ترغب بنشر مسار تعليمي؟ اضغط هنا

74 - J. Rojo , R. D. Ball , V. Bertone 2010
We discuss the implementation of the FONLL general-mass scheme for heavy quarks in deep-inelastic scattering in the FastKernel framework, used in the NNPDF series of global PDF analysis. We present the general features of FONLL and benchmark the accu racy of its implementation in FastKernel comparing with the Les Houches heavy quark benchmark tables. We then show preliminary results of the NNPDF2.1 analysis, in which heavy quark mass effects are included following the FONLL-A GM scheme.
Direct photon production is an important process at hadron colliders, being relevant both for precision measurement of the gluon density, and as background to Higgs and other new physics searches. Here we explore the implications of recently derived results for high energy resummation of direct photon production for the interpretation of measurements at the Tevatron and the LHC. The effects of resummation are compared to various sources of theoretical uncertainties like PDFs and scale variations. We show how the high--energy resummation procedure stabilizes the logarithmic enhancement of the cross section at high--energy which is present at any fixed order in the perturbative expansion starting at NNLO. The effects of high--energy resummation are found to be negligible at Tevatron, while they enhance the cross section by a few percent for $p_T lsim 10$ GeV at the LHC. Our results imply that the discrepancy at small $p_T$ between fixed order NLO and Tevatron data cannot be explained by unresummed high--energy contributions.
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا