THE ENDPOINT REGION IN RADIATIVE QUARKONIA DECAYS
نویسندگان
چکیده
منابع مشابه
The Endpoint Region in Radiative Quarkonia Decays
The use of perturbation theory to describe radiative decays of quarkonia is based on the fact that, as long as the velocity v of the heavy quark is small, these decay processes involve two widely separated distance scales: the scale 1/(mv) over which the quark and antiquark bind into the quarkonium and the scale 1/m over which the quark-antiquark pair decays (with m the heavy quark mass). By ex...
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Non-relativistic QCD (NRQCD) predicts colour octet contributions to be significant not only in many production processes of heavy quarkonia but also in their radiative decays. We investigate the photon energy distributions in these processes in the endpoint region. There the velocity expansion of NRQCD breaks down which requires a resummation of an infinite class of colour octet operators to so...
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We argue that the photon spectra in radiative decays of various heavy quarkonium states provide important information on their nature. If two of these states are in the strong coupling regime, we are able to produce a parameter-free model-independent formula, which holds at next-to-leading order and includes both direct and fragmentation contributions. When the formula is checked against recent...
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We study infrared QCD effects in radiative quarkonia decays. We examine the endpoint region z → 1 of the photon spectrum. We point out a cancellation mechanism for the corrections in α s ln (1− z), m ≤ 2n, in the short-distance coefficient for the color-singlet Fock state in the quarkonium. The cancellation is due to the coherence of the color radiation, and applies even though logarithmic cont...
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The Operator Product Expansion, in conjunction with the power counting of nonrelativistic field theory, is used to examine the end-point region of the radiative decay of heavy quark bound states with S1 quantum numbers, QQ̄ → γ + X. We identify an infinite class of operators that determine the shape of the photonic end-point spectrum. These operators can be resummed to form an octet structure fu...
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ژورنال
عنوان ژورنال: International Journal of Modern Physics A
سال: 2001
ISSN: 0217-751X,1793-656X
DOI: 10.1142/s0217751x01006395