MATHUSLA

MATHUSLA, a proposed large-area surface detector for the High-Luminosity Large Hadron Collider (HL-LHC) at CERN. The name is an acronym for "Massive Argon & Titanium Hub for Ultra-Stable Location of prompt Hadron decays."

Overview:

MATHUSLA aims to detect long-lived particles (LLPs) that are produced in collisions at the LHC and decay outside of the existing detectors. These LLPs are predicted by many beyond-the-Standard-Model theories and are often difficult to detect because of their long lifetimes and weakly interacting nature. MATHUSLA is designed to be situated on the surface, approximately 100 meters above the ATLAS or CMS detector, to take advantage of the high flux of LLPs produced in these experiments. The surface location offers reduced background compared to underground detectors.

Design:

The proposed detector design involves a large air-filled or gas-filled decay volume instrumented with layers of tracking detectors. The size of the detector is crucial for capturing a sufficient number of LLP decays. Proposals have considered sizes on the order of 100m x 100m x 25m. The tracking detectors typically consist of scintillators or Resistive Plate Chambers (RPCs) to reconstruct the trajectories of the decay products. The detector's design emphasizes high efficiency for reconstructing vertices within the decay volume and excellent background rejection.

Physics Goals:

MATHUSLA's primary physics goal is to search for LLPs, providing sensitivity to a wide range of models, including:

• Hidden sector models
• Neutralinos in R-parity violating Supersymmetry
• Heavy neutral leptons
• Axion-like particles

Detecting these particles would provide evidence for physics beyond the Standard Model and offer insights into fundamental questions such as dark matter and the origin of neutrino masses.

Challenges:

Building and operating MATHUSLA presents several challenges:

• Background Reduction: Cosmic ray muons are a significant background source. Efficient shielding and robust tracking algorithms are required to mitigate this background.
• Detector Construction and Cost: The large size of the detector necessitates significant resources for construction and operation.
• Triggering: Developing efficient triggering strategies to identify LLP decays in the presence of background is crucial.
• Data Acquisition and Analysis: Managing and analyzing the large volume of data produced by the detector poses a significant challenge.

Status:

MATHUSLA is currently a proposed detector, and several R&D efforts are underway to address the technological challenges. Small-scale prototype detectors, such as the MATHUSLA demonstrator at the LHC, have been constructed to test detector concepts and validate background simulations. The project aims to secure funding and begin construction in the coming years, with the goal of operating alongside the HL-LHC.