20,799 research outputs found
CP violation in supersymmetric theories
We review the present status of CP violating problem in supersymmetric
extensions of the standard model. We analyze the constraints imposed by the
experimental limits of the electron, neutron, and mercury electric dipole
moments on the supersymmetric CP phases and show that only the scenarios with
flavour-off- diagonal CP violation remain attractive. These scenarios require
hermitian Yukawa matrices which naturally arise in models with left-right
symmetry or a SU(3) flavour symmetry. In this case, epsilon_K and
epsilon'/epsilon can be saturated by a small non-universality of the soft
scalar masses through the gluino and chargino contributions respectively. The
model also predicts a strong correlation between A_{CP}(b-> s gamma) and the
neutron electric dipole moment. In this framework, the standard model gives a
the leading contribution to the CP asymmetry in B ->psi K_S decay, while the
dominant chargino contribution to this asymmetry is < 0.2. Thus, no constraint
is set on the non-universality of this model by the recent BaBar and Belle
measureets.Comment: 34 pages, 10 figures. Invited review article for International
Journal of Modern Physics
Upper bounds on SUSY contributions to b to s transitions from B_s - B_sbar mixing
We study the constraints on supersymmetric contributions to b to s
transitions from the recent allowed range and measurement of Bs-Bsbar mixing
obtained by the D0 and CDF collaborations at the Tevatron. We compute the upper
bounds on the relevant off-diagonal squark mass terms and compare them with the
bounds coming from Delta F=1 decays. We find that the constraints on
chirality-flipping mass insertions are unaffected. Conversely, the measurement
of Bs-Bsbar mixing is effective in constraining chirality-conserving mass
insertions, and it has striking effects in the case in which left- and
right-handed insertions have similar size. Finally, we discuss the phase of the
Bs-Bsbar mixing amplitude in the presence of SUSY contributions.Comment: 4 pages, 4 figures; v2: CDF measurement include
Dark Left-Right Model: CDMS, LHC, etc
The Standard Model of particle interactions is extended to include fermion
doublets (n,e)_R transforming under the gauge group SU(2)_R such that n is a
Dirac scotino (dark-matter fermion), with odd R parity. Based on recent CDMS
data, it is shown how this new dark left-right model (DLRM2) favors a Z' gauge
boson at around 1 or 2 TeV and be observable at the LHC. The new W_R gauge
bosons may also contribute significantly to lepton-flavor-changing processes
such as mu to e gamma and mu-e conversion in a nucleus or muonic atom.Comment: 7 pages, 4 figures, typo corrected, talk at Dark Side of Universe
2010, Leon, Mexic
On the Parity-Flavor-Breaking Phase in QCD With Two Flavors of Wilson Fermions
We present further data in search of a parity-flavor-breaking phase in
simulations of dynamical QCD with two flavors of light Wilson fermions in the
strong coupling region. This is done on lattice sizes of 4^4 an up to 10^4 for
a variety of values of beta and kappa as well as the coefficient, h, of an
explicit breaking term included in the action. We confirm the existence of a
region in the beta-kappa plane where such a phase exists at beta=6/g^2 smaller
than 5.0 and above kappa_c.Comment: 3 pages latex209 with 3 postscript figures included by epsf,
contribution to LAT'9
Phenomenological Aspects of TeV Scale Alternative Left-Right Model
We revisit the alternative left-right symmetric model, motivated by
superstring-inspired model. We systematically analyze the constraints
imposed by theoretical and experimental bounds on the parameter space of this
class of models. We perform a comprehensive analysis of the Higgs sector and
show that three neutral CP-even and two CP-odd Higgs bosons in addition to two
charged Higgs bosons can be light, of GeV.
We emphasise that our model has a potential to account for the recent Large
Hadron Collider results for signal strength of Higgs decays. We also explore
discovery signatures of the exotic down-type quark, which is one of the salient
predictions of this model.Comment: 21 pages, 8 figure
Path Integrals and Voronin's Theorem on the Universality of the Riemann Zeta Function
We explore a new approach to the path integral for a latticized quantum
theory. This talk is based on work with N. Khuri and H. Ren
Black Hole with Quantum Potential
In this work, we investigate black hole (BH) physics in the context of
quantum corrections. These quantum corrections were introduced recently by
replacing classical geodesics with quantal (Bohmian) trajectories and hence
form a quantum Raychaudhuri equation (QRE). From the QRE, we derive a modified
Schwarzschild metric, and use that metric to investigate BH singularity and
thermodynamics. We find that these quantum corrections change the picture of
Hawking radiation greatly when the size of BH approaches the Planck scale. They
prevent the BH from total evaporation, predicting the existence of a quantum BH
remnant, which may introduce a possible resolution for the catastrophic
behavior of Hawking radiation as the BH mass approaches zero. Those corrections
also turn the spacelike singularity of the black hole to be timelike, and hence
this may ameliorate the information loss problem.Comment: 16 pages, 6 figures; Accepted in Nucl.Phys.
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