Narrow Results

Gauge invariant generation of mass for a supersymmetric U(1) vector field through the use of a chiral Stueckelberg superfield is considered. When a Fayet–Iliopoulos D-term is also present, no breaking of supersymmetry ever occurs so long as the Stueckelberg mass is not zero. A moduli space in which gauge symmetry is spontaneously broken arises if there is no mass term for the matter superfields.

In this review we consider the distinctive phenomenology of supersymmetric models in which the scale of SUSY breaking is very low, , focusing on the Higgs sector and the process of electroweak breaking. Using an effective Lagrangian description of the interactions between the observable fields and the SUSY breaking sector, it is shown how the conventional MSSM picture can be substantially modified. For instance, the Higgs potential has non-negligible SUSY breaking quartic couplings that can modify completely the pattern of electroweak breaking and the Higgs spectrum with respect to that of the conventional MSSM-like models.

We discuss a framework to analyze the transmission of supersymmetry breaking in models of intersecting D-branes. Generically, different intersections preserve different fractions of an extended bulk supersymmetry, thus breaking supersymmetry completely but in a nonlocal way. We analyze this mechanism in a 5D toy model where two brane intersections, which are separated in the fifth dimension, break different halves of an extended supersymmetry. The sector of the theory on one brane intersection feels the breakdown of the residual supersymmetry only through two-loop interactions involving a coupling to fields from the other intersection. We compute the diagrams that contribute to scalar masses on one intersection and find that the masses are proportional to the compactification scale up to logarithmic corrections. We also compute the three-loop diagrams relevant to the Casimir energy between the two intersections and find a repulsive Casimir force.

Signatures of anomaly mediated supersymmetry breaking in linear colliders are briefly reviewed after presenting an outline of the theoretical framework. A unique and distinct feature of a large class of models of this type is a winolike chargino which is very closely degenerate in mass with the lightest neutralino. The very slow decay of this chargino results in a heavily ionizing charged track and one soft charged pion with a characteristic momentum distribution, leading to unique signals in linear colliders which are essentially free of background. The determination of chargino and slepton masses from such events is a distinctly interesting possibility.

We review the mechanisms of supersymmetry breaking mediation that occur in sequestered models, where the visible and the hidden sectors are separated by an extra dimension and communicate only via gravitational interactions. By locality, soft breaking terms are forbidden at the classical level and reliably computable within an effective field theory approach at the quantum level. We present a self-contained discussion of these radiative gravitational effects and the resulting pattern of soft masses, and give an overview of realistic model building based on this setup. We consider both flat and warped extra dimensions, as well as the possibility that there be localized kinetic terms for the gravitational fields.

In the context of 5D N = 1 supersymmetric models compactified on S₁/Z₂ or S₁/(Z₂×Z₂′) orbifolds and with brane-localized superpotential, higher derivative operators are generated radiatively as one-loop counterterms to the mass of the (brane or zero mode of the bulk) scalar field. It is shown that the presence of such operators which are brane-localised is not related to the mechanism of supersymmetry breaking considered (F-term, discrete or continuous Scherk–Schwarz breaking) and initial supersymmetry does not protect against the dynamical generation of such operators. Since in many realistic models the scalar field is commonly regarded as the Higgs field, and the higher derivative operators seem a generic presence in orbifold compactifications, we stress the importance of these operators for solving the hierarchy problem.

We investigate the relation between large N duality applied to systems of D5's and 's wrapping vanishing cycles of local CY in type IIB and M-theory lifts of the NS5/D4/ systems in type IIA to which they are related by T-duality. Through a simple example based on a local CY constructed using an A₂ singularity, we review this well-known correspondence in the supersymmetric setting and describe the manner in which it generalizes when antibranes are added. Agreement between the IIB and IIA pictures, which supports the assertion that supersymmetry is spontaneously broken in these systems at string tree level, is demonstrated when g_s ≪ 1. Novel nonholomorphic features can arise away from this regime and their physical origin is discussed. This note is based on talks given at KITP, Harvard University, TIFR, the University of Tokyo at Hongo, the 2007 Les Houches Summer School, and the 2007 Simons Workshop, is based on work done in collaboration with K. Papadodimas and M. Shigemori, and contains some previously unpublished results.

Supersymmetry breaking together by constant boundary superpotentials and by the O'Raifeartaigh model is studied in a warped space model. It is shown that the contribution of constant boundary superpotentials enables the moduli of chiral supermultiplets to be stabilized and that the vacuum at the stationary point has zero cosmological constant in a wide region of parameters.

We review on a recent construction of the on-shell supersymmetric brane action for the codimension-two branes with nonzero tension in the flux compactification of a 6D chiral gauged supergravity. On dimensionally reducing on 4D gauged supergravity for a new supersymmetric unwarped background with conical branes, we consider the modulus stabilization for determining the soft masses of the scalars localized on the branes and show that the bulk U(1)_R provides a new mechanism for mediating the SUSY breaking.

This is an invited summary of a seminar talk given at various institutions in the United States and Canada. After a brief introduction, a review of the minimal R-symmetric supersymmetric standard model is given, and the benefits to the flavor sector are discussed. R-symmetric gauge mediation is an attempt to realize this model using metastable supersymmetry breaking techniques. Sample low energy spectra are presented and tuning is discussed. Various other phenomenological results are summarized.

