152 research outputs found
Same-sign single dilepton productions at the LHC
We examine the same-sign single dilepton productions of
in high-energy proton-proton
collisions at the Large Hadron Collider (LHC) in models with doubly charged
Higgs scalars as well as heavy Majorana neutrinos. We demonstrate that these
spectacular productions can be detected at the LHC for a class model in which
the doubly charged Higgs scalars couple only to the right-handed charged
leptons. The ranges of the possible doubly charged Higgs masses and mixings to
observe the processes at the LHC are discussed.Comment: 10 pages, 5 figure
An A_5 Model of Four Lepton Generations
We study the lepton sector of a four generations model based on the discrete
flavor group (the even permutation of five objects). The best features of
the three family model survive, including the tribimaximal pattern of
three generation neutrino mixings. At leading order the three light neutrino
mass relations of and are predicted.
The splitting of the neutrino masses can be naturally obtained as a result of
the breaking of down to and a degenerate spectrum is preferred in
our model. In our model, the electron mass is zero at tree level, but
calculable through quantum corrections.Comment: 20 pages, 3 figures, and 3 tables; references and Appendix C added,
version accepted for publication in JHE
Neutrino masses, muon g-2, dark matter, lithium problem, and leptogenesis at TeV-scale
Observational evidences of nonzero neutrino masses and the existence of dark
matter request physics beyond standard model. A model with extra scalars and
leptonic vector-like fermions is introduced. By imposing a Z_2 symmetry, the
neutrino masses as well as anomalous muon magnetic moment can be generated via
one-loop effects at TeV-scale. An effort of explaining dark matter, Lithium
problem, and leptogenesis is presented. This scenario can be tested at LHC
and/or future experiments.Comment: 5 pages, 5 figure
Non-zero U_{e3} and TeV-Leptogenesis through A_4 symmetry breaking
We consider an effective theory with an symmetry and investigate the possibility of a linking
TeV-leptogenesis with a reactor angle through spontaneous
symmetry breaking which is at a scale higher than electroweak scale under the
framework of radiative seesaw. It has been shown that tri-bimaximal(TBM) can be
obtained by forging vacuum expectation value (VEV) alignment of the .
Especially, one triplet scalar field with cut-off scale is
added in neutrino Yukawa sector, which is responsible for the deviation of the
exact TBM, to explain leptogenesis as well as a non-zero . Above the
scale of the leptonic Yukawa sectors will lead to the exact TBM. We
analyze possible spectrums of light neutrinos and their flavor mixing angles
corresponding to heavy Majorana neutrino mass ordering, and show that
non-resonance leptogenesis at TeV-scale constrained by low energy data is
achievable, both analytically as well as numerically. We show that only normal
hierarchical spectrum of light neutrino would be strongly favored by the
current Wilkinson Microwave Anisotropy Probe (WMAP) data, and also show that a
relatively large corresponds to the value of baryon asymmetry
.Comment: 32 pages, 21 figures, 3 tables. Final version to appear in Phys. Rev.
Relating Neutrino Masses by dilepton modes of Doubly Charged Scalars
We study a model with Majorana neutrino masses generated through doubly
charged scalars at two-loop level. We give explicit relationships between the
neutrino masses and the same sign dilepton decays of the doubly charged
scalars. In particular, we demonstrate that at the tribimaximal limit of the
neutrino mixings, the absolute neutrino masses and Majorana phases can be
extracted through the measurements of the dilepton modes at colliders.Comment: 14 pages, 8 figures, references added, version to be published in PR
Neutrino mass generation and H → γγ/Zγ correlation with scalar multiplets
One natural way to understand the excess of the measured H → γγ rate over the standard model (SM) expectation at the Large Hadron Collider (LHC) is to have charged scalar bosons, existing in most of the SM extensions. Motivated by
this LHC result, we explore if it also sheds light on solving the small neutrino mass generation problem. We concentrate on a class of models with high-dimensional
representations of scalars to realize Majorana neutrino masses at the two-loop level without imposing any new symmetry. In these models, multi scalars with electric
charges higher than two are naturally expected, which not only enhance the H → γγ rate, but provide more searching grounds at the LHC. In particular, the rate of H → Zγ is also correlated to that of the diphoton channel
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