Perturbative QCD factorization of {pi}{gamma}{sup *}{r_arrow}{gamma}({pi}) and B{r_arrow}{gamma}({pi})l{bar {nu}}
We prove the factorization theorem for the processes {pi}{gamma}{sup *}{r_arrow}{gamma} and {pi}{gamma}{sup *}{r_arrow}{pi} to leading twist in the covariant gauge by means of the Ward identity. Soft divergences cancel and collinear divergences are grouped into a pion wave function defined by a nonlocal matrix element. The gauge invariance and universality of the pion wave function are confirmed. The proof is then extended to the exclusive B meson decays B{r_arrow}{gamma}l{bar {nu}} and B{r_arrow}{pi}l{bar {nu}} in the heavy quark limit. It is shown that a light-cone B meson wave function, though absorbing soft dynamics, can be defined in an appropriate frame. Factorization of the B{r_arrow}{pi}l{bar {nu}} decay in k{sub T} space, k{sub T} being parton transverse momenta, is briefly discussed. We comment on the extraction of the leading-twist pion wave function from experimental data.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40204460
- Journal Information:
- Physical Review D, Vol. 64, Issue 1; Other Information: DOI: 10.1103/PhysRevD.64.014019; Othernumber: PRVDAQ000064000001014019000001; 048113PRD; PBD: 1 Jul 2001; ISSN 0556-2821
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
Similar Records
Two-loop large-m{sub t} electroweak corrections to K{r_arrow}{pi}{nu}{bar {nu}} for an arbitrary Higgs boson mass
Relativistic description of exclusive heavy-to-light semileptonic decays {ital B}{r_arrow}{pi}({rho}){ital e}{nu}