14 research outputs found
Analyzing Chiral Symmetry Breaking in Supersymmetric Gauge Theories
We compare gap equation predictions for the spontaneous breaking of global
symmetries in supersymmetric Yang-Mills theory to nonperturbative results from
holomorphic effective action techniques. In the theory without matter fields,
both approaches describe the formation of a gluino condensate. With
flavors of quark and squark fields, and with below a certain critical
value, the coupled gap equations have a solution for quark and gluino
condensate formation, corresponding to breaking of global symmetries and of
supersymmetry. This appears to disagree with the newer nonperturbative
techniques, but the reliability of gap equations in this context and whether
the solution represents the ground state remain unclear.Comment: LaTex, 14 pages, including 1 figure in EPS format. Revised to correct
gluino anomalous dimension, with minor accompanying text change
Exact Results And Soft Breaking Masses In Supersymmetric Gauge Theory
We give an explicit formalism connecting softly broken supersymmetric gauge
theories (with QCD as one limit) to and supersymmetric theories
possessing exact solutions, using spurion fields to embed these models in an
enlarged model. The functional forms of effective Lagrangian terms
resulting from soft supersymmetry breaking are constrained by the symmetries of
the enlarged model, although not well enough to fully determine the vacuum
structure of generic softly broken models. Nevertheless by perturbing the exact
model results with sufficiently small soft breaking masses, we show that
there exist nonsupersymmetric models that exhibit monopole condensation and
confinement in the same modes as the case.Comment: Final version to appear in Nucl. Phys. B; LaTex, 19 pgs, no figures.
Corrected references and some formulae, with no effect on conclusion
Static Properties of Quark Solitons
It has been conjectured that at distances smaller than the confinement scale
but large enough to allow for nonperturbative effects, QCD is described by an
effective chiral
Lagrangian. The soliton solutions of such a Lagrangian are extended objects
with spin . For , they are triplets of color and
flavor and have baryon number , to be identified as constituent
quarks. We investigate in detail the static properties of such
constituent-quark solitons for the simplest case . The mass
of these objects comes from the energy of the static soliton and from quantum
effects, described semiclassically by rotation of collective coordinates around
the classical solution. The quantum corrections tend to be large, but can be
controlled by exploring the Lagrangian's parameter space so as to maximize the
inertia tensor. We comment on the acceptable parameter space and discuss the
model's further predictive power.Comment: 8 pages + 1 PostScript figure; plain LaTe
Phenomenology of the Top Mass in Realistic Extended Technicolor Models
Extended technicolor (ETC) theories typically require ETC gauge bosons
lighter than of order 1 TeV, to perturbatively generate the quark mass. We
point out that explicit models of mass splitting also typically contain
additional TeV scale ETC gauge bosons transforming in the {\it adjoint} of
technicolor, leading to large weak-isospin-breaking effects observable in the
parameter. Viable ETC models may thus require a lowest ETC scale of
order 10 TeV, with relatively strong and finely tuned couplings to generate
. Such models do not generate observable corrections to the
vertex.Comment: LaTex, 12 pages, including 2 EPS figures in 5 file
Instantons and the Chiral Phase Transition
We examine the role of instantons in the zero-temperature chiral phase
transition in an SU(N) gauge theory. For a range of N_f (the number of fermion
flavors) depending on N, the theory exhibits an infrared fixed point at
coupling . As N_f decreases, increases, and it eventually
exceeds a critical value sufficient to trigger chiral symmetry breaking. For
the case N = 2, we estimate the critical values of N_f and due to
instantons by numerically solving a gap equation with an instanton-generated
kernel. We find instanton effects of strength comparable to that of gluon
exchange.Comment: LaTeX, 9 pages, including 2 figures in EPS forma
A strongly first order electroweak phase transition from strong symmetry-breaking interactions
We argue that a strongly first order electroweak phase transition is natural
in the presence of strong symmetry-breaking interactions, such as technicolor.
We demonstrate this using an effective linear scalar theory of the
symmetry-breaking sector.Comment: LaTex, 15 pages, 3 figures in EPS format. Phys. Rev. D approved
Typographically Correct version, minor grammatical change