Producing and detecting long-lived particles at different experiments at the LHC

Abstract

We propose a new strategy to look for long-lived particles (LLP) at the LHC. The LLPs are produced at one experiment, but its decay products are detected by a detector at another experiment. We use a confining Hidden Valley scenario as a benchmark. Through showering and hadronization, the multiplicity of hidden mesons can be large, and their decay products, dimuon as chosen in this study, are typically too soft to pass triggers in traditional LHC searches. We find the best acceptance is achieved if we produce LLPs at collision points at the LHCb and ALICE experiments, and use the muon chamber of ATLAS for detection. This new search is cost-efficient since it does not require a new detector to be built. Meanwhile, it can provide coverage of interesting parameter space, which is complementary to other proposed LLP searches.

Perturbative benchmark models for a dark shower search program

“…Attractive choices for the massive mediator are a new vector boson [1,8,10,16,19,20,22,24,26,33,[35][36][37], a new scalar boson [8,18,23,25,35,44,46], the SM Higgs [1,4,6,14,15,17,35,40,57,58] or the SM W/Z bosons [1,12,51]. In this class of models, the mediator mass sets the overall energy scale of the event.…”

“…A growing body of work has further developed hidden valleys as ingredients in models that address longstanding mysteries of particle physics, such as the stability of the electroweak hierarchy [2][3][4], the matterantimatter asymmetry [5], dark matter [6][7][8][9][10], and the origin of neutrino masses [11,12]. More generally, the collider phenomenology of light, strongly-coupled hidden sectors is extremely rich and the subject of a substantial amount of work, which includes studies focusing on displaced signatures [13][14][15][16][17][18][19][20], event or jet shape variables [21][22][23][24][25][26][27][28][29][30] and machine learning techniques [31,32], as well as more general explorations and model-building efforts [33][34][35][36][37][38][39][40][41][42][43][44][45][46]…”

Quantum Simulations of Dark Sector Showers

“…The dark sector shower may be converted back into Standard Model particles through, e.g., the decay of dark photons. These events are efficiently searched for by utilizing displaced signals [33][34][35][36][37], lepton jets [38][39][40][41], jets / event shapes [42][43][44][45][46][47][48][49][50][51], and so on.…”