Weak symmetry breaking by radiative corrections in broken supergravity

We re-examine our former predictions \cite{kahanath1,kahanath2} of the top and Higgs masses via dynamical symmetry breaking in a 4-fermion theory which produces the Higgs as a bound state, and relates the top and Higgs masses to $m_W$. The use of dynamical symmetry breaking was stongly motivated by the apparent equality, within a factor of two, of the known and expected masses of the $W$, $Z$, top and Higgs. In later work \cite{kahanath2} we evaluated the masses self-consistently at the mass-poles, which resulted in predictions of $m_t \sim 175$ GeV, and $m_H \sim 125$ GeV as central values within ranges produced by varying the measured strong coupling. Figures (1) and (2) result from evolution down to $m_W$ while the number quoted for the top quark mass, i.e. 175 GeV includes an evolution back up to the top and use of the determination of $\alpha_s$ at LEP at that time. $m_H$ is less dependent on the value of the strong coupling. The variation of the predicted masses for a range of...

Physics Letters B, 1991

In a general softly broken supcrsymmetric theory with Higgs doublets only, we calculate the radiative corrections to the mass of the lightcst neutral ttiggs boson in the particular case where all the extra particles introduced by supersymmetry are close in mass and all heavier than the Fermi scale. In this situation the corrections are large and trivially calculable. We also consider the limiting case in which all the superpartners become arbitrarily heavy. The connection of these considerations with the Higgs of the standard model is elucidated.

Nuclear Physics B, 1979

The super Higgs effect is studied in the (2, $) + (&, O+, OK) model. The most general action is obtained using the recently developed tensor calculus: it contains an arbitrary function of two variables Q(A, B), A and B being the O+ scalar and O-pseudoscalar fields of the matter system. The conditions are given which 9 must satisfy in order that both the gravitino $J,, becomes massive and no cosmological yrn is*induced. Explicit examples are given, a class of them leading to the mass formula mA + mg = 4m$, .

Symmetry, 2018

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories, which can be made finite to all orders in perturbation theory, based on the principle of the reduction of couplings. The latter consists of searching for renormalization group invariant relations among parameters of a renormalizable theory holding to all orders in perturbation theory. FUTs have proven very successful so far. In particular, they predicted the top quark mass one and half years before its experimental discovery, while around five years before the Higgs boson discovery, a particular FUT was predicting the light Higgs boson in the mass range ∼121-126 GeV, in striking agreement with the discovery at LHC. Here, we review the basic properties of the supersymmetric theories and in particular finite theories resulting from the application of the method of reduction of couplings in their dimensionless and dimensionful sectors. Then, we analyze the phenomenologically-favored FUT, based on SU(5). This particular FUT leads to a finiteness constrained version of the Minimal SUSY Standard Model (MSSM), which naturally predicts a relatively heavy spectrum with colored supersymmetric particles above 2.7 TeV, consistent with the non-observation of those particles at the LHC. The electroweak supersymmetric spectrum starts below 1 TeV, and large parts of the allowed spectrum of the lighter might be accessible at CLIC. The FCC-hhwill be able to fully test the predicted spectrum.

Nuclear Physics B, 1985

Spontaneous violation of lepton number without breaking Lorentz invariance can, in principle, be incorporated in models with softly broken supersymmetry. We study the situation for minimal low-energy supergravity models coming from a GUT (hence not having hierarchy destabilizing light singlets) and where the SU(2) × U(1) breaking is radiative. It is found that for this type of model, R-parity breaking requires either too heavy a top quark for a realistic superpartner spectrum or too light a superpartner spectrum for a realistic top quark, making the spontaneous violation of lepton number in the third generation incompatible with present experimental data. We do not discard the possibility of having it in a fourth, heavier, generation. * Supported in part by "Comisi6n Asesora de Investigaci6n Cientifica y Trcnica" under contract 3209.

Nuclear Physics B, 1997

We explore some topics in the phenomenology of gauge-mediated SUSY-breaking scenarios having a large hierarchy of Higgs VEVs, vv/vo = tan fl >> 1. Some motivation for this scenario is first presented. We then use a systematic, analytic expansion (including some threshold corrections) to calculate the/z-parameter needed for proper electroweak breaking and the radiative corrections to the B-parameter, which fortuitously cancel at leading order. If B = 0 at the messenger scale then tan fl is naturally large and calculable; we calculate it. We then confront this prediction with classical and quantum vacuum stability constraints arising from the Higgs-slepton potential, and indicate the preferred values of the top quark mass and messenger scale(s). The possibility of vacuum instability in a different direction yields an upper bound on the messenger mass scale complementary to the familiar bound from gravitino relic abundance. Next, we calculate the rate for b ---, sy and show the possibility of large deviations (in the direction currently favored by experiment) from standard-model and small tan/3 predictions. Finally, we discuss the implications of these findings and their applicability to future, broader and more detailed investigations. © 1997 Elsevier Science B.V.

