MATHUSLA

MATHUSLA
Name	MATHUSLA
Type	proposed surface detector
Location	near Large Hadron Collider, CERN, Geneva
Status	prototyping and planning

MATHUSLA

MATHUSLA is a proposed large-area surface detector sited near the Large Hadron Collider complex at CERN in Geneva. It is designed to search for long-lived particles produced in collisions at the High-Luminosity Large Hadron Collider and to provide complementary coverage to experiments such as ATLAS, CMS, and LHCb. The project brings together institutions including national laboratories and universities from the United States Department of Energy, European Organization for Nuclear Research, and partners associated with Fermilab, SLAC National Accelerator Laboratory, and multiple European research centers.

Introduction

The concept emerged from proposals to extend sensitivity to new physics scenarios not well covered by existing detectors like ATLAS and CMS during the High-Luminosity LHC era. It targets weakly coupled, long-lived particles predicted by frameworks such as supersymmetry variants tested by ALEPH, dark sector portals studied in BaBar and Belle II, and exotic Higgs decays motivated by results from ATLAS and CMS. The design philosophy emphasizes large geometric acceptance and low-background operation leveraging techniques developed at Super-Kamiokande, IceCube, and surface-array experiments like Pierre Auger Observatory.

Design and Detector Layout

The conceptual detector is a modular, roofed tracking volume with layers of charged-particle detectors above a cleared, instrumented decay volume. Technologies under consideration include scintillator bars similar to those used in MINOS, resistive plate chambers developed for ALICE and CMS, and extruded plastic components analogous to NOvA modules. The footprint envisaged is comparable to sports fields and is arranged in repeating modules to facilitate construction near infrastructure used by ATLAS and CMS. The layout provides directional tracking, timing resolution comparable to that achieved by OPERA and T2K subdetectors, and veto systems informed by cosmic-ray suppression strategies from AMS-02 and PAMELA.

Physics Goals and Sensitivity

Science drivers include discovery potential for long-lived particles arising in models linked to dark matter phenomenology investigated by Fermi Gamma-ray Space Telescope and Planck, heavy neutral leptons considered in studies at NA62 and SHiP, and exotic decays of the Higgs boson explored by Tevatron analyses and current ATLAS and CMS searches. Sensitivity projections use benchmark scenarios from literature associated with Minimal Supersymmetric Standard Model, hidden valley frameworks influenced by work at BaBar and Belle II, and portal interactions related to constraints from LHCb and IceCube. Projected reach complements displaced-vertex searches at ATLAS and CMS by covering long lifetimes and lower visible-energy decays, improving limits set by past experiments like LEP and proposals such as FASER.

Construction and Timeline

A staged program begins with test-stand prototypes and a small-scale engineering detector to validate technologies, drawing on experience from prototype campaigns at Fermilab and integration work similar to CERN test beams. Milestones include site preparation near the Large Hadron Collider access points, module fabrication in collaboration with university groups at institutions like MIT, University of Oxford, and University of California, Berkeley, and installation phases coordinated with CERN shutdown periods. The timeline targets readiness in the High-Luminosity LHC era, aligning deployment windows with upgrades at ATLAS and CMS and schedule coordination with European Strategy for Particle Physics recommendations.

Collaboration and Funding

The collaboration is international, with membership spanning national laboratories such as Fermilab, Brookhaven National Laboratory, and SLAC, universities including Harvard University, Princeton University, University of Cambridge, and research institutes across Europe and Asia. Funding discussions involve agencies like the U.S. Department of Energy, national science foundations exemplified by the National Science Foundation (United States), and European funding bodies associated with CERN member states. Governance structures proposed mirror models used by large experiments such as ATLAS, CMS, and LIGO, with working groups for detector systems, physics, software, and outreach.

Simulations and Background Studies

Comprehensive Monte Carlo simulations couple proton–proton collision generators validated against ATLAS and CMS data with detailed particle propagation using toolkits such as GEANT4. Background studies address cosmic-ray muons, atmospheric neutrinos constrained by Super-Kamiokande and IceCube results, and rare muon-induced processes benchmarked by experiments like MICE and Muon g-2. Shielding and trigger strategies leverage analyses from surface detectors including Pierre Auger Observatory and timing techniques from AMS-02 to suppress backgrounds to negligible levels for many signal models. Sensitivity studies are cross-checked with independent frameworks developed in collaboration with groups experienced in FASER and proposed initiatives like CODEX-b.

Related Experiments and Future Prospects

MATHUSLA complements a suite of dedicated long-lived particle experiments and proposals such as FASER, CODEX-b, SHiP, and upgrades to LHCb. Synergies include shared simulation tools, common trigger interfaces with ATLAS and CMS, and coordinated physics benchmarking against results from LEP, Tevatron, and flavor factories like Belle II. Future prospects consider adaptation of modular elements for other accelerator complexes, potential applications at facilities such as Future Circular Collider studies, and contributions to broader searches for hidden sectors informed by astrophysical observations from Fermi Gamma-ray Space Telescope and cosmological constraints from Planck.

Category:Particle physics detectors