Electroweak breaking and Higgs boson profile in the simplest linear seesaw model

Abstract

We examine the simplest realization of the linear seesaw mechanism within the Standard Model gauge structure. Besides the standard scalar doublet, there are two lepton-number-carrying scalars, a nearly inert SU(2) L doublet and a singlet. Neutrino masses result from the spontaneous violation of lepton number, implying the existence of a Nambu-Goldstone boson. Such "majoron" would be copiously produced in stars, leading to stringent astrophysical constraints. We study the profile of the Higgs bosons in this model, including their effective couplings to the vector bosons and their invisible decay branching ratios. A consistent electroweak symmetry breaking pattern emerges with a compressed spectrum of scalars in which the "Standard Model" Higgs boson can have a sizeable invisible decay into the invisible majorons. A Unitarity Constraints 22 A.1 Q = 2, Y = 2 23 A.2 Q = 1, Y = 2 23 A.3 Q = 1, Y = 1 23 A.4 Q = 1, Y = 0 23 A.5 Q = 0, Y = 2 24 A.6 Q = 0, Y = 1 24 A.7 Q = 0, Y = 0 24

Phenomenology of fermion dark matter as neutrino mass mediator with gauged B-L

“…Invisible Higgs decay: It is well-known that theories with continuous global symmetries spontaneously broken at accessible scales < ∼ few TeV lead to Goldstone bosons that can couple to the Higgs. An example is the invisible Higgs decay to the invisible Majorons [21][22][23][24]. In the present model the role of the Majoron is played by the Diracon.…”

“…Dilepton final state searches at these experiments with 36.1 fb −1 luminosity [20] rule out values of m BL /g BL for a new Z BL not satisfying the following condition m BL /g BL ≥ 6.9 TeV (24) at 95% C.L.…”

Current bounds on the Type-Z $Z_3$ three Higgs doublet model

“…We will introduce sufficient conditions for BFB by bounding the potential by a lower potential. To do that we follow [22,23], checking for neutral minima. Neutral directions in the Higgs space correspond to situations when all φ i are proportional to each other 3 .…”

Dynamical inverse seesaw mechanism as a simple benchmark for electroweak breaking and Higgs boson studies

“…These can modify the so-called signal "strength parameter" µ f associated to a given "visible" final-state f , which can be tested at the LHC [24,25]. The modified couplings and the existence of invisible decays are constrained by Higgs measurements at the LEP and LHC experiments [26][27][28]. Here we adopt the conservative range,…”