Identifying DsJ(2700)D_{sJ}(2700) through its decay modes

We study how to assign the recently observed $D_{sJ}(2700)$ meson to an appropriate level of the $c \bar s$ spectrum by the analysis of its decay modes in final states comprising a light pseudoscalar meson. We use an effective lagrangian approach with heavy quark and chiral symmetries, obtaining that the measurement of the $D^* K$ decay width would allow to distinguish between two possible assignments.Comment: RevTex, 6 pages - references adde

Puzzles in charm spectroscopy

We briefly analyze aspects of open and hidden charm resonances, discussing in particular the mesons $D_{sJ}(2860)$ and X(3872).Comment: 8 pages, 4 figures. Invited talk given at the YKIS Seminar on New Frontiers in QCD: Exotic Hadrons and Hadronic Matter, Kyoto, Japan, 20 Nov. - 8 Dec. 200

The effects of enhanced Z penguins on lepton polarizations in B→Xsℓ+ℓ−B \to X_s \ell^+ \ell^-

The sensitivity of the $B \to \pi K$ mode to electroweak penguins and the recent experimental data for the $B \to \pi \pi$, $\pi K$ modes has given rise to what is known as the ``$B \to \pi K$ puzzle''. Recently it has been observed that this {\sl puzzle} can be resolved by considering the new physics which can enter via $Z^0$ penguins. In this note we analyze the effect of this enhanced $Z^0$ penguins on the lepton polarization asymmetries of $b \to s \ell^+ \ell^-$.Comment: Published versio

The electromagnetic effects in Ke4K_{e4} decay

The final state interaction of pions in $K_{e4}$ decay allows one to obtain the value of the isospin and angular momentum zero $\pi\pi$ scattering length $a_0^0$.We take into account the electromagnetic interaction of pions and isospin symmetry breaking effects caused by different masses of neutral and charged pions and estimate the impact of these effects on the procedure of scattering length extraction from $K_{e4}$ decay.Comment: 8 pages,1 figur

Strong Interactions at Low Energy

The lectures review some of the basic concepts relevant for an understanding of the low energy properties of the strong interactions: chiral symmetry, spontaneous symmetry breakdown, Goldstone bosons, quark condensate. The effective field theory used to analyze the low energy structure is briefly sketched. As an illustration, I discuss the implications of the recent data on the decay $K\to \pi\pi e\nu$ for the magnitude of the quark condensate.Comment: Lectures given at the school of physics "Understanding the structure of hadrons", Prague, July 2001, 20 p

Observation of a Broad L=1 cqˉc\bar{q} State in B−→D∗+π−π−B^{-}\to D^{*+}\pi^{-}\pi^{-} at CLEO

Using 4.7 fb^-1 of data taken at CESR at energies at and near the Upsilon(4S) we have studied the decay B- -> D{*+}pi-pi- (and its conjugate). We observe a new, broad charmed meson state, which we interpret as D_J(j=1/2), in its decay to D{*+}pi-. Our preliminary results indicate the mass and width of this L=1 state to be m = (2461 +41/-3} +/-10 +/-32) MeV and Gamma = (290 +101/-79 +/-26 +/-36) MeV, with the third uncertainty associated with the parameterization of the relative strong phases. In addition we have measured several new branching fractions of charged B mesons. All quoted results are preliminary.Comment: 7 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

The isospin symmetry breaking effects in Ke4K_{e4} decays

The Fermi-Watson theorem is generalized to the case of two coupled channels with different masses and applied to final state interaction in $K_{e4}$ decays. The impact of considered effect on the phase of the $\pi\pi$ scattering is estimated and shown that it can be crucial for scattering lengths extraction from experimental data on $K_{e4}$ decays