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 $\sim 30-350\hbox{ GeV}$. The allowed mixing angle $\alpha$ between the SM-like Higgs particle and the second Higgs particle is constrained to $\alpha \lesssim 28^{\circ}$. The DM particle mass is predicted to be in the range $\sim 15-350\hbox{ GeV}$. 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 $B->J/\Psi K_S$ 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 $beta$ measured from $B->J/\Psi K_S$ 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