Presentation Title

Dark Matter Detection at the Jefferson Lab Accelerator; Modeling Cosmic Background

Faculty Mentor

Daniel P Snowden-Ifft

Start Date

23-11-2019 9:30 AM

End Date

23-11-2019 9:45 AM

Location

Markstein 303

Session

oral 1

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

The experimental design to detect “light dark matter” at the Thomas Jefferson National Laboratory (JLab) accelerator in Virginia consists of a particle beam that could create dark matter and a detector nearby to record dark matter interactions. However, it is possible for cosmic ray particles to interact inside the detector in a similar way that dark matter should. An essential part of the experiment is to then predict these background interactions to distinguish normal cosmic rays from dark matter. Multiple two stage simulations were run using the Monte Carlo simulation GEANT4 to estimate the background interference due to cosmic ray muons, protons, and neutrons. The CRY (cosmic ray) library (version 1.7) was used in GEANT4 to simulate these cosmic ray particles. The final recoil rate due to cosmic ray muons, protons, and neutrons was found to be 33.1 recoils per 1022 electrons on target (EOT) in the beam dump, where 10^22 EOT at JLab is equivalent to 285 days. Separate simulations were done to determine the background of these cosmic rays after filling in the “chimney” with dirt, which would be an ideal case to shield the detector from background. The expected recoil rate of the “chimney filled in” simulation yields 2.25 recoils per 1022 EOT. A more realistic simulation was then carried out which included a tunnel to allow entry to the underground facility. The tunnel design forecasts 7.1 recoils per 1022 EOT. In summary, we find that in the ideal case of filling in the chimney the background drops by a factor of fifteen, and in the more realistic tunnel design, the background drops by a factor of five.

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Nov 23rd, 9:30 AM Nov 23rd, 9:45 AM

Dark Matter Detection at the Jefferson Lab Accelerator; Modeling Cosmic Background

Markstein 303

The experimental design to detect “light dark matter” at the Thomas Jefferson National Laboratory (JLab) accelerator in Virginia consists of a particle beam that could create dark matter and a detector nearby to record dark matter interactions. However, it is possible for cosmic ray particles to interact inside the detector in a similar way that dark matter should. An essential part of the experiment is to then predict these background interactions to distinguish normal cosmic rays from dark matter. Multiple two stage simulations were run using the Monte Carlo simulation GEANT4 to estimate the background interference due to cosmic ray muons, protons, and neutrons. The CRY (cosmic ray) library (version 1.7) was used in GEANT4 to simulate these cosmic ray particles. The final recoil rate due to cosmic ray muons, protons, and neutrons was found to be 33.1 recoils per 1022 electrons on target (EOT) in the beam dump, where 10^22 EOT at JLab is equivalent to 285 days. Separate simulations were done to determine the background of these cosmic rays after filling in the “chimney” with dirt, which would be an ideal case to shield the detector from background. The expected recoil rate of the “chimney filled in” simulation yields 2.25 recoils per 1022 EOT. A more realistic simulation was then carried out which included a tunnel to allow entry to the underground facility. The tunnel design forecasts 7.1 recoils per 1022 EOT. In summary, we find that in the ideal case of filling in the chimney the background drops by a factor of fifteen, and in the more realistic tunnel design, the background drops by a factor of five.