1,564 research outputs found
Lepton Masses in a Minimal Model with Triplet Higgs Bosons and Flavor Symmetry
Viable neutrino and charged lepton masses and mixings are obtained by
imposing a flavor symmetry in a model with a few
additional Higgs. We use two triplet Higgs which are arranged as a
doublet of , and standard model singlet Higgs which are also put as
doublets of . We break the symmetry in this minimal model by giving
vacuum expectation values (VEV) to the additional Higgs fields. Dictated by the
minimum condition for the scalar potential, we obtain certain VEV alignments
which allow us to maintain symmetry in the neutrino sector, while
breaking it maximally for the charged leptons. This helps us to simultaneously
explain the hierarchical charged lepton masses, and the neutrino masses and
mixings. In particular, we obtain maximal and zero .
We allow for a mild breaking of the symmetry for the neutrinos and
study the phenomenology. We give predictions for and the CP
violating Jarlskog invariant , as a function of the symmetry
breaking parameter. We also discuss possible collider signatures and
phenomenology associated with lepton flavor violating processes.Comment: 29 pages, 5 figures. Version to be appeared in PRD. Phenomenology of
Lepton flavor violation and possible collider signatures of this model have
been include
Two Higgs Doublet Type III Seesaw with mu-tau symmetry at LHC
We propose a two Higgs doublet Type III seesaw model with - flavor
symmetry. We add an additional SU(2) Higgs doublet and three SU(2) fermion
triplets in our model. The presence of two Higgs doublets allows for natural
explanation of small neutrino masses with triplet fermions in the 100 GeV mass
range, without fine tuning of the Yukawa couplings to extremely small values.
The triplet fermions couple to the gauge bosons and can be thus produced at the
LHC. We study in detail the effective cross-sections for the production and
subsequent decays of these heavy exotic fermions. We show for the first time
that the - flavor symmetry in the low energy neutrino mass matrix
results in mixing matrices for the neutral and charged heavy fermions that are
not unity and which carry the flavor symmetry pattern. This flavor structure
can be observed in the decays of the heavy fermions at LHC. The large Yukawa
couplings in our model result in the decay of the heavy fermions into lighter
leptons and Higgs with a decay rate which is about times larger than
what is expected for the one Higgs Type III seesaw model with 100 GeV triplet
fermions. The smallness of neutrino masses constrains the neutral Higgs mixing
angle in our model in such a way that the heavy fermions decay
into the lighter neutral CP even Higgs , CP odd Higgs and the
charged Higgs , but almost never to the heavier neutral CP even Higgs
. The small value for also results in a very long lifetime
for . This displaced decay vertex should be visible at LHC. We provide an
exhaustive list of collider signature channels for our model and identify those
that have very large effective cross-sections at LHC and almost no standard
model background.Comment: 51 pages, 11 tables, 8 figure
Singlet-triplet fermionic dark matter and LHC phenomenology
It is well known that for the pure standard model triplet fermionic WIMP-type dark matter (DM), the relic density is satisfied around 2 TeV. For such a heavy mass particle, the production cross-section at 13 TeV run of LHC will be very small. Extending the model further with a singlet fermion and a triplet scalar, DM relic density can be satisfied for even much lower masses. The lower mass DM can be copiously produced at LHC and hence the model can be tested at collider. For the present model we have studied the multi jet (>= 2 j) + missing energy ((sic)(T)) signal and show that this can be detected in the near future of the LHC 13 TeV run. We also predict that the present model is testable by the earth based DM direct detection experiments like Xenon-1T and in future by Darwin.Peer reviewe
Polymeric Piezoelectric Transducers for Hydrophone Applications
Conventional ceramic piezoelectric materials have been used in hydrophones for sonarapplications since 1940's. In the last few years since the discovery of polymeric piezoelectrichydrophones, the technology has matured, applications have emerged in extraordinary number ofcases such as underwater navigation, biomedical applications, biomimetics, etc. Hydrophones areused underwater at high hydrostatic pressures. In the presence of hydrostatic pressures, theanisotropic piezoelectric response of ceramic materials is such that it has poor hydrophone performancecharacteristics whereas polymeric piezoelectric materials show enough hydrostatic piezoelectriccoefficients. Moreover, piezoelectric polymers have low acoustic impedance, which is only 2-6 timethat of water, whereas in piezoelectric ceramics, it is typically 11-time greater than that of water. Aclose impedance match permits efficient transduction of acoustic signals in water and tissues. Newlydeveloped hydrostatic-mode polyvinylidene flouride (PVDF) hydrophones use a pressure-releasesystem to achieve improved sensitivity. Recently, voided PVDF materials have been used for makinghydrophones having higher sensitivity and figure of merit than unvoided PVDF materials
PRELIMINARY PHYTOCHEMICAL, PHARMACOGNOSTIC AND PHYSICOCHEMICAL EVALUATION OF ERANTHEMUM NIGRUM LEAF
Objective: To analyze the pharmacognostic characteristics and physiochemical parameters of the leaves of Eranthemum nigrum (E. nigrum).
