10 research outputs found
Uplifted supersymmetric Higgs region
We show that the parameter space of the Minimal Supersymmetric Standard Model
includes a region where the down-type fermion masses are generated by the
loop-induced couplings to the up-type Higgs doublet. In this region the
down-type Higgs doublet does not acquire a vacuum expectation value at tree
level, and has sizable couplings in the superpotential to the tau leptons and
bottom quarks. Besides a light standard-like Higgs boson, the Higgs spectrum
includes the nearly degenerate states of a heavy spin-0 doublet which can be
produced through their couplings to the quark and decay predominantly into
\tau^+\tau^- or \tau\nu.Comment: 14 pages; Signs in Eqns. (3.1) and (4.2) corrected, appendix include
CP violation in in the model III 2HDM
We have calculated the Wilson coefficients (i=1,2) in the
renormalization scheme in the model III 2HDM. Using the obtained
Wilson coefficients, we have analyzed the CP violation in decays (q=d,s) in the model. The CP asymmetry, , depends on the
parameters of models and in can be as large as 40% and
35% for and respectively. It can reach 4% for decays.
Because in SM CP violation is smaller than or equal to O() which is
unobservably small, an observation of CP asymmetry in the decays would unambiguously signal the existence of new physics.Comment: revtex4, 16 pages, 7 figure
Dark Matter And With Minimal Soft SUSY Breaking
CMSSM boundary conditions are usually used when calculating cosmological dark
matter densities. In this paper we calculate the cosmological density of dark
matter in the MSSM using minimal soft SUSY breaking boundary
conditions. These boundary conditions incorporate several attractive features:
they are consistent with Yukawa unification, they result in a
"natural" inverted scalar mass hierarchy and they reduce the dimension 5
operator contribution to the proton decay rate. With regards to dark matter, on
the other hand, this is to a large extent an unexplored territory with large
squark and slepton masses , large and small . We find that in most regions of parameter space the cosmological density of
dark matter is considerably less than required by the data. However there is a
well--defined, narrow region of parameter space which provides the observed
relic density of dark matter, as well as a good fit to precision electroweak
data, including top, bottom and tau masses, and acceptable bounds on the
branching fraction of . We present predictions for Higgs
and SUSY spectra, the dark matter detection cross section and the branching
ratio in this region of parameter space.Comment: 15 pages, 5 figure
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ
Supersymmetry beyond minimal flavour violation
We review the sources and phenomenology of non-minimal flavour violation in
the MSSM. We discuss in some detail the most important theoretical and
experimental constraints, as well as promising observables to look for
supersymmetric effects at the LHC and in the future. We emphasize the
sensitivity of flavour physics to the mechanism of supersymmetry breaking and
to new degrees of freedom present at fundamental scales, such as the grand
unification scale. We include a discussion of present data that may hint at
departures from the Standard Model.Comment: 23pp. Version to appear in the EPJC special volume "Supersymmetry on
the Eve of the LHC", dedicated to the memory of Julius Wess. References and
brief discussion on collider signatures adde