13,704 research outputs found
Neutrinoless double beta decay with scalar bilinears
One possible probe to physics beyond the standard model is to look for scalar
bilinears, which couple to two fermions of the standard model. We point out
that the scalar bilinears allow new diagrams contributing to the neutrinoless
double beta decay. The upper bound on the neutrinoless double beta decay
lifetime would then give new constraints on the ratio of the masses of these
scalars to their couplings to the fermions.Comment: 11 pages latex with 3 figure
Non-perturbative unification in the light of LEP results
We consider an alternative to conventional GUTs originally proposed by
Maiani, Parisi and Petronzio, where owing to the existence of extra fermion
generations at some intermediate scale, the gauge couplings become large at
high energies. We first comment on how the non- supersymmetric version of this
scenario is ruled out; we then consider the two-loop evolution of the couplings
in the supersymmetric extension of this scenario, and check whether such a
scenario is feasible in the light of the precies values of couplings now
available from LEP.Comment: Latex file 7 pages+1 fig. (ps file appended after the latex file),
CERN-TH.6913/9
Effects of New Gravitational Interactions on Neutrinoless Double Beta Decay
It has recently been proposed that violations of Lorentz invariance or
violations of the equivalence principle can be constrained from the
non-observation of neutrinoless double beta decay. We generalize this analysis
to all possible new gravitational interactions and discuss briefly the
constraints for different cases.Comment: 10 page
Baryogenesis through lepton number violation
The most promising scenarios of baryogenesis seems to be the one through lepton number violation. Lepton number violation through a Majarana mass of the right-handed neutrinos can generate a lepton asymmetry of the universe when the right-handed neutrinos decay. The left-handed neutrinos get small Majorana masses through see-saw mechanism in these models. A triplet higgs scalar violating lepton number explicitly through its couplings to two leptons or two higgs doublets can also naturally give small Majorana masses to the left-handed neutrinos and also generate a lepton asymmetry of the universe. We review both these models of leptogenesis, where the lepton number asymmetry then gets converted to a baryon asymmetry of the universe before the electroweak phase transition
Liquid-phase hydrogenation of bio-refined succinic acid to 1,4-butanediol using bimetallic catalysts
open access articleDevelopment of a Crotalaria juncea based biorefinery produce large quantity of waste glycerol after trans-esterification
of the juncea seeds. This glycerol, after purification, is used as a substrate for producing succinic acid on a microbial
route. Hydrogenation of this bio-refined succinic acid is carried out under high pressure in order to produce 1,4-
butanediol (BDO) using a batch slurry reactor with cobalt supported ruthenium bimetallic catalysts, synthesized inhouse.
It is demonstrated that, using small amounts of ruthenium to cobalt increases the overall hydrogenation activity
for the production of 1,4-butanediol. Hydrogenation reactions are carried out at various operating temperatures and
pressures along with changes in the mixing ratios of ruthenium chloride and cobalt chloride hexahydrate, which are
used to synthesize the catalyst. The Ru-Co bimetallic catalysts are characterized by XRD, FE-SEM and TGA.
Concentrations of the hydrogenation product are analyzed using Gas chromatography-Mass spectrometry (GC-MS).
Statistical analysis of the overall hydrogenation process is performed using a Box-Behnken Design (BBD)
Electroweak Baryon Number Violation and Constraints on Left-handed Majorana Neutrino Masses
During a large period of time, the anomalous baryon number violating interactions are in equilibrium, when the asymmetry is washed out. If there is any lepton number violation during this period, that will also erase the asymmetry. As a result, survival of the baryon asymmetry of the universe pose strong constraints on lepton number violating interactions. We review here the constraints on the left-handed Majorana neutrino masses arising from this survival requirement of the baryon asymmetry of the universe. We then briefly review models of leptogenesis, where lepton number violation is used to generate a baryon asymmetry of the universe and hence the constraints on the Majorana neutrino mass is relaxed
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