Snowmass RF6 - August 12, 2020 Dark Sector Portals at High Intensity Adam Ritz University of Victoria – New physics in a dark sector Empirical evidence for new physics, e.g. neutrino mass, dark matter, arguably points to a dark/hidden sector (but not directly to a specific mass scale) mediators Standard Model Dark Sector May contain light states, if UV Physics sufficiently weakly coupled • Neutrino mass - (HL)(HL)/ΛUV • DM - WIMPs etc Discoverability frontier IR Physics Direct • Neutrino mass - light (RH) singlets searches • DM - axions, sterile neutrinos, etc Energy Frontier Visibility Frontier ➠ Dark sectors present a huge model-space a priori, but an EFT approach to the mediator channel allows for a classification (large community effort over past decade) EFT for a (neutral) dark sector mediators Standard Model Dark Sector (+ gravity) There are just three UV-complete relevant or marginal “portals” to a SM-neutral hidden sector, unsuppressed by the (possibly large) new physics scale Λ c 1 = n (SM) (med) = + L ⇤n Ok Ol Lportals O ⇤ n=k+l 4 ✓ ◆ X− ✏ µ⌫ 2 ij 1 = B A0 H†H(AS + λS ) Y L¯ HN ++ −2 µ⌫ − − N i j OO ⇤ Vector portal Higgs portal Neutrino portal ✓ ◆◆ [Okun; Galison & Manohar; [Patt & Wilczek] Holdom; Foot et al] Many more UV-sensitive interactions at dim # 5 "3 EFT for a (neutral) dark sector mediators Standard Model Dark Sector (+ gravity) There are just three UV-complete relevant or marginal “portals” to a SM-neutral hidden sector, unsuppressed by the (possibly large) new physics scale ! c 1 = n (SM) (med) = + L ⇤n Ok Ol Lportals O ⇤ n=k+l 4 ✓ ◆ X− ✏ µ⌫ 2 ij 1 = B A0 H†H(AS + λS ) Y L¯ HN + −2 µ⌫ − − N i j O ⇤ Vector portal Higgs portal Neutrino portal ✓ ◆ [Okun; Galison & Manohar; [Patt & Wilczek] Holdom; Foot et al] 1 ˜ ˜ µ + tr(GG)+cF F F + c @µjA a + (dim 5) fa O ≥ ⇣ Axion portal ⌘ [Weinberg, Wilczek, KSVZ, DFSZ] "4 EFT for a (neutral) dark sector mediators Standard Model Dark Sector (+ gravity) There are just three UV-complete relevant or marginal “portals” to a SM-neutral hidden sector, unsuppressed by the (possibly large) new physics scale ! cn (SM) (med) CERN PBC1 = = portals + L ⇤n Ok Ol L benchmarkO ⇤ cases n=k+l 4 ✓ ◆ X− ✏ µ⌫ 2 ij 1 = B A0 H†H(AS + λS ) Y L¯ HN + −2 µ⌫ − − N i j O ⇤ ✓ ◆ BC 1-3 BC 4-5 BC 6-8 1 ˜ ˜ µ + tr(GG)+cF F F + c @µjA a + (dim 5) fa O ≥ ⇣ BC 9-11 ⌘ "5 EFT for a (neutral) dark sector mediators Standard Model Dark Sector (+ gravity) There are just three UV-complete relevant or marginal “portals” to a SM-neutral hidden sector, unsuppressed by the (possibly large) new physics scale ! ✏ µ⌫ 2 ij 1 = B A0 H†H(AS + λS ) Y L¯ HN + L −2 µ⌫ − − N i j O ⇤ Vector portal Higgs portal Neutrino portal ✓ ◆ Applications of the portals fields a, A’, S and N: • minimal models of neutrino mass, and leptogenesis • viable (and minimal) non-thermal cold DM candidates (sub MeV) • new `dark force’ mediators enabling sufficient annihilation of thermal relic MeV-GeV (hidden sector) dark matter in the early universe "6 EFT for a (neutral) dark sector mediators Standard Model Dark Sector (+ gravity) There are just three UV-complete relevant or marginal “portals” to a SM-neutral hidden sector, unsuppressed by the (possibly large) new physics scale ! ✏ µ⌫ 2 ij 1 = B A0 H†H(AS + λS ) Y L¯ HN + L −2 µ⌫ − − N i j O ⇤ ✓ ◆ A2 3 6 < 2λH ✏1 2loop 10− 10− 2 − ⇠ − mS Relevant operator, but does not $ A’ induce further UV sensitivity in loops, which generically scale as A2 log ⇤ ee0 ✏1 loop log ⇤ − ⇠ 12⇡2 "7 EFT for a (neutral) dark sector mediators Standard Model Dark Sector (+ gravity) There are just three UV-complete relevant or marginal “portals” to a SM-neutral hidden sector, unsuppressed by the (possibly large) new physics scale ! ✏ µ⌫ 2 ij 1 = B A0 H†H(AS + λS ) Y L¯ HN + L −2 µ⌫ − − N i j O ⇤ Vector portal Higgs portal Neutrino portal ✓ ◆ 2 µ Av ij ✏A0 J µ EM 2 SJS vYN ⌫¯iNj mh Universal couplings to EM/scalar currents at low energy, so hidden sector models have correlated observable effects "8 Signatures at the intensity frontier mediators Standard Model Dark Sector “Visible” and “hidden” signatures • Precision corrections • Rare (invisible) decays, E/pmiss • Rare (visible) decays • Anomalous NC-like scattering • Astrophys/cosmology • Astrophys/cosmology Overlap with searches for light DM High intensity/luminosity experiments provide excellent sensitivity to MeV-GeV mass mediators "9 Signatures at the intensity frontier Standard Model Dark Sector “Visible” and “hidden” signatures Vector Higgs Neutrino Axion Visible BC1 BC4,5 BC6-8 BC 9-11 Invisible BC2 Scattering BC2 Consider BC1-7 here, with other BC’s in backup slides"10 Vector portal • Production channels /f – e+ e- ) A’ $ – ', (, (’ ) A’$, D* ) DA’ /f – Vector-meson mixing – Bremsstrahlung (e and p) – Drell-Yan, DIS 9 GeV proton fixed target '0 %,& ( brem Normalizedrate qq [deNiverville et al ‘16] "11 Vector portal - signatures if Br(SM) ~ 1 Visible decays (e.g. A’ ) dileptons) [Fabbrichesi et al ’20] "12 Vector portal - signatures if Br(SM) ~ 1 Visible decays (e.g. A’ ) dileptons) [Fabbrichesi et al ’20] Projections "13 Vector portal - signatures if Br(hid) ~ 1 Missing mass, E, or mtm - O(*2) [Fabbrichesi et al ’20] "14 Vector portal - signatures if Br(hid) ~ 1 Missing mass, E, or mtm - O(*2) [Fabbrichesi et al ’20] BaBar (2017) NA64 (2019) Projections "15 Vector portal - signatures if Br(hid) ~ 1 Missing mass, E, mtm - O(*2), or scattering - O(*4) [Fabbrichesi et al ’20] 4D parameter space {mA’, m+, *, ,D} "16 Vector portal - signatures if Br(hid) ~ 1 Missing mass, E, mtm - O(*2), or scattering - O(*4) [Fabbrichesi et al ’20] BaBar E137 NA64 LSND Projections 4D parameter space {mA’, m+, *, ,D} "17 Vector portal - signatures if Br(hid) ~ 1 Missing mass, E, mtm - O(*2), or scattering - O(*4) [Berlin et al ’20] 4D parameter space {mA’, m+, *, ,D} "18 Higgs portal - visible decays (-=0) • Production channels (S)f+f-) K, B decay [Boiarska et al '19] – Bremsstrahlung (p) Brem, DIS – K)'S, B)K(*)S – DIS Weaker limits Seaquest above ~5 GeV from LEP [PBC Beacham et al '19] "19 mS(GeV) Higgs portal - visible decays (Br(h->SS) ~ 0.01) • Production channels (S)f+f-) K, B decay [Boiarska et al '19] – Bremsstrahlung (p) Brem, DIS – K)'S, B)K(*)S – DIS + Higgs decay Weaker limits Seaquest above ~5 GeV are from LEP [PBC Beacham et al '19] "20 mS(GeV) Higgs portal - invisible decays • Production channels (S)f+f-) K, B decay [Boiarska et al '19] – Bremsstrahlung (p) Brem, DIS – K)'S, B)K(*)S – DIS Thermal target excluded in minimal MeV-GeV mass DM model by K, B meson decays [Krnjaic '15] [See also Boehm & Fayet; deNiverville et al ’12] "21 Neutrino portal - electron flavour • Production modes – ', K ) l., B ) Xl. decays – Neutrino mixing – Z decay [PBC Beacham et al '19] "22 Neutrino portal - tau flavour • Production modes – ', K ) l., D, B ) Xl. decays – Neutrino mixing – Z decay [PBC Beacham et al '19] "23 Discussion Standard Model Dark Sector UV Physics • EFT arguments focus attention on the Discoverability frontier UV-complete portal interactions • Considerable progress over past decade ➡ Are there clear coupling and mass Direct searches IR Physics targets in BC 1-11 for next-gen Energy Frontier intensity frontier searches? Visibility Frontier Vector Higgs Neutrino Axion Visible 2-loop scale/ Mass > 5 GeV �-flavour/ Thermal target Thermal target Invisible (DOE light DM BRN) “excluded” Backup Material (additional PBC benchmark cases) "25 Vector portal - massless A’ (millcharge) Ionization, Z decays "26 Neutrino portal - muon flavour • Production modes – ', K ) l., B ) Xl. decays – Neutrino mixing – Z decay [PBC Beacham et al '19] "27 Axion portal (photon coupling) • Production channels – e+ e- ) $ a – Primakov conversion – Pseudoscalar meson mixing – K, B meson decay [PBC Beacham et al '19] "28 Axion portal (fermion coupling) • Production channels – e+ e- ) $ a – Primakov conversion – Pseudoscalar meson mixing – K, B meson decay [PBC Beacham et al '19] "29 Axion portal (gluon coupling) • Production channels – e+ e- ) $ a – Primakov conversion – Pseudoscalar meson mixing – K, B meson decay [PBC Beacham et al '19] "30.