyzed, which cover a wider kinematical range than in previous fits. The
{\tt SKMHS22} diffractive PDFs sets presented in this work are available via
the {\tt LHAPDF} interface. We also make suggestions for future research in
this area
Nuclear parton distribution functions with uncertainties in a general mass variable flavor number scheme
In this article, we obtain a new set of nuclear Parton distribution functions (nuclear PDFs) at next-to-leading order and next-to-next-to-leading order accuracy in perturbative QCD. The common nuclear deep-inelastic scattering (DIS) data analyzed in our study are complemented by the available charged-current neutrino DIS data with nuclear targets and data from Drell-Yan cross-section measurements for several nuclear targets. In addition, the most recent DIS data from the Jefferson Lab CLAS and Hall C experiments are also added to our data sample. For these specific datasets, we consider the impact of target mass corrections and higher twist effects which are expected to be important in the region of large x and intermediate-to-low Q2. Our analysis is based on a publicly available open-source tool, APFEL, which has been modified to be applicable for our analysis of nuclear PDFs. Heavy-quark contributions to nuclear DIS are considered within the framework of the FONLL general-mass variable-flavor-number scheme. The most recent CT18 PDFs are used as baseline proton PDFs. The uncertainties of nuclear PDFs are determined using the standard Hessian approach. The results of our global QCD analysis are compared with existing nuclear PDF sets and with the fitted cross-sections, for which our set of nuclear PDFs provides a very good description
QCD analysis of pion fragmentation functions in the xFitter framework
We present the first open-source analysis of fragmentation functions (FFs) of charged pions (entitled IPM-xFitter) computed at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) accuracy in perturbative QCD using the xFitter framework. This study incorporates a comprehensive and up-to-date set of pion production data from single-inclusive annihilation (SIA) processes, as well as the most recent measurements of inclusive cross-sections of single pion by the BELLE collaboration. The determination of pion FFs along with their theoretical uncertainties is performed in the Zero-Mass Variable-Flavor Number Scheme (ZM-VFNS). We also present comparisons of our FFs set with recent fits from the literature. The resulting NLO and NNLO pion FFs provide valuable insights for applications in present and future high-energy analysis of pion final state processes
Transverse momentum dependent of charged pion, kaon, and proton/antiproton fragmentation functions from e + e − annihilation process
The main aim of this paper is a new determination of transverse momentum dependence of unpolarized fragmentation function (TMD FF) in single inclusive hadron production in electron-positron annihilation (SIA) process. Motivated by the need for a reliable and consistent determination of TMD FFs, we use the most recent TMD production cross sections of charged pions (π±), kaons (K±), and protons/antiprotons (p/¯p) measured in inclusive e+e− collisions by Belle Collaboration. These datasets are the first transverse momentum dependence of identified light charged hadron measurements SIA process. In this analysis, referred to as SK19 TMD FFs, the common Gaussian distribution is used for the PhT dependent of the cross section. The uncertainties in the extraction of SK19 TMD FFs are estimated using the standard “Hessian” technique. We study the quality of the TMD FFs determined in this analysis by comparing with the available recent Belle cross sections measurement. For all hadron species, we found a very good agreement between this particular set of experimental data and the corresponding theory calculations over a relatively wide range of transverse momentum PhT. As a result of this study, suggestions are identified for possible future research considering the theory improvements and other available experimental observables
First NNLO fragmentation functions of K0S and Lambda and their uncertainties in the presence of hadron mass corrections
The current paper presents a determination of K^0_SK S0 and \Lambda/\bar{\Lambda}Λ/ Λ ˉ fragmentation functions (FFs) from QCD analysis of single-inclusive electron-positron annihilation process (SIA). Our FFs determinations are performed at next-to-leading order (NLO), and for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative Quantum Chromodynamics (pQCD) which is designated as {\tt SAK20} FFs. Each of these FFs is accompanied by their uncertainties which are determined using the `Hessian' method. Considering the hadron mass corrections, we clearly investigate the reliability of our results upon the inclusion of higher-order QCD correction. We provide comparisons of {\tt SAK20} FFs set with the available analysis from another group, finding in general a reasonable agreement, and also considerable differences. In order to judge the fit quality, our theoretical predictions are compared with the analyzed SIA datasets. {\tt SAK20} FFs at NLO and NNLO accuracy along with their uncertainties are made available in the standard {\tt LHAPDF} format in order to use for predictions of present and future measurements in high-energy collisions such as LHC and RHIC