2,335 research outputs found

    GRB 980329: Determining Density Without a Redshift

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    We fit models to the late-time broadband dataset of gamma-ray burst (GRB) 980329. Despite being limited by sparse early optical data and no redshift measurement, we determine some parameters of the afterglow and its host robustly. The fireball expanded into a relatively dense medium with n ~ 200 cm^(-3). The host is far bluer than the afterglow, and is not compatible with high z ~ 5

    QED X QCD Exponentiation: Shower/ME Matching and IR-Improved DGLAP Theory at the LHC

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    We discuss the elements of QED X QCD exponentiation and its interplay with shower/ME matching and IR-improved DGLAP theory in precision LHC physics scenarios. Applications to single heavy gauge boson production at hadron colliders are illustrated.Comment: 5 pages, 1 figure; presented by B.F.L. Ward at ICHEP0

    New Approach to Parton Shower MC's for Precision QCD Theory: HERWIRI1.0(31)

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    By implementing the new IR-improved Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-Callan-Symanzik (DGLAP-CS) kernels recently developed by one of us in the HERWIG6.5 environment we generate a new MC, HERWIRI1.0(31), for hadron-hadron scattering at high energies. We use MC data to illustrate the comparison between the parton shower generated by the standard DGLAP-CS kernels and that generated by the new IR-improved DGLAP-CS kernels. The interface to MC@NLO, MC@NLO/HERWIRI, is illustrated. Comparisons with FNAL data and some discussion of possible implications for LHC phenomenology are also presented.Comment: 24 pages, 10 figures; published versio
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