Feebly interacting particle explained

Feebly interacting particles (FIPs) are subatomic particles defined by having extremely suppressed interactions with the Standard Model (SM) bosons and / or fermions. These particles are potential thermal dark matter candidates, extending the model of weakly interacting massive particles (WIMPs) to include weakly interacting sub-eV particles (WISPs) and others. FIP physics is also known as dark-sector physics.^[1]

Candidates

FIP candidates could be massive (FIMP / WIMP) or massless and coupled to the SM particles through some minimal coupling strength.^[1] The light FIPs are theorized to be dark matter candidates, and, they provide an explanation for the origin of neutrino masses and CP symmetry in strong interactions.^[2]

Neutrinos technically qualify as FIPs, but usually when the acronym "FIP" is used, it is intended to refer to some other, as-yet unknown particle.Cai, Cacciapaglia, and Lee (2022) proposed massive gravitons as feebly Interacting particle candidates.^{[3] [4]}

See also

• WIMP – weakly interacting massive particle
• WISP – weakly interacting sub-eV / slight / slender particle

Notes and References

1. Lanfranchi . Gaia . Pospelov . Maxim . Schuster . Philip . 2020-11-04 . The search for feebly-interacting particles . . 71 . 279–313 . 10.1146/annurev-nucl-102419-055056 . 226246183 . 2011.02157.
2. Agrawal . Prateek . Bauer . Martin . Beacham . James . Berlin . Asher . Boyarsky . Alexey . Cebrian . Susana . Cid-Vidal . Xabier . d'Enterria . David . de Roeck . Albert . Drewes . Marco . Echenard . Bertrand . 6 . 2021-02-24 . Feebly-interacting particles: FIPs 2020 Workshop report . The European Physical Journal C . 81 . 11 . 1015 . 10.1140/epjc/s10052-021-09703-7 . 2102.12143 . 232035757 . 2021EPJC...81.1015A.
3. Cai . Haiying . Cacciapaglia . Giacomo . Lee . Seung J. . 2022-02-23 . Massive gravitons as feebly interacting dark matter candidates . . 128 . 8 . 081806 . 10.1103/PhysRevLett.128.081806 . 35275667 . 2107.14548 . 2022PhRvL.128h1806C . en . 236635132 . 0031-9007 .
4. News: Robert . Lea . 2022-04-09 . Dark matter could be a cosmic relic from extra dimensions . livescience.com . 2022-04-22 . en . 23 April 2022 . https://web.archive.org/web/20220423111158/https://www.livescience.com/dark-matter-particles-from-extra-dimensions . live .