Phenomenology of flavor-mediated supersymmetry breaking

Abstract

The phenomenology of a new economical SUSY model that utilizes dynamical SUSY breaking and gauge-mediation (GM) for the generation of the sparticle spectrum and the hierarchy of fermion masses is discussed. Similarities between the communication of SUSY breaking through a messenger sector, and the generation of flavor using the Froggatt-Nielsen (FN) mechanism are exploited, leading to the identification of vector-like messenger fields with FN fields, and the messenger U(1) as a flavor symmetry. An immediate consequence is that the first and second generation scalars acquire flavor-dependent masses, but do not violate FCNC bounds since their mass scale, consistent with effective SUSY, is of order 10 TeV. We define and advocate a minimal flavor-mediated model (MFMM), recently introduced in the literature, that successfully accommodates the small flavor-breaking parameters of the standard model using order one couplings and ratios of flavon field vevs. The mediation of SUSY breaking occurs via two-loop log-enhanced GM contributions, as well as several one-loop and two-loop Yukawa-mediated contributions for which we provide analytical expressions. The MFMM is parameterized by a small set of masses and couplings, with values restricted by several model constraints and experimental data. The next-to-lightest sparticle (NLSP) always has a decay length that is larger than the scale of a detector, and is either the lightest stau or the lightest neutralino. Similar to ordinary GM models, the best collider search strategies are, respectively, inclusive production of at least one highly ionizing track, or events with many taus plus missing energy. In addition, D^0 - \bar{D}^0 mixing is also a generic low energy signal. Finally, the dynamical generation of the neutrino masses is briefly discussed.Comment: 54 pages, LaTeX, 8 figure

Localized supersoft supersymmetry breaking

“…In the context of higher dimensional models similar operators were considered in [22]. They cannot be forbidden by any symmetry, and generate flavor diagonal scalar masses at one loop.…”

“…Pushing mà high allows EWSB to go through as in the MSSM but for large infrared scale this reintroduces the problem of large negative contributions to the soft scalar massed squared, Eqn. (22). When minimising the Higgs potential in subsequent sections we take into account the small correction to the quartic coming from the triplet and singlet ESP scalars.…”

Distinguishing anomaly mediation from gauge mediation with aW-ino next-to-lightest supersymmetric particle

“…Other precision observables, such as b → sγ and g − 2 may be useful in this regard. 11 Another important difference is that in anomaly mediation |A t | is larger, and the top squarks are more widely separated in mass. The second term in Eq.…”

“…(Third generation squark masses are somewhat more distinct, but complicated by left-right mixing.) Furthermore, pure anomaly mediation predicts slepton (mass) 2 that are negative, requiring one of several proposed remedies [1,2,6,7,8,9,10,11]. Each "solution" to the negative slepton (mass) 2 problem must at least provide additional contributions to the slepton masses, and can have varying effects on the remainder of the mass mass spectrum.…”

Combining anomaly and Z′ mediation of supersymmetry breaking

“…Instead, we focus on the possibility of a Z ′ -gaugino mediation that is co-dominant with anomaly mediation (AMSB). A model of combining MSSM gaugino mediation and anomaly mediation has been proposed in [13]. By considering the Z ′ gaugino as a mediator instead, as well as a different underlying model, our setup and its phenomenological features are very different.…”