111,129 research outputs found
Ultra-violet Finiteness in Noncommutative Supersymmetric Theories
We consider the ultra-violet divergence structure of general noncommutative
supersymmetric gauge theories, and seek theories which are all-orders
finite.Comment: 11 pages, Tex, one figure. Uses harvmac (big) and eps
Fayet-Iliopoulos D-terms and anomaly mediated supersymmetry breaking
We show that in a minimal extension of the MSSM by means of an extra U(1)
gauge group, the negative mass-squared problem characteristic of the Anomaly
Mediated Supersymmetry Breaking scenario is naturally solved by means of
Fayet-Iliopoulos D-terms. We derive a set of sum rules for the sparticle masses
which are consequences of the resulting framework.Comment: 11 pages, including 1 figure. Plain TeX. Uses Harvmac and epsf. Final
version to appear in Phys. Lett. B; some minor improvement
The Exact Tachyon Beta-Function for the Wess-Zumino-Witten Model
We derive an exact expression for the tachyon -function for the
Wess-Zumino-Witten model. We check our result up to three loops by calculating
the three-loop tachyon -function for a general non-linear -model
with torsion, and then specialising to the case of the WZW model.Comment: 13pp, uses harvmac (with figures appended as a a standard PostScript
file), LTH 31
Quasi-infra-red fixed points and renormalisation group invariant trajectories for non-holomorphic soft supersymmetry breaking
In the MSSM the quasi-infra-red fixed point for the top-quark Yukawa coupling
gives rise to specific predictions for the soft-breaking parameters. We discuss
the extent to which these predictions are modified by the introduction of
additional ``non-holomorphic'' soft-breaking terms. We also show that in a
specific class of theories there exists an RG-invariant trajectory for the
``non-holomorphic'' terms, which can be understood using a holomorphic spurion
term.Comment: 24 pages, TeX, two figures. Uses Harvmac (big) and epsf. Minor errors
corrected, and the RG trajectory explained in terms of a holomorphic spurion
ter
The Gaugino \beta-Function
We present an elegant exact formula for the gaugino -function in a
softly-broken supersymmetric gauge theory, of the form , where is the gauge function and is
a simple differential operator acting on the gauge coupling and the Yukawa
coupling.Comment: 11 pages, tex, no figures. Uses harvmac. Minor error in derivation of
Eq. (14) correcte
Six-loop divergences in the supersymmetric Kahler sigma model
The two-dimensional supersymmetric \s-model on a K\"ahler manifold has a
non-vanishing \b-function at four loops, but the \b-function at five loops
can be made to vanish by a specific choice of renormalisation scheme. We
investigate whether this phenomenon persists at six loops, and conclude that it
does not; there is a non-vanishing six-loop \b-function irrespective of
renormalisation scheme ambiguities.Comment: 13pp, uses phyzzx, LTH 287 (published in Int. J. Mod. Phys. A
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