[Paper Review] MoEDAL-MAPP, an LHC Dedicated Detector Search Facility

J. L. Pinfold|arXiv (Cornell University)|Sep 8, 2022

Particle physics theoretical and experimental studies4 citations

TL;DR

MoEDAL-MAPP proposes a dedicated LHC detector facility to search for highly ionizing, feebly interacting, and long-lived particles beyond the Standard Model, with Phase-1 upgrades enhancing MoEDAL’s sensitivity to milli-charged and long-lived particles at Run-3 and HL-LHC. The project, approved by CERN, features a new detector (MAPP-1) in the UA83 gallery with a cost of under 1M CHF, extending the LHC’s discovery reach to higher masses and lower cross-sections for new physics scenarios.

ABSTRACT

During LHC's Run-2 the MoEDAL experiment, the LHC's first dedicated search experiment, took over 6 fb^-1 of data at IP8, with p-p and Pb-Pb collisions, operating with 100% efficiency. The LHCC has endorsed the LoI of the MoEDAL Collaboration describing an exciting program to expand the search for Highly Ionizing Particles (HIPs) in p-p and heavy-ion collisions to include feebly ionizing and Long Lived Particle (LLP) messengers of new physics (NP) at LHC's RUN-3 and eventually HL-LHC. In 2021, as part of Phase-1 of the program, the baseline MoEDAL detector was approved by CERN for reinstallation for Run-3 with increased efficiency, lower threshold, a factor of 5 increase in instantaneous luminosity, and, a higher Ecm. MoEDAL will continue the search for HIP avatars of NP with an emphasis on the search for massive, single and multiply electrically charged avatars of BSM physics arising from, eg, supersymmetry, neutrino mass models, L-R symmetry, etc. As part of Phase-1 of the MoEDAL-MAPP project CERN also approved in 2021 the installation of the MoEDAL Apparatus for Penetrating Particles (MAPP) in the UA83 tunnel 100m away from IP8. The MAPP detector has sensitivity to feebly-interacting particles with charge, or effective charge, as low as 10^-3e. Additionally, the MAPP detector, in conjunction with MoEDAL's trapping detector, gives us a unique sensitivity to charged LLPs. MAPP also has some sensitivity to neutral LLPs. In Phase-2 of the project we will instal the MAPP-2 upgrade for the HL-LHC. We envisage that this detector will be deployed in the UGC1 gallery near to IP8. This phase of the experiment is designed to ensure that MoEDAL-MAPP's sensitivity to neutral LLP messengers of BSM physics is competitive and complementary to other planned projects in this arena. Initial MoEDAL plans for the MEDICI facility at the 100 TeV FCC-hh machine will also be briefly presented.

Motivation & Objective

• To extend the LHC’s discovery reach beyond the Standard Model by searching for highly ionizing particles (HIPS), feebly interacting particles (FIPs), and long-lived particles (LLPs), including milli-charged particles and monopoles.
• To address the limitations of main LHC experiments, which are not optimized for detecting weakly interacting or long-lived new physics candidates.
• To provide a complementary, trigger-less, and background-free detection system with a permanent physical record of signals, enhancing discovery confidence.
• To develop a cost-effective, scalable detector infrastructure for future high-energy colliders, such as the FCC-hh, through phased upgrades including MAPP-2 and the MEDICI facility.
• To enable sensitivity to new physics models such as supersymmetry, L-R symmetric models, and neutrino mass mechanisms via highly charged or massive particles.

Proposed method

• Install the MAPP-1 detector in the UA83 gallery, 100 m from IP8, to operate in parallel with MoEDAL during Run-3 and HL-LHC.
• Utilize a trigger-less, permanently recording detection system based on nuclear track detectors and nuclear emulsions to capture rare, long-lived, or highly ionizing events.
• Implement a lower detection threshold and increased instantaneous luminosity (by a factor of five) to enhance sensitivity to low-cross-section and high-mass particles.
• Design a future MAPP-2 detector in the UGC1 gallery adjacent to IP8, featuring a dedicated decay zone for long-lived particles, with initial cost estimates of 5–6M CHF.
• Develop a conceptual design for a future MEDICI facility at the FCC-hh, including an open interaction point and a decay zone for LLPs, with a potential NTD 'Ball' detector for monopoles up to 20–30 TeV/c².
• Leverage existing CERN infrastructure and collaboration networks to minimize costs and ensure integration with LHC operations and other experimental programs.

Experimental results

Research questions

• RQ1 Can MoEDAL-MAPP achieve competitive sensitivity to long-lived and feebly interacting particles, such as milli-charged particles and monopoles, in proton-proton and heavy-ion collisions?
• RQ2 To what extent can the MAPP-1 and MAPP-2 detectors extend the LHC’s reach for highly ionizing particles and long-lived particles beyond the capabilities of main LHC experiments?
• RQ3 What is the achievable sensitivity of a cost-effective, dedicated detector facility like MoEDAL-MAPP for new physics scenarios involving massive, highly charged particles or dark sector models?
• RQ4 How does the permanent physical record and lack of SM backgrounds in MoEDAL-MAPP enhance the reliability and confirmation potential of any new physics discovery?
• RQ5 What is the feasibility and physics potential of a future MEDICI facility at the FCC-hh for detecting long-lived particles and monopoles with masses up to 30 TeV/c²?

Key findings

• The MoEDAL-MAPP project has been approved by CERN’s Research Board for Phase-1, with the MAPP-1 detector currently being installed in the UA83 gallery, 100 m from IP8.
• The MAPP-1 upgrade increases MoEDAL’s instantaneous luminosity by a factor of five and lowers the detection threshold, significantly enhancing sensitivity to long-lived and feebly interacting particles.
• MoEDAL-MAPP achieves competitive and complementary sensitivity to both main LHC experiments and high-cost dedicated projects like MATHUSLA and SHiP, particularly for long-lived particles and milli-charged particles.
• Initial physics studies indicate that MAPP-2, planned for installation in the UGC1 gallery during LS3 (2025–2026), would provide sensitivity to long-lived particles comparable to MATHUSLA and MAPP-2 combined for key benchmark scenarios.
• The cost of MAPP-1, excluding personnel, is less than 1 million CHF, demonstrating a highly cost-effective approach to expanding the LHC’s discovery potential.
• Preliminary studies for the MEDICI facility at FCC-hh suggest that an NTD 'Ball' detector could probe monopoles with masses up to 20–30 TeV/c², and the decay zone design would match the sensitivity of MATHUSLA and MAPP-2 combined for dark scalar decays to muon pairs.