O. Vives

General flavor blind MSSM and CP violation

We study the implications on flavor changing neutral current and CP violating processes in the context of supersymmetric theories without a new flavor structure (flavor blind supersymmetry). The low-energy parameters are determined by the running of the soft breaking terms from the grand unified scale with supersymmetric (SUSY) phases consistent with the electric dipole moment constraints. We find that the CP asymmetry in b{yields}s{gamma} can reach large values potentially measurable at B factories, especially in the low BR(b{yields}s{gamma}) region, while the contributions to electric dipole moments are kept under control through a cancellation mechanism. We perform a fit of the unitarity triangle including all the relevant observables. In this case, no sizable deviations from the standard model expectations are found. Finally, we analyze the SUSY contributions to the anomalous magnetic moment of the muon pointing out its impact on the b{yields}s{gamma} CP asymmetry and on the SUSY spectrum including chargino and top squark masses.

Massive neutrinos and flavour violation

In spite of the large lepton flavour violation (LFV) observed in neutrino oscillations, within the Standard Model, we do not expect any visible LFV in the charged lepton sector (? ? e, ?, ? ? ?, ?, etc). On the contrary, the presence of new physics close to the electroweak scale can enhance the amplitudes of these processes. We discuss this in general and focus on a particularly interesting case: the marriage of low-energy supersymmetry (SUSY) and seesaw mechanism for neutrino masses (SUSY seesaw). Several ideas presented in this context are reviewed both in the bottom-up and top-down approaches. We show that there exist attractive models where the rate for LFV processes can attain values to be probed in pre-LHC experiments.

Kähler corrections and softly broken family symmetries

Spontaneously broken family symmetry provides a promising origin for the observed quark and lepton mass and mixing angle structure. In a supersymmetric theory such structure comes from a combination of the contributions from the superpotential and the Kahler potential. The superpotential effects have been widely studied but relatively little attention has been given to the effects of the Kahler sector. In this paper we develop techniques to simplify the analysis of such Kahler effects. Using them we show that in the class of theories with an hierarchical structure for the Yukawa couplings the Kahler corrections to both the masses and mixing angles are subdominant. This is true even in cases that texture zeros are filled in by the terms coming from the Kahler potential.

Invariant approach to flavour-dependent CP-violating phases in the MSSM

We use a new weak basis invariant approach to classify all the observable phases in any extension of the Standard Model (SM). We apply this formalism to determine the invariant CP phases in a simplified version of the Minimal Supersymmetric SM with only three non-trivial flavour structures. We propose four experimental measures to fix completely all the observable phases in the model. After these phases have been determined from experiment, we are able to make predictions on any other CP-violating observable in the theory, much in the same way as in the Standard Model all CP-violation observables are proportional to the Jarlskog invariant.

SUSY Seesaw and FCNC

After a quarter of century of intense search for new physics beyond the Standard Model (SM), two ideas stand out to naturally cope with (i) small neutrino masses and (ii) a light higgs boson : Seesaw and SUSY. The combination of these two ideas, i.e. SUSY seesaw exhibits a potentially striking signature: a strong (or even very strong) enhancement of lepton flavour violation (LFV), which on the contrary remains unobservable in the SM seesaw. Indeed, even when supersymmetry breaking is completely flavour blind, Renormalisation Group running effects are expected to generate large lepton flavour violating entries at the weak scale. In Grand Unified theories, these effects can be felt even in hadronic physics. We explicitly show that in a class of SUSY SO(10) GUTs there exist cases where LFV and CP violation in B-physics can constitute a major road in simultaneously confirming the ideas of Seesaw and low-energy SUSY.

Flavour and CPV in SUSYGUTs: Prospects of Observability

After a quarter of century of intense search for new physics beyond the Standard Model (SM), two ideas stand out to naturally cope with (i) small neutrino masses and (ii) a light higgs boson : Seesaw and SUSY. The combination of these two ideas, i.e. SUSY seesaw exhibits a potentially striking signature: a strong (or even very strong) enhancement of lepton flavour violation (LFV), which on the contrary remains unobservable in the SM seesaw. Indeed, even when supersymmetry breaking is completely flavour blind, Renormalisation Group running effects are expected to generate large lepton flavour violating entries at the weak scale. In Grand Unified theories, these effects can be felt even in hadronic physics. We explicitly show that in a class of SUSY SO(10) GUTs there exist cases where LFV and CP violation in B‐physics can constitute a major road in simultaneously confirming the ideas of Seesaw and low‐energy SUSY.