arXiv subjects

Martin Schmaltz

Publications and source records attributed to Martin Schmaltz.

67 records · Page 4Linked to original sources

arXiv1998

Gauge Theories with Tensors from Branes and Orientifolds

We present brane constructions in Type IIA string theory for N=1 supersymmetric SO and Sp gauge theories with tensor representations using an orientifold 6-plane. One limit of these set-ups corresponds to N=2 theories previously constructed by Landsteiner and Lopez, while a different limit yields N=1 SO or Sp theories with a massless tensor and no superpotential. For the Sp-type orientifold projection comparison with the field theory moduli space leads us to postulate two new rules governing the stability of configurations of D-branes intersecting the orientifold. Lifting one of our configurations to M-theory by finding the corresponding curves, we re-derive the N=1 dualities for SO and Sp groups using semi-infinite D4 branes.

hep-th↗

arXiv1997

N = 1 Field Theory Duality from M-theory

We investigate Seiberg's N=1 field theory duality for four-dimensional supersymmetric QCD with the M-theory 5-brane. We find that the M-theory configuration for the magnetic dual theory arises via a smooth deformation of the M-theory configuration for the electric theory. The creation of Dirichlet 4-branes as Neveu-Schwarz 5-branes are passed through each other in Type IIA string theory is given a nice derivation from M-theory.

hep-th↗

arXiv1997

Flavor from Strongly Coupled Supersymmetry

Strongly coupled supersymmetric theories can give rise to composite quarks and leptons at low energy. We show that the internal structure of these particles can explain the origin of three generations and provide a qualitative understanding of mass ratios and mixing angles between the different flavors of fermions, all within a renormalizable theory. The main point of the paper is to show how fermion masses and mixing angles can result from a ``dual'' Frogatt-Nielsen mechanism: fields neutral under $SU(3) \times SU(2) \times U(1)$ which carry flavor quantum numbers are confined within quarks and leptons, and from their perturbative interactions arises the observed flavor structure.

hep-ph↗

arXiv1997

Confinement in N=1 SUSY Gauge Theories and Model Building Tools

We develop a systematic approach to confinement in N=1 supersymmetric theories. We identify simple necessary conditions for theories to confine without chiral symmetry breaking and to generate a superpotential non-perturbatively (s-confine). Applying these conditions we identify all N=1 theories with a single gauge group and no tree-level superpotential which s-confine. We give a complete list of the confined spectra and superpotentials. Some of these theories are of great interest for model building. We give several new examples of models which break supersymmetry dynamically.

hep-th↗

arXiv1997

Self-Dual N=1 SUSY Gauge Theories

We present a large set of new self-dual N=1 SUSY gauge theories. Examples include SU(N) theories with tensors and SO(N) theories with spinors. Using these dualities as starting points, new non-trivial duals can be derived by higgsing the gauge group or by integrating out matter. General lessons that can be learned from these duals are: ``accidental" infrared symmetries play an important role in duality, many theories have more than one ``dual", and there seems to be no simple organizing pattern which relates duals of theories with different number of flavors.

hep-th↗

arXiv1996

A Systematic Approach to Confinement in N=1 Supersymmetric Gauge Theories

We give necessary criteria for N=1 supersymmetric theories to be in a smoothly confining phase without chiral symmetry breaking and with a dynamically generated superpotential. Using our general arguments we find all such confining SU and Sp theories with a single gauge group and no tree level superpotential.

hep-th↗

arXiv1996

A Sequence of Duals for Sp(2N) Supersymmetric Gauge Theories with Adjoint Matter

We consider supersymmetric Sp(2N) gauge theories with F matter fields in the defining representation, one matter field in the adjoint representation, and no superpotential. We construct a sequence of dual descriptions of this theory using the dualities of Seiberg combined with the ``deconfinement'' method introduced by Berkooz. Our duals hint at a new non-perturbative phenomenon that seems to be taking place at asymptotically low energies in these theories: for small F some of the degrees of freedom form massless, non-interacting bound states while the theory remains in an interacting non-Abelian Coulomb phase. This phenomenon is the result of strong coupling gauge dynamics in the original description, but has a simple classical origin in the dual descriptions. The methods used for constructing these duals can be generalized to any model involving arbitrary 2-index tensor representations of Sp(2N), SO(N), or SU(N) groups.

