10 research outputs found
Coupling Unification, GUT-Scale Baryogenesis and Neutron-Antineutron Oscillation in SO(10)
We show that unification of the three gauge couplings can be realized
consistently in a class of non-supersymmetric SO(10) models with a one-step
breaking to the Standard Model if a color-sextet scalar field survives down to
the TeV scale. Such scalars, which should be accessible to the LHC for direct
detection, arise naturally in SO(10) as remnants of the seesaw mechanism for
neutrino masses. The diquark couplings of these scalars lead to \Delta B = 2
baryon number violating processes such as neutron-antineutron oscillation. We
estimate the free neutron-antineutron transition time to be \tau_{n-\bar{n}}
\approx (10^9-10^{12}) sec., which is in the interesting range for next
generation n-\bar{n} oscillation experiments. These models also realize
naturally the recently proposed (B-L)-violating GUT scale baryogenesis which
survives to low temperatures unaffected by the electroweak sphaleron
interactions.Comment: 15 pages, 4 eps figures, references added, to appear in Phys. Lett.
Lepton Flavour Violating Leptonic/Semileptonic Decays of Charged Leptons in the Minimal Supersymmetric Standard Model
We consider the leptonic and semileptonic (SL) lepton flavour violating (LFV)
decays of the charged leptons in the minimal supersymmetric standard model
(MSSM). The formalism for evaluation of branching fractions for the SL LFV
charged-lepton decays with one or two pseudoscalar mesons, or one vector meson
in the final state, is given. Previous amplitudes for the SL LFV charged-lepton
decays in MSSM are improved, for instance the -penguin amplitude is
corrected to assure the gauge invariance. The decays are studied not only in
the model-independent formulation of the theory in the frame of MSSM, but also
within the frame of the minimal supersymmetric SO(10) model within which the
parameters of the MSSM are determined. The latter model gives predictions for
the neutrino-Dirac Yukawa coupling matrix, once free parameters in the model
are appropriately fixed to accommodate the recent neutrino oscillation data.
Using this unambiguous neutrino-Dirac Yukawa couplings, we calculate the LFV
leptonic and SL decay processes assuming the minimal supergravity scenario. A
very detailed numerical analysis is done to constrain the MSSM parameters.
Numerical results for SL LFV processes are given, for instance for tau -> e
(mu) pi0, tau -> e (mu) eta, tau -> e (mu) eta', tau -> e (mu) rho0, tau -> e
(mu) phi, tau -> e (mu) omega, etc.Comment: 36 pages, 3 tables, 5 .eps figure
Electromagnetic probes
We introduce the seminal developments in the theory and experiments of
electromagnetic probes for the study of the dynamics of relativistic heavy ion
collisions and quark gluon plasma.Comment: 47 pages, 33 Figures; Lectures delivered by Dinesh K. Srivastava at
QGP Winter School (QGPWS08) at Jaipur, India, February 1-3, 200
Modeling of Flexible Rotor Machines Supported with Hydrostatic Bearings
In this paper a method is described that takes the nonlinear dynamic stiffness and damping coefficients for multiple hydrostatic bearings and incorporates them into a rotordynamic FEM model for a rotating machine. A Newton-Raphson iteration scheme is presented that uses updated bearing coefficients at every iteration to the solution. A non-linear computer program was written using the method described which models transient and synchronous response and calculates damped eigenvalues.Center for Electromechanic