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تسجيل مستخدم جديدLight Hadron Spectroscopy and Charmonium
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تأليف
Frederick A. Harris
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During the last few years there has been a renaissance in charm and charmonium spectroscopy with higher precision measurements at the $psi^{}$ and $psi(3770)$ coming from BESII and CLEOc and many new discoveries coming from B-factories. In this paper, I review some new results on classical charmonium and $e^+ e^- to$ hadrons using B-factory Initial State Radiation and two photon events.
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The latest results of CMS in the area of exotic quarkonium decays will be presented: observation of a peaking structure in $J/psiPhi$ mass spectrum in the decay $B^pm rightarrow J/psi Phi K^pm$, search for new bottomonium states in $Upsilon(1mathrm{S
})pi^+pi^-$ mass spectrum, measurement of prompt $J/psi$ pair production.
QCD-motivated models for hadrons predict an assortment of exotic hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark baryons, the six-
quark H-dibaryon, and tetraquark, hybrid and glueball mesons. Despite extensive experimental searches, no unambiguous candidates for any of these exotic configurations have been identified. On the other hand, a number of meson states, one that seems to be a proton-antiproton bound state, and others that contain either charmed-anticharmed quark pairs or bottom-antibottom quark pairs, have been recently discovered that neither fit into the quark-antiquark meson picture nor match the expected properties of the QCD-inspired exotics. Here I briefly review results from a recent search for the H-dibaryon, and discuss some properties of the newly discovered states --the proton-antiproton state and the so-called XYZ mesons-- and compare them with expectations for conventional quark-antiquark mesons and the predicted QCD-exotic states.
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The QCD light-front Hamitonian equation derived from quantization at fixed LF time provides a causal, frame-independent, method for computing hadron spectroscopy and dynamical observables. de Alfaro, Fubini, and Furlan (dAFF) have made an important o
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