Abstract

In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

Highlights

  • We show the reach for certain R-parity violating (RPV) supersymmetric scenarios in section 6, finding excellent reach for this class of models shown in figure 16

  • While here we assume that Zd originates from a U(1) symmetry broken at the TeV scale, it could in principle originate from a non-abelian horizontal symmetry as in ref. [32], where the Sphaleron associated with this gauge interaction is used to connect the dark matter with the baryon asymmetry

  • In order to simulate production and dynamics of the dark sector at the LHC, we use a modified version of the Hidden Valley implementation [58, 59] of Pythia [51], and we describe the details of the simulation in appendix A

Read more

Summary

Models

We describe our general setup which is shown schematically in figure 2. We consider a class of models with a dark sector with a non-abelian gauge symmetry, dark QCD, that confines in the infrared, in a way similar to QCD. Where GSM = SU(3)c × SU(2) × U(1) is the standard model gauge symmetry, and Nd ≥ 2 is the number of dark colors. Where qj are the right-handed down-type SM quarks and κ is a nf × 3 matrix of Yukawa couplings Such couplings could in general lead to large flavor violating processes, but can be brought into agreement with experimental bounds if dark flavor originates from the same dynamics as the SM flavor structure or certainly if flavor symmetries are imposed on the dark sector [45,46,47]. While here we assume that Zd originates from a U(1) symmetry broken at the TeV scale, it could in principle originate from a non-abelian horizontal symmetry as in ref. [32], where the Sphaleron associated with this gauge interaction is used to connect the dark matter with the baryon asymmetry

Mass scales
Dark pions
GeV 2 fπd
14 TeV pp
Collider signal
Existing searches and constraints
Analysis strategy
Benchmarks
GeV 5 mm
Triggering
Background
Event selection
Backgrounds
Emerging jets
Alternative strategy: pT weighting
Prospects at LHCb
Sensitivity to other new physics scenarios
Conclusions
Signal events
Modified background events
Findings
B Exploring dark sector parameters
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call