hep-th↗

arXiv1996

A Diagramatic Analysis of Duality in Supersymmetric Gauge Theories

We introduce a diagramatic notation for supersymmetric gauge theories. The notation is a tool for exploring duality and helps to present the field content of more complicated models in a simple visual way. We introduce the notation with a few examples from the literature. The power of the formalism allows us to study new models with gauge group $(SU(N))^k$ and their duals. Amongst these are models which, contrary to a naive analysis, possess no conformal phase.

hep-th↗

arXiv1996

Exact Results and Duality for SP(2N) SUSY Gauge Theories with an Antisymmetric Tensor

We study supersymmetric Sp(2N) gauge theories with matter in the antisymmetric tensor representation and F fundamentals. For F=6 we solve the theory exactly in terms of confined degrees of freedom and a superpotential. By adding mass terms we obtain the theories with F<6 which we find to exhibit a host of interesting non-perturbative phenomena: quantum deformed moduli spaces with N constraints, instanton-induced superpotentials and non-equivalent disjoint branches of moduli spaces. We find a simple dual for F=8 and no superpotential. We show how the F=4 and F=2 theories can be modified to break supersymmetry spontaneously and point out that the Sp(6) theory with F=6 may be very interesting for model builders.

hep-th↗

arXiv1995

Domain Wall Fermions and the Eta Invariant

We extend work by Callan and Harvey and show how the phase of the chiral fermion determinant in four dimensions is reproduced by zeromodes bound to a domain wall in five dimensions. The analysis could shed light on the applicability of zeromode fermions and the vacuum overlap formulation of Narayanan and Neuberger for chiral gauge theories on the lattice.

hep-th↗

arXiv1994

Neutrino Oscillations from Discrete Non-Abelian Symmetries

I discuss a SUSY-GUT model with a non-Abelian discrete family symmetry that explains the observed hierarchical pattern of quark and lepton masses. This $SO(10) \times Δ(75)$ model predicts modified quadratic seesaw neutrino masses and mixing angles which are interesting for three reasons: i.) they offer a solution to the solar neutrino problem, ii.) the tau neutrino has the right mass for a cosmologically interesting hot dark matter candidate, and iii.) they suggest a positive result for the $ν_μ\rightarrow ν_τ$ oscillation searches by the CHORUS and NOMAD collaborations. However, the model shares some problems with many other predictive GUT models of quark and lepton masses. Well-known and once successful mass and angle relations, such as the $SU(5)$ relation $λ_b^{GUT}=λ_τ^{GUT}$, are found to be in conflict with the current experimental status. Attempts to correct these relations seem to lead to rather contrived models.

hep-ph↗

arXiv1993

Flavor Unification and Discrete Nonabelian Symmetries

Grand unified theories with fermions transforming as irreducible representations of a discrete nonabelian flavor symmetry can lead to realistic fermion masses, without requiring very small fundamental parameters. We construct a specific example of a supersymmetric GUT based on the flavor symmetry $Δ(75)$ --- a subgroup of $SU(3)$ --- which can explain the observed quark and lepton masses and mixing angles. The model predicts $\tanβ\simeq 2-5$ and gives a $τ$ neutrino mass $m_ν\simeq M_p/G_F M_{GUT}^2 = 10$ eV, with other neutrino masses much lighter. Combined constraints of light quark masses and perturbative unification place flavor symmetry breaking near the GUT scale; it may be possible to probe these extremely high energies by continuing the search for flavor changing neutral currents.

hep-ph↗

arXiv1992

Critical Momenta of Lattice Chiral Fermions

We determine the critical momenta for chiral fermions in the domain wall model recently suggested by Kaplan. For a wide range of domain wall masses $m$ and Wilson couplings $r$ we explicitly exhibit the regions in momentum space where the fermions are chiral. We compare the critical momenta for the infinitely large system with those obtained on a finite lattice.

hep-lat↗