Search Results

Advanced search parameters have been applied.
open access

Effective theories and thresholds in particle physics

Description: The role of effective theories in probing a more fundamental underlying theory and in indicating new physics thresholds is discussed, with examples from the standard model and more speculative applications to superstring theory. 38 refs.
Date: June 7, 1991
Creator: Gaillard, M. K.
Partner: UNT Libraries Government Documents Department
open access

Simple de Sitter Solutions

Description: We present a framework for de Sitter model building in type IIA string theory, illustrated with specific examples. We find metastable dS minima of the potential for moduli obtained from a compactification on a product of two Nil three-manifolds (which have negative scalar curvature) combined with orientifolds, branes, fractional Chern-Simons forms, and fluxes. As a discrete quantum number is taken large, the curvature, field strengths, inverse volume, and four dimensional string coupling become… more
Date: January 7, 2008
Creator: Silverstein, Eva
Partner: UNT Libraries Government Documents Department
open access

Collider Aspects of Flavour Physics at High Q

Description: This chapter of the report of the 'Flavour in the era of LHC' workshop discusses flavor related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavor aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We al… more
Date: March 7, 2008
Creator: del Aguila, F.; Aguilar-Saavedra, J. A.; Allanach, B. C.; Alwall, J.; Andreev, Yu.; Aristizabal Sierra, D. et al.
Partner: UNT Libraries Government Documents Department
open access

Late Time Neutrino Masses, the LSND Experiment and the Cosmic Microwave Background

Description: Models with low-scale breaking of global symmetries in the neutrino sector provide an alternative to the seesaw mechanism for understanding why neutrinos are light. Such models can easily incorporate light sterile neutrinos required by the LSND experiment. Furthermore, the constraints on the sterile neutrino properties from nucleosynthesis and large scale structure can be removed due to the non-conventional cosmological evolution of neutrino masses and densities. We present explicit, fully real… more
Date: May 7, 2004
Creator: Chacko, Z.; Hall, Lawrence J.; Oliver, Steven J. & Perelstein, Maxim
Partner: UNT Libraries Government Documents Department
open access

Dynamics of Supersymmetric SU(n_c) and USp(2n_c) Gauge Theories

Description: We study dynamical flavor symmetry breaking in the context of a class of N=1 supersymmetric SU(n_c) and USp(2 n_c) gauge theories, constructed from the exactly solvable N=2 theories by perturbing them with small adjoint and generic bare hypermultiplet (quark) masses. We find that the flavor U(n_f) symmetry in SU(n_c) theories is dynamically broken to $U(r)\times U(n_f-r)$ groups for $n_f \leq n_c$. In the r=1 case the dynamical symmetry breaking is caused by the condensation of monopoles in the… more
Date: January 7, 2000
Creator: Carlino, Giuseppe; Konishi, Kenichi & Murayama, Hitoshi
Partner: UNT Libraries Government Documents Department
open access

Dark Matter in the MSSM

Description: We have recently examined a large number of points in the parameter space of the phenomenological MSSM, the 19-dimensional parameter space of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing experimental and theoretical constraints. This analysis provides insight into general features of the MSSM without reference to a particular SUSY breaking scenario or any other assumptions at the GUT scale. This study opens up new possibilit… more
Date: April 7, 2009
Creator: Cotta, R. C.; Gainer, J. S.; Hewett, J. L. & Rizzo, T. G.
Partner: UNT Libraries Government Documents Department
open access

String-Corrected Black Holes

Description: We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metr… more
Date: February 7, 2005
Creator: Hubeny, Veronika; Maloney, Alexander & Rangamani, Mukund
Partner: UNT Libraries Government Documents Department
open access

Naturalness from Runaways in Direct Mediation

Description: Postulating that the NMSSM singlet is a meson of a microscopic confining theory opens up new model-building possibilities. Based on this, we construct calculable models of direct mediation that solve the {mu}/B{mu} problem and simultaneously lead to realistic phenomenology. The singlet that couples to the Higgs fields develops a runaway produced by soft interactions, then stabilized by a small superpotential perturbation. The mechanism is first realized in an O'Raifeartaigh model of direct gaug… more
Date: February 7, 2011
Creator: Schafer-Nameki, Sakura; Tamarit, Carlos & Torroba, Gonzalo
Partner: UNT Libraries Government Documents Department
open access

Minimal Direct Gauge Mediation

Description: We propose a simple model of gauge mediation with a small gravitino mass, m{sub 3/2} < O(10) eV, where supersymmetry is broken by a strong dynamics at O(10) TeV.
Date: November 7, 2007
Creator: Ibe, Masahiro & Kitano, Ryuichiro
Partner: UNT Libraries Government Documents Department
open access

Discovering the Higgs Bosons of Minimal Supersymmetry with Tau Leptons and a Bottom Quark

