624 research outputs found

### Non-Supersymmetric Brane Configurations, Seiberg Duality and Dynamical Symmetry Breaking

We consider type IIA brane configurations, similar to those that realize
SO(2N) supersymmetric QCD, that include orientifold planes and anti-branes.
Such brane configurations lead to Sp(2N) field theories that become
supersymmetric in the large-N limit and break supersymmetry upon the inclusion
of 1/N corrections. We argue that this class of field theories admit Seiberg
duality and interpret the potential between branes and orientifolds as field
theory phenomena. In particular we find in the magnetic theory a meson
potential that leads to dynamical symmetry breaking and a meson condensate
similar to the anticipated quark condensate in QCD.Comment: 22 pages. LaTex. 5 eps figures. v2: minor changes, reference and a
comment about the GMOR relation added. To appear in Phys.Rev.

### Goldstinos, Supercurrents and Metastable SUSY Breaking in N=2 Supersymmetric Gauge Theories

We construct an N=2 supersymmetric generalization of the N=1 supercurrent
formalism of Komargodski and Seiberg (KS) and use it to show that N=2 theories
with linear superconformal anomalies cannot break SUSY under certain broad
assumptions. This result suggests that there are no metastable SUSY breaking
vacua in a large class of theories that includes N=2 Super Yang-Mills (SYM).Comment: 19 pages; minor revisions; JHEP versio

### A Bound on the Superpotential

We prove a general bound on the superpotential in theories with broken
supersymmetry and broken R-symmetry, 2|W|< f_a F, where f_a and F are the
R-axion and Goldstino decay constants, respectively. The bound holds for weakly
coupled as well as strongly coupled theories, thereby providing an exact result
in theories with broken supersymmetry. We briefly discuss several possible
applications.Comment: 20 page

### On the Thermal History of Calculable Gauge Mediation

Many messenger models with realistic gaugino masses are based on meta-stable
vacua. In this work we study the thermal history of some of these models.
Analyzing R-symmetric models, we point out that while some of the known
messenger models clearly prefer the supersymmetric vacuum, there is a vast
class of models where the answer depends on the initial conditions. Along with
the vacuum at the origin, the high temperature thermal potential also possesses
a local minimum far away from the origin. This vacuum has no analog at zero
temperature. The first order phase transition from this vacuum into the
supersymmetric vacuum is parametrically suppressed, and the theory, starting
from that vacuum, is likely to evolve to the desired gauge-mediation vacuum. We
also comment on the thermal evolution of models without R-symmetry.Comment: 22 pages. V2: Comments on the SM effects added. Minor corrections.
Reference added. Valuable discussion with S. Abel, J. Jaeckel and V. Khoze
acknowledged. V3: Types of EOGM explicitly defined in the introduction.
Discussions about the phase transitions expanded. Typo corrected. Journal
versio

### Semi-Direct Gauge Mediation with the 4-1 Model

We analyze a model of Semi-Direct Gauge Mediation in which the hidden sector
is the 4-1 model and the messenger fields are charged under the U(1) gauge
group. At tree level, the SUSY-breaking F-terms induce D-terms from which
SUSY-split messenger masses arise. We calculate these masses by three
complementary methods. Additionally, we compute the one-loop corrections to the
masses. We consider this model both with and without a Fayet-Iliopoulos term
for the hidden sector U(1). Finally, we write down a simple model of Minimal
Gauge Mediation in which the only scale is dynamically generated.Comment: 29 pages, 5 figures, harvma

### Nonlinear Realization of Spontaneously Broken N=1 Supersymmetry Revisited

This paper revisits the nonlinear realization of spontaneously broken N=1
supersymmetry. It is shown that the constrained superfield formalism can be
reinterpreted in the language of standard realization of nonlinear
supersymmetry via a new and simpler route. Explicit formulas of actions are
presented for general renormalizable theories with or without gauge
interactions. The nonlinear Wess-Zumino gauge is discussed and relations are
pointed out for different definitions of gauge fields. In addition, a general
procedure is provided to deal with theories of arbitrary Kahler potentials.Comment: 1+18 pages, LaTe