In this paper conformal hidden sectors of Ferrara–Zumino multiplets are investigated in framework of gravity mediation. The two-point correlator of Ferrara–Zumino multiplets can be parametrized, which implies the wave function renormalizations of components fields in gravity supermultiplet can be evaluated in relatively simple form. Soft terms are calculated via supercurrent approach. We find gaugino masses are independent of sfermion masses on general grounds. The unification of gaugino masses is not universal. In comparison with general gauge mediation, there are no sum rules for sfermion masses of each generation.

We propose a supersymmetric extension of the dynamical dark energy function and the scalar (super)potential in supergravity. Our model is viable in the Einstein approximation, and also has an analytic (regular) scalar potential. The hidden sector responsible for spontaneous supersymmetry breaking is also given.

We present a semi-analytic exploration of some low-$\ell$ angular power spectra inspired by “brane supersymmetry breaking (BSB)”. This mechanism splits Bose and Fermi excitations in string theory, leaving behind an exponential potential that is just too steep for the inflaton to emerge from the initial singularity while descending it. As a result, the scalar generically bounces against the exponential wall, which typically introduces an infrared depression and a pre-inflationary peak in the power spectrum of scalar perturbations. We elaborate on a possible link between this phenomenon and the low-$\ell$ CMB. For the first 32 multipoles, combining the hard exponential with a milder one leading to $n_s\simeq 0.96$ and with a small Gaussian bump, we have attained a reduction of ${\chi }^2$ to about 46% of the standard ΛCDM setting, with both WMAP9 and PLANCK 2013 data. This result corresponds to a ${\chi }^2∕DOF$ of about 0.45, to be compared with a ΛCDM value of about 0.85. The preferred choices combine naturally quadrupole depression, a first peak around $\ell =5$ and a wide minimum around $\ell =20$. We have also gathered some evidence that similar spectra emerge if the hard exponential is combined with more realistic models of inflation. A problem of the preferred examples is their slow convergence to an almost scale-invariant profile.

In this paper, we study and construct a set of Witten indexes for K, where K is any n-dimensional knot in Sⁿ⁺² and n is any natural number. We form a supersymmetric quantum system for K by, first, constructing a set of functional spaces (spaces of fermionic (resp. bosonic) states) and a set of operators (supersymmetric infinitesimal transformations) in an explicit way. Our Witten indexes are topological invariant and they are nonzero in general. These indexes are zero if K is equivalent to a trivial knot. Besides, our Witten indexes restrict to the Alexander polynomials of n-knots, and one of the Alexander polynomials of K is nontrivial if any of the Witten indexes is nonzero. Our indexes are related to homology with twisted coefficients. Roughly speaking, these indexes posseses path-integral representation in the usual manner of supersymmetric theory.

We construct the type IIA nonsupersymmetric meta-stable brane configuration consisting of (2k+1) NS5-branes and D4-branes where the electric gauge theory superpotential has an order (2k+2) polynomial for the bifundamentals. We find a rich pattern of nonsupersymmetric meta-stable states as well as the supersymmetric stable ones. By adding the orientifold 4-plane to this brane configuration, we also describe the intersecting brane configuration of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of corresponding gauge theory.

The type IIA nonsupersymmetric meta-stable brane configuration consisting of three NS5-branes, D4-branes and anti-D4-branes where the electric gauge theory superpotential has a quartic term for the bifundamentals besides a mass term is constructed. By adding the orientifold 4-plane and 6-plane to this brane configuration, we also describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of corresponding gauge theories.

From an supersymmetric electric gauge theory with the gauge group SU(N_c) × SU(N′_c) with fundamentals for each gauge group, the bifundamentals and a symmetric flavor and a conjugate symmetric flavor for SU(N_c), we apply Seiberg dual to each gauge group independently and obtain two supersymmetric dual magnetic gauge theories with dual matters including the gauge singlets. By analyzing the F-term equations of the dual magnetic superpotentials, we describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of these gauge theories. The case where the above symmetric flavor is replaced by an antisymmetric flavor is also discussed.

We construct the type IIA nonsupersymmetric meta-stable brane configurations corresponding to the various supersymmetric gauge theories. The D6-branes are both displaced and rotated where these deformations are described as the mass term and quartic term for the fundamental flavors, respectively. The multiplicity of the NS5-branes occurs in the superpotential order for adjoint, symmetric, or bifundamental matters. A rich pattern of nonsupersymmetric meta-stable states as well as the supersymmetric stable states is found.

We reexamine the supersymmetric gauge theories with product gauge groups by adding the mass terms and the quartic terms for the flavors: two-gauge group theory with fundamentals, bifundamentals and adjoints, three-gauge group theory with fundamentals and bifundamentals, and their orientifold 4-plane generalizations. By moving the branes appropriately, we obtain the corresponding dual gauge theories. By analyzing the dual superpotentials, we present the type IIA nonsupersymmetric meta-stable brane configurations.

We consider the supersymmetric gauge theories with product gauge groups. The two kinds of D6-branes in the electric theory are both displaced and rotated respectively where these deformations are interpreted as the mass terms and quartic terms for the two kinds of flavors. Then we apply the Seiberg dual to the whole gauge group factors by moving the branes and obtain the corresponding dual gauge theories. By analyzing the magnetic superpotentials consisting of an interaction term between a magnetic meson field and dual matters as well as the above deformations for each gauge group, we present the type IIA nonsupersymmetric meta-stable brane configurations.