Hunting the CKM weak phase with time-integrated Dalitz analyses of Bs -> K pi pi decays

We present a new technique to extract information on the Unitarity Triangle from the study of Bs -> K pi pi Dalitz plot. Using isospin symmetry and the possibility to access the decay amplitudes from Dalitz analyses, we propose a new strategy to extract the weak phase gamma from Bs to K pi pi.Comment: 2 pages. v2: Discussion of interference on Dalitz plot clarified. Bs -> K K pi channels removed. v3: Improved discussion of experimental aspects. Final version to appear in Phys. Lett.

CP violation in supersymmetric theories

We review the present status of CP violating problem in supersymmetric extensions of the standard model. We analyze the constraints imposed by the experimental limits of the electron, neutron, and mercury electric dipole moments on the supersymmetric CP phases and show that only the scenarios with flavour-off- diagonal CP violation remain attractive. These scenarios require hermitian Yukawa matrices which naturally arise in models with left-right symmetry or a SU(3) flavour symmetry. In this case, epsilon_K and epsilon'/epsilon can be saturated by a small non-universality of the soft scalar masses through the gluino and chargino contributions respectively. The model also predicts a strong correlation between A_{CP}(b-> s gamma) and the neutron electric dipole moment. In this framework, the standard model gives a the leading contribution to the CP asymmetry in B ->psi K_S decay, while the dominant chargino contribution to this asymmetry is < 0.2. Thus, no constraint is set on the non-universality of this model by the recent BaBar and Belle measureets.Comment: 34 pages, 10 figures. Invited review article for International Journal of Modern Physics

B_s to K^(*)0 \bar K^(*)0 decays: the golden channels for new physics searches

We point out that time-dependent CP asymmetries in B_s to K^{*0} \bar K^{*0} decays probe the presence of new physics in b to s transitions with an unprecedented theoretical accuracy. We show that, contrary to the case of B_d to phi K_S, it is possible to obtain a model-independent prediction for the coefficient S(B_s to K^{*0} \bar K^{*0}) in the Standard Model. We give an estimate of the experimental precision achievable with the next generation of B physics experiments. We also discuss how this approach can be extended to the case of B_s to \bar K^{*0} K^0, B_s to K^{*0} \bar K^0 and B_s to K^0 \bar K^0 decays and the different experimental challenges for these channels.Comment: 4 pages, 1 figure. v2: Corrected dependence on CKM angles, expanded discussion of multiple polarizations, conclusions strengthened. Final version to appear in PR

Testing the Standard Model and searching for New Physics with Bd→ππB_d \to \pi \pi and Bs→KKB_s \to K K decays

We propose to perform a combined analysis of $B \to \pi\pi$ and $B_s \to K^+ K^-$ modes, in the framework of a global CKM fit. The method optimizes the constraining power of these decays and allows to derive constraints on NP contributions to penguin amplitudes or on the $B_s$ mixing phase. We illustrate these capabilities with a simplified analysis using the recent measurements by the LHCb Collaboration, neglecting correlations with other SM observables.Comment: 5 pages, 4 figures. v2: references and clarifications added, version published in JHE

The Chromomagnetic Dipole Operator and the B Semileptonic Branching Ratio

We consider the possibility of having a large branching ratio for the decay $b\to s g$ coming from an enhanced Wilson coefficient of the chromomagnetic dipole operator. We show that values of $BR(b\to s g)$ up to $\sim 10\%$ or more are compatible with the constraints coming from the CLEO experimental results on $BR(B\to X_s\gamma)$ and $BR(B\to X_s\phi)$. Such large values can reconcile the predictions of both the semileptonic branching ratio and the charm counting with the present experimental results. We also discuss a supersymmetric model with gluino-mediated flavour violations, which can account for such large values of $BR(b\to s g)$.Comment: 19 pages, 3 eps figures included, replacement with minor change

b -> s Transitions: A New Frontier for Indirect SUSY Searches

The present unitarity triangle fit, whose essential input is represented by the s to d and b to d transition processes, fully agrees with the SM. However, most of the phenomena involving b to s transitions are still largely unexplored and hence b to s phenomenology still constitutes a place for new physics manifestations, in spite of the tremendous experimental and theoretical progress on B to X_s gamma. We perform a systematic study of the CP conserving and violating SUSY contributions to b to s processes in a generic MSSM. We consider gluino exchange contributions including NLO QCD corrections and lattice hadronic matrix elements for Delta B = 2 and Delta B = 1 processes. We take into account all available experimental information on processes involving b to s transitions (B to X_s gamma, B to X_s l^+ l^- and the lower bound on the B_s - bar B_s mass difference Delta M_s). We study the correlations among the relevant observables under scrutiny at present or in a not too far future: Delta M_s and the amount of CP violation in B to phi K_s, B_s to J/psi phi, B to X_s gamma. In particular we discuss the recent data by BaBar and BELLE on the time-dependent CP asymmetry in the decay B to phi K_s which suggest a deviation from the SM expectation. Our results show that the processes involving b to s transitions represent a splendid opportunity to constrain different MSSM realizations, and, even more important, that they offer concrete prospects to exhibit SUSY signals at B factories and hadron colliders in spite of all the past frustration in FCNC searches of new physics hints.Comment: 20 pages, 8 figures. Bug in the code corrected, figures for RL and RL=RR cases and some conclusions change

Worries and Hopes for SUSY in CKM Physics: The b to s Example

We discuss the twofold role of flavor and CP violation as a constraint in model building and as a signal of SUSY. Considering as an example b to s transitions, we analyze present bounds on SUSY parameters, discuss possible deviations from SM predictions in Bd and Bs physics and present strategies to reveal SUSY signals in present and future experiments in the CKM domain.Comment: Invited talks given by A. Masiero and L. Silvestrini at the Workshop on the CKM Unitarity Triangle, IPPP Durham, April 2003 (eConf C0304052). 9 pages, 5 figure