Exotic Charges, Multicomponent Dark Matter and Light Sterile Neutrinos

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1 Exotic Charges, Multicomponent and Light Sterile Neutrinos Julian Heeck Max-Planck-Institut für Kernphysik, Heidelberg based on J.H., He Zhang, arxiv:1210.xxxx.

2 Sterile Neutrinos Hints for ev sterile neutrino Neutrino Experiments: LSND (ν µ ν e ): 3.8σ excess at low energies: m 2 LSND 1 ev2 (3 + 1 scheme). MiniBooNE pre 2012: ν µ ν e compatible with LSND, ν µ ν e not CP-violation (3 + 2 scheme). Short baseline reactor experiments (reevaluation of fluxes). Gallium anomaly. sterile neutrino(s) with m s 1 ev and large mixing U as = O(0.1). MiniBooNE 2012: ν µ ν e compatible with ν µ ν e. ICARUS 2012: New bounds on active-sterile mixing: U as < Agreement with LSND worsens... Very fast and exciting field! No need for anymore? Wait for global fits? Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 1 / 18

3 Sterile Neutrinos Hints for ev sterile neutrino II Cosmology: Light d.o.f. in ΛCDM: BBN, CMB and LSS: N s al., JCAP (2011)] BUT, for 3 + 1: m s 0.5 ev at 95%. [Hamann et al., PRL (2010)] Assumes thermalized ν s (makes sense for large mixing). Extend ΛCDM? No thermalization? Wait for Planck? Let s embrace the hints! 0.6. [Hamann et Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 2 / 18

4 Sterile Neutrinos How to make ν s light? Isn t new physics always at TeV? Just put it in: ev-seesaw ( ) 0 md M = m T D M R with m D 0.1 ev, M R 1 ev. [de Gouvêa, PRD (2005)] Active-sterile mixing automatically large: U as m D /M R m ν /m s 0.1. Minimal scheme: two ν R at ev scale, works fine. [Donini, Schwetz et al., JHEP (2012)] The heavy ev-scale suppresses the light 0.1 ev? Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 3 / 18

5 Sterile Neutrinos How to make ν s light? II Put ν s on the other side of the seesaw: ν α ν s ν R Suppressed BY seesaw: additional singlet S, mass matrix for (ν α, ν c R,j, S c ) 0 m D 0 M MES = md T M R m S. 0 ms T 0 Minimal Extended Seesaw (MES) [Barry, Rodejohann, Zhang, JHEP (2011)][Zhang, PLB (2012)] Works also for 3 + 2, 3 + 3,..., just add more singlets. Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 4 / 18

6 Sterile Neutrinos Minimal extended seesaw 0 m D 0 M MES = md T M R m S 0 ms T 0 Assume M R m D, m S, usual seesaw: ( md M 1 M 4 4 ν For m S m D, one more seesaw: and M 3 3 ν m D M 1 R m S ms T M 1 R mt D ms T M 1 R m S R mt D m D M 1 R ). mt D + m D M 1 m S (ms T M 1 m S) 1 ms T M 1 R m 4 m s m T S M 1 R m S. R R mt D Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 5 / 18

7 Mixing Sterile Neutrinos Diagonalize M 4 4 ν with ( (1 1 V 2 RR )U PMNS R R U PMNS R R ), active sterile mixing vector R = m D M 1 R m S (ms T M 1 R m S) 1 O(m D /m S ). m D 100 GeV, m S 500 GeV and M R GeV give m ν 0.05 ev, m s 1.3 ev, R 0.2 Great, but how to get MES structure? Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 6 / 18

8 How to get MES Sterile Neutrinos Need and forbid couplings L H ν R, m S S c ν R, M R ν c R ν R L H S, S c S. Flavor symmetry A 4 Z 4. [Zhang, PLB (2012)] Global U(1) : Y (S) = 1, new scalar φ with Y (φ) = +1: wφs c ν R w φ S }{{} ν R m S Goldstone boson problematic? Contributes 4/7 neutrino species to BBN, so together with ν s : N eff = 11/ Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 7 / 18

9 Local U(1) Sterile Neutrinos More interesting: gauge the U(1) : need more chiral fermions S j to cancel anomalies n Y (S j ) = 0 j and n (Y (S j )) 3 = 0. j make all new particles massive via φ. Try n = 2: Y (S 1 )! = Y (S 2 ), allows M S c 1 S MES only if M 1 ev. bare mass terms are bad... same for n = 3, 4. For n 5, exotic charges open up: Y (S i ) Y (S j ), i, j = 1,..., n. [Babu, Seidl, PLB (2004)] E.g. (10, 4, 9, 2, 7) or ( 5, 5, 1, 6, 2, 3). Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 8 / 18

