2,846 research outputs found
Renormalization Group Improved Radiative Corrections to the Supersymmetric Higgs Boson Masses
The one-loop radiative corrections to the Higgs boson potential in the MSSM,
originating from the top quark and squark loops, are summed in the leading log
approximation using the renormalization group. The RG improved effective
potential is minimized and the corrections to the CP-odd and CP-even Higgs
boson masses are calculated. The resulting masses exhibit smoother top mass
dependence than those calculated without RG summation. We have also found that
for preferable values of the top mass the light Higgs mass does not exceed 100
GeV.Comment: 10 PAGES, 1 FIGURE ENCLOSED, LATE
IS (Low Energy) SUSY STILL ALIVE?
Supersymmetry, a new symmetry that relates bosons and fermions in particle
physics, still escapes observation. Search for supersymmetry is one of the main
aims of the Large Hadron Collider. The other possible manifestation of
supersymmetry is the Dark Matter in the Universe. The present lectures contain
a brief introduction to supersymmetry in particle physics. The main notions of
supersymmetry are introduced. The supersymmetric extension of the Standard
Model -- the Minimal Supersymmetric Standard Model -- is considered in more
detail. Phenomenological features of the Minimal Supersymmetric Standard Model
as well as possible experimental signatures of supersymmetry at the Large
Hadron Collider are described. The present limits on supersymmetric particles
are presented and the allowed region of parameter space of the MSSM is shown.Comment: 59 pages, 35 figures, PDFLatex, Lectures at the European School of
High-Energy Physics, June 2012, Anjou, Franc
On free energy of 2-d black hole in bosonic string theory
Trying to interpret recent matrix model results (hep-th/0101011) we discuss
computation of classical free energy of exact dilatonic 2-d black hole from the
effective action of string theory. The euclidean space-time action evaluated on
the black hole background is divergent due to linear dilaton vacuum
contribution, and its finite part depends on a subtraction procedure. The
thermodynamic approach based on subtracting the vacuum contribution for fixed
values of temperature and dilaton charge at the "wall" gives (as in the
leading-order black hole case) S= M/T for the entropy and zero value for the
free energy F. We suggest that in order to establish a correspondence with a
non-vanishing matrix model result for F one may need an alternative
reparametrization-invariant subtraction procedure using analogy with
non-critical string theory (i.e. replacing the spatial coordinate by the
dilaton field). The subtraction of the dilaton divergence then produces a
finite value for the free energy. We also propose a microscopic estimate for
the entropy and energy of the black hole based on the contribution of
non-singlet states of the matrix model.Comment: 25 pages, lanlma
Conformal Invariance = Finiteness and Beta Deformed N=4 SYM Theory
We claim that if by a choice of the couplings the theory can be made
conformally invariant (vanishing of the beta functions) it is automatically
finite and vice versa. This is demonstrated by explicit example in
supersymmetric gauge theory. The formalism is then applied to the beta deformed
SYM theory and it is shown that the requirement of conformal
invariance = finiteness can be achieved for any complex parameter of
deformations.Comment: 15 pages, Latex, 1 figure axodraw styl
- …