Gil Paz

Factorization and shape-function effects in inclusive B-meson decays

Abstract Using methods of effective field theory, factorized expressions for arbitrary B ¯ → X u l − ν ¯ decay distributions in the shape-function region of large hadronic energy and moderate hadronic invariant mass are derived. Large logarithms are resummed at next-to-leading order in renormalization-group improved perturbation theory. The operator product expansion is employed to relate moments of the renormalized shape function with HQET parameters such as m b , Λ ¯ and λ 1 defined in a new physical subtraction scheme. An analytic expression for the asymptotic behavior of the shape function is obtained, which reveals that it is not positive definite. Explicit expressions are presented for the charged-lepton energy spectrum, the hadronic invariant mass distribution, and the spectrum in the hadronic light-cone momentum P + = E H − | P → H | . A new method for a precision measurement of | V u b | is proposed, which combines good theoretical control with high efficiency and a powerful discrimination against charm background.

The Flavor of a little Higgs with T-parity

We analyze flavor constraints in the littlest Higgs model with T-parity. In particular, we focus on neutral meson mixing in the K, B, and D systems due to one loop contributions from T-parity odd fermions and gauge bosons. We calculate the short distance contributions to mixing for a general choice of T-odd fermion Yukawa couplings. We find that for a generic choice of textures, a TeV scale GIM suppression is necessary to avoid large contributions. If order one mixing angles are allowed in the extended flavor structure, the mass spectrum is severely constrained, and must be degenerate at the 1-5% level. However, there are still regions of parameter space where only a loose degeneracy is necessary to avoid constraints. We also consider the B(s) system, and identify a scenario in which the mixing can be significantly enhanced beyond the standard model prediction while still satisfying bounds on the other mixing observables. We present both analytical and numerical results as functions of the T-odd fermion mass eigenvalues.

Factorization at subleading power and irreducible uncertainties in \( \bar{B} \to {X_s}\gamma \) decay

Using methods from soft-collinear and heavy-quark effective theory, a systematic factorization analysis is performed for the

Subleading shape functions in inclusive B decays

\bar{B} \to {X_s}\gamma

Model independent analysis of proton structure for hydrogenic bound states

photon spectrum in the endpoint region

Model independent extraction of the proton charge radius from electron scattering

{m_b} - 2{E_\gamma } = \mathcal{O}\left( {{\Lambda_{\text{QCD}}}} \right)

Long-Distance Dominance of the CP Asymmetry in B̄→Xs,dγ Decays

. It is proposed that, to all orders in 1/mb, the spectrum obeys a novel factorization formula, which besides terms with the structure H J ⊗ S familiar from inclusive

Model-independent determination of the axial mass parameter in quasielastic neutrino-nucleon scattering

\bar{B} \to {X_u}l\bar{\nu }

A two-loop relation between inclusive radiative and semileptonic B-decay spectra

decay distributions contains “resolved photon” contributions of the form

NRQED Lagrangian at order

H\;J \otimes S \otimes \bar{J}