Showing papers on "Parton published in 1991"
TL;DR: In this article, the authors present techniques and results that are useful in the calculation of cross sections for processes with many final state partons which have applications in the study of multi-jet phenomena in high-energy Colliders.
710 citations
TL;DR: In this paper, the authors investigated the QCD corrections to the cross section and single-particle inclusive differential distributions for p + p → Q(Q) + X where Q and Q are heavy quarks.
350 citations
TL;DR: In this paper, a model for diffractive elastic hadron-hadron scattering at high cm energies squared s and small momentum transfer squared |t| is developed, based on quantum chromodynamics (QCD).
201 citations
TL;DR: In this article, the full order α 2 S correction to the singlet (quark) as well as the non-singlet part of the Wilson coefficient appearing in deep inelastic lepton-hadron scattering was presented.
195 citations
TL;DR: In this article, the evaluation of matrix elements for a vector boson decaying into n partons (n ⩽ 6) is presented, where recursive techniques and Weyl-van der Waerden spinor calculus are used.
179 citations
TL;DR: In this article, the order α s 2 correction to the deep inelastic Wilson coefficient for all parton subprocesses with a gluon in the initial state was presented.
148 citations
TL;DR: In this paper, a study of events containing at least four high transverse momentum jets and a search for double parton scattering (DPS) have been performed using data collected with the UA2 detector at the CERN p p Collider (√s=630 GeV).
144 citations
TL;DR: In this article, a new parametrization for parton distributions in the real photon is obtained by solving the inhomogeneous leading order Altarelli-Parisi equations for the photon case.
136 citations
TL;DR: Parton distribution functions consistent with neutrino and muon deep inelastic scattering as well as Drell-Yan pair production results have been extracted in this paper, where the dependence of the results on factors such as kinematic cuts in the data, heavy target corrections, and choice of initial functional form are also explored.
Abstract: Parton distribution functions consistent with neutrino and muon deep inelastic scattering as well as Drell-Yan pair production results have been extracted. This analysis incorporates experimental systematic errors which are the dominant errors in recent deep inelastic scattering experiments. The dependence of the results on factors such as kinematic cuts in the data, heavy target corrections, and choice of initial functional form are also explored. The form adopted is motivated by perturbative QCD and particularly useful in exploring the small-x extrapolation of the distributions. This is crucial for studying the range of predictions for Collider, HERA, and SSC/LHC cross sections. Representative distribution function sets are presented in a very compact parametrized form both in the DIS and MS-bar renormalization schemes.
125 citations
TL;DR: The result confirms the presence of significant twist-3 effects in g2(x, Q2), and discusses two questions raised by the analysis: the validity of the Burkhardt-Cottingham sum rule and the relation to previous calculations of g2 (x,–Q2) in versions of the parton model.
Abstract: We study the transverse spin-dependent nucleon structure function g2(x, Q2) in leading order at large Q2. After reviewing the operator-product-expansion analysis of g2(x, Q2) we calculate the twist-3 contributions which arise from quark-gluon interactions and quark masses in the bag model. The result confirms the presence of significant twist-3 effects in g2(x, Q2). We discuss two questions raised by our analysis: the validity of the Burkhardt-Cottingham sum rule and the relation to previous calculations of g2(x, Q2) in versions of the parton model.
98 citations
CERN1
TL;DR: In this article, the corrections of order α for Z pair production in hadronic collisions are calculated and the corrections are of the order of 20% to 30% of the total.
TL;DR: In this paper, a method of the event reconstruction based on the parton level dynamics is formulated, and the mass probability for the 2→2 processes where 0 or 1 missing particles per channel are included in the final states.
Abstract: A method of the event reconstruction based on the parton level dynamics is formulated. Formulae for the mass probability are given for the 2→2 processes where 0 or 1 missing particles per channel are included in the final states. Uncertainties of the final parton momenta and their propagation to the reconstructed intermediate states are integrated into the formulation. An application to analysis of the top quark pair production with standard decay modes is discussed.
TL;DR: In this paper, a new parametrization of parton distributions is presented, which is designed to update the older Duke-Owens Set 1 (DOW) parametric model.
TL;DR: In this article, a comprehensive QCD-based model for the xf and nuclear dependences of heavy quarkonium production in photon-, hadron-, and nuclear-induced collisions is presented.
TL;DR: In this paper, the application of the analytical perturbative technique to the description of inclusive particle spectra in QCD jets is reviewed and the authors discuss characteristic properties of the jets generated by heavy quarks and list the prospects for future studies of coherent parton cascades.
Abstract: The application of the analytical perturbative technique to the description of inclusive particle spectra in QCD jets is reviewed The authors discuss characteristic properties of the jets generated by heavy quarks and list the prospects for future studies of coherent parton cascades
TL;DR: The polarized gluon contribution to the {ital g}{sub 1} structure function of the nucleon is computed using the modified minimal-subtraction scheme as a simple example of the calculational method.
