QCD Interactions of Heavy Mesons with Pions by Light-Cone Sum Rules

Light-cone QCD sum rules are employed to compute the strong coupling constants: g_{B^* B^* pi}, g_{B_1 B_0 pi} and g_{B_1 B^* pi}, where (B,B^*) and (B_0,B_1) are negative and positive parity (0^-,1^-) and (0^+,1^+) \bar qQ doublets. The couplings are calculated both for finite values of the heavy quark mass and in the infinite heavy quark mass limit, deriving sum rules for m_Q \to \infty.Comment: Latex, 23 pages, 6 figures. Revised version to appear in Z. Phys.

On three-body B0→D∗−D(∗)0K+B^0 \to D^{*-} D^{(*)0} K^+ decays and couplings of heavy mesons to light pseudoscalar mesons

We analyze the decay modes $B^0 \to D^{*-} D^0 K^+$ and $B^0 \to D^{*-} D^{*0} K^+$ and, using the available experimental data, we find bounds for the constants g and h describing the strong coupling of heavy mesons to light pseudoscalar mesons. Both the decay channels are dominated by broad L=1 charm resonances; the dominance is effective also in $B^0 \to D^{-} D^0 K^+$ and $B^0 \to D^{-} D^{*0} K^+$.Comment: LaTex, 16 pages, 5 figure

B→Kη(′)γB\to K \eta^{(\prime)} \gamma decays in the standard model and in scenarios with universal extra dimensions

We study the radiative $B \to K \eta^{(\prime)} \gamma$ decays, which are important to investigate CP violation, and are also relevant to assess the role of the exclusive modes induced by the $b \to s \gamma$ transition to saturate the inclusive $B \to X_s \gamma$ decay rate. Moreover, these channels do not display the same hierarchy as $B \to K \eta^{(\prime)}$ modes, for which the decay into $\eta^\prime$ is enhanced with respect to one into $\eta$. The three-body radiative decays reverse the role: we find that this experimentally observed behavior (although affected by a large uncertainty in the case of the $\eta^\prime$) is reproduced in the theoretical analysis. We compute a $B^* \to K$ form factor, needed for this study, using light cone QCD sum rules, and discuss a relation expected to hold in the large energy limit for the light meson. Finally, we examine $B\to K \eta \gamma$ in two extensions of the standard model with universal extra dimensions, to investigate the sensitivity of this rare mode to such a kind of new physics effects.Comment: RevTeX, 17 pages, 7 figures. High resolution figures available upon request. Matches the published versio

Radiative transitions of DsJ∗(2317)D^*_{sJ}(2317) and DsJ(2460)D_{sJ}(2460)

We study radiative decays of $D^*_{sJ}(2317)$ and $D_{sJ}(2460)$ using light-cone QCD sum rules. In particular, we consider the decay modes $D^*_{sJ}(2317)\to D_s^* \gamma$ and $D_{sJ}(2460)\to D_s^{(*)} \gamma, D^*_{sJ}(2317) \gamma$ and evaluate the hadronic parameters in the transition amplitudes analyzing correlation functions of scalar, pseudoscalar, vector and axial-vector quark currents. In the case of $D^*_{sJ}(2317)\to D_s^* \gamma$ we also consider determinations based on two different correlation functions in HQET. The decay widths turn out to be different than previous estimates obtained by other methods; the results favour the interpretation of $D^*_{sJ}(2317)$ and $D_{sJ}(2460)$ as ordinary $\bar c s$ mesons.Comment: RevTex, 23 pages, 9 eps figure

On thermalization of a boost-invariant non Abelian plasma

Using a holographic method, we further investigate the relaxation towards the hydrodynamic regime of a boost-invariant non-Abelian plasma taken out-of-equilibrium. In the dual description, the system is driven out-of-equilibrium by boundary sourcing, a deformation of the boundary metric, as proposed by Chesler and Yaffe. The effects of several deformation profiles on the bulk geometry are investigated by the analysis of the corresponding solutions of the Einstein equations. The time of restoration of the hydrodynamic regime is investigated: setting the effective temperature of the system at the end of the boundary quenching to $T_{eff}(\tau^*)=500$ MeV, the hydrodynamic regime is reached after a lapse of time of ${\cal O}$(1 fm/c).Comment: 24 pages, 11 figures. Improved numerical analysis, one more appendix, two new figures. To appear in JHE

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