Bilocal Field Approach and Semileptonic Heavy Meson Decays

In this paper we consider the bilocal field approach for $QCD$. We obtain a bilocal effective meson action with a potential kernel given in relativistic covariant form. The corresponding Schwinger--Dyson and Bethe--Salpeter equations are investigated in detail. By introducing weak interactions into the theory we study heavy meson properties as decay constants and semileptonic decay amplitudes. Thereby, the transition from the bilocal field description to the heavy quark effective theory is discussed. Considering as example the semileptonic decay of a pseudoscalar $B$--meson into a pseudoscalar $D$--meson we obtain an integral expression for the corresponding Isgur--Wise function in terms of meson wave functions.Comment: 27 pages and 2 figures (available upon request), DESY 92-07

Obama and Medvedev – Improving US-Russian relations

After Dmitry Medvedev delivered his message to the Federation Council here last week, news outlets in the U.S. and Britain jumped on the Russian president’s seemingly hostile rhetoric regarding the planned missile defense system to be placed in Poland and the Czech Republic. Russia, Medvedev said, would respond by planting a system in Kaliningrad, on the Baltic Sea. The New York Times, which accompanied its coverage with a photo of troops on parade in Red Square, focused on his harsh words as well as the fact that that he did not congratulate Barack Obama on his election victory

Mott dissociation of D-mesons at the chiral phase transition and anomalous J/Psi suppression

We investigate the in-medium modification of the charmonium breakup processes due to the Mott-effect for D-mesons at the chiral phase transition. A model calculation for the process J/Psi+pi --> D+D^*+ h.c. is presented which demonstrates that threshold effects in the thermal averaged breakup cross section can be explained as a Mott transition where final state quark-antiquark bound states enter the continuum of resonant states at the QCD phase transition. Applications to heavy-ion collisions within a modified Glauber model scenario and the phenomenon of anomalous J/$\psi$ suppression in the CERN NA50 experiment are addressed.Comment: 5 pages, 4 figures, uses JHEP.cls styl

η−η′\eta - \eta' in a hot and dense medium

The behavior of $\eta$ and $\eta'$ in hot strange quark matter in weak equilibrium with temperature, is investigated within the SU(3) Nambu-Jona-Lasinio [NJL] model. Possible manifestations of restoration of symmetries, by temperature or density, in the behavior of $\eta$ and $\eta'$ are discussed. The role played by the combined effect of temperature and density in the nature of the phase transition and meson behavior is also analyzed.Comment: 15 pages, 5 figures. Contribution to the Second International Workshop on Hadron Physics, Effective Theories of Low Energy QCD, 25-29 September, 2002 (Coimbra, Portugal

Zubok, Leffler…

Since fellow IDEAS blogger Nick Kitchen has started us off with a post on IR theory, I’m going to take the liberty of writing on of the first posts from the history side of our humble office on Aldwych