### Limit Cycles and Conformal Invariance

There is a widely held belief that conformal field theories (CFTs) require
zero beta functions. Nevertheless, the work of Jack and Osborn implies that the
beta functions are not actually the quantites that decide conformality, but
until recently no such behavior had been exhibited. Our recent work has led to
the discovery of CFTs with nonzero beta functions, more precisely CFTs that
live on recurrent trajectories, e.g., limit cycles, of the beta-function vector
field. To demonstrate this we study the S function of Jack and Osborn. We use
Weyl consistency conditions to show that it vanishes at fixed points and agrees
with the generator Q of limit cycles on them. Moreover, we compute S to third
order in perturbation theory, and explicitly verify that it agrees with our
previous determinations of Q. A byproduct of our analysis is that, in
perturbation theory, unitarity and scale invariance imply conformal invariance
in four-dimensional quantum field theories. Finally, we study some properties
of these new, "cyclic" CFTs, and point out that the a-theorem still governs the
asymptotic behavior of renormalization-group flows.Comment: 31 pages, 4 figures. Expanded introduction to make clear that cycles
discussed in this work are not associated with unitary theories that are
scale but not conformally invarian

### Classicalization and Unitarity

We point out that the scenario for UV completion by "classicalization",
proposed recently is in fact Wilsonian in the classical Wilsonian sense. It
corresponds to the situation when a field theory has a nontrivial UV fixed
point governed by a higher dimensional operator. Provided the kinetic term is a
relevant operator around this point the theory will flow in the IR to the free
scalar theory. Physically, "classicalization", if it can be realized, would
correspond to a situation when the fluctuations of the field operator in the UV
are smaller than in the IR. As a result there exists a clear tension between
the "classicalization" scenario and constraints imposed by unitarity on a
quantum field theory, making the existence of classicalizing unitary theories
questionable.Comment: Some clarifications and refs added. Accepted as a JHEP publication;
12 page

### Three form potential in (special) minimal supergravity superspace and supermembrane supercurrent

This contribution begins the study of the complete superfield Lagrangian
description of the interacting system of D=4 N=1 supergravity (SUGRA) and
supermembrane. Firstly, we review a 'three form supergravity' by Ovrut and
Waldram, which we prefer to call 'special minimal supergravity'. This off-shell
formulation of simple SUGRA is appropriate for our purposes as the
supermembrane action contains the so-called Wess-Zumino term given by the
integral over a three form potential in superspace, C3. We describe this
formulation in the frame of Wess--Zumino superfield approach, showing how the
basic variations of minimal SUGRA are restricted by the conditions of the
existence of a three-form potential C3 in its superspace. In this language the
effect of dynamical generation of cosmological constant, known to be
characteristic for this formulation of SUGRA, appears in its superfield form,
first described by Ogievetsky and Sokatchev in their formulation of SUGRA as a
theory of axial vector superfield. Secondly, we vary the supermembrane action
with respect to the special minimal SUGRA superfields (basic variations) and
obtain the supercurrent superfields as well as the supergravity superfield
equations with the supermembrane contributions.Comment: 18 pages, no figures. V2: Important references added. The abstract
and presentation have been changed to reflect the overloop with that.
Submitted to the QTS7 Proceedings. J. Phys. style use

### Making confining strings out of mesons

The light mesons such as pi, rho, omega, f0, and a0 are possible candidates
of magnetic degrees of freedom, if a magnetic dual picture of QCD exists. We
construct a linear sigma model to describe spontaneous breaking of the magnetic
gauge group, in which there is a stable vortex configuration of vector and
scalar mesons. We numerically examine whether such a string can be interpreted
as the confining string. By using meson masses and couplings as inputs, we
calculate the tension of the string as well as the strength of the Coulomb
force between static quarks. They are found to be consistent with those
inferred from the quarkonium spectrum and the Regge trajectories of hadrons. By
using the same Lagrangian, the critical temperature of the QCD phase transition
is estimated, and a non-trivial flavor dependence is predicted. We also discuss
a possible connection between the Seiberg duality and the magnetic model we
studied.Comment: 22 pages, 2 figures, 3 tables, typos corrected, references adde

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