Showing papers on "Parton published in 1984"
CERN1
TL;DR: In this paper, a new model for hadronic jet fragmentation in hard processes is presented based on a QCD parton branching mechanism with correct treatment of leading collinear and infra-red singularities (i.e. including soft gluon interference).
725 citations
TL;DR: In this paper, a new Monte Carlo simulation scheme for jet evolution in perturative QCD is presented, which takes into account the results of recent analyses of soft-gluon interference.
515 citations
TL;DR: In this article, the authors studied the fragmentation of arbitrary parton configurations, with particular emphasis on events where two partons have a small invariant mass, and formulated an explicit model for the fragmentation process.
134 citations
TL;DR: In this paper, quantum chromodynamic (QCD) predictions are made for the large transverse momentum production of single and double photons in proton-proton, protonantiproton, and pionproton collisions, and it is found that the QCD-induced subprocess gg→γγ provides an important source of double photons.
76 citations
TL;DR: In this paper, the authors performed a QCD calculation of semi-inclusive Higgs-boson production in conjunction with a heavy-quark pair in pp-bar collisions.
Abstract: We have performed a QCD calculation of semi-inclusive Higgs-boson production in conjunction with a heavy-quark pair in pp-bar collisions. Numerical results are obtained through a Monte Carlo integration. Several differential cross sections relevant to experiment are given.
63 citations
TL;DR: In this paper, the average multiplicities, rapidity densities and dispersion in high-energy nucleus-nucleus collisions are computed in the framework of the dual parton model.
59 citations
TL;DR: In this article, the role of multiple parton collisions giving rise to three and four large pT jets in high energy p p reactions is discussed, and it is shown that these effects can be observable at the CERN collider, and that they appreciably increase with increasing CMS energy.
53 citations
TL;DR: Particle production in soft hadron-hadron collisions at collider energies is investigated in a two-step dual parton model in this paper, where the initial collision color-singlets or strings of hadronic matter are formed from constituents of the incident particles.
Abstract: Particle production in soft hadron-hadron collisions at collider energies is investigated in a two-step dual parton model. In the initial collision color-singlets or strings of hadronic matter are formed from constituents of the incident particles. These strings subsequently decay into chains of hadrons, analogously to the\(q\bar q\) system in low energye+e− physics. Relying on the Monte-Carlo method we generate exclusive events and evaluate quantities of interest which include inclusive and semi-inclusive pseudorapidity spectra, topological cross-section, correlations and charge transfer distributions.
37 citations
TL;DR: The net charge of final state hadrons in both the current and target fragmentation regions has been measured in 280 GeV/c muon-proton scattering experiment in this article, and a clean kinematic separation of the two regions in the centre-of-mass rapidity is demonstrated.
30 citations
CERN1
TL;DR: In this article, the neutral analogue for the pp collider, constructed from the transverse energies and azimuthal angles of the final state hadrons, is presented, and leading order QCD predictions are calculated.
30 citations
CERN1
TL;DR: The measurements of the z and p T 2 distribution of hadrons produced in the interactions of 200 GeV muons with copper and carbon nuclei are shown in different x Bj and virtual photon energy intervals as mentioned in this paper.
TL;DR: The EMC and SLAC data on iron and deuterium targets show enhanced and suppresed scattering for kinematic regions where Bjorken x 1.5 as mentioned in this paper.
TL;DR: In this paper, the energy flow and particle flow distributions of planar three-jet events produced in e+e−→ hadrons at CM energies between 29.5 and 36.4 GeV have been interpreted in terms of the reactions e−e−q q g and compared with the distributions calculated from two different fragmentation schemes, one based on independent parton fragmentation, the other one on fragmentation along colour flux lines.
TL;DR: In this paper, a large long-range correlation between particles produced in two rapidity intervals is predicted, provided these two rapidities are properly chosen, and the predicted effect is easily measurable.
Abstract: Long-range rapidity correlations between particles produced in proton-nucleus interactions at 200 GeV/c are studied in the multichain dual parton model. A large long-range correlation between particles produced in two rapidity intervals is predicted, provided these two rapidity intervals are properly chosen. The predicted effect is easily measurable. Predictions at 1 TeV are also given.
