分类: 物理学 >> 核物理学 提交时间: 2016-09-19
摘要: Motivated by the recent 750 GeV diphoton excess observed by the ATLAS and CMS collaborations, we propose a simplified model to explain this excess. Model-independent constraints and predictions on the allowed couplings for generating the observed diphoton excess are studied in detail, and the compatibility between Run 1 and Run 2 data is considered simultaneously. We demonstrate that the possible four photon signal can be used to test this scenario, and also explain the interesting deviation for a diphoton mass of about 1.6 TeV by ATLAS, where the local significance is 2.8 σ. Meanwhile, this scenario also provides us with the dark matter candidates.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: We study the collider phenomenology of the electroweak phase transition and electroweak baryogenesis in the framework of the effective field theory. Our study shows that the effective theory using the dimension-6 operators can enforce strong first order phase transition and provide sizable CP violation to realize a successful electroweak baryogenesis. Such dimension-6 operators can induce interesting Higgs phenomenology that can be verified at colliders such as the LHC and the planning CEPC. We then demonstrate that this effective theory can originate from vector-like quarks and the triplet Higgs.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: It is of great interest to connect cosmology in the early universe to the Standard Model of particle physics. In this paper, we try to construct a bounce inflation model with the standard model Higgs boson, where the one loop correction is taken into account in the effective potential of Higgs field. In this model, a Galileon term has been introduced to eliminate the ghost mode when bounce happens. Moreover, due to the fact that the Fermion loop correction can make part of the Higgs potential negative, one naturally obtains a large equation of state(EoS) parameter in the contracting phase, which can eliminate the anisotropy problem. After the bounce, the model can drive the universe into the standard higgs inflation phase, which can generate nearly scale-invariant power spectrum.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: The observed value of the Higgs mass indicates an instability of the Higgs scalar at large energy scales, and hence also at large field values. In the context of early universe cosmology, this is often considered to lead to problems. Here we point out that we can use the instability of the Higgs field to generate an Ekpyrotic phase of contraction. In the context of string theory it is possible that at very high energy densities extra states become massless, leading to an S-brane which leads to the transition between a contracting phase in the past and the current expanding phase. Thus, the Higgs field can be used to generate a non-singular bouncing cosmology in which the anisotropy problem of usual bouncing scenarios is mitigated.