4,767 research outputs found
Rare decays and MSSM phenomenology
No full textIn this article I review some aspects of flavour phenomenology in the MSSM. After an overview of various flavour observables I discuss the constraints on the off-diagonal elements of the squark mass matrices. In this context I present the Fortran code SUSY_FLAVOR which calculates these processes in the generic MSSM including the complete resummation of all chirally enhanced effects as a new feature of version 2. Than I discuss where large new physics effects in the MSSM are still possible. As an example of a model which can give large effects in flavour physics I review a model with "radiative flavour violation" (RFV) and update the results in the light of the recent LHCb measurement of Bs -> \mu \mu. Finally, I recall that the MSSM can generate a sizable right-handed W-coupling which affects B -> \tau\nu and can solve the Vub problem
New Constraints on Dark Matter Effective Theories from Standard Model Loops
No full textWe consider an effective field theory for a gauge singlet Dirac dark matter particle interacting with the standard model fields via effective operators suppressed by the scale Λ≳1 TeV. We perform a systematic analysis of the leading loop contributions to spin-independent Dirac dark matter–nucleon scattering using renormalization group evolution between Λ and the low-energy scale probed by direct detection experiments. We find that electroweak interactions induce operator mixings such that operators that are naively velocity suppressed and spin dependent can actually contribute to spin-independent scattering. This allows us to put novel constraints on Wilson coefficients that were so far poorly bounded by direct detection. Constraints from current searches are already significantly stronger than LHC bounds, and will improve in the near future. Interestingly, the loop contribution we find is isospin violating even if the underlying theory is isospin conserving
Chiral Enhancement in the MSSM: An Overview
No full textIn this article I review the origin and the effects of chirally enhanced loop-corrections in the MSSM based on previous papers. Chiral enhancement is related to fermion-Higgs couplings (or self-energies when the Higgs field is replaced by its vev). I describe the resummation of these chirally-enhanced corrections to all orders in perturbation theory and the calculation of the effective fermion-Higgs
and gaugino (higgsino)-fermion vertices. As an application a model with radiative flavor-violation is discussed which can solve the SUSY-CP and the SUSY-flavor problem while it is still capable of explaining the observed deviation from the SM in the Bs − Bs mixing phase
Low- and high-energy phenomenology of a doubly charged scalar
No full textWe explore the phenomenology of an SU(2)-singlet doubly charged scalar at the high and low energy frontier. Such a particle is predicted in different new physics models, like left-right symmetric models or the Zee-Babu model. Nonetheless, since its interactions with Standard Model (SM) leptons are gauge invariant, it can be consistently studied as a UV complete SM extension. Its signatures range from same-sign dilepton pairs to flavor changing decays of charged leptons to muonium-antimuonium oscillations. In this article, we use a systematic effective-field-theory approach for studying the low-energy observables and comparing them consistently to collider bounds. For this purpose, experimental searches for doubly charged scalars at the Large Hadron Collider are reinterpreted, including large width effects, and projections for exclusion and discovery reaches in the high-luminosity phase are provided. The sensitivities of the future International Linear Collider and Compact Linear Collider for the doubly charged scalar are presented with a focus on dilepton final states and resonant production. Theoretically and phenomenologically motivated benchmark scenarios are considered showing the different impact of low- and high-energy observables. We find that future low- and high-energy experiments display strong complementarity in studying the parameter space of the model.</p
Stylos kai edraiōma tēs ekklēsias, sive, Dissertatio de iustificatione hominis
No full textquam ... sub praesidio ... Ioh. Henrici Heideggeri ... placido eruditorum examini subiicit Andreas Steinerus, Vitod. author & respondens, ad diem Octobris loco horisque solitisDiss. Hohe Schule Zürich, 167
Consequences of chirally enhanced explanations of for and
No full textWith the long-standing tension between experiment and Standard-Model (SM)
prediction in the anomalous magnetic moment of the muon recently
reaffirmed by the Fermilab experiment, the crucial question becomes which other
observables could be sensitive to the underlying physics beyond the SM to which
may be pointing. While from the effective field theory (EFT) point of
view no direct correlations exist, this changes in specific new physics models.
In particular, in the case of explanations involving heavy new particles above
the electroweak (EW) scale with chiral enhancement, which are preferred to
evade exclusion limits from direct searches, correlations with other
observables sensitive to EW symmetry breaking are expected. Such scenarios can
be classified according to the representations and the hypercharges
of the new particles. We match the resulting class of models with heavy new
scalars and fermions onto SMEFT and study the resulting correlations with
and decays, where, via symmetry, the latter
process is related to and modified -- couplings.Comment: 19 pages, 3 figures; factors correcte
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