Mr
Philipp Kant
(Karlsruhe University)

7/26/07, 2:00 PM

Theoretical Models (String Theory and Formal Aspects of SUSY)

Parallel Talk

We consider regularization of a non-supersymmetric Yang-Mills theory by dimensional reduction (DRED). In particular, the anomalous dimensions of fermion masses and gauge coupling are computed to four-loop order.
We put special emphasis on the treatment of evanescent couplings which appear when DRED is applied to non-supersymmetric theories. We highlight the importance of distinguishing...

Dr
Tomohisa Takimi
(Theoretical Physics Laboratory, The Institute of Physical and Chemical Research (RIKEN))

7/26/07, 2:20 PM

Theoretical Models (String Theory and Formal Aspects of SUSY)

Parallel Talk

We investigate an integrable property and observables of 2 dimensional N=
(4,4) topological field theory defined on a discrete lattice by using
the "orbifolding" and "deconstruction" methods. We show that our lattice
model possesses the integrability and the partition function reduces to matrix
integrals of scalar fields on sites in consequence. We make clear meaningful
differences...

Prof.
Shoichi Ichinose
(University of Shizuoka)

7/26/07, 2:40 PM

Theoretical Models (String Theory and Formal Aspects of SUSY)

Parallel Talk

A graphical representation of supersymmetry is presented. It clearly expresses
the chiral flow appearing in SUSY quantities, by representing spinors by
directed lines (arrows). The chiral suffixes are expressed by the directions (up,
down, left, right) of the arrows. The SL(2,C) invariants are represented by
wedges. Both the Weyl spinor and the Majorana spinor are treated. We are...

Dr
Etsuko Itou
(Kyoto University, YITP)

7/26/07, 3:00 PM

Theoretical Models (String Theory and Formal Aspects of SUSY)

Parallel Talk

We construct novel conformal sigma models in three dimensions. Nonlinear sigma models
in three dimensions are nonrenormalizable in perturbation theory. We use Wilsonian
renormalization group equation method to find the fixed points. Existence of fixed
points is extremely important in this approach to show the renormalizability.
Conformal sigma models are defined as the fixed point theories...

Dr
Dumitru Ghilencea
(University of Oxford, Physics Dept)

7/26/07, 3:20 PM

Theoretical Models (String Theory and Formal Aspects of SUSY)

Parallel Talk

The role of higher derivative operators in 4D effective field theories is discussed
in both non-supersymmetric and supersymmetric contexts. It is showed that theories
with higher derivative operators do not always have an improved UV behaviour as
usually considered, due to subtleties related to the analytical continuation from the
Minkowski to the Euclidean metric. Radiative corrections...

Nathaniel Craig
(Stanford University)

7/26/07, 3:40 PM

Theoretical Models (String Theory and Formal Aspects of SUSY)

Parallel Talk

In theories with multiple vacua, reheating to a temperature greater than the height of a barrier can stimulate
transitions from a desirable metastable vacuum to a lower energy state. We discuss the constraints this places on
various theories and demonstrate that in a class of supersymmetric models this transition does not occur even for
arbitrarily high reheating temperature.