TL;DR: In this article, the x dependence of the longitudinal structure function F L with neutrino and antineutrino wide-band beams of the CERN 400 GeV SPS was determined.
TL;DR: In this article, a phenomenological analysis of the role of nucleon and quark correlations in the nuclear ground state on the quark momentum distribution in nuclei is made based on the recent observations in deep-inelastic lepton nuclear scattering of an anomalous nuclear effect.
Abstract: A phenomenological analysis is made of the role of nucleon and quark correlations in the nuclear ground state on the quark momentum distribution in nuclei. The analysis is based on the recent observations in deep-inelastic lepton nuclear scattering of an anomalous nuclear effect. The discussion is framed in the QCD-improved quark parton model. The incoherent nucleon contribution is augmented by contributions representative of correlation effects which are described in a simple cluster model. Two distinct mechanisms are considered: one invoking two-nucleon and three-nucleon clusters with high intrinsic momenta and the other invoking six-quark correlated clusters. It is found that the second six-quark cluster mechanism provides a viable explanation of the anomaly, especially the depletion at large x. The enhancement observed at small x remains problematical in this cluster approach and an explanation of it is attempted in a parton-model approach of Regge behaviour for the sea-quark distribution in nuclei.
TL;DR: In this paper, the same physical picture was implemented with a spectrum of discrete hadrons, the Artru-Mennessier model being recovered in the limit of a dense spectrum, where fragmentation functions are mass dependent and heavy hadrons are dynamically suppressed relative to lighter.
Abstract: The Artru-Mennessier model for the breakup of strings of colour connecting partons yields a continuous hadron spectrum. I show how the same physical picture may be implemented with a spectrum of discrete hadrons, the Artru-Mennessier model being recovered in the limit of a dense spectrum. As in the Artru-Mennessier model, fragmentation functions are mass dependent and heavy hadrons are dynamically suppressed relative to lighter.
TL;DR: In this article, a dynamical mechanism for the production of baryons in e + e − annihilations both on and off the upsilon resonance is presented, and Parton showers are produced using an approximation to QCD perturbation theory.
CERN1
TL;DR: In this paper, the primordial transverse momentum of the partons in the incoming hadrons was modelled for particle production and it was shown that the average transverse acceleration of secondaries increases with multiplicity.
TL;DR: In this article, the pion can be considered as a parton in the nucleon for low momentum transfer Q 2, for the kinematical conditions photon mass Q 2 2 and electron energy loss ν > 2.2 GeV, and pion electroproduction in the direction of virtual photon can be viewed upon as quasielastic e π + → e′ π+ scattering.
TL;DR: In this paper, it is shown that the quantum numbers of triggering charged particles and positive particles are correlated with the flavour of the scattered parent parton, thus one can enhance data samples with a particular flavour of a scattered parton.
Abstract: High energy proton-proton interactions yielding a single trigger particle with large transverse momentum give rise to a four-jet event structure with two transverse jets and two jets along the beam direction. The transverse jets are due to the fragmentation of point like scattered partons. It is shown that the quantum numbers of triggering charged pions and positive kaons are correlated with the flavour of the scattered parent parton; thus one can enhance data samples with a particular flavour of a scattered parton. The analysis, which is independent of detailed model calculations, exploits (a) the identification of the leading particles in the trigger jets (trigger particles), (b) the measurement of their relative production rates, (c) short range quantum number correlations within the trigger jets, and (d) long range correlations between leading particles from different jets. The data were obtained at\(\sqrt s \) =62 GeV with the Split Field Magnet detector at the CERN ISR.
TL;DR: Perturbative QCD is applied to large p/sub T/ production of hadrons, one jet, and two jets at CERN collider and CERN ISR (..sqrt..s = 63 GeV) energies as discussed by the authors.
Abstract: Perturbative QCD is applied to large-p/sub T/ production of hadrons, one jet, and two jets at CERN collider (..sqrt..s = 540 GeV) and CERN ISR (..sqrt..s = 63 GeV) energies. Two sets of gluon and other parton distributions determined from deep-inelastic scattering are used, and the results are compared. K factors (order-..cap alpha../sub s/ /sup 3/ perturbative corrections) are approximately taken into account. On the whole, experimental data are well accounted for.
