Patricia Ball

Symmetries and asymmetries of B → K*μ+μ− decays in the Standard Model and beyond

The rare decay B → K*(→ Kπ)μ+μ− is regarded as one of the crucial channels for B physics as the polarization of the K* allows a precise angular reconstruction resulting in many observables that offer new important tests of the Standard Model and its extensions. These angular observables can be expressed in terms of CP-conserving and CP-violating quantities which we study in terms of the full form factors calculated from QCD sum rules on the light-cone, including QCD factorization corrections. We investigate all observables in the context of the Standard Model and various New Physics models, in particular the Littlest Higgs model with T-parity and various MSSM scenarios, identifying those observables with small to moderate dependence on hadronic quantities and large impact of New Physics. One important result of our studies is that new CP-violating phases will produce clean signals in CP-violating asymmetries. We also identify a number of correlations between various observables which will allow a clear distinction between different New Physics scenarios.

A Comparative Study of the Decays

Using improved theoretical calculations of the decay form factors in the Light Cone-QCD sum rule approach, we investigate the decay rates, dilepton invariant mass spectra and the forward-backward (FB) asymmetry in the decays B → (K, K ∗ )l + l − (l ± = e ± , µ ± , τ ± ) in the standard model (SM) and a number of popular variants of the supersymmetric (SUSY) models. Theoretical precision on the differential decay rates and FB-asymmetry is estimated in these theories taking into account various parametric uncertainties. We show that existing data on B → Xsγ and the experimental upper limit on the branching ratio B(B → K ∗ µ + µ − ) provide interesting bounds on the coefficients of the underlying effective theory. We argue that the FB-asymmetry in B → K ∗ l + l − constitutes a precision test of the SM and its measurement in forthcoming experiments may reveal new physics. In particular, the presently allowed largetan β solutions in SUGRA models, as well as more general flavor-violating SUSY models, yield FB-asymmetries which are characteristically different from the corresponding ones in the SM.

B \to (K,K^*) \ell^+ \ell^-

We present the first complete results for the semileptonic and rare radiative form factors of the B meson’s weak decay into a light vector meson (r,v,K*,f) in the light-cone sum rule approach. The calculation includes radiative corrections, higher twist corrections, and SU ~3! breaking effects. The theoretical uncertainty is investigated in detail. A simple parametrization of the form factors is given in terms of three parameters each. We find that the form factors observe several relations inspired by heavy quark symmetry. @S0556-2821~98!06519-9# The challenge to understand the physics of CP violation related to the structure of the Cabibbo-Kobayashi-Maskawa ~CKM! mixing matrix in ~and beyond! the standard model is fueling an impressive experimental program for the study of B decays, both exclusive and inclusive. Abundant data in various exclusive channels are expected to arrive within the next few years from the dedicated B factories BaBar and Belle, and their potential impact on our understanding of CP violation at the electroweak scale will depend crucially on our possibility to control the effects of strong interactions. For exclusive decays with only one hadron in the final state the task is to calculate various transition form factors; it has already attracted significant attention in the literature. In this paper we present the first complete results for the exclusive semileptonic and rare radiative B decays to light vector mesons in the light-cone sum rule approach. Exclusive decays which are the principal concern of this work can be grouped as semileptonic decays Bu,d!ren, Bs!K*en, rare decays corresponding to b!s transitions which we term CKM-allowed, Bu,d!K*1g, Bu,d!K*1l 1 l 2 , Bs!f 1g, Bs!f1l 1 l 2 , and b!d transitions which we call CKM suppressed, Bd!(r,v)1g, Bd!(r,v)1l 1 l 2 , Bu !r1g, B u !r1l 1 l 2 , B s !K*1g, B s !K*1l 1 l 2 .

in Standard Model and Supersymmetric Theories

We present an improved calculation of

Exclusive semileptonic and rare B meson decays in QCD

B\ensuremath{\rightarrow}

New results on B → π, K, η decay form factors from light-cone sum rules

light pseudoscalar form factors from light-cone sum rules, including one-loop radiative corrections to twist-2 and twist-3 contributions, and leading-order twist-4 corrections. The total theoretical uncertainty of our results at zero momentum transfer is 10 to 13% and can be improved, at least in part, by reducing the uncertainty of hadronic input parameters, in particular, those describing the twist-2 distribution amplitudes of the

Higher-twist distribution amplitudes of the K meson in QCD

\ensuremath{\pi}

B ---> pi and B ---> K transitions from QCD sum rules on the light cone

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Theoretical update of pseudoscalar meson distribution amplitudes of higher twist: the nonsinglet case

K

Resummation of (ß0αs)n corrections in QCD: techniques and applications to the τ hadronic width and the heavy quark pole mass

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