119216213
Electroweak baryogenesis in R -symmetric supersymmetry
We demonstrate that electroweak baryogenesis can occur in a supersymmetric model with an exact R-symmetry. The minimal R-symmetric supersymmetric model contains chiral superfields in the adjoint representation, giving Dirac gaugino masses, and an additional set of "R-partner" Higgs superfields, giving R-symmetric \mu-terms. New superpotential couplings between the adjoints and the Higgs fields can simultaneously increase the strength of the electroweak phase transition and provide additional tree-level contributions to the lightest Higgs mass. Notably, no light stop is present in this framework, and in fact, we require both stops to be above a few TeV to provide sufficient radiative corrections to the lightest Higgs mass to bring it up to 125 GeV. Large CP-violating phases in the gaugino/higgsino sector allow us to match the baryon asymmetry of the Universe with no constraints from electric dipole moments due to R-symmetry. We briefly discuss some of the more interesting phenomenology, particularly of the of the lightest CP-odd scalar.
119194513
Neutralino Oscillations at the LHC
We study a supersymmetric phenomenon that can give spectacular signals at the LHC: oscillations of neutralinos. Such oscillations can be naturally realised in Rsymmetric models, where additional elds are introduced as Dirac mass partners of gauginos and Higgsinos. Majorana masses for gauginos, necessarily generated from anomaly mediation, can create tiny mass splittings between degenerate mass eigenstates, causing states produced at the LHC to oscillate between neutralinos and their Dirac partner elds. Scenarios where such states decay with displaced vertices can lead to striking signatures at the LHC, where the oscillation can be visible directly in the distribution of displaced vertex lengths. We elaborate on the theory and LHC phenomenology of this feature within a specic scenario of a Higgsino decaying with a displaced vertex into a gravitino and a Z boson.
15753083
Singlet-Stabilized Minimal Gauge Mediation
We propose Singlet Stabilized Minimal Gauge Mediation as a simple ISS-based model of Direct Gauge Mediation which avoids both light gauginos and Landau poles. The hidden sector is a massive s-conning SQCD that is distinguished by a minimal SU(5) avor group. The uplifted vacuum is stabilized by coupling the meson to an additional singlet sector with its own U(1) gauge symmetry via non-renormalizable interactions suppressed by a higher scale UV in the electric theory. This generates a nonzero VEV for the singlet meson via the inverted hierarchy mechanism, but requires tuning to a precision ( = UV ) 2 , which is 10 4 . In the course of this analysis we also outline some simple model-building rules for stabilizing uplifted ISS models, which lead us to conclude that meson deformations are required (or at least heavily favored) to stabilize the adjoint component of the magnetic meson.
118736479
Direct detection with dark mediators
We introduce dark mediator Dark matter (dmDM) where the dark and visible sectors are connected by at least one light mediator carrying the same dark charge that stabilizes DM. is coupled to the Standard Model via an operator qq =, and to dark matter via a Yukawa coupling y c . Direct detection is
118502677
Spontaneous R-symmetry Breaking with Multiple Pseudomoduli
We examine generalized O’Raifeartaigh models that feature multiple tree-level flat directions and only contain fields with R-charges 0 or 2. We show that spontaneous R-breaking at up to one-loop order is impossible in such theories. Specifically, we prove that the R-symmetric origin of field space is always a local minimum of the one-loop Coleman-Weinberg potential, generalizing an earlier result for the case of a single flat direction. This result has consequences for phenomenology and helps elucidate the behavior of various models of dynamical SUSY breaking.
51428350
Soft RPV through the baryon portal
A bstractSupersymmetric (SUSY) models with R-parity generically predict sparticle decays with invisible neutralinos, which yield distinctive missing energy events at colliders. Since most LHC searches are designed with this expectation, the putative bounds on sparticle masses become considerably weaker if R-parity is violated so that squarks and gluinos decay to jets with large QCD backgrounds. Here we introduce a scenario in which baryonic R-parity violation (RPV) arises effectively from soft SUSY breaking interactions, but leptonic RPV remains accidentally forbidden to evade constraints from proton decay and FCNCs. The model features a global R-symmetry that initially forbids RPV interactions, a hidden R-breaking sector, and a heavy mediator that communicates this breaking to the visible sector. After R-symmetry breaking, the mediator is integrated out and an effective RPV A-term arises at tree level; RPV couplings between quarks and squarks arise only at loop level and receive additional suppression. Although this mediator must be heavy compared to soft masses, the model introduces no new hierarchy since viable RPV can arise when the mediator mass is near the SUSY breaking scale. In generic regions of parameter space, a light thermally-produced gravitino is stable and can be a viable dark matter candidate.