TL;DR: In this article, the authors examined the extent to which reactions of the form gg→gb b, qg→qb b and q q →b b g (and charmed quark pairs) can give rise to prompt leptons and event topologies that simulate those expected from t-quark production via W → t b and gg (or q q ) → t t .
TL;DR: In this paper, the authors argue that QCD with the maximum number of fermions allowed by asymptotic freedom provides a "parton-model" description of soft high-energy collisions.
Abstract: We argue that QCD with the maximum number of fermions allowed by asymptotic freedom provides a ''parton-model'' description of soft high-energy collisions. That is, infinite-momentum quantization can be based on the perturbative vacuum and yet produce confinement and chiral-symmetry breaking. A first-stage infrared construction gives SU(2) gauge invariance and confinement. An infrared fixed point produces transverse momentum scaling and associated infrared divergences which couple to an anomaly-current component of a Fock-space wave function. The divergences factor on to color-zero states allowing the wave function zeros needed by transverse gauge invariance. Parton interactions are dominated by fermion-loop anomalies coupled to the divergences. As a result a pion has a vector valence-quark component. The infrared limit giving SU(3) gauge invariance is argued to be accompanied by critical-Pomeron high-energy behavior and spontaneous chiral-symmetry breaking, but is only briefly discussed in this paper.
01 Jan 1984
TL;DR: In this article, it was shown that the standard methods of perturbative QCD are valid to extremely small x. The methods are valid provided a quantity we call the packing fraction of partons in a hadron is much less than one.
Abstract: It is shown how the standard methods of perturbative QCD are valid to extremely small x. The methods are valid provided a quantity we call the packing fraction of partons in a hadron is much less than one. One surprising consequence is that the cross-section for production of jets of a few GeV energy can be reliably calculated. Since this cross-section in tens of millibarns, the phenomenology of minimum bias events at the SSC will be different than at lower energy; this will have a significant effect on the backgrounds for new physics events. 8 references.
TL;DR: In this article, it was shown that carefully measured momemtum distributions in the inclusive reactionspp→C+X,C=π+, π−,K+,K− can be quantitatively understood in a parton fragmentation approach provided both diquark fragmentation as well as diffractive resonance production and decay are taken into account.
Abstract: It is shown that carefully measured momemtum distributions in the inclusive reactionspp→C+X,C=π+, π−,K+,K− can be quantitatively understood in a parton fragmentation approach provided both diquark fragmentation as well as diffractive resonance production and decay are taken into a account.
TL;DR: In this article, the first four moments of the rescattering chains in the dual parton model at ISR, SPS collider and Tevatron energies, and for different rapidity intervals are computed.
Abstract: The first four moments of the
$$\bar p$$
p multiplicity distribution are computed in the framework of the dual parton model at ISR, SPS collider and Tevatron energies, and for different rapidity intervals. Our results exhibit a striking dependence of the various moments on the size of the rapidity interval which is characteristic of the nature of the rescattering chains in the dual parton model. They also show a violation of KNO scaling throughout the considered energy range. Our results indicate that only light clusters (consistent with known resonances) are produced at all energies.
TL;DR: In this paper, the cross sections of hadron pair production with symmetric momenta produced back-to-back in the c.m.s. collisions in the range 0.45 ⩽ PT⩽ 1.99 GeV/c.
TL;DR: In this paper, the anomalous behavior of the nuclear structure functions is discussed in the framework of a simple statistical parton model, where the nucleus is treated as a bag of uncorrelated partons.
Abstract: The anomalous behaviour of the nuclear structure functions is discussed in the framework of a simple statistical parton model, where the nucleus is treated as a bag of uncorrelated partons. We show that the model reproduces correctly the main features of the effect and, to some extent, it is even successful at the numerical level. The characteristic prediction of the model (to be tested experimentally) is a saturation law: for largeA (=nuclear mass number) the anomalous nuclear behaviour of the structure functions is described by a universal (i.e.A-independent) function of the Bjorken variable.