Parton

About: Parton is a research topic. Over the lifetime, 13484 publications have been published within this topic receiving 368877 citations.

Double parton scattering in [Formula presented] collisions at [Formula presented]

Abstract: A strong signal for double parton (DP) scattering is observed in a 16pb−1 sample of p¯p→γ/π0+3jets+X data from the CDF experiment at the Fermilab Tevatron. In DP events, two separate hard scatterings take place in a single p¯p collision. We isolate a large sample of data (∼14000events) of which 53% are found to be DP. The process-independent parameter of double parton scattering, σeff, is obtained without reference to theoretical calculations by comparing observed DP events to events with hard scatterings in separate p¯p collisions. The result σeff=(14.5±1.7−2.3+1.7)mb represents a significant improvement over previous measurements, and is used to constrain simple models of parton spatial density. The Feynman x dependence of σeff is investigated and none is apparent. Further, no evidence is found for kinematic correlations between the two scatterings in DP events.

The Structure of the Nucleon

Abstract: Introduction ELECTROMAGNETIC STRUCTURE OF THE NUCLEON Elastic Electron Scattering Electromagnetic Form Factors of the Nucleon Nucleon Resonances Compton Scattering WEAK PROBES OF NUCLEON STRUCTURE Matrix Elements of the Weak Currents The Axial Matrix Elements in Charged Current Neutrino Reactions Beta-Decay Myon Capture Near Threshold Pion Electroproduction Neutral Current Interactions DEEP-INELASTIC LEPTON SCATTERING ON THE NUCLEON The Parton Model Scaling Violations Sum Rules Neutrino Deep-Inelastic Scattering Experimental Results for Unpolarised Targets Spin Dependent Structure Functions Qualitative Understanding of Parton Distributions ELEMENTS OF QCD Basic Lagrangian Feynman Rules Renormalization The Renormalization Group Deep Inelastic Scattering: Parton Model Deep Inelastic Scattering within QCD ASPECTS OF NON-PERTUBATIVE QCD Symmetries, Currents and Anomalies Structure of the QCD Vacuum: Brief Survey QCD Sum Rules Lattice QCD and the Nucleon CHIRAL SYMMETRY AND NUCLEON STRUCTURE Chiral Effective Field Theory Baryon Masses and Sigma Terms Chiral Low Energy Theorems Summary: The Pion Cloud of the Nucleon MODELS OF THE NUCLEON Survey Non-relativistic Quark Models Soliton Models Bag Models Chiral Quark Models Chiral Solitons Final Remarks Appendix A: Notations and Conventions Appendix B: Cross Sections for Lepton and Photon Nucleon Scattering.

Parton distributions for high energy collisions

Abstract: Recent data from deep inelastic scattering experiments atx≳10−2 are used to fix the parton distributions down tox⋟10−4 andQ2⋟0.3 GeV2. The predicted extrapolations are uniquely determined by the requirement of avalence-like structure ofall parton distributions at some low resolution scale and are furthermore shown to be insensitive in the small-x region, 10−4≲x≦10−2, to the detailed experimental input at the presently accessiblex>10−2. Simple parameterizations of the resulting parton distributions are presented in the range 10−5≲x<1 and 0.3≲Q2≲108 GeV2 as obtained from the leading- and higher-order evolution equations.