TY  - JOUR
AU  - Curtin, D. et al
AU  - Hirsch, M.
PY  - 2019
DA  - 2019//
TI  - Long-lived particles at the energy frontier: the MATHUSLA physics case
T2  - Rep. Prog. Phys.
JO  - Reports on Progress in Physics
SP  - 116201
EP  - 133pp
VL  - 82
IS  - 11
PB  - Iop Publishing Ltd
KW  - Large Hadron Collider
KW  - long-lived particles
KW  - hierarchy problem
KW  - dark matter
KW  - baryogenesis
KW  - neutrinos
KW  - simplified models
AB  - We examine the theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of standard model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). In most cases the LLP lifetime can be treated as a free parameter from the μm scale up to the Big Bang Nucleosynthesis limit of similar to 10(7) m. Neutral LLPs with lifetimes above similar to 100 m are particularly difficult to probe, as the sensitivity of the LHC main detectors is limited by challenging backgrounds, triggers, and small acceptances. MATHUSLA is a proposal for a minimally instrumented, large-volume surface detector near ATLAS or CMS. It would search for neutral LLPs produced in HL-LHC collisions by reconstructing displaced vertices (DVs) in a low-background environment, extending the sensitivity of the main detectors by orders of magnitude in the long-lifetime regime. We study the LLP physics opportunities afforded by a MATHUSLA-like detector at the HL-LHC, assuming backgrounds can be rejected as expected. We develop a model-independent approach to describe the sensitivity of MATHUSLA to BSM LLP signals, and compare it to DV and missing energy searches at ATLAS or CMS. We then explore the BSM motivations for LLPs in considerable detail, presenting a large number of new sensitivity studies. While our discussion is especially oriented towards the long-lifetime regime at MATHUSLA, this survey underlines the importance of a varied LLP search program at the LHC in general. By synthesizing these results into a general discussion of the top-down and bottom-up motivations for LLP searches, it is our aim to demonstrate the exceptional strength and breadth of the physics case for the construction of the MATHUSLA detector.
SN  - 0034-4885
UR  - https://arxiv.org/abs/1806.07396
UR  - https://doi.org/10.1088/1361-6633/ab28d6
DO  - 10.1088/1361-6633/ab28d6
LA  - English
N1  - WOS:000499698000001
ID  - Curtin+Hirsch2019
ER  -