Related papers: The Isgur-Wise function in the BPS limit

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…

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 a preceeding study in the heavy quark limit of QCD, it has been demonstrated that the best lower bound on the curvature of the Isgur-Wise function Xsi(w) is Xsi"(1) > (4rho2+3(rho2)2) > 15/16. The quadratic term (rho2)2 is dominant in a…

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…

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…

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 integral representation for Isgur -- Wise function (IWF) is obtained in the framework of instant--form relativistic Hamiltonian dynamics for mesons with one heavy quark. The upper and lower limits are calculated for the slope parameter…

We derive optimal upper and lower bounds on the slope of the Isgur-Wise function at the zero recoil point in terms of the sum of the $\Upsilon B\bar{B}$ couplings, estimated recently from a $QCD$ Spectral Sum Rule ($QSSR$). The problem is…

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 use the Dirac equation with a ``(asymptotically free) Coulomb + (Lorentz scalar) linear '' potential to estimate the light quark wavefunction for $ q\bar Q$ mesons in the limit $m_Q\to \infty$. We use these wavefunctions to calculate the…

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…

We pursue the group theoretical method to study Isgur-Wise functions. We apply the general formalism, formerly applied to the baryon case j^P = 0^+ (for \Lambda_b -> \Lambda_c \ell \nu), to mesons with j^P = 1/2^-, i.e. $\overline{B} ->…

We discuss constraints imposed on the zero-recoil curvature and higher derivatives of the Isgur-Wise function by a general quark model. These constraints are expressed as bounds for a given slope parameter, and compared with those based…

We consider the Isgur-Wise function xi(omega) within a new modified version of a heavy-light chiral quark model. While early versions of such models gave too small absolute value of the slope, namely xi'(1) of about -0.4 to -0.3, we show…

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 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…

We study light quark dependence of the Isgur-Wise function for $B_a\rightarrow D_a$ and $B_a\rightarrow D^{*}_a$ in the framework of QCD sum rules. At zero recoil , all the Isgur-Wise functions equal as required by heavy quark symmetry and…

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…

We calculate the Isgur-Wise function ($\xi_0$) by measuring the heavy-heavy meson transition matrix element on the lattice in the quenched approximation. The standard Wilson action is used for both the heavy and the light quarks. Our…