CP violation tests of alignment models at LHCII

Abstract

We analyse the low-energy phenomenology of alignment models both modelindependently and within supersymmetric (SUSY) scenarios focusing on their CP violation tests at LHCII. Assuming that New Physics (NP) contributes to K 0 −K 0 and D 0 −D 0 mixings only through non-renormalizable operators involving SU(2) L quark-doublets, we derive model-independent correlations among CP violating observables of the two systems. Due to universality of CP violation in ∆F = 1 processes the bound on CP violation in Kaon mixing generically leads to an upper bound on the size of CP violation in D mixing. Interestingly, this bound is similar in magnitude to the current sensitivity reached by the LHCb experiment which is starting now to probe the natural predictions of alignment models. Within SUSY, we perform an exact analytical computation of the full set of contributions for the D 0 −D 0 mixing amplitude. We point out that chargino effects are comparable and often dominant with respect to gluino contributions making their inclusion in phenomenological analyses essential. As a byproduct, we clarify the limit of applicability of the commonly used mass insertion approximation in scenarios with quasi-degenerate and split squarks.

LHC benchmarks from flavored gauge mediation

“…In the models considered below, there is a single dominant source of flavor violation, so the MIA gives a reasonable estimate. As is well known, this approximation breaks down with O(1) mass differences (see for example [35,49] for recent analyses). In some of the examples below, the relative mass splitting is very small, so the MIA is reliable.…”

“…As a result, the flavor symmetry is manifest at the (possibly) low messenger scale. A generic feature of these models is O(λ) mixing in the first and second generation L-squarks, either in the up sector only [35], or, in models of type (1) and (2), in both the up and down sector.We present several examples with non-trivial squark spectra for tan β = 10 and one or two messenger pairs. Our benchmark points (BPs) have negligible messenger-lepton couplings, so the slepton masses remain degenerate as in GMSB.…”

“…As a result, the flavor symmetry is manifest at the (possibly) low messenger scale. A generic feature of these models is O(λ) mixing in the first and second generation L-squarks, either in the up sector only [35], or, in models of type (1) and (2), in both the up and down sector.…”

Bs(d) − $$ \overline{B} $$s(d) mixing and Bs → μ+μ− decay in the NMSSM with the Flavour Expansion Theorem

“…CKM matrix, have difficulties in describing the current data on ∆M s(d) . Thus, in order to reconcile such a tension, one has to resort to the scenarios with non-minimal flavour violation (NMFV), which involve extra sources of flavour-and/or CP-violation and can, therefore, provide potential negative contributions to ∆M s(d) [56][57][58]. This motivates us to investigate whether the Z 3 -invariant NMSSM with NMFV, in which the extra flavour violations arise from the non-diagonal parts of the squark mass matrices related to the soft SUSY breaking terms, can accommodate the observed deviation for ∆M s(d) .…”