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Presence and absence of scaling violations in inclusive leptoproduction

In the standard model, the heavy-quark-parton scaling variable is used to study the effects of the color-octet piece of the integrally- charged-quark-parton electromagnetic current which would violate scaling in deep-inelastic leptoproduction. With spin-1/2 partons it is found that sigma /sub L// si...

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Detalles Bibliográficos
Autor principal: Nelson, C A
Lenguaje:eng
Publicado: 1978
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevD.18.2345
http://cds.cern.ch/record/879089
Descripción
Sumario:In the standard model, the heavy-quark-parton scaling variable is used to study the effects of the color-octet piece of the integrally- charged-quark-parton electromagnetic current which would violate scaling in deep-inelastic leptoproduction. With spin-1/2 partons it is found that sigma /sub L// sigma /sub T/ would deviate significantly from zero since ( sigma /sub L// sigma /sub T/)/sub mu N/ approximately=4m/sub c//sup 2/f/sub nu /(z)/ 5Q/sup 2/f/sub nu /(x), where f/sub nu /(z)=u/sub nu / (z)+d/sub nu /(z), m/sub c//sup 2 /=effective mass-squared of quark-parton in color-excited hadron, and z approximately=x+m/sub c//sup 2//2ME gamma . Such scaling violations must occur in the mu data at currently available energies if the step of 2 units of R (beyond charm) in the 4-GeV region in the SPEAR data for ee annihilation is due to a color threshold for the production of color-octet qq mesons, qqq baryons, and/or quark-antiquark pairs. Consistency is shown between the scaling violations in the muoproduction and electroproduction data in the x<0.2 region and the energy independence in the data of the CERN-Dortmund-Heidelberg-Saclay collaboration for charged-current neutrino distributions for average y and for sigma /sup antineutrino// sigma /sup neutrino/. Exclusive final states responsible for electroproduction scaling violations in the x<0.2 region would contain the tau -particle-antiparticle pairs (i.e., integrally charged quarks) and/or high-momentum photons (few Ge V) from radiative decay modes of color-octet hadrons. (22 refs).