Search for Strongly Interacting Massive Particles with HPS at Jefferson Lab
ORAL
Abstract
Dark Matter (DM) remains one of the most profound mysteries in modern physics. Yet, the current Standard Model (SM) of particle physics does not provide viable candidates to explain the DM abundance we observe today. This shortcoming, which leaves roughly 85% of the mass in our Universe unaccounted for, drives the search for new physics beyond the Standard Model (BSM).
Several well-motivated BSM scenarios propose that DM may belong to a Hidden Sector (HS) of particles isolated from SM forces but interact indirectly through new force carriers.
One intriguing scenario suggests that DM could consist of Strongly Interacting Massive Particles (SIMPs). In this model, an SU(3) symmetry, similar to Quantum Chromodynamics (QCD), gives rise to dark pions (DP) and dark vector mesons (VD), analogous to particles in SM QCD, both of which could make up DM. The role of the U(1) gauge boson is assigned to a heavy (or "dark") photon A', which kinetically mixes with the SM photon with a coupling strength ε. Under specific mass hierarchies and parameter constraints, the SIMP model can achieve the correct thermal DM relic abundance, with the dark photon mass (m(A’)) in the 0.01–1 GeV range and ε values between 10-6 and 10-2.
The Heavy Photon Search (HPS) experiment at Jefferson Lab is fit to probe this model by searching for the electro-production of heavy photons that decay into a DP-VD pair. The VD is expected to be long-lived and decay via a virtual A' into a resonant e+e– pair.
In this presentation, the ongoing search at HPS for displaced VD decays will be illustrated, and the results achieved in the analysis of the 2016 HPS engineering run will be presented.
Several well-motivated BSM scenarios propose that DM may belong to a Hidden Sector (HS) of particles isolated from SM forces but interact indirectly through new force carriers.
One intriguing scenario suggests that DM could consist of Strongly Interacting Massive Particles (SIMPs). In this model, an SU(3) symmetry, similar to Quantum Chromodynamics (QCD), gives rise to dark pions (DP) and dark vector mesons (VD), analogous to particles in SM QCD, both of which could make up DM. The role of the U(1) gauge boson is assigned to a heavy (or "dark") photon A', which kinetically mixes with the SM photon with a coupling strength ε. Under specific mass hierarchies and parameter constraints, the SIMP model can achieve the correct thermal DM relic abundance, with the dark photon mass (m(A’)) in the 0.01–1 GeV range and ε values between 10-6 and 10-2.
The Heavy Photon Search (HPS) experiment at Jefferson Lab is fit to probe this model by searching for the electro-production of heavy photons that decay into a DP-VD pair. The VD is expected to be long-lived and decay via a virtual A' into a resonant e+e– pair.
In this presentation, the ongoing search at HPS for displaced VD decays will be illustrated, and the results achieved in the analysis of the 2016 HPS engineering run will be presented.
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Presenters
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Lauren Tompkins
Stanford University
Authors
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Mathew Graham
SLAC National Accelerator Laboratory
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Lauren Tompkins
Stanford University