We attempt to reconcile seemingly conflicting experimental results on the Higgs boson mass, the anomalous magnetic moment of the muon, null results in search for supersymmetry at the LHC within the 8 TeV data and results from B-physics, all within the context of supersymmetric grand unified theories. Specifically, we consider a supergravity grand unification model with non-universal gaugino masses where we take the SU(3)C gaugino field to be much heavier than the other gaugino and sfermion fields at the unification scale. This construction naturally leads to a large mass splitting between the slepton and squark masses, due to the mass splitting between the electroweak gauginos and the gluino. The heavy Higgs bosons and Higgsinos also follow the gluino toward large masses. We carry out a Bayesian Monte Carlo analysis of the parametric space and find that it can simultaneously explain the large Higgs mass, and the anomalous magnetic moment of the muon, while producing a negligible correction to the Standard Model prediction for Br(B0s→μ+μ−). We also find that the model leads to an excess in the Higgs diphoton decay rate. A brief discussion of the possibility of detection of the light particles is given. Also discussed are the implications of the model for dark matter.

Nuclear Physics B, 2006

We construct realistic supersymmetric theories in which the correct scale for electroweak symmetry breaking is obtained without significant fine-tuning. We consider two classes of models. In one class supersymmetry breaking is transmitted to the supersymmetric standard model sector through Dirac gaugino mass terms generated by a D-term vacuum expectation value of a U (1) gauge field. In the other class the supersymmetry breaking sector is separated from the supersymmetric standard model sector in an extra dimension, and the transmission of supersymmetry breaking occurs through gauge mediation. In both these theories the Higgs sector contains two Higgs doublets and a singlet, but unlike the case for the next-to-minimal supersymmetric standard model the singlet field is not responsible for generating the supersymmetric or supersymmetry breaking mass for the Higgs doublets. These masses, as well as the mass for the singlet, are generated through gravitational-strength interactions. The scale at which the squark and slepton masses are generated is of order (1 ∼ 100) TeV, and the generated masses do not respect the unified mass relations. We find that electroweak symmetry breaking in these theories is caused by an interplay between the top-stop radiative correction and the holomorphic supersymmetry breaking mass for the Higgs doublets and that the fine-tuning can be reduced to the level of 20%. The theories have rich phenomenology, including a variety of possibilities for the lightest supersymmetric particle.

Physics Letters B, 1993

We discuss the implications of global symmetries on the radiative corrections to the Higgs sector. We focus on two examples: the charged Higgs mass in the minimal supersymmetric model and the Higgs couplings to vector boson pairs. In the first case, we find that in the absence of squark mixing a global SU(2)×SU(2) symmetry protects the charged Higgs mass from corrections of O(g 2 m 4 t /m 2 W). In the second case, it is the custodial symmetry which plays an analogous role in constraining the fermion-mass dependence of the radiative corrections.

Physical Review D, 2010

We study the radiative electroweak symmetry breaking and the relic abundance of neutralino dark matter in supersymmetric type I seesaw model. In this model, there exist threshold corrections to Higgs bilinear terms coming from heavy singlet sneutrino loops, which make the soft supersymmetry breaking (SSB) mass for up-type Higgs shift at the seesaw scale and thus a minimization condition for the Higgs potential is affected. We show that the required fine-tuning between the Higgsino mass parameter µ and SSB mass for up-type Higgs may be reduced at electroweak scale, due to the threshold corrections. We also present how the parameter µ depends on SSB B-parameter for heavy singlet sneutrinos. Since the property of neutralino dark matter is quite sensitive to the size of µ, we discuss how the relic abundance of neutralino dark matter is affected by the SSB B-parameter. Taking the SSB B-parameter of order of a few hundreds TeV, the required relic abundance of neutralino dark matter can be correctly achieved. In this case, dark matter is a mixture of bino and Higgsino, under the condition that gaugino masses are universal at the grand unification scale.