Deep Inelastic Lepton-Nucleon Scattering and the Core Structure of Nucleons in the Framework of the Quark-Parton Model (original) (raw)

Nucleon parton distributions and nuclear structure

Nuclear Physics A, 1991

' ' ••^.T he current experimental status of measurements of nucleon structure funcSid' fi.' S.vind eep inelastic lepton scattering is presented. Recent BCDMS and SLAG results provide " " •-.. a consistent data set for charged lepton scattering. New probes of parton distributions: direct photons, Drell Yan di-muon production, W, Z and heavy quark production are providing information on the gluon and antiquark distributions. The implications of these data on our understanding of the structure of the nucleon, and the structure of the nucleon in the nucleus are discussed.

Connection between In Medium Nucleon Form Factors and Deep Inelastic Structure Functions

2006

We present a connection between the modifications induced by the nuclear medium of the nucleon form factors and of the deep inelastic structure functions, obtained using the concept of generalized parton distributions. Generalized parton distributions allow us to access elements of the partonic structure that are common to both the hard inclusive and exclusive scattering processes in nuclei. PACS numbers: 13.60.Hb, 13.40.Gp, 24.85.+p An important question that remains currently unsolved in Quantum Chromodynamics (QCD), is the determination of the quark and gluon structure of nuclei. Theoretical efforts have so far concentrated on two apparently distinct areas. Many studies were dedicated on one side to pinning down the mechanisms producing nuclear medium modifications of quark and gluon momentum distributions from inclusive (and semi-inclusive) deep inelastic scattering experiments. Sizable A-dependent effects have in fact been observed during the past two decades (see the review in Ref.

Spin-dependent parton distributions in polarized deep inelastic lepton nucleon scattering

Zeitschrift f�r Physik C Particles and Fields, 1988

We analyze the recently measured first moment FP(Q 2) of the structure function gpl(x,Q 2) obtained in deep inelastic scattering of polarized electrons from polarized protons. It is shown that the recent experimental result _F'P(( Q2 > ~ 10 GeV 2) ,-~ 0.113 implies a polarized strange quark sea whose total polarization As(p 2) ~_-0.22 is comparable to Au(/~ 2) -0.74 and Ad(# 2) _ -0.50 already at a typically hadronic scale # = 0(1 GeV). Most remarkably, the total polarization due to quark distributions du(~t 2) + Ad(# 2) + As(# 2) practically vanishes which implies that the spin of the proton is carried by the gluons, A G(#2), and/or the angular momentum of the partons. This surprising conjecture can be experimentally tested with heavy quark production in longitudinally polarized lepton-nucleon scattering. In particular the (real) photon-gluon fusion process 79 ~ Q Q provides a rather unique measure of A G(x, Q2).

Parton and valon distributions in the nucleon

Physical Review D, 1981

Structure functions of the nucleon are analyzed in the valon model in which a nucleon is assumed to be a bound state of three valence quark clusters Ivalons}. At high g' the structure of the valons is described by leading-order results in the perturbative quantum chromodynamics. From the experimental data on deep-inelastic scattering off protons and neutrons, the flavor-dependent valon distributions in the nucleon are determined. Predictions for the parton distributions are then made for high Q without guesses concerning the quark and gluon distributions at low Q'. The sea-quark and gluon distributions are found to have a 'sharp peak at very small x. Convenient parametrization is provided which interpolates between different numbers of flavors.