954 research outputs found
Order (αs2) QCD corrections to inclusive jet production in deep inelastic scattering
No full textWe analyze the order αs2 corrections to the single inclusive jet cross section in lepton-nucleon deep inelastic scattering. The full calculation is done analytically, in the small cone approximation, obtaining finite NLO partonic level cross sections for these processes. A detailed study of the different underlying partonic reactions is presented focusing in the size of the corrections they get at NLO accuracy, their relative weight, and the residual scale uncertainty they leave in the full cross section depending on the kinematical region explored. In agreement with what has already been found in forward production of π0, we show that the dominant partonic process in very forward jet production is found to start at order αs2, being effectively a lowest order estimate, with the consequent large factorization scale uncertainty, and the likelihood of non-negligible corrections at the subsequent order in perturbation theory. © 2006 The American Physical Society.Fil: Daleo, A.. University Of Zurich, Institute For Theoretical Physics; AlemaniaFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin
Unveiling the proton spin decomposition at a future electron-ion collider
No full textWe present a detailed assessment of how well a future Electron-Ion Collider could constrain helicity parton distributions in the proton, and therefore unveil the role of the spin of quarks and gluons, as well as that of their orbital angular momentum, in the proton spin budget. Specifically, this is done in the light of the most recent polarized proton-protoncollision data obtained at BNL-RHIC, that suggest a significant contribution of the gluon spin, and have modified considerably our picture of the gluon helicity distribution in QCD global analyses.Fil: Aschenauer, Elke Caroline. Brookhaven National Laboratory; Estados UnidosFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Stratmann, Marco. University of Tübingen; Alemani
Sea quark polarization and semi-inclusive DIS data
No full textWe investigate the potential impact of forthcoming Jefferson Lab semi-inclusive polarized deep inelastic scattering proton measurements in the determination of the sea quark polarization in the nucleons by means of a next to leading order global QCD analysis. Specifically, we estimate the resulting improvement in the constraints on polarized parton densities for different flavors, which is found to be significant for up and strange quarks, and the correlation between remaining uncertainty ranges for each of the parton species.Fil: Jiang, X.. State University of New Jersey; Estados UnidosFil: Navarro, Gabriela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin
Consistency in NLO analyses of inclusive and semi-inclusive polarized DIS data
No full textWe perform a detailed study of the consistency between different sets of polarized deep inelastic scattering data and theory, from the standpoint of a next to leading order QCD global analysis, and following the criteria proposed by Collins and Pumplin. In face of recent suggestions that challenge the usual assumption about parent parton spin independence of unpolarized fragmentation functions, we specially focus on polarized semi-inclusive data.Fil: Navarro, Gabriela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin
Helicity parton distributions at a future electron-ion collider: A quantitative appraisal
No full textWe present a quantitative assessment of the impact a future electron-ion collider will have on determinations of helicity quark and gluon densities and their contributions to the proton spin. Our results are obtained by performing a series of global QCD analyses at next-to-leading order accuracy based on realistic sets of pseudo-data for the inclusive and semi-inclusive deep-inelastic scattering of longitudinally polarized electrons and protons at different, conceivable center-of-mass system energies. © 2012 American Physical Society.Fil: Aschenauer, Elke C.. Brookhaven National Laboratory; Estados UnidosFil: Stratmann, Marco. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Sassot, Rodolfo. Brookhaven National Laboratory; Estados Unido
Inclusive hadron production in the CERN-LHC era
No full textWe present a detailed phenomenological analysis of single-inclusive hadron production at the CERN-LHC in both proton-proton and proton-lead collisions. First data from the LHC experiments on charged hadron spectra are compared to next-to-leading order QCD expectations, and predictions are made for identified pion, kaon, and proton distributions differential in transverse momentum and rapidity for LHC energies from 900 GeV to 14 TeV. The results are obtained with the latest sets of vacuum fragmentation functions based on global QCD analyses, and recently proposed medium modified fragmentation functions are used to model hadronization in proton-lead collisions assuming standard QCD factorization. Besides estimating theoretical ambiguities due to the choice of factorization and renormalization scales and parton densities, we carefully assess uncertainties due to our present knowledge of parton-to-hadron fragmentation functions with the Lagrange multiplier technique. It is outlined to what extent future LHC data will contribute to further our quantitative understanding of hadronization processes.Fil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Zurita, María Pía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Stratmann, Marco. Universitat Regensburg; Alemania. Universitat Wurzburg; Alemani
