相关论文: Slope of the Isgur-Wise Function from a QSSR Const…

We estimate the sum of the $\Upsilon \bar BB $ couplings using QCD Spectral Sum Rules (QSSR). Our result implies the phenomenological bound $\xi'(vv'=1) \geq -1.04$ for the slope of the Isgur-Wise function. An analytic estimate of the…

From sum rules in the heavy quark limit of QCD, using the non-forward amplitude, we demonstrate that if the slope rho^2 = -xsi'(1) of the Isgur-Wise function xsi(w) attains its lower bound 3/4 (as happens in the BPS limit proposed by…

Sum rules based upon heavy quark effective theory indicate that the Isgur-Wise function $\xi(w)$ has a minimum slope as w approaches 1, which is zero for light degrees of freedom with zero spin and 1/4 for light spin 1/2. Quark-model…

We discuss the Isgur-Wise function $\xi (y)$ in the small velocity (SV) limit within the QCD sum rule method. The behavior of $\xi (y)$ in the SV limit is sensitive to the particular form of the duality relations used to decontaminate the…

Using previously formulated sum rules in the heavy quark limit of QCD, we demonstrate that if the slope rho^2 = -xi'(1) of the Isgur-Wise function xi(w) attains its lower bound 3/4, then all the derivatives (-1)^L xi^(L)(1) attain their…

Using the OPE, we obtain new sum rules in the heavy quark limit of QCD, in addition to those previously formulated. Key elements in their derivation are the consideration of the non-forward amplitude, plus the systematic use of boundary…

In the heavy quark limit of QCD, using the Operator Product Expansion, the formalism of Falk for hadrons or arbitrary spin, and the non-forward amplitude, as proposed by Uraltsev, we formulate sum rules involving the Isgur-Wise function…

We reconsider the recent derivation by de Rafael and Taron of bounds on the slope of the Isgur-Wise function. We argue that one must be careful to include cuts starting below the heavy meson pair production threshold, arising from heavy…

In the leading order of the heavy quark expansion, we propose a method within the OPE and the trace formalism, that allows to obtain, in a systematic way, Bjorken-like sum rules for the derivatives of the elastic Isgur-Wise function…

The original de Rafael-Taron bound on the slope of the Isgur-Wise function at zero recoil is known to be violated in QCD by singularities appearing in an unphysical region. To be consistent, quark models must have corresponding singularity…

Using the OPE and the trace formalism, we have obtained a number of sum rules in the heavy quark limit of QCD that include the sum over all excited states for any value $j^P$ of the light cloud. We show that these sum rules imply that the…

Radiative corrections to both perturbative and non-perturbative contributions are added to existing calculations of the Isgur-Wise function $\xi_{IW}$. To this end, we develop a method for calculating two-loop integrals in the heavy quark…

In the heavy quark limit of QCD, using the Operator Product Expansion and the non-forward amplitude, as proposed by Nikolai Uraltsev, we formulate sum rules that generalize Bjorken and Uraltsev sum rules. We recover the Uraltsev lower bound…

Considering nonforward scattering amplitude off the heavy quark in the Small Velocity limit two exact superconvergent sum rules are derived. The first sum rule leads to the lower bound \rho^2 > 3/4 for the slope of the Isgur-Wise function.…

We use a $1S$ lattice QCD heavy-light wavefunction to generate a single parameter, model independent description of the Isgur-Wise function. Using recent data we find the zero-recoil slope to be $\xi'(1)= -1.16\pm 0.17$, while the second…

We consider the dominant $c\bar{c}$ contribution to $\Delta \Gamma$ for the $B_s^0$-$\bar{B}_s^0$ system in the heavy quark limit for both $b$ and $c$ quarks. In analogy with the Bjorken-Isgur-Wise sum rule in semileptonic heavy hadron…

We show that the sum rule recently proved by Uraltsev in the heavy quark limit of QCD holds in relativistic quark models \`a la Bakamjian and Thomas, that were already shown to satisfy Isgur-Wise scaling and Bjorken sum rule. This new sum…

We have recently reported the calculation of slope and curvature of Isgur-Wise function based on Variationally Improved Perturbation Theory (VIPT) in a QCD inspired potential model. In that work, Coulombic potential was taken as the parent…

Using the OPE, we formulate new sum rules in the heavy quark limit of QCD. These sum rules imply that the elastic Isgur-Wise function $\xi (w)$ is an alternate series in powers of $(w-1)$. Moreover, one gets that the $n$-th derivative of…

Recently, Gilmer proved the first constant lower bound for the union-closed sets conjecture via an information-theoretic argument. The heart of the argument is an entropic inequality involving the OR function of two i.i.d.\ binary vectors,…