In the supersymmetric models with nontrivial flavour structure in the soft-breaking sector the exchange of neutral Higgses mediates ∆F = 2 transitions. This mechanism is studied for ∆S, ∆B = 2 processes and for a generic form of the soft-breaking terms. We find that Higgs-mediated FCNC amplitudes increase very rapidly with tan β and can exceed SUSY box contribution by up to two orders of magnitude when tan β ∼ m t /m b .

We consider the scalar sector of the Randall-Sundrum model. We derive the effective potential for the Standard Model Higgs-boson sector interacting with Kaluza-Klein excitations of the graviton (h ν n µ ) and the radion (φ) and show that only the Standard Model vacuum solution of ∂V (h)/∂h = 0 (h is the Higgs field) is allowed. We then turn to our main focus: the consequences of the curvaturescalar mixing ξ R H † H (where H is a Higgs doublet field on the visible brane), which causes the physical mass eigenstates h and φ to be mixtures of the original Higgs and radion fields. First, we discuss the theoretical constraints on the allowed parameter space. Next, we give precise procedures for computing the h and φ couplings given the physical eigenstate masses, m h and m φ , ξ and the new physics scales of the model. Relations among these new-physics scales are discussed and a set of values not far above the smallest values required by precision electroweak constraints and RunI data is chosen. A simple result for the sum of the ZZh and ZZφ squared couplings relative to the ZZh SM squared coupling is derived. We demonstrate that this sum rule in combination with LEP/LEP2 data implies that a) not both the h and φ can be light. We present explicit results for the still allowed region in the (m h , m φ ) plane that remains after imposing the appropriate LEP/LEP2 upper limits coming from the Higgs-strahlung channel. In the remaining allowed region of parameter space, we examine numerically the couplings and branching ratios of the h and φ for several cases with m h = 120 GeV and m φ ≤ 300 GeV.The resulting prospects for detection of the h and φ at the LHC, a future LC and a γγ collider are reviewed. For moderate |ξ|, both the anomalous h → gg coupling and (when m h > 2m φ ) the non-standard decay channel h → φφ can substantially impact h discovery. Presence of the latter is a direct signature for non-zero ξ. We find that BR(h → φφ) as large as 30 ÷ 40 % is possible when |ξ| is large. Conversely, if m φ > 2m h then BR(φ → hh) is generally large. Detection of a light φ might require the LC. Detection of a heavy φ might need to take into account the φ → hh channel. The feasibility of experimentally measuring the anomalous gg and γγ couplings of the h and φ is examined. PACS: 04.50.+h, 12.60.Fr Keywords: extra dimensions, Higgs-boson sector, Randall-Sundrum model 2 In other words we consider here contributions from the massless zero Kaluza-Klein mode, see Eq. (11).3 We note that our ǫ 2 is related to the κ 2 of [2] by ǫ 2 = 2κ 2 .

In the context of a warped extra-dimension with Standard Model fields in the bulk, we obtain the general flavor structure of the Radion couplings to fermions and show that the result is independent on the particular nature of the Higgs mechanism (bulk or brane localized). These couplings will be generically misaligned with respect to the fermion mass matrix when the fermion bulk mass parameters are not all degenerate. When the Radion is light enough, the generic size of these treelevel flavor changing couplings will be strongly constrained by the experimental bounds on ∆F = 2 processes. At the LHC the possibility of a heavier Radion decaying into top and charm quarks is then considered as a promising signal to probe the flavor structure of both the Radion sector and the whole scenario. PACS numbers:Introducing a warped extra-dimension in such a way as to create an exponential scale hierarchy between the two boundaries of the extra dimension [1] has generated a lot of attention in the recent years as a novel approach to solve the hierarchy problem. By placing the Standard Model (SM) fermions in the bulk of the extra dimension it was then realized that one can simultaneously address the fermion mass hierarchy puzzle [2]. In this context the main constraints come from precision electroweak bounds as well as from low energy flavor violating processes [3,4,5,6], pushing the scale of new physics (the mass of the lowest KK excitations) to several TeV. In these scenarios, the metric fluctuations contain a scalar degree of freedom -the Radion, whose mass and couplings could make it the first new physics state to be discovered at the LHC. In the original RS1 setup [1], the Radion phenomenology was extensively studied and analyzed including the possibility of some amount of mixing with the Higgs scalar [7,8,9]. But it wasn't until relatively recently [10,11,12] that Radion interactions with bulk SM fields were fully considered. In this letter we want to extend these last investigations to include the full fermion flavor structure to the Radion couplings and show that as opposed to the original RS1 scenario, there is a prediction for generic flavor violating Radion couplings to fermions. The spacetime we consider takes the usual Randall-Sundrum form [1]:with the UV (IR) branes localized at z = R (z = R ′ ). The Radion can be parametrized by the following scalar perturbation of metric:Demanding that the perturbed metric solves the Einstein equation and that the Radion field is canonically normalized, we getwhere r(x) is the corresponding canonically normalized Radion graviscalar with its associated interaction scale Λ r = √ 6 R R ′ M P l . We assume that some unknown dynamics (e.g. the Goldberger-Wise mechanism [13]) will fix the inter-brane distance and give a positive mass squared to the Radion, and that it gives negligible back-reaction to the metric. The couplings between bulk SM fermions and the Radion are calculated in [11] in the case of one generation, with a brane localized Higgs. We are interested here in the flavor...

In the context of a warped extra-dimension with Standard Model fields in the bulk, we obtain the general flavor structure of the Higgs couplings to fermions. These couplings will be generically misaligned with respect to the fermion mass matrix, producing large and potentially dangerous flavor changing neutral currents (FCNC's). As recently pointed out in [arXiv:0906.1542], a similar effect is expected from the point of view of a composite Higgs sector, which corresponds to a 4D theory dual to the 5D setup by the AdS-CFT correspondence. We also point out that the effect is independent of the geographical nature of the Higgs (bulk or brane localized), and specifically that it does not go away as the Higgs is pushed towards the IR boundary. The FCNC's mediated by a light enough Higgs (specially their contribution to ǫK ) could become of comparable size as the ones coming from the exchange of Kaluza-Klein (KK) gluons. Moreover, both sources of flavor violation are complementary since they have inverse dependence on the 5D Yukawa couplings, such that we cannot decouple the flavor violation effects by increasing or decreasing these couplings. We also find that for KK scales of a few TeV, the Higgs couplings to third generation fermions could experience suppressions of up to 40% while the rest of diagonal couplings would suffer much milder corrections. Potential LHC signatures like the Higgs flavor violating decays h → µτ or h → tc, or the exotic top decay channel t → ch, are finally addressed.

We compute gluino decay widths in supersymmetric theories with arbitrary flavor and CP violation angles. Our emphasis is on theories with scalar superpartner masses heavier than the gluino such that tree-level two-body decays are not allowed, which is relevant, for example, in split supersymmetry. We compute gluino decay branching fractions in several specific examples and show that it is plausible that the only accessible signal of supersymmetry at the LHC could be four top quarks plus missing energy. We show another example where the only accessible signal for supersymmetry is two gluon jets plus missing energy.hep-ph/0503175