ar X iv : h ep - p h / 99 04 25 4 v 1 7 A pr 1 99 9 TWO - PHOTON PRODUCTION OF FOUR - QUARK STATES UP TO THE J / ψ ENERGY ∗
نویسندگان
چکیده
Evidence for an explicitly exotic state with isospin 2 and spin-parity 2 + near the ρρ threshold and nontrivial complementary indications of the unusual quark composition of the f0(980) and a0(980) states obtained from the reactions of two-photon formation of neutral meson resonances are discussed, together with puzzling phenomena in the channels γγ → ρ 0 φ and γγ → ρ 0 ρ 0 at high energies.
منابع مشابه
ar X iv : h ep - p h / 99 09 27 0 v 1 7 S ep 1 99 9 HARD EXCLUSIVE PHOTOPRODUCTION OF Φ
We consider the reaction γ p → M p, with M being either a Φ or a J/Ψ meson, within perturbative QCD treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to (spatially extended) diquarks and the quark-diquark distribution amplitude of the proton are adopted from previous investigations of baryon form factors and two-photon processes. Going beyond leading ...
متن کاملar X iv : h ep - p h / 99 12 32 0 v 1 1 3 D ec 1 99 9 Top mass determination in leptonic final states with J / ψ
Taking advantage of large top production rates at the LHC, the leptonic final states with J/ψ are explored for a precise determination of the top quark mass. The top is partially reconstructed by combining the isolated lepton from the W with the J/ψ from the decays of the corresponding b-quark. The method relies, to a large extent, on the proper Monte-Carlo description of top production and dec...
متن کاملar X iv : h ep - p h / 99 04 34 5 v 1 1 5 A pr 1 99 9 Supercooling in viscous hydrodynamics for QCD phase transition
First order quark hadron phase transition is considered in scaling hydrodynamics including the Csernai-Kapusta model of nucleation of hadronic bubbles leading to supercooling. The effect of viscosity on the entropy production is studied in ideal as well as in viscous hydrodynamics with and without supercooling. It is found that the excess entropy produced due to supercooling depends weakly on v...
متن کاملar X iv : h ep - p h / 99 12 39 3 v 1 1 7 D ec 1 99 9 Final - state interaction phase difference in J / ψ → ρη and ωη decays
Final-state interaction phase difference in J/ψ → ρη and ωη decays Abstract It is shown that the study of the ω − ρ 0 interference pattern in the J/ψ → (ρ 0 + ω)η → π + π − η decay provides the evidence for the large (nearly 90 •) relative phase between the one-photon and the three-gluon decay amplitudes.
متن کاملar X iv : h ep - p h / 98 04 39 7 v 1 2 4 A pr 1 99 8 Quark and Gluon Orbital Angular Momentum and Spin in Hard Processes ∗
We suggest a method of constructing gauge invariant quark and gluon distributions that describe an abstract QCD observable and apply this method to analyze angular momentum of a hadron. In addition to the known quark and gluon polarized structure functions, we obtain gauge invariant distributions for quark and gluon orbital angular momenta, and consider some basic properties of these distributi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1999