Deep-inelastic two-particle diustributions in the two-component parton model (original) (raw)

Deep-inelastic one-particle inclusive processes in the parton model

Nuclear Physics B, 1973

We study the processes e + N ~ e' + h + anything, e + + e-~ h + anything, within the parton model of Landshoff, Polkmghorne and Short Defimte and pecuhar predletlons are obtained, also common to the Drell, Levy and Yah cutoff theory and to the h~ 3 ladder model. These predictions can be summarized as follows 0) m the photon fragmentation region the cross section factorizes after integration over transverse momentum of h, (n) m the target fragmentaUon region Regge behavlour, vahd at large to, gwes rise to double Regge exchange for small values of the Feynman variable y, but only up to y ~-l/to, (m) the structure functions vamsh at y = 0, 0v) total multiplicities in the first process mcrease hke In to for large to, and m the second reach a fmlte limit at large q~ In the case where only one SU(3) multlplet of partons is present (as m the quark parton model) umque relations, vahd m the ltmlt of exact SU(3), are found between the cross section and multipheltles m the first process and the analogous quantities for the forward reglon of the second process * For sanphclty of notation we shall suppress the dependence upon the pamcular ha&on h m all of the structure functions that we introduce

Two particle inclusive distributions in the dual parton model

Physics Letters B, 1982

It is shown that the dual parton fragmentation model for low-pT multiparticle production in hadronic collisions successfully describes recently measured two particle inclusive distributions into pi+pi+, pi+pi-and pi-pi- pairs. Laboratoire associé au Centre National de la Recherche Scientifique.

The parton model and its applications

International Journal of Modern Physics A, 2014

This is a review of the program we started in 1968 to understand and generalize Bjorken scaling and Feynman's parton model in a canonical quantum field theory. It is shown that the parton model proposed for deep inelastic electron scatterings can be derived if a transverse momentum cutoff is imposed on all particles in the theory so that the impulse approximation holds. The deep inelastic electron-positron annihilation into a nucleon plus anything else is related by the crossing symmetry of quantum field theory to the deep inelastic electron-nucleon scattering. We have investigated the implication of crossing symmetry and found that the structure functions satisfy a scaling behavior analogous to the Bjorken limit for deep inelastic electron scattering. We then find that massive lepton pair production in collisions of two high energy hadrons can be treated by the parton model with an interesting scaling behavior for the differential cross sections. This turns out to be the first example of a class of hard processes involving two initial hadrons.

Deep-inelastic scattering, partons and strong interactin ideas

The quark-parton model as applied to deep-inelastic lepton-hadron scattering is used as a laboratory model for the study of ideas encountered in strong interaction physics. First, two-component duality constraints are imposed on single-particle inclusive deep-inelastic distributions. In the target fragmentation region this involves a modification of the def'mition of the E functions introduced by Feynman. A duality relation connecting neutrino and electroproduction singie-particle inclusive distributions is obtained. For to ~ 1 and w --* ** we predict in the target fragmentation region an excess of ~r + over ~-production for proton targets and an excess of~r-over ~r + for neutron targets. For deuteron targets we f'md an excess of lr-over Ir + for to --, 1.

Photoproduction within the two-component Dual Parton Model: Amplitudes and cross sections

European Physical Journal C, 1995

In the framework of the Dual Parton Model an approximation scheme to describe high energy photoproduction processes is presented. Based on the distinction between direct, resolved soft, and resolved hard interaction processes we construct effective impact parameter amplitudes. In order to treat low mass diffraction within the eikonal formalism in a consistent way a phenomenological ansatz is proposed. The free parameters of the model are determined by fits to high energy hadro- and photoproduction cross sections. We calculate the partial photoproduction cross sections and discuss predictions of the model at HERA energies. Using hadro- and photoproduction data together, the uncertainties of the model predictions are strongly reduced.

Generalized Parton Distributions: Status and Perspectives

AIP Conference Proceedings, 2009

We summarize recent developments in understanding the concept of generalized parton distributions (GPDs), its relation to nucleon structure, and its application to high-Q 2 electroproduction processes. Following a brief review of QCD factorization and transverse nucleon structure, we discuss (a) new theoretical methods for the analysis of deeply-virtual Compton scattering (t-channel-based GPD parametrizations, dispersion relations); (b) the phenomenology of hard exclusive meson production (experimental tests of dominance of small-size configurations, modelindependent comparative studies); (c) the role of GPDs in small-x physics and pp scattering (QCD dipole model, central exclusive diffraction). We emphasize the usefulness of the transverse spatial (or impact parameter) representation for both understanding the reaction mechanism in hard exclusive processes and visualizing the physical content of the GPDs.

Correlations in double parton distributions at small x ∗

2011

We present a dynamical study of the double parton distribution in impact parameter space, which enters into the double scattering cross section in hadronic collisions. This distribution is analogous to the generalized parton densities in momentum space. We use the Lund Dipole Cascade model, presented in earlier articles, which is based on BFKL evolution including essential higher order corrections and saturation effects. As result we find large correlation effects, which break the factorization of the double scattering process. At small transverse separation we see the development of "hot spots", which become stronger with increasing Q 2. At smaller x-values the distribution widens, consistent with the shrinking of the diffractive peak in elastic scattering. The dependence on Q 2 is, however, significantly stronger than the dependence on x, which has implications for extrapolations to LHC, e.g. for results for underlying events associated with the production of new heavy particles.

Smallp T particle production in the dual parton model

Zeitschrift für Physik C: Particles and Fields, 1990

The rise in the ratio of the normalized Pr distributions in small Pr region at high multiplicities to that for minimum bias events, observed for pp collisions at x/s = 63 GeV, is explained as a kinematical effect in the dual parton model. Our interpretation is rather general so that it can be applied to recent nucleus-nucleus experiments.