Description: We investigate the prospects for the discovery at the CERN Large Hadron Collider or at the Fermilab Tevatron of neutral Higgs bosons through the channel where the Higgs are produced together with a single bottom quark and the Higgs decays into a pair of tau leptons, bg {yields} b{phi}{sup 0} {yields} b{tau}{sup +}{tau}{sup -}, {phi}{sup 0} = h{sup 0},H{sup 0},A{sup 0}. We work within the framework of the minimal supersymmetric model. The dominant physics background from the production of b{tau}… more
Date: November 7, 2007
Creator: Kao, Chung; Dicus, Duane; Malhotra, Rahul & Wang, Yili
Partner: UNT Libraries Government Documents Department
open access

Chiral Gauge Dynamics and Dynamical Supersymmetry Breaking

Description: We study the dynamics of a chiral SU(2) gauge theory with a Weyl fermion in the I = 3/2 representation and of its supersymmetric generalization. In the former, we find a new and exotic mechanism of confinement, induced by topological excitations that we refer to as magnetic quintets. The supersymmetric version was examined earlier in the context of dynamical supersymmetry breaking by Intriligator, Seiberg, and Shenker, who showed that if this gauge theory confines at the origin of moduli space,… more
Date: May 7, 2009
Creator: Poppitz, Erich; U., /Toronto; Unsal, Mithat & U., /SLAC /Stanford
Partner: UNT Libraries Government Documents Department
open access

Cosmological moduli problem in a supersymmetric model with direct gauge mediation

Description: Recently, an interesting class of the direct gauge mediation supersymmetry (SUSY) breaking models are proposed, in which the minimum of the potential of the SUSY breaking field is determined by the inverted hierarchy mechanism. We consider their cosmological implications. In this class of models, SUSY breaking field has a very flat potential, which may have a cosmological importance. Assuming the initial amplitude of the SUSY breaking field to be of the order of the Planck scale, it can be a so… more
Date: July 7, 1998
Creator: Moroi, Takeo
Partner: UNT Libraries Government Documents Department
open access

R-Parity From the Heterotic String

Description: In T-duality invariant effective supergravity with gaugino condensation as the mechanism for supersymmetry breaking, there is a residual discrete symmetry that could play the role of R-parity in supersymmetric extensions of the Standard Model.
Date: December 7, 2004
Creator: Gaillard, Mary K.
Partner: UNT Libraries Government Documents Department
open access

Extrapolation of supersymmetry-breaking parameters to high energy scales

Description: The author studies how well one can extrapolate the values of supersymmetry-breaking parameters to very high energy scales using future data from the Large Hadron Collider and an e{sup +}e{sup -} linear collider. He considers tests of the unification of squark and slepton masses in supergravity-inspired models. In gauge-mediated supersymmetry breaking models, he assess the ability to measure the mass scales associated with supersymmetry breaking. He also shows that it is possible to get good co… more
Date: November 7, 2002
Creator: Martin, Stephen P
Partner: UNT Libraries Government Documents Department
open access

Neutrino masses and sneutrino mixing in R-parity violating supersymmetry

Description: R-parity-violating supersymmetry with a conserved baryon number $B$ provides a framework for particle physics with lepton number ($L$) violating interactions. Two important probes of the $L$-violating physics are neutrino masses and sneutrino-antisneutrino mass-splittings. We evaluate these quantities in the context of the most general CP-conserving, R-parity-violating $B$-conserving extension of the minimal supersymmetric standard model. In generic three-generation models, three sneutrino-anti… more
Date: June 7, 1999
Creator: Grossman, yuval
Partner: UNT Libraries Government Documents Department
open access

Gauge mediation with D-term SUSY breaking

Description: We construct a gauge-mediation model with a D-term supersymmetry (SUSY) breaking. R-symmetry breaking necessary for generating the SUSY standard-model gaugino masses is given by gaugino condensation of a strongly coupled gauge theory in the hidden sector. The energy scale of the strong dynamics of the hidden sector gauge theory should be around the messenger mass scale M, or otherwise perturbative calculations would be reliable and would lead to negative soft mass squared for squarks and slepto… more
Date: May 7, 2007
Creator: Nakayama, Y.; Taki, Masato; Watari, Taizan & Yanagida, T. T.
Partner: UNT Libraries Government Documents Department
open access

Conformal Supersymmetry Breaking and Dynamical Tuningof the Cosmological Constant

Description: We propose 'conformal supersymmetry breaking' models, which tightly relate the conformal breaking scale (i.e. R-symmetry breaking scale) and the supersymmetry breaking scale. The both scales are originated from the constant term in the superpotential through the common source of the R-symmetry breaking. We show that dynamical tuning between those mass scales significantly reduces the degree of fine-tuning necessary for generating the almost vanishing cosmological constant.
Date: March 7, 2008
Creator: Ibe, M.; Nakayama, Y. & Yanagida, T. T.
Partner: UNT Libraries Government Documents Department
open access

Precise predictions for slepton pair production

Description: At a future linear collider, the masses and couplings of scalar leptons can be measured with high accuracy, thus requiring precise theoretical predictions for the relevant processes. In this work, after a discussion of the expected experimental precision, the complete one-loop corrections to smuon and selectron pair production in the MSSM are presented and the effect of different contributions in the result is analyzed.
Date: November 7, 2002
Creator: Freitas, Ayres & Manteuffel, Andreas von
Partner: UNT Libraries Government Documents Department
Back to Top of Screen