Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.
|Original language||English (US)|
|Journal||Journal of Physics G: Nuclear and Particle Physics|
|State||Published - Sep 2020|
Bibliographical noteFunding Information:
Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. European Cooperation in Science and Technology https://doi.org/10.13039/501100000921 CA15108 CA16201 Javna Agencija za Raziskovalno Dejavnost RS https://doi.org/10.13039/501100004329 J1-8137 P1-0035 Ministry of Education and Science of the Russian Federation https://doi.org/10.13039/501100003443 02.a03.21.0005 27.08.2013 Fondo Nacional de Desarrollo Cient�fico y Tecnol�gico https://doi.org/10.13039/501100002850 1161463 Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659 39083149 Agence Nationale de la Recherche https://doi.org/10.13039/501100001665 ANR-11-IDEX-0001-02 ANR-11-LABX-0060 Conseller�a de Cultura, Educaci�n e Ordenaci�n Universitaria, Xunta de Galicia https://doi.org/10.13039/501100008425 ED431F 2018/01 Ministerio de Econom�a y Competitividad https://doi.org/10.13039/501100003329 FPA2015-65652-C4-1-R RYC-2016-20073 Simons Foundation https://doi.org/10.13039/100000893 376204 National Science Foundation https://doi.org/10.13039/100000001 PHY-1620074 PHY-1620638 PHY-1820770 U.S. Department of Energy https://doi.org/10.13039/100000015 DE-AC02-07CH11359 DE-SC0008541 DE-SC0009988 DE-SC0010008 DE-SC0011095 DE-SC0011784 DE-SC0011925 DE-SC0013607 DE-SC0015973 DE-SC0017840 Ministerstwo Nauki i Szkolnictwa Wyższego https://doi.org/10.13039/501100004569 W17065 Science and Technology Facilities Council https://doi.org/10.13039/501100000271 ST/L000520/1 Horizon 2020 Framework Programme https://doi.org/10.13039/100010661 674896 724777 Generalitat Valenciana https://doi.org/10.13039/501100003359 PROMETEO-II/2017/033 Narodowe Centrum Nauki https://doi.org/10.13039/501100004281 2014/15/B/ST2/03998 Ministry of Science and Technology, Taiwan https://doi.org/10.13039/501100004663 MOST-106-2811-M-002-035 MOST-107-2811-M-002-3120 Funda��o de Amparo � Pesquisa do Estado de S�o Paulo https://doi.org/10.13039/501100001807 2015/20570-1 Schweizerischer Nationalfonds zur F�rderung der Wissenschaftlichen Forschung https://doi.org/10.13039/501100001711 PP00P2_150583 yes � 2020 The Author(s). Published by IOP Publishing Ltd Creative Commons Attribution 3.0 licence
© 2020 The Author(s). Published by IOP Publishing Ltd.