282 research outputs found
Electroweak symmetry breaking and cold dark matter from hidden sector technicolor
We consider models with a vectorlike confining gauge theory in the hidden
sector, and demonstrate that the origin of the electroweak symmetry breaking
(EWSB) is due to the dimensional transmutation in the hidden sector gauge
theory, and the lightest mesons in the hidden sector could be a good cold dark
matter (CDM) candidate. There would be more than one neutral Higgs-like scalar
bosons, and they could decay mainly into the CDM pair, if that decay channel is
kinemtically allowed.Comment: To appear in the proceeding of the 4th International Conference on
Flavor Physic
A simple modification of the maximal mixing scenario for three light neutrinos
We suggest a simple modification of the maximal mixing scenario (with
permutation symmetry) for three light neutrinos. Our neutrino mass matrix has
smaller permutation symmetry (), and
is consistent with all neutrino experiments except the Cl experiment.
The resulting mass eigenvalues for three neutrinos are for . Then these light neutrinos can account for
of the dark matter for . Our
model predicts the oscillation probability
in the range sensitive to the future experiments such as CHORUS and NOMAD.Comment: The title has been changed, to appear in Z. Phys.
Sflavor mixing map viewed from a high scale in supersymmetric SU(5)
We study flavor violation in a supersymmetric SU(5) grand unification
scenario in a model-independent way employing mass insertions. We examine how
the quark and the lepton sector observables restrict sfermion mixings. With a
low soft scalar mass, a lepton flavor violating process provides a stringent
constraint on the flavor structure of right-handed down-type squarks. In
particular, mu -> e gamma turns out to be highly susceptible to the 1-3 and 2-3
mixings thereof, due to the radiative correction from the top Yukawa coupling
to the scalar mass terms of 10. With a higher scalar mass around the optimal
value, in contrast, the quark sector inputs such as B-meson mixings and hadron
electric dipole moment, essentially determine the room for sfermion mixing. We
also discuss the recent deviation observed in B_s mixing phase, projected
sensitivity of forthcoming experiments, and ways to maintain the power of
leptonic restrictions even after incorporating a solution to fix the incorrect
quark-lepton mass relations.Comment: 40 pages, updated using phi_s from HFAG, conclusion unchange
Metastable supersymmetry breaking vacua from conformal dynamics
We study the scenario that conformal dynamics leads to metastable
supersymmetry breaking vacua. At a high energy scale, the superpotential is not
R-symmetric, and has a supersymmetric minimum. However, conformal dynamics
suppresses several operators along renormalization group flow toward the
infrared fixed point. Then we can find an approximately R-symmetric
superpotential, which has a metastable supersymmetry breaking vacuum, and the
supersymmetric vacuum moves far away from the metastable supersymmetry breaking
vacuum. We show a 4D simple model. Furthermore, we can construct 5D models with
the same behavior, because of the AdS/CFT dual.Comment: 3 pages; Talk given at SUSY0
Orbifold SUSY GUT from the Heterotic String
From the string partition function, we discuss the mass-shell and GSO
projection conditions valid for Kaluza-Klein (KK) as well as massless states in
the heterotic string theory compactified on a nonprime orbifold. Based on the
obtained conditions we construct a 4D string standard model, which is embedded
in a 6D SUSY GUT by including KK states above the compactification scale. We
discuss the stringy threshold corrections to gauge couplings, including the
Wilson line effects.Comment: To appear in the SUSY08 proceedings, 3 pages, LaTE
Indirect Signatures of Gravitino Dark Matter
Supersymmetric models provide very interesting scenarios to account for the
dark matter of the Universe. In this talk we discuss scenarios with gravitino
dark matter in R-parity breaking vacua, which not only reproduce very naturally
the observed dark matter relic density, but also lead to a thermal history of
the Universe consistent with the observed abundances of primordial elements and
the observed matter-antimatter asymmetry. In this class of scenarios the dark
matter gravitinos are no longer stable, but decay with very long lifetimes into
Standard Model particles, thus opening the possibility of their indirect
detection. We have computed the expected contribution from gravitino decay to
the primary cosmic rays and we have found that a gravitino with a mass of 150
GeV and a lifetime of 10^26 s could simultaneously explain the EGRET anomaly in
the extragalactic gamma-ray background and the HEAT excess in the positron
fraction.Comment: 6 pages, 4 figures. To appear in the proceedings of SUSY08, Seoul,
Kore
Sequestering in models of F-term uplifting
We discuss the nature of sequestering supersymmetry breaking sectors in a
certain class of moduli stabilization in supergravity/string models, where a
negative vacuum energy of the nonperturbative moduli potential is canceled by
dynamically generated F-terms. Two illustrating examples are shown to sketch
the issues around the supersymmetry breaking, flavors and sequestering within
such a framework.Comment: 6 pages, no figure; Talks given at PASCOS08 (the 14th International
Symposium on Particles, Strings and Cosmology, Waterloo, Canada, June 2-6,
2008) and SUSY08 (the 16th International Conference on Supersymmetry and the
Unification of Fundamental Interactions, Seoul, Korea, June 16-21, 2008
Aspects of Unparticle Physics
We review some theoretical and experimental issues in unparticle physics,
focusing mainly on collider signatures.Comment: 4 pages, latex. Based on talk at ICHEP0
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