Heavy baryon--light vector meson couplings in QCD

The strong coupling constants of heavy baryons with light vector mesons are calculated in the framework of the light cone QCD sum rules using the most general form of the interpolating currents for the heavy baryons. It is shown that the sextet--sextet, sextet--antitriplet and antitriplet--antitriplet transitions are described by one invariant function for each class of transitions. The values of the electric and magnetic coupling constants for these transitions are obtained.Comment: 16 Pages, 4 Figures and 7 Table

Heavy-to-light transition form factors and their relations in light-cone QCD sum rules

The improved light-cone QCD sum rules by using chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable chiral currents, the light-cone sum rules for all the form factors are greatly simplified and depend mainly on one leading twist distribution amplitude of the light meson. As a result, relations between these form factors arise naturally. At the considered accuracy these relations reproduce the results obtained in the literature. Moreover, since the explicit dependence on the leading twist distribution amplitudes is preserved, these relations may be more useful to simulate the experimental data and extract the information on the distribution amplitude.Comment: 1+16 pages, no figure

Determination of the magnetic susceptibility of the quark condensate using radiative heavy meson decays

We use a light-cone sum rule (LCSR) analysis of the branching ratios of radiative meson decays to contrain the value of the magnetic susceptibility of the quark condensate $\chi(\mu)$. For the first time, we use a complete set of three-particle distribution amplitudes that enables us to give a consistent prediction for the branching ratios. Furthermore we will make use of a very recent update of several non-perturbative parameters. Our final result for $\chi(\mu= 1 {\rm GeV})= 2.85 \pm 0.5 {\rm GeV}^{-2}$ (assuming asymptotic wave functions) agrees with the currently used value of $3.15 \pm 0.3 {\rm GeV}^{-2}$.Comment: 21 pages, 4 figures, references adde

Analysis of the vertexes ΞQ∗ΞQ′V\Xi_Q^*\Xi'_Q V, ΣQ∗ΣQV\Sigma_Q^*\Sigma_Q V and radiative decays ΞQ∗→ΞQ′γ\Xi_Q^*\to \Xi'_Q \gamma, ΣQ∗→ΣQγ\Sigma_Q^*\to \Sigma_Q \gamma

In this article, we study the vertexes $\Xi_Q^*\Xi'_Q V$ and $\Sigma_Q^* \Sigma_Q V$ with the light-cone QCD sum rules, then assume the vector meson dominance of the intermediate $\phi(1020)$, $\rho(770)$ and $\omega(782)$, and calculate the radiative decays $\Xi_Q^*\to \Xi'_Q \gamma$ and $\Sigma_Q^*\to \Sigma_Q \gamma$.Comment: 28 pages, 4 tables, revised versio

Light-cone sum rules for B→πB \to \pi form factors revisited

We reconsider and update the QCD light-cone sum rules for $B\to \pi$ form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The $\bar{MS}$ $b$-quark mass is employed, instead of the one-loop pole mass used in the previous analyses. The light-cone sum rule for $f^+_{B\pi}(q^2)$ is fitted to the measured $q^2$-distribution in $B\to \pi l \nu_l$, fixing the input parameters with the largest uncertainty: the Gegenbauer moments of the pion distribution amplitude. For the $B\to \pi$ vector form factor at zero momentum transfer we predict $f^+_{B\pi}(0)= 0.26^{+0.04}_{-0.03}$. Combining it with the value of the product $|V_{ub}f^+_{B\pi}(0)|$ extracted from experiment, we obtain $|V_{ub}|=(3.5\pm 0.4\pm 0.2\pm 0.1) \times 10^{-3}$. In addition, the scalar and penguin $B\to \pi$ form factors $f^0_{B\pi}(q^2)$ and $f^T_{B\pi}(q^2)$ are calculated.Comment: 33 pages, 7 figures, one figure and a few comments added, version to appear in JHE

Strong transitions of decuplet to octet baryons and pseudoscalar mesons

The strong coupling constants of light pseudoscalar $\pi$, $K$ and $\eta$ mesons with decuplet--octet baryons are studied within light cone QCD sum rules, where $SU(3)_f$ symmetry breaking effects are taken into account. It is obtained that all coupling constants under the consideration are described by only one universal function even if $SU(3)_f$ symmetry breaking effects are switched into the game.Comment: 21 Pages, 2 Figures and 3 Table

The Semileptonic Decays D→π(ρ)eνD\to \pi(\rho) e \nu and B→π(ρ)eνB\to \pi (\rho) e \nu from QCD Sum Rules

We investigate the semileptonic decays of B and D mesons into $\pi$ and $\rho$ mesons, respectively, by means of QCD sum rules. We find that for the vector formfactors involved the pole dominance hypothesis is valid to good accuracy with pole masses in the expected range. Pole dominance, however, does not apply to the axial formfactors which results in specific predictions for the predominant polarization of the $\rho$ meson and the shape of the lepton spectrum. For the total decay rates we find $\Gamma (\bar B^0 \to \pi^+ e^- \bar\nu) = (5.1\pm 1.1)\,|V_{ub}|^2\, 10^{12}\,{\rm s^{-1}}$, $\Gamma ( D^0 \to \pi^- e^+ \nu) = (8.0\pm 1.7)\,|V_{cd}|^2\, 10^{10}\,{\rm s^{-1}}$, $\Gamma (\bar B^0 \to \rho^+ e^- \bar\nu) = (1.2\pm 0.4\,)\,|V_{ub}|^2\, 10^{13}\,{\rm s^{-1}}$ and $\Gamma (D^0 \to \rho^- e^+\nu) = (2.4\pm 0.7)\,|V_{cd}|^2\, 10^{9}\,{\rm s^{-1}}$.Comment: 23 pages, 12 figures included as uu-encoded file, needs REVTEX, TUM--T31--39/9

Strong coupling constants of heavy spin--3/2 baryons with light pseudoscalar mesons

The strong coupling constants among members of the heavy spin--3/2 baryons containing single heavy quark with light pseudoscalar mesons are calculated in the framework of the light cone QCD sum rules. Using symmetry arguments, the structure independent relations among different correlation functions are obtained. It is shown that all possible transitions can be described in terms of one universal invariant function whose explicit expression is Lorenz structure dependent.Comment: 16 Pages, 1 figure and 1 Tabl

Semileptonic Bs ->DsJ(2460)l nu decay in QCD

Using three point QCD sum rules method, the form factors relevant to the semileptonic Bs ->DsJ (2460)l nu decay are calculated. The q2 dependence of these form factors is evaluated and compared with the heavy quark effective theory predictions. The dependence of the asymmetry parameter alpha, characterizing the polarization of DsJ meson, on q2 is studied .The branching ratio of this decay is also estimated and is shown that it can be easily detected at LHC.Comment: 21 pages, 5 figures and 1 Tabl

General analysis of time evolution of decay spectrum in B^0 -> pi^+ pi^- l^+ l^-

Using the general, model independent form of effective Hamiltonian, the decay spectrum of B^0 -> pi^+ pi^- l^+ l^- decay is studied. The sensitivity of experimentally measurable asymmetries to the new Wilson coefficients and time is studied. It is observed that different asymmetries are sensitive to the new Wilson coefficients and they can serve as an efficient tool for establishing new physics beyond SM.Comment: 15 pp, 4 figures (postscript formatted), LaTex formatte