676 research outputs found
Grand unification in the minimal left-right symmetric extension of the standard model
The simplest minimal left-right symmetric extension of the standard model is
studied in the high energy limit, and some consequences of the grand
unification hypothesis are explored assuming that the parity breaking scale is
the only relevant energy between the electro-weak scale and the unification
point. While the model is shown to be compatible with the observed neutrino
phenomenology, the parity breaking scale and the heavy boson masses are
predicted to be above 10^7 TeV, quite far from the reach of nowadays
experiments. Below that scale only an almost sterile right handed neutrino is
allowed with a mass M \approx 100 TeV
Studies on uracils : a facile one-pot synthesis of oxazino[4,5- d]-, pyrano[2,3-d]-, pyrido[2,3-d]- and pyrimido[4,5-d]pyrimidines using microwave irradiation in the solid state
—N,N-Dimethyl-5-formylbarbituric acid 1 reacts with maleimide 2 and phenyl isocyanate/phenyl isothiocyanate 4 under
microwave-assisted conditions in the solid phase to afford pyrano[2,3-d]pyrimidines3 and oxazino[4,5-d]pyrimidines5 in excellent
yields. Under identical conditions, N,N-dimethyl-6-amino-5-formyluracil 6 reacts with 2 and 4 to give pyrido[2,3-d]pyrimidine
derivative 7 and pyrimido[4,5-d]pyrimidines 8 in high yield
Baker's Yeast-catalysed ring opening of benzofuroxans : an efficient green synthesis of aryl-1,2-diamines
A simple and inexpensive method for the reductive cleavage of N–O
bond of benzofuroxans with bakers’ yeast under nonfermenting condition in
aqueous media was achieved. The procedure gives excellent yields of aryl-1,
2-diamines
Studies on uracils : synthesis of novel pyrido[2,3-d]- pyrimidine oxides via ring transformation of isoxazolo[3,4-d]pyrimidine
The reaction of isoxazolo[3,4-d]pyrimidine 1 and cyanoolefins 2 in the presence of triethylamine (Et3N) as a catalyst
afforded an unprecedented one-pot synthesis of biologically important pyrido[2,3-d]pyrimidine oxides 3 in excellent yields
A facile one pot synthesis of pyrazolo[3,4-D] pyrimidines
The reaction of 6-hydrazino uracils 1 with isocyanates 2 gave access to an efficient one-pot synthesis of pyrazolo[3,4-
d]pyrimidines 3 in excellent yield
STEREOSELECTIVE INTRAMOLECULAR HETERO-DIELS-ALDER REACTIONS OF 1-OXA-1,3-BUTADIENES - SYNTHESIS OF NOVEL ANNELATED PYRROLO[1,2-A]INDOLES
14Novelclassesofpyrano-1,3-dioxane-,pyranopyrimidine-andpyranopyrazole-fusedpyrrolo[1,2-a]indolesaresynthesised
via stereoselective intramolecular 1-oxa-1,3-butadiene hetero Diels 13Alder reaction
Lowering solar mixing angle in inverted hierarchy without charged lepton corrections
In the present work, the inverted hierarchical neutrino mass model which is
characterised by opposite CP parity in the first two mass eigenvalues
, is studied in order to lower the predicted value of solar
mixing angle , from the tri-bimaximal mixing (TBM), without
sacrificing the conditions of maximal atmospheric mixing angle and zero reactor
angle. The present attempt is different from the earlier approach where the
correction from the charged lepton mass matrix is included in the leptonic
mixing matrix to lower the prediction on solar mixing angle. The lowering of
the solar mixing angle without charged lepton correction, can be obtained
through the variation of the input value of a flavour twister term present in
the texture of neutrino mass matrix having a 2-3 symmetry. The present analysis
agrees with the latest experimental bounds on neutrino mass parameters and also
represents an important result on the survival of the inverted hierarchical
neutrino mass models having opposite CP parity in the first two eigenvalues.Comment: 10 pages, two figures. Accepted for publication in Journal of Physics
G:Nuclear and Particle Physic
Deviation from tri-bimaximal mixings in two types of inverted hierarchical neutrino mass models
An attempt is made to explore the possibility for deviations of solar mixing
angle () from tri-bimaximal mixings, without sacrificing the
predictions of maximal atmospheric mixing angle () and zero
reactor angle (). We find that the above conjecture can be
automatically realised in the inverted hierarchical neutrino mass model having
2-3 symmetry, in the basis where charged lepton mass matrix is diagonal. For
the observed ranges of and \bigtriangleup m^2_{23],
we calculate the predictions on for
different input values of the parameters in the neutrino mass matrix. We also
observe a possible crossing over from one type of inverted hierarchical model
having same CP parity (Type-IHA) to other type having opposite CP parity
(Type-IHB). Such neutrino mass matrices can be obtained from the canonical
seesaw formula using diagonal form of Dirac neutrino mass matrix and
non-diagonal texture of right-handed Majorana mass matrix, and may have
important implications in model building using discrete as well as non-abelian
symmetry groups.Comment: 13 pages, 7 figure
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