24,808 research outputs found
Strongly first order phase transition in the singlet fermionic dark matter model after LUX
We investigate an extension of the standard model (SM) with a singlet
fermionic dark matter (DM) particle which interacts with the SM sector through
a real singlet scalar. The presence of a new scalar provides the possibility of
generating a strongly first order phase transition needed for electroweak
baryogenesis. Taking into account the latest Higgs search results at the LHC
and the upper limits from the DM direct detection experiments especially that
from the LUX experiment, and combining the constraints from the LEP experiment
and the electroweak precision test, we explore the parameter space of this
model which can lead to the strongly first order phase transition. Both the
tree- and loop-level barriers are included in the calculations. We find that
the allowed mass of the second Higgs particle is in the range . The allowed mixing angle between the SM-like Higgs
particle and the second Higgs particle is constrained to . The DM particle mass is predicted to be in the range . The future XENON1T experiment can rule out a significant
proportion of the parameter space of this model. The constraint can be relaxed
only when the mass of the SM-like Higgs particle is degenerate with that of the
second Higgs particle, or the mixing angle is small enough.Comment: 37 pages, 9 figures; v4: the version accepted by JHE
Implications from recent measurements on sin 2\beta and muon g-2
The recent data on CP asymmetry in and muon g-2 are discussed
in the framework of standard model and beyond. Possible new phase effects
besides the CKM phase are discussed in the processes concerning CP violation in
B decays and muon anomalous magnetic moment (muon g-2). It is found that the
new phases will result in difference between angles measured from
and the one from global fit. The ration between them serves as
a probe of not only new physics but also new phase besides the CKM phase In the
case of muon g-2, the new phase may change the interferences between various
contributions. By including the new phases, some cancelations in the real
coupling cases can be avoided and the large value of muon g-2 observed in the
recent measurements can be understood.Comment: 7 pages, no figure. Talk delivered by Y.F.Zhou at International
Conference on Flavor Physics (ICFP2001), May 31-June.6, at Zhang-Jia-Jie,
Chin
Shifts of neutrino oscillation parameters in reactor antineutrino experiments with non-standard interactions
We discuss reactor antineutrino oscillations with non-standard interactions
(NSIs) at the neutrino production and detection processes. The neutrino
oscillation probability is calculated with a parametrization of the NSI
parameters by splitting them into the averages and differences of the
production and detection processes respectively. The average parts induce
constant shifts of the neutrino mixing angles from their true values, and the
difference parts can generate the energy (and baseline) dependent corrections
to the initial mass-squared differences. We stress that only the shifts of
mass-squared differences are measurable in reactor antineutrino experiments.
Taking Jiangmen Underground Neutrino Observatory (JUNO) as an example, we
analyze how NSIs influence the standard neutrino measurements and to what
extent we can constrain the NSI parameters.Comment: a typo in Eq.(25) fixed after published version, discussion and
conclusion unchange
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