• Lepton-Flavored Electroweak Baryogenesis

    分类: 物理学 >> 基本粒子与场物理学 提交时间: 2017-08-02

    摘要: We explore lepton-flavored electroweak baryogenesis, driven by CP-violation in leptonic Yukawa sector, using the τ −µ system in the two Higgs doublet model as an example. This setup generically yields, together with the flavor-changing decay h → τµ, a tree-level Jarlskog-invariant that can drive dynamical generation of baryon asymmetry during a first-order electroweak phase transition and results in CP-violating effect in the decay h → τ τ . We find that the observed baryon asymmetry can be generated in parameter space compatible with current experimental results for the decays h → τµ, h → τ τ and τ → µγ, as well as the present bound on the electric dipole moment of the electron. The baryon asymmetry generated is intrinsically correlated with the CP-violating decay h → τ τ and the flavor-changing decay h → τµ, which thus may serve as “smoking guns” to test lepton-flavored electroweak baryogenesis.

  • GravitationalWave Signals of Electroweak Phase Transition Triggered by Dark Matter

    分类: 物理学 >> 基本粒子与场物理学 提交时间: 2017-08-02

    摘要: We study in this work a scenario that the universe undergoes a two step phase transition with the first step happened to the dark matter sector and the second step being the transition between the dark matter and the electroweak vacuums, where the barrier between the two vacuums, that is necessary for a strongly first order electroweak phase transition (EWPT) as required by the electroweak baryogenesis mechanism, arises at the tree-level. We illustrate this idea by working with the standard model (SM) augmented by a scalar singlet dark matter and an extra scalar singlet which mixes with the SM Higgs boson. We study the conditions for such pattern of phase transition to occur and especially for the strongly first order EWPT to take place, as well as its compatibility with the basic requirements of a successful dark matter, such as observed relic density and constraints of direct detections. We further explore the discovery possibility of this pattern EWPT by searching for the gravitational waves generated during this process in spaced based interferometer, by showing a representative benchmark point of the parameter space that the generated gravitational waves fall within the sensitivity of eLISA, DECIGO and BBO.