We study a gauge B − L extension of the standard model of quarks and leptons with unconventional charges for the singlet right-handed neutrinos, and extra singlet scalars, such that a residual Z 3 symmetry remains after the spontaneous breaking of B − L. We discuss the phenomenological consequences of this scenario, including the possibility of long-lived self-interacting dark matter and Z collider signatures.

The neutron lifetime anomaly has been used to motivate the introduction of new physics with hidden-sector particles coupled to baryon number, and on which neutron stars provide powerful constraints. Although the neutron lifetime anomaly may eventually prove to be of mundane origin, we use it as motivation for a broader review of the ways that baryon number violation, be it real or apparent, and dark sectors can intertwine and how neutron star observables, both present and future, can constrain them.

Models of fermion and scalar dark matter abound. Here we consider instead vector dark matter, from an SU (2) N extension of the standard model. It has a number of interesting properties, including a possible implementation of the inverse seesaw mechanism for neutrino mass. The annihilation of dark matter for calculating its relic abundance in this model is not dominated by its cross-section to standard-model particles, but rather to other new particles which are in thermal equilibrium with those of the standard model.Keywords: Vector dark matter; gauge extension of standard model; inverse seesaw neutrino mass.PACS numbers: 95.35.+d, 12.60.Cn, 14.60.Pq Whereas the existence of dark matter is universally accepted, its nature remains unknown. It is usually assumed to be a single particle, but it may also be more than one. 1 In specific models, it is often considered to be a fermion or scalar. However, vector dark matter is certainly also possible. [2][3][4][5][6][7][8][9] In this paper we consider a variant of an SU (2) N model proposed previously. 5,6 The difference is that in our present study, all standard model (SM) fermions are singlets under SU (2) N , whereas in the earlier work, that was not the case.The new particles of our model are the three neutral gauge bosons X 1,2,3 of SU (2) N , three copies of a neutral Dirac fermion SU (2) N doublet (n 1 , n 2 ) L,R , a neutral scalar SU (2) N doublet (χ 1 , χ 2 ), and a scalar bidoublet1550018-1

An SU (2) N extension (N stands for neutral) of the Standard Model (SM) is proposed with an additional U (1) = S global symmetry, which stabilizes the lightest of the vector boson (X,X) as dark matter (DM) through unbroken S = T 3N + S . The field content of the model is motivated to address neutrino mass generation, a possible unification to SU (7), along with spontaneous symmetry breaking of SU (2) N resulting in massive gauge bosons. None of the SM particles are charged under SU (2) N and therefore X,X do not have a direct coupling to the visible sector besides a Higgs portal, which is tiny to avoid any conflict with Higgs data. We show that, a large kinematic region of this model allows the neutral component of SU (2) N scalar triplet and heavy neutrinos introduced here to become additional DM components. In this paper we explore the viability of such multipartite DM parameter space, including non-zero DM-DM interactions, to comply with relic density and direct search constraints. We also demonstrate that the model may yield hadronically quiet single lepton and two lepton signatures with missing energy at the Large Hadron Collider (LHC) that can be accessed with high luminosity.

In this analysis we demonstrate the freeze-in realization of a non-abelian vector boson dark matter (DM). We choose to elaborate an existing SU (2) N extension (N stands for neutral) of the Standard Model (SM) with an additional U (1) = S global symmetry, which stabilizes the vector boson (X,X) as DM through unbroken S = T 3N + S and as lightest odd S particle. The analysis reveals that the contribution to the freeze-in production of DM from the decay of a heavier scalar bidoublet ζ 0,± 1 → ζ 0,± 2 X is important even after the freeze-out of ζ 0,± 1 in equilibrium with thermal bath. Moreover, the neutral component of SU (2) N scalar triplet (∆), responsible for neutrino mass generation in this framework, turns out to serve as additional DMs in the model and offers a multipartite freeze-in DM set up to explore. The allowed parameter space is obtained after estimating constraints from CMB, BBN and AMS-02 bound. This exercise nicely complements the freeze-out realization of (X,X) as weakly interacting massive particle (WIMP) and distinguishes it through stable charge track signature at collider compared to leptonic signal excess as found in WIMP scenario.