Probing the sea quark content of the proton with one-particle-inclusive processes
No full textWe investigate the feasibility of constraining parton distribution functions in the proton through a comparison with data on semi-inclusive deep-inelastic lepton-nucleon scattering. Specifically, we reweight replicas of these distributions according to how well they reproduce recent, very precise charged kaon multiplicity measurements and analyze how this procedure optimizes the determination of the sea quark densities and improves their uncertainties. The results can help to shed new light on the long standing question on the size of the flavor and charge symmetry breaking among quarks of radiative origin. An iterative method is proposed and adopted to account for the inevitable correlation with what is assumed about the parton-To-hadron fragmentation functions in the reweighting procedure. It is shown how the fragmentation functions can be optimized simultaneously in each step of the iteration. As a first case study, we implement this method to analyze kaon production data.Fil: Borsa Sanjuán, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Stratmann, Marco. Universitat Tubingen; Alemani
script O sign(αs2) QCD corrections to the electroproduction of hadrons with high transverse momentum
No full textWe compute the order αs2 corrections to the one particle inclusive electroproduction cross section of hadrons with nonvanishing transverse momentum. We perform the full calculation analytically, and obtain the expression of the factorized (finite) cross section at this order. We compare our results with H1 data on forward production of π0, and discuss the phenomenological implications of the rather large higher order contributions obtained in that case. Specifically, we analyze the cross section sensitivity to the factorization and renormalization scales, and to the input fragmentation functions, over the kinematical region covered by data. We conclude that the data is well described by the script O sign(α s2) predictions within the theoretical uncertainties and without the inclusion of any physics content beyond the Dokshitzer-Grivov- Lipatov-Altarelli-Parisi (DGLAP) approach. © 2005 The American Physical Society.Fil: Daleo, A.. University Of Zurich, Institute For Theoretical Physics; AlemaniaFil: de Florian, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin
Charged hadron fragmentation functions at high energy colliders
No full textWe update our extraction of parton-to-charged hadron fragmentation functions at next-to-leading order accuracy in quantum chromodynamics (QCD), focusing on the wealth of data collected at the Large Hadron Collider over the past decade. We obtain an accurate description of single-inclusive processes involving unidentified charged hadrons produced at different rapidities and transverse momenta in proton-proton collisions in a wide range of center-of-mass system energies between 0.9 and 13 TeV, along with measurements performed in proton-antiproton collisions at the Tevatron Collider in the past. Next-to-leading order estimates of charged hadron production rates agree best with data when the theoretical factorization scales are selected similar to those optimized for identified pions, kaons, and protons in a recent global QCD analysis.Fil: Borsa, Ignacio. Eberhard Karls Universität Tübingen; AlemaniaFil: Stratmann, Marco. Eberhard Karls Universität Tübingen; AlemaniaFil: de Florian, Daniel Enrique. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Ciencias Fisicas. - Universidad Nacional de San Martin. Instituto de Ciencias Fisicas.; ArgentinaFil: Sassot, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin
Role of heavy quarks in light hadron fragmentation
No full textWe investigate the role of heavy quarks in the production of light flavored hadrons and in the determination of the corresponding nonperturbative hadronization probabilities. We define a general mass variable flavor number scheme for fragmentation functions that accounts for heavy quark mass effects, and perform a global QCD analysis to an up-to-date data set including very precise Belle and BABAR results. We show that the mass dependent picture provides a much more accurate and consistent description of the data.Fil: Epele, Manuel. Universidad Nacional de La Plata; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; ArgentinaFil: García Canal, Carlos. Universidad Nacional de La Plata; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; ArgentinaFil: Sassot, Rodolfo. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; Argentina. Universidad Nacional de La Plata; Argentin
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