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.
Highlights
As the LHC continues its operation, the most sought after models of Beyond the Standard Model (BSM) physics will have to hide in an increasingly small window if they are to remain both unexcluded and potentially discoverable at that collider
A great source of such signatures is Hidden Valley models [1,2,3]. This ubiquitous class of models is characterized by a new low energy confining sector that communicates with the Standard Model (SM) via some heavy mediators
Previous searches on the collider phenomenology of semivisible jets include refs. [21, 22]. With these considerations in mind, the purpose of the present article is to investigate direct production of Hidden Valley mediators of spin 0 or 1/2 that are non-trivially charged under both the Standard Model gauge groups and a single new confining group
Summary
As the LHC continues its operation, the most sought after models of Beyond the Standard Model (BSM) physics will have to hide in an increasingly small window if they are to remain both unexcluded and potentially discoverable at that collider. A great source of such signatures is Hidden Valley models [1,2,3]. This ubiquitous class of models is characterized by a new low energy confining sector that communicates with the Standard Model (SM) via some heavy mediators. UV completions of Twin Higgs models [10] can include fermions that are charged under both Standard Model electroweak groups and mirror QCD. They even represent one of the best directions to discover these models [11]. Mediators of spin 0 or 1/2 appear in several models of composite dark matter or their UV completions (see [14,15,16,17] for several reviews)
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