Abstract: Polarized parton distribution functions for a hadron target are defined in terms of gauge-invariant correlation functions. The polarized gluon contribution to the {ital g}{sub 1} structure function of the nucleon is computed using the modified minimal-subtraction scheme as a simple example of the calculational method. The gluon contribution to the integral of the {ital g}{sub 1} structure function is shown to vanish.
TL;DR: In this article, the energy loss of a high-energy parton traversing the equilibrium quark-gluon plasma is discussed, and the collisions with the thermalized plasma partons and the plasma polarization effects are considered in detail.
TL;DR: In this article, the authors present a work carried out in collaboration with Xiangdong Ji, and a compressed version of it is published in Physical Review Letters (PRL).
Abstract: The work I will present was carried out in collaboration with Xiangdong Ji. A compressed version will be published in Physical Review Letters.1
TL;DR: In this article, the authors focus on the conceptually simplest way to make an analytical model-independent prediction for the inclusive spectrum of hadrons, which is known to have a general factorized form in the moment representation.
Abstract: According to the LPHD, the conversion of partons into hadrons occurs at a low virtuality scale, independent of the scale of the primary hard process, and involves only low-momentum transfer. The non-PT effects are reduced to a few normalizing constants relating hadronic characteristics to partonic ones. Various algorithmic model approaches to the quantitative realization of the LPHD have been discussed. There is, moreover, a consistent field-theoretic approach to the physics of colour blanching which exhibits LPHD properties, namely Gribov's confinement scenario. The authors focus on the conceptually simplest way to make an analytical model-independent prediction for the inclusive spectrum of hadrons. In the leading twist approximation, the spectrum is known to have a general factorized form in the moment representation.
TL;DR: Charm leptroproduction asymmetries at Q2 = 0 are estimated for forthcoming experiments with polarized lepton (e, μ) beams and polarized fixed targets in this article, where they show that δG(x, Q2) is unsuitable for extracting ΔG. Other possible charm production asymmetry determinations, at higher values of Q2, as well as polarized deep inelastic large-kT jet production are furthermore critically considered for realistic experimental situations.
TL;DR: In this paper, a Monte Carlo version of the dual parton model for the description of particle production in hadron-nucleus and nucleus nucleus collisions with a complete formation zone intranuclear cascade is presented.
Abstract: We present a Monte Carlo version of the dual parton model for the description of particle production in hadron-nucleus and nucleus-nucleus collisions with a complete formation zone intranuclear cascade. All generations of secondary interactions are considered. Furthermore, Fermi motion and Pauli's principle are introduced to control the generation of low-energy nucleons. The model is compared with rapidity distributions and grey-particle production in hadron-nucleus interactions as well as with results from nucleus-nucleus collisions. Within the DPM the number of chains with sea-quarks at their ends grows with the complexity of the target and/or projectile nuclei as well as with the collision energy. We discuss this increase of chain-end sea-quarks as a mechanism for strangeness enhancement within the model. Furthermore we study the properties of the model at the energies of future heavy ion colliders.
TL;DR: The analysis of very recent and accurate deep-inelastic scattering data leads to the conclusion that isospin is strongly violated in the proton sea-quark distributions.
Abstract: The analysis of very recent and accurate deep-inelastic scattering data leads us to conclude that isospin is strongly violated in the proton sea-quark distributions. Such findings have severe implications for reliable global parton-distribution fitting programs.
TL;DR: NLLjet as mentioned in this paper is a Monte Carlo generator for the parton shower in e + e - -annihilation, which can be used to determine the QCD Λ-parameter from e+ e -jet events since it includes the next-to-leading order contribution.
TL;DR: In this paper, a study of 43, 000 3-jet events from Z0 boson decays is presented, where the measured jet energy distributions and the event orientation are reproduced by second order QCD.
TL;DR: In this article, the authors measured the production of high energy isolated photons in hadronic Z decays with the ALEPH detector at LEP using a sample of 180 000 hadronic events.
TL;DR: In this article, the authors measured the strong coupling constant alpha S from an analysis of particle clusters in the reaction e+e- to hadrons at centre-of-mass energies near the Z resonance.
Abstract: The author has measured the strong-coupling constant alpha S from an analysis of particle clusters in the reaction e+e- to hadrons at centre-of-mass energies near the Z resonance. After the Z decays into a quark-antiquark pair, the quarks radiate gluons, which themselves decay into gluons or quark-antiquark pairs. This phase can be described by perturbative QCD. At a certain point the partons are transformed into colour neutral hadrons (hadronization). This phase cannot be described by perturbative QCD, but rather by phenomenological models.
TL;DR: Differential cross sections for production of hadrons in pA collisions are usually assumed to be proportional to A α, but a compilation of data shows that α depends in general on the type of hadron, its momentum, collision energy, and even on A α.
TL;DR: In this paper, up to ∼ 20% corrections to the conventional predictions for the neutrino structure functions at small x are predicted, and the effects are in leading twist and persist numerically up to large values of Q2.
TL;DR: In this paper, the authors show that the rise in the γp total inelastic cross section for √s⩾100 GeV is considerably less significant than has been advocated in previous work.