相关论文: Form Factors for Semileptonic B -> pi and D -> pi …
We have computed the form factors for B --> pi and D --> K(pi) semileptonic decays on the lattice by using full non-perturbative O(a) improvement, in the quenched approximation. Our results are expressed in terms of few parameters which…
The form factors of the semileptonic $B\to \pi\pi\ell\bar\nu$ decay are calculated from QCD light-cone sum rules with the distribution amplitudes of dipion states. This method is valid in the kinematical region, where the hadronic dipion…
We present lattice results for the vector and scalar form factors of the semileptonic decays D -> \pi \ell \nu_ell and D -> K \ell \nu_\ell in the physical range of values of squared four momentum transfer q^2, obtained with N_f=2 maximally…
Omnes dispersion relations make a connection between form factors for exclusive semileptonic decays and phase shifts in the corresponding elastic scattering channels. We describe two applications. In the first, we use lattice form factor…
The form factors of $B_{(s)}$ decays into P-wave excited charmed mesons (including $D^*_0(2300)$, $D_1(2430)$, $D_1(2420)$, $D^*_2(2460)$ and their strange counterparts, denoted generically as $D^{**}_{(s)}$) are systematically calculated…
We reanalyze B -> D pi and B -> K J/psi data to extract a set of parameters which give the relevant hadronic matrix elements in terms of factorized amplitudes. Various sources of theoretical uncertainties are studied, in particular those…
We compute semi-leptonic $B_s$ decay form factors using Heavy Quark Effective Theory on the lattice. To obtain good control of the $1/m_b$ expansion, one has to take into account not only the leading static order but also the terms arising…
Using partially twisted boundary conditions we compute the K->pi semi-leptonic form factors in the range of momentum transfers 0 <~ q^2 <= q^2_{max}=(mK-mpi)^2 in lattice QCD with N_f=2+1 dynamical flavours. In this way we are able to…
We present the current status of the computation of the form factor $f_+ (q^2)$ for the semi-leptonic decay $\mathrm B_\mathrm s \to \mathrm K \ell \nu$ by the ALPHA collaboration. We use gauge configurations which were generated as part of…
We extract the form factors relevant for semileptonic decays of D and B mesons from a relativistic computation on a fine lattice in the quenched approximation. The lattice spacing is a=0.04 fm (corresponding to a^{-1}=4.97 GeV), which…
We present a quenched calculation of the form factors of the semileptonic weak decay $B \to \pi l \bar{\nu}$ with $O(1/m_Q)$ NRQCD heavy quark and Wilson light quark on a $16^3 \times 32$ lattice at $\beta=5.8$. The form factors are…
We present a new and very high statistics study of D and D_s semileptonic decay form factors on the lattice. We work with MILC N_f=2+1 lattices and use the Highly Improved Staggered Action (HISQ) for both the charm and the light valence…
The semileptonic $B\to \pi l^+ \nu_l$ decay is studied starting from a simple quark model which includes the influence of the $B^*$ pole. To extend the predictions of a nonrelativistic constituent quark model from its region of…
The form factors relevant to $B_{q}\to D^{\ast}_{q}(J^{P}=1^{-})\ell\nu$ $(q=s, d, u)$ decays are calculated in the framework of the three point QCD sum rules approach. The heavy quark effective theory prediction of the form factors are…
We investigate the form factors for exclusive semileptonic decays of $B$-meson to $D,~D^*$, based on the parton picture and helped by the results of the HQET. We obtain the numerical results for the slope of the Isgur-Wise function, which…
We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function…
Quark model results for the $B\to \pi,\rho$ decays are analysed, making use of the dispersion formulation of the model: The form factors at $q^2>0$ are expressed as relativistic invariant double spectral representation over invariant masses…
The form factors for semi-leptonic B decays, $\bar{B}\to\pi l\bar{\nu}_l$, are calculated under collinear factorization approach. The end-point divergences are regularized by a $\xi$-regularization, where $\xi$ means the collinear fraction…
We present a very high statistics study of D and D_s semileptonic decay form factors on the lattice. We work with MILC N_f=2+1 lattices and use the Highly Improved Staggered Quark action (HISQ) for both the charm and the strange and light…
The S and P wave $\pi \pi$ phase shifts are recalculated in terms of two phenomenological parameters using the one loop CPTh and the elastic unitarity condition. Using these phase shifts, the vector and scalar form factors are calculated…