885 research outputs found
Lepton Electric Dipole Moment and Strong CP Violation
Contribution of the strong CP angle, , to the Wilson Coefficients
of electron and muon electric dipole moment (EDM) operators are discussed.
Previously, contribution to the electron EDM operator was
calculated by Choi and Hong. However, the effect of CP-violating three meson
coupling was missing there. We include this missing contribution for the first
time in the literature, and reevaluate the Wilson coefficients of the lepton
EDM operator. We obtain e-cm
which is 15 - 70 % of the result obtained in Choi and Hong. We also estimated
the muon EDM as e-cm. Using
suggested by the neutron EDM measurements, we
obtain e-cm and e-cm. The contribution to the muon EDM is much
below the sensitivities of the current and near future experiments. Our result
shows that the contribution to can be larger than the
CKM contributions by many orders of magnitude.Comment: 10 pages, 2 figures; v3: version published, reference adde
LHC Future Prospects of the 750 GeV Resonance
A quantitative discussion on the future prospects of the 750 GeV resonance at
the LHC experiment is given using a simple effective field theory analysis. The
relative size of two effective operators relevant to diphoton decays can be
probed by ratios of diboson signals in a robust way. We obtain the future
sensitivities of , and resonance searches at the high
luminosity LHC, rescaling from the current sensitivities at TeV.
Then, we show that a large fraction of parameter space in the effective field
theory will be covered with 300 fb and almost the whole parameter space
will be tested with 3000 fb. This discussion is independent of
production processes, other decay modes and total decay width.Comment: version published, reference added, 4 pages, 3 figure
Composite Accidental Axions
We present several models where the QCD axion arises accidentally. Confining
gauge theories can generate axion candidates whose properties are uniquely
determined by the quantum numbers of the new fermions under the Standard Model.
The Peccei-Quinn symmetry can emerge accidentally if the gauge theory is
chiral. We generalise previous constructions in a unified framework. In some
cases these models can be understood as the deconstruction of 5-dimensional
gauge theories where the Peccei-Quinn symmetry is protected by locality but
more general constructions are possible.Comment: 24 pages, 3 figure
Quantum corrections to the spin-independent cross section of the inert doublet dark matter
The inert Higgs doublet model contains a stable neutral boson as a candidate
of dark matter. We calculate cross section for spin-independent scattering of
the dark matter on nucleon. We take into account electroweak and scalar quartic
interactions, and evaluate effects of scattering with quarks at one-loop level
and with gluon at two-loop level. These contributions give an important effect
for the dark matter mass to be around m_h/2, because a coupling with the
standard model Higgs boson which gives the leading order contribution should be
suppressed to reproduce the correct amount of the thermal relic abundance in
this mass region. In particular, we show that the dark matter self coupling
changes the value of the spin-independent cross section significantly.Comment: 38 pages, 18 figure
Neutrinoful Universe
The Standard Model of particle physics fails to explain the important pieces
in the standard cosmology, such as inflation, baryogenesis, and dark matter of
the Universe. We consider the possibility that the sector to generate small
neutrino masses is responsible for all of them; the inflation is driven by the
Higgs field to break gauge symmetry which provides the Majorana masses to
the right-handed neutrinos, and the reheating process by the decay of the
Higgs boson supplies the second lightest right-handed neutrinos whose CP
violating decays produce asymmetry, a la, leptogenesis. The lightest
right-handed neutrinos are also produced by the reheating process, and remain
today as the dark matter of the Universe. In the minimal model of the inflaton
potential, one can set the parameter of the potential by the data from CMB
observations including the BICEP2 and the Planck experiments. In such a
scenario, the mass of the dark matter particle is predicted to be of the order
of PeV. We find that the decay of the PeV right-handed neutrinos can explain
the high-energy neutrino flux observed at the IceCube experiments if the
lifetime is of the order of s.Comment: 21 pages, 9 figures; v2: added reference and fixed typ
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