MoEDAL

MoEDAL

MoEDAL is a dedicated particle physics experiment sited at the Large Hadron Collider complex at CERN concentrating on signatures that elude the general-purpose detectors ATLAS (particle detector), CMS experiment, LHCb experiment, and ALICE (A Large Ion Collider Experiment). The collaboration brings together research groups from institutions such as University of Oxford, Imperial College London, University of Montreal, TRIUMF, and INFN to exploit unique detector technologies developed in the tradition of searches performed at facilities like the Tevatron and the Large Electron–Positron Collider. The experiment's design prioritizes sensitivity to highly ionizing and long-lived particles predicted in extensions of the Standard Model (particle physics), drawing theoretical motivation from frameworks including Supersymmetry, Magnetic monopole theories, and various Dark matter scenarios.

Overview

MoEDAL was proposed to address experimental gaps left by contemporaneous detectors at the Large Hadron Collider by focusing on non-standard signatures such as slow-moving massive particles and magnetically charged states. The project evolved through design reviews with input from collaborations experienced at SLAC National Accelerator Laboratory, Fermilab, and DESY and received technical support from laboratories like CERN. Its siting in the LHCb experiment cavern leverages infrastructure and beam conditions compatible with searches for rare, high-ionization phenomena, while maintaining operational independence from ATLAS (particle detector) and CMS experiment trigger-driven workflows.

Experimental Apparatus

The apparatus integrates passive and active detector systems optimized for detection of highly ionizing particles and persistent ionization tracks. The core technologies include stacks of nuclear track detectors such as CR-39, Makrofol, and Lexan plastics deployed in modular arrays; arrays of magnetic monopole trapping volumes composed of materials like aluminium; and time-of-flight instrumentation inspired by techniques developed at NA48/2, OPAL, and Belle II. The nuclear track detectors register damage trails from ionizing transits that are later revealed by chemical etching and optical scanning, following processing protocols used in searches at RSU and analyses analogous to workflows at SNO. Trapping detectors are periodically removed and analyzed using superconducting magnetometers similar to apparatus employed by MoEDAL's predecessor projects and experiments at University of Washington and Gran Sasso National Laboratory. Environmental monitoring and background characterization incorporate radiation survey methods established at CERN facilities and heritage from instrumentation at ISR and SPS accelerator studies.

Physics Goals and Searches

MoEDAL targets several classes of beyond-Standard Model (particle physics) phenomena: magnetic monopoles predicted in grand unified extensions such as those inspired by Dirac (physicist), 't Hooft–Polyakov monopole, and Cho–Maison solutions; electrically charged long-lived particles arising in scenarios of Split supersymmetry, Gauge-mediated supersymmetry breaking, and R-parity violating supersymmetry; and multiply charged exotica proposed in models connected to Composite Higgs models and Extra dimensions. The experiment also explores signatures from quasi-stable dyons, Q-balls, and massive stable particles that could provide insight into Dark matter constituents theorized in proposals from Witten (physicist), Farrar (physicist), and Kusenko. Its sensitivity complements limits set by searches at ATLAS (particle detector), CMS experiment, ALEPH, and CDF by extending reach in magnetic charge, fractional charge, and extremely low velocity (β) regimes.

Data Analysis and Results

Data handling combines manual and automated readout paths: etched nuclear track detectors are scanned with optical microscopy systems and image-analysis pipelines developed alongside groups experienced with large-scale scanning such as teams from Imperial College London and University of Birmingham. Trapping volumes are interrogated with superconducting quantum interference devices akin to instruments used at ETH Zurich and University of Glasgow. Analysis strategies employ blind and unblinded approaches calibrated against control samples from beam-halo studies at Large Hadron Collider runs and Monte Carlo simulations generated with toolchains including PYTHIA, GEANT4, and specialized monopole production models informed by calculations in effective field theory. Published results have set leading bounds on magnetic charge and placed competitive lower-mass limits for long-lived charged particles, complementing exclusion contours reported by ATLAS (particle detector) and CMS experiment. Null searches have constrained parameter spaces in Supersymmetry models and monopole production cross sections, while candidate events are scrutinized through cross-corroboration with LHCb experiment and archival data from experiments at LEP and the Tevatron.

Collaboration and Organization

The collaboration comprises principal investigators and research groups from universities and national laboratories across Europe, North America, and Asia, including contributors from Oxford University, University College London, Università di Napoli, Universidad Nacional Autónoma de México, Indian Institute of Science, and University of Tokyo. Governance follows a spokesperson-led structure supported by an executive board, technical coordination, physics working groups, and publication committees modeled on organizational practices at CERN experiments such as ATLAS (particle detector) and CMS experiment. Outreach and education activities engage with programs at institutions like Royal Society initiatives, summer student schemes affiliated with CERN and exchanges with partner labs including TRIUMF and INFN. The collaboration maintains data preservation and stewardship practices aligned with policies advocated by CERN and international funding agencies.

Category:Particle physics experiments