Methods: Microscopic characters and powder analysis had been carried out with the help of a microscope. The physiochemical properties such as loss on drying, total ash value, acid insoluble ash value, water soluble ash value, extractive values and fluorescence of E. nigrum had been performed.
Results: Macroscopically, the leaves are simple, elliptical in shape, dull with smooth margins and acute apex. Microscopically, the leaf showed the presence of epidermal cells with uniseriate multicellular covering trichomes and diacytic stomata, followed by 4-6 layered collenchymatous cells and 10-14 numbered conjoint, collateral closed vascular bundles are some of the diagnostic characteristics observed from an anatomical study. Powder microscopy of leaf revealed the presence of uniseriate multicellular covering trichomes, lignified xylem vessels, epidermis with diacytic stomata and parenchyma cells. The investigations also included leaf surface data i.e., quantitative leaf microscopy and fluorescence analysis. Physiochemical parameters such as loss on drying, extractive values and ash values were also determined. Preliminary phytochemical screening showed the presence of steroids, alkaloids, tannins, saponins, carbohydrates, glycosides, amino acids and proteins.
Conclusion: The morphological, microscopical and physicochemical parameter results provided in this paper may be utilized as a basis for the preparation of a monograph on E. nigrum leaves
GeneDB--an annotation database for pathogens.
GeneDB (http://www.genedb.org) is a genome database for prokaryotic and eukaryotic pathogens and closely related organisms. The resource provides a portal to genome sequence and annotation data, which is primarily generated by the Pathogen Genomics group at the Wellcome Trust Sanger Institute. It combines data from completed and ongoing genome projects with curated annotation, which is readily accessible from a web based resource. The development of the database in recent years has focused on providing database-driven annotation tools and pipelines, as well as catering for increasingly frequent assembly updates. The website has been significantly redesigned to take advantage of current web technologies, and improve usability. The current release stores 41 data sets, of which 17 are manually curated and maintained by biologists, who review and incorporate data from the scientific literature, as well as other sources. GeneDB is primarily a production and annotation database for the genomes of predominantly pathogenic organisms
Lepton Number and Lepton Flavor Violation through Color Octet States
We discuss neutrinoless double beta decay and lepton flavor violating decays
such as in the colored seesaw scenario. In this mechanism,
neutrino masses are generated at one-loop via the exchange of TeV-scale
fermionic and scalar color octets. The same particles mediate lepton number and
flavor violating processes. We show that within this framework a dominant color
octet contribution to neutrinoless double beta decay is possible without being
in conflict with constraints from lepton flavor violating processes. We
furthermore compare the "direct" color octet contribution to neutrinoless
double beta decay with the "indirect" contribution, namely the usual standard
light Majorana neutrino exchange. For degenerate color octet fermionic states
both contributions are proportional to the usual effective mass, while for
non-degenerate octet fermions this feature is not present. Depending on the
model parameters, either of the contributions can be dominant.Comment: 17 pages, 16 figure
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