122803295
Constrained next-to-minimal supersymmetric standard model with a 126 GeV Higgs boson: A global analysis
We present the first global analysis of the constrained next-to-minimal supersymmetric standard model that investigates the impact of the recent discovery of a 126 GeV Higgs-like boson, of the observation of a signal for branching ratio $\mathrm{BR}({\mathrm{B}}_{\mathrm{s}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$, and of constraints on supersymmetry from $\ensuremath{\sim}5/\mathrm{fb}$ of data accumulated at the LHC, as well as of other relevant constraints from colliders, flavor physics and dark matter. We consider three possible cases, assuming in turn that the discovered Higgs boson is (i) the lightest Higgs boson of the model; (ii) the next-to-lightest Higgs boson; and (iii) a combination of both roughly degenerate in mass. The likelihood function for the Higgs signal uses signal rates in the $\ensuremath{\gamma}\ensuremath{\gamma}$ and $ZZ\ensuremath{\rightarrow}4l$ channels, while that for the Higgs exclusion limits assumes decay through the $\ensuremath{\gamma}\ensuremath{\gamma}$, $\ensuremath{\tau}\ensuremath{\tau}$, $ZZ$ and ${W}^{+}{W}^{\ensuremath{-}}$ channels. In all cases considered we identify the 68% and 95% credible posterior probability regions in a Bayesian approach. We find that, when the constraints are applied with their respective uncertainties, the first case shows strong CMSSM-like behavior, with the stau coannihilation region featuring highest posterior probability, the best-fit point, a correct mass of the lightest Higgs boson and the lighter top squark mass in the ballpark of 1 TeV. We also expose in this region a linear relationship between the trilinear couplings of the stau and the top squark, with both of them being strongly negative as enforced by the Higgs mass and the relic density, which outside of the stau coannihilation region show some tension. The second and the third case, on the other hand, while allowed are disfavored by the constraints from direct detection of dark matter and from $\mathrm{BR}({\mathrm{B}}_{\mathrm{s}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$. Without the anomalous magnetic moment of the muon the fit improves considerably, especially for negative effective $\ensuremath{\mu}$ parameter. We discuss how the considered scenarios could be tested further at the LHC and in dark matter searches.
122883218
Radiative Corrections to Electron-Proton Scattering
The radiative corrections to the electron-proton scattering are calculated with the effects of the proton recoil taken into account. We assumed the experimental conditions of Hofstadter et al. at Stanford, namely only the final electrons are momentum-analyzed. The anisotropy in the maximum energy of photons which can be emitted and the radiation from the proton current are the two main effects due to the proton recoil, and both effects are considered. The mesonic effects in the two-photon exchange diagrams are not considered. Other than the uncertainty in the mesonic effects, our formula is good up to about 5 Bev.
12584737
Improved Weizsaecker--Williams method and its application to lepton and W- boson pair production
A Weishcker-Williams method is derived which handles the elastic and inelastic target form factors properly. The method is applied to calculate energy-angle distributions of photoproduced lepton pairs: electrons, muons, and heavy leptons, using target form factors appropriate to each case. The agreement with the exact result is found to be excellent. Simple formulas for pair production of spin-0 and spin-1 particles are also given. (auth)
123620386
Magnetic Dipole and Electric Quadrupole Moments of the W+/- Meson
119194201
Global Study of the Simplest Scalar Phantom Dark Matter Model
We present a global study of the simplest scalar phantom dark matter model. The best fit parameters of the model are determined by simultaneously imposing (i) relic density constraint from WMAP, (ii) 225 live days data from direct experiment XENON100, (iii) upper limit of gamma-ray flux from Fermi-LAT indirect detection based on dwarf spheroidal satellite galaxies, and (iv) the Higgs boson candidate with a mass about 125 GeV and its invisible branching ratio no larger than 40% if the decay of the Higgs boson into a pair of dark matter is kinematically allowed. The allowed parameter space is then used to predict annihilation cross sections for gamma-ray lines, event rates for three processes mono-b jet, single charged lepton and two charged leptons plus missing energies at the Large Hadron Collider, as well as to evaluate the muon anomalous magnetic dipole moment for the model.