arXiv subjects

Gil Paz

Publications and source records attributed to Gil Paz.

59 records · Page 4Linked to original sources

arXiv2004

Subleading Shape Functions in Inclusive B Decays

The contributions of subleading shape functions to inclusive decay distributions of B mesons are derived from a systematic two-step matching of QCD current correlators onto soft-collinear and heavy-quark effective theory. At tree-level, the results can be expressed in terms of forward matrix elements of bi-local light-cone operators. Four-quark operators, which arise at O(g^2), are included. Their effects can be absorbed entirely into a redefinition of other shape functions. Our results are in disagreement with some previous studies of subleading shape-function effects in the literature. A numerical analysis of B->X_u+l+nu decay distributions suggests that power corrections are small, with the possible exception of the endpoint region of the charged-lepton energy spectrum.

hep-ph↗

arXiv2004

Proposal for a Precision Measurement of |Vub|

A new method for a precision measurement of the CKM matrix element |Vub| is discussed, which combines good theoretical control with high efficiency and a powerful discrimination against charm background. The resulting combined theoretical uncertainty on |Vub| is estimated to be 10%.

hep-ph↗

arXiv2002

SU(3) - Flavor Symmetry in $B \to VP$ Decays

In the framework of SU(3) symmetry, we present a general analysis of $B$ meson decays into two lighter uncharmed mesons (both pairs of pseudoscalar mesons and pairs of vector and pseudoscalar mesons). From the analysis we find constraints on $γ$ and discuss their validity. The most useful new constraint is obtained by considering the decay modes $B^{0} \to Kπ$ and $B^{+} \to π^{0}π^{+}$. In decays into pairs of vector and pseudeuscalar mesons, no constraints can be obtained using SU(3) symmetry alone and further assumptions are needed. Based on these assumptions, we obtain new (weaker) constraints using $B^{0} \to ρK/B^{0} \to K^{*}π$ and $B^{+} \to ρπ$. We show that no other constraints can be obtained. We also suggest a method to measure $γ$ using $B^{0}_{s} \to ρπ$ and $B^{0} \to K^{*\pm}K^{\mp}$.

hep-ph↗

arXiv2002

The non-self-adjointness of the radial momentum operator in n dimensions

The non self-adjointness of the radial momentum operator has been noted before by several authors, but the various proofs are incorrect. We give a rigorous proof that the $n$-dimensional radial momentum operator is not self- adjoint and has no self-adjoint extensions. The main idea of the proof is to show that this operator is unitarily equivalent to the momentum operator on $L^{2}[(0,\infty),dr]$ which is not self-adjoint and has no self-adjoint extensions.

math-ph↗

arXiv2001

On the connection between the radial momentum operator and the Hamiltonian in n dimensions

The radial momentum operator in quantum mechanics is usually obtained through canonical quantization of the (symmetrical form of the) classical radial momentum. We show that the well known connection between the Hamiltonian of a free particle and the radial momentum operator $\hat{H}=\hat{P}_{r}^2/2m+ $\hat{L}^2$}/2mr^{2}$ is true only in one or three dimensions. In general, an extra term of the form $\hbar^{2}(n-1)(n-3)/ 2m \cdot 4r^{2}$ has to be added to the Hamiltonian.

quant-ph↗