Collider phenomenology of Hidden Valley mediators of spin 0 or 1/2 with semivisible jets

Abstract

Many models of Beyond the Standard Model physics contain particles that are charged under both Standard Model and Hidden Valley gauge groups, yet very little effort has been put into establishing their experimental signatures. We provide a general overview of the collider phenomenology of spin 0 or 1/2 mediators with non-trivial gauge numbers under both the Standard Model and a single new confining group. Due to the possibility of many unconventional signatures, the focus is on direct production with semivisible jets. For the mediators to be able to decay, a global U (1) symmetry must be broken. This is best done by introducing a set of operators explicitly violating this symmetry. We find that there is only a finite number of such renormalizable operators and that the phenomenology can be classified into five distinct categories. We show that large regions of the parameter space are already excluded, while others are unconstrained by current search strategies. We also discuss how searches could be modified to better probe these unconstrained regions by exploiting special properties of semivisible jets.

Dark matter in Hidden Valley models with stable and unstable light dark mesons

“…In many ways, the present article is a continuation of Ref. [21] and shows how the models presented in that article can explain the dark matter relic abundance.…”

Operators from flavored dark sectors running to low energy

“…where J D and J SM are currents involving, respectively, dark and SM fields only, c is an appropriate coefficient ensuring the right dimensions, and we do not write possible Lorentz indices. This generic framework resembles typical Hidden Valley constructions [1,9], and can be obtained with a variety of mediators [3]. Also, the nature of the dark current depends crucially on the details of the dark sector, as it can be composed by elementary or composite fields.…”

“…The same kind of interactions have been considered in Ref. [3] in the context of collider searches of Hidden Valley models. Taking the mediator to be heavy, we obtain at low energy…”

“…Over the last few years, dark sectors have started to play an increasingly important role in Beyond the Standard Model (BSM) physics. The reason is twofold: on one hand, the null results from the LHC and other experiments are pushing 'traditional' BSM theories to more and more tuned regions of their parameter space, motivating the search for new unconventional signatures [1][2][3]. On the other hand, dark sectors are implicitly present in many Dark Matter (DM) models (especially in connection with light mediators, see for instance [4]), and are starting to appear in more recent solutions of the Hierarchy Problem like Twin Higgs [5], Folded SUSY [6] and the relaxation of the electroweak (EW) scale [7].…”

Classification of dark pion multiplets as dark matter candidates and collider phenomenology

“…Generically, both stable and unstable dark pions can be produced in a parton shower. Assuming the unstable pions decay hadronically, this will result in the production of semivisible jets [17,59,60]. These roughly look like generic jets, but are accompanied by collinear stable particles that escape the detector and contribute to the missing transverse energy (MET).…”