14435342
Slepton production as a probe of the squark mass scale
We investigate an important radiative correction to the slepton and chargino production processes. We consider a supersymmetric spectrum with a large splitting between the squark and slepton masses. In this case, in the effective theory below the squark mass threshold, the supersymmetric Slavnov-Taylor identities which enforce the equality of the gauge and gaugino couplings are violated. The gaugino propagators receive potentially large corrections due to virtual quark or squark loop effects. We compute the full one-loop (s)quark corrected slepton production cross sections. The t-channel one-loop scattering amplitudes are factorized into an effective chargino-neutralino mass matrix and an effective fermion-sfermion-gaugino coupling. The difference between the effective gaugino coupling and the gauge coupling is proportional to ln(M{sub {tilde Q}}/m{sub scr(l{tilde )}}) in the large squark mass limit. We find that the one-loop corrected slepton production cross sections can depend on the squark mass strongly, up to 9{percent}{times}log{sub 10}(M{sub {tilde Q}}/m{sub scr(l{tilde )}}). We investigate the squark mass sensitivity of the slepton cross-section measurements at a future linear collider. For sneutrino production accessible at {radical} (s) =500 GeV there can be sensitivity to squark masses at or larger than 1 TeV. {copyright} {ital 1998} {ital The American Physical Society}
16212962
Motivations for and implications of nonuniversal GUT scale boundary conditions for soft SUSY breaking parameters
We outline several well-motivated models in which GUT boundary conditions for SUSY breaking are non-universal. The diverse phenomenological implications of the non-universality for SUSY discovery at LEP2, the Tevatron, the LHC and the NLC are sketched.
2040672
Radiative corrections to a supersymmetric relation: A new approach
Recently it has been realized that the production and decay processes of charginos, neutralinos, and sleptons receive corrections which grow like logm{sub {tilde q}} for large m{sub {tilde q}}. In this paper we calculate the chargino pair production cross section at e{sup +}e{sup {minus}} colliders with quark-squark loop corrections. We introduce a novel formulation, where the one-loop amplitude is reorganized into two parts. One part is expressed in terms of the {open_quotes}effective{close_quotes} chargino coupling {bar g}{sub e{tilde {nu}}{tilde W}} and mixing matrices U{sup P},V{sup P}, and includes all O(logm{sub {tilde q}}) corrections, while the other decouples for large m{sub {tilde q}}. The form of the one-loop cross section then becomes physically transparent. Our formulation can be easily extended to other loops and processes. Numerically, we find significant corrections due to the effective t-channel coupling {bar g}{sub e{tilde {nu}}{tilde W}}, for gaugino-like charginos. In the mixed region, where the chargino has large gaugino and Higgsino components, the corrections due to (U{sup P},V{sup P}) are also significant. Our numerical results disagree with a previous calculation. We reexamine previous studies of the determination of {bar g}{sub e{tilde {nu}}{tilde W}} through the measurement of the chargino production cross section. We point out that amore » previous study, which claimed that the measurement suffers large systematic errors, was performed at a {open_quotes}pessimistic{close_quotes} point in MSSM parameter space. We provide reasons why the systematic errors are not a limiting factor for generic parameter choices. {copyright} {ital 1998} {ital The American Physical Society}« less
17333378
SUSY - QCD corrections to top and bottom squark decays into Higgs bosons
We calculate the $\mathcal{O}({\ensuremath{\alpha}}_{s})$ SUSY-QCD corrections to the widths of top and bottom squark decays into Higgs bosons within the minimal supersymmetric standard model. We give the complete analytical formulas, paying particular attention to the on-shell renormalization of the soft SUSY-breaking parameters. We also perform a detailed numerical analysis of both top and bottom squark decays into all Higgs bosons ${h}^{0},$ ${H}^{0},$ ${A}^{0},$ and ${H}^{\ifmmode\pm\else\textpm\fi{}}.$ We find that the SUSY-QCD corrections are significant, mostly negative, and of the order of a few ten percent.
