15940103
Neutralino decays at the CERN LHC
We study the distribution of lepton pairs from the second lightest neutralino decay \tchi^0_2\to\tchi^0_1 l^+l^-. This decay mode is important to measure the mass difference between \tchi^0_2 and the lightest neutralino \tchi^0_1, which helps to determine the parameters of the minimal supersymmetric standard model at the CERN LHC. We found that the decay distribution strongly depends on the values of underlying MSSM parameters. For some extreme cases, the amplitude near the end point of the lepton invariant mass distribution can be suppressed so strongly that one needs the information of the whole m_{ll} distribution to extract m_{\tchi^0_2}-m_{\tchi^0_1}. On the other hand, if systematic errors on the acceptance can be controlled, this distribution can be used to constrain slepton masses and the Z\tchi^0_2\tchi^0_1 coupling. Measurements of the velocity distribution of \tchi^0_2 from samples near the end point of the m_{ll} distribution, and of the asymmetry of the p_T of leptons, would be useful to reduce the systematic errors.
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 $\tilde b$.
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.
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
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.
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.
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.
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.
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.
44450900
Illustrating SUSY breaking effects on various inflation mechanisms
A bstractWe consider the supersymmetry breaking effects on typical inflation models with different types of Kähler potential. The critical size of supersymmetry-breaking scale, above which the flatness of the inflaton potential is spoiled, drastically changes model by model. We present the universal description of such effects in terms of a field-dependent scaling factor by which gravity-mediated supersymmetry breaking terms are suppressed or enhanced, based on the conformal supergravity framework. Such a description would be useful when we estimate them in constructing supersymmetric models of particle cosmology.