Eur. Phys. J. C (2022) 82: 1132
https://doi.org/10.1140/epjc/s10052-022-11048-8

Review

Theory, phenomenology, and experimental avenues for dark showers: a Snowmass 2021 report

¹ Univ. Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 38000, Grenoble, France
² Physics Division, National Center for Theoretical Sciences, 10617, Taipei, Taiwan
³ Fermi National Accelerator Laboratory, 60510, Batavia, IL, USA
⁴ School of Physics and Astronomy, Queen Mary University of London, London, UK
⁵ ETH Zurich-Institute for Particle Physics and Astrophysics (IPA), Zurich, Switzerland
⁶ Institute for Fundamental Science, University of Oregon, 97403, Eugene, OR, USA
⁷ Department of Physics and Astronomy, University of Rochester, 14627, Rochester, NY, USA
⁸ Department of Physics, University of Toronto, M5S 1A7, Toronto, ON, Canada
⁹ Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, C.P. 13, 00044, Frascati, Italy
¹⁰ European Organization for Nuclear Research (CERN), Geneva, Switzerland
¹¹ Theoretical Physics Group, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA
¹² Department of Physics, Berkeley Center for Theoretical Physics, University of California, 94720, Berkeley, CA, USA
¹³ Institute of Physics, NAWI Graz, University of Graz, Universitätsplatz 5, 8010, Graz, Austria
¹⁴ PRISMA+ Cluster of Excellence and Mainz Institute for Theoretical Physics, Johannes Gutenberg University, 55099, Mainz, Germany
¹⁵ Ottawa-Carleton Institute for Physics, Carleton University, 1125 Colonel By Drive, K1S 5B6, Ottawa, ON, Canada
¹⁶ Department of Physics, Harvard University, 02138, Cambridge, MA, USA
¹⁷ Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands
¹⁸ Department of Physics and Astronomy, Brigham Young University, 84602, Provo, UT, USA
¹⁹ Vrije Universiteit Brussel, Brussels, Belgium
²⁰ PRISMA+ Cluster of Excellence and Mainz Institute for Theoretical Physics, Johannes Gutenberg-Universitaet Mainz, 55099, Mainz, Germany
²¹ Theoretical Particle Physics, Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, 223 62, Lund, Sweden
²² Department of Physics, University of Mumbai, Santacruz (East), 400098, Mumbai, India
²³ Fysikum, Division of Particle Physics, Lund University, Lund, Sweden
²⁴ Institut für Theoretische Physik, Universität Heidelberg, Heidelberg, Germany
²⁵ University of Witwatersrand, Johannesburg, South Africa
²⁶ School of Physics & Astronomy, The University of Manchester, M13 9PL, Manchester, UK
²⁷ Massachusetts Institute of Technology, Cambridge, MA, USA
²⁸ Boston University, Boston, USA
²⁹ University of Tennessee, Knoxville, USA
³⁰ University of Maryland, College Park, USA
³¹ University of Colorado Boulder, 80309, Boulder, CO, USA
³² Department of Physics, University of Illinois at Urbana-Champaign, 61801, Urbana, IL, USA

^w genest@lpsc.in2p3.fr
^ad suchita.kulkarni@uni-graz.at

Received: 11 July 2022
Accepted: 28 September 2022
Published online: 14 December 2022

Abstract

In this work, we consider the case of a strongly coupled dark/hidden sector, which extends the Standard Model (SM) by adding an additional non-Abelian gauge group. These extensions generally contain matter fields, much like the SM quarks, and gauge fields similar to the SM gluons. We focus on the exploration of such sectors where the dark particles are produced at the LHC through a portal and undergo rapid hadronization within the dark sector before decaying back, at least in part and potentially with sizeable lifetimes, to SM particles, giving a range of possibly spectacular signatures such as emerging or semi-visible jets. Other, non-QCD-like scenarios leading to soft unclustered energy patterns or glueballs are also discussed. After a review of the theory, existing benchmarks and constraints, this work addresses how to build consistent benchmarks from the underlying physical parameters and present new developments for the pythia Hidden Valley module, along with jet substructure studies. Finally, a series of improved search strategies is presented in order to pave the way for a better exploration of the dark showers at the LHC.