11356307
Two-loop renormalization of gaugino masses in general supersymmetric gauge models.
We calculate the two-loop renormalization group equations for the running gaugino masses in general supersymmetry (SUSY) gauge models, improving our previous result. We also study its consequences on the unification of the gaugino masses in the SUSY SU(5) model. The two-loop correction to the one-loop relation [ital m][sub [ital i]]([mu])[proportional to][alpha][sub [ital i]]([mu]) is found to be of the order of a few percent.
16486262
SUSY--QCD Corrections to Higgs Particle Decays into Quarks and Squarks
We study the decays of the Higgs bosons $H^{\pm}$, $H^0$, and $A^0$ within the Minimal Supersymmetric Standard Model. For decays into quarks and squarks we include the supersymmetric QCD radiative corrections. We find that the corrections are significant and can go up to 50%. The supersymmetric decay modes $H^+ \to \tilde t \bar{\tilde b}$ and $H^0 (A^0) \to \tilde t \bar{\tilde t}$ can be dominant in a wide range of the model parameters due to the large Yukawa couplings and mixings of $\tilde t$ and $\tilde b$.
119238697
Natural realization of a large extra dimension in 5D supersymmetric theory
An exponentially large extra dimension can be naturally realized by the Casimir energy and the gaugino condensation in 5D supersymmetric theory. The model does not require any hierarchies among the 5D parameters. The key ingredient is an additional modulus other than the radion, which generically exists in 5D supergravity. SUSY is broken at the vacuum, which can be regarded as the Scherk-Schwarz SUSY breaking. We also analyze the mass spectrum and discuss some phenomenological aspects.
119260215
Instant uplifted inflation: a solution for a tension between inflation and SUSY breaking scale
A bstractThe Hubble parameter during an inflationary era must be smaller than the gravitino mass if moduli fields are stabilized by the Kachru-Kallosh-Linde-Trivedi mechanism. This condition represents a difficulty to combine low scale SUSY breaking and high scale inflation. We propose a simple mechanism which can naturally separate the inflation scale from the SUSY breaking scale today.
119158878
Inflation in supergravity without Kähler potential
We propose a new class of inflation models in supergravity with higher derivative terms. In those models, the K\"ahler potential does not contain the inflaton multiplet, but a supersymmetric derivative term does. In the models, inflation is effectively driven by a single scalar field with a standard kinetic term and a scalar potential. Remarkably, the so-called $\eta$ problem does not exist in our models.
119288533
Reheating processes after Starobinsky inflation in old-minimal supergravity
A bstractWe study reheating processes and its cosmological consequences in the Starobinsky model embedded in the old-minimal supergravity. First, we consider minimal coupling between the gravity and matter sectors in the higher curvature theory, and transform it to the equivalent standard supergravity coupled to additional matter superfields. We then discuss characteristic decay modes of the inflaton and the reheating temperature TR. Considering a simple model of supersymmetry breaking sector, we estimate gravitino abundance from inflaton decay, and obtain limits on the masses of gravitino and supersymmetry breaking field. We find TR ≃ 1.0 × 109 GeV and the allowed range of gravitino mass as 104 GeV ≲ m3/2 ≲ 105 GeV, assuming anomaly-induced decay into the gauge sector as the dominant decay channel.
119118937
Impacts of non-geometric moduli on effective theory of 5D supergravity
A bstract5D supergravity generically has moduli other than the radion that belong to 5D vector multiplets. We summarize the impacts of such non-geometric moduli on 4D effective theory of 5D supergravity on S1/Z2. We mainly discuss the structure of the effective Kähler potential including the one-loop quantum corrections. As an illustrative example, we construct a model in which the size of the extra dimension is stabilized at an exponentially large value compared to the Planck length, which is similar to the LARGE volume scenario in string theory.