10 Magic numbers Sterile Neutrinos Try n = 7, i.e. ten right-handed neutrinos : ν R,1 ν R,2 ν R,3 S 1 S 2 S 3 S 4 S 5 S 6 S 7 φ Y Mass matrix has nice block structure: ( ) (MMES ) M = (M S ) 6 6 with 0 y 1 φ y 1 φ M S = y 2 φ y 2 φ y 3 φ y 3 φ 0. S 1 gives MES, S 2,3,4,5,6,7 decouple and form 3 Dirac fermions Ψ 1,2,3! Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 9 / 18

11 More numbers Sterile Neutrinos Happy accident : φ breaks U(1) to Z 11. all three Ψ j stable! Active-sterile mixing V 4j O(m D /m S )! = O(0.1). For O(1) Yukawas U(1) breaking at φ 10 H TeV. masses for Z, Re(φ), Ψ 1,2,3 around 100 GeV TeV. No U(1) Landau pole below M Pl : g Multicomponent WIMP dark matter. Breakdown of neutral fermions: ν e, ν µ, ν τ, S 1, S 2, S 3, S }{{}}{{} 4, S 5, S }{{} 6, S 7, }{{} ν R,1, ν R,2, ν R,3 }{{} (3+1) MES Ψ 1 } Ψ 2 Ψ 3 {{} seesaw/leptogenesis DM Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 10 / 18

12 Sterile Neutrinos Dark matter interactions Lagrangian: ( [iψ j γ µ µ Ψ j M j 1 + Re(φ) ) Re(φ) j Ψ j Ψ j + g 2 Z µψ j γ µ ( gj V + g A j γ 5 ) Ψj ] with g V 1 = 1, g V 2 = 13, g V 3 = 7, g A 1 = 11, g A 2 = 11, g A 3 = 11. Connection to the Standard Model just like all other U(1) DM models: Scalar mixing (Higgs portal): L δ H 2 φ 2 Ψ j couple to Higgs. [Lopez-Honorez et al., PLB (2012)] Vector mixing (kinetic-mixing portal): L sin ξ F µν Y F µν Ψ j couple to Z boson. [Mambrini, JCAP (2011)] New: Fermion mixing (neutrino portal): L 11g 2 Z µ 4 V4iV 4j (ν i γ µ γ 5 ν j + ν i γ µ ν j ). i,j=1 Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 11 / 18

13 Neutrino portal Sterile Neutrinos M R GeV ν R,j φ Z, φ DM : Ψ i Ψ j TeV Z Z H φ H 100 GeV SM Z ev W, Z, H ν α V 4j ν s Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 12 / 18

14 Relic density Sterile Neutrinos Large active-sterile mixing sterile neutrinos are thermalized (probably... ) Z interactions νν ΨΨ thermalize Ψ j. At T < M j, Ψ j annihilates away into lighter Ψ and neutrinos. Freeze-out of lightest Ψ j near Z resonance gives Ωh M = M = M = 800 GeV M = 1 TeV M = M = M = 800 GeV M = 500 GeV 10 0 h h M Z' [GeV] M Z' [GeV] Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 13 / 18

15 Sterile Neutrinos Neutrino portal DM phenomenology 10 1 M = 600 GeV M = 800 GeV M = 1 TeV 10 0 M = 1 TeV 10 1 M = 600 GeV M = 800 GeV 10 0 M = 1 TeV M = 500 GeV h h M Z' [GeV] M Z' [GeV] For M i M j : multicomponent aspect interesting, e.g. coannihilation Ψ j Ψ j Z, φ Ψ i Ψ i. Direct detection is loop-suppressed: m 2 41 /(100 GeV) Indirect detection: BR(ΨΨ νν) 100% gives monochromatic neutrinos from Galactic halo. Too small for IceCube... Including Higgs portal and kinetic-mixing portal gives the usual measurable effects. Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 14 / 18

16 Neutrino portal Sterile Neutrinos M R GeV ν R,j φ Z, φ DM : Ψ i Ψ j TeV Z Z H φ H 100 GeV SM Z ev W, Z, H ν α V 4j ν s Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 15 / 18

17 Sterile Neutrinos Other charges: ν R,1 ν R,2 ν R,3 ν R,4 S 1 S 2 S 3 S 4 S 5 S 6 φ Y Same number of right-handed neutrinos, different decomposition. Only two Dirac DM particles, independently stable by U(1) Z 5. Same qualitative phenomenology. ν e, ν µ, ν τ, S 1, S 2, S 3, S 4, S }{{}}{{} 5, S 6, ν }{{} R,1, ν R,2, ν R,3, ν R,4 }{{} (3+2) MES Ψ 1 } Ψ 2 {{} seesaw/leptogenesis DM Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 16 / 18

18 Sterile Neutrinos Other charges: Unstable dark matter ν R,1 ν R,2 ν R,3 S 1 S 2 S 3 S 4 S 5 S 6 S 7 φ Y ν e, ν µ, ν τ, S 1, S 2, S 3, S }{{}}{{} 4, S 5, S }{{} 6, S 7, }{{} ν R,1, ν R,2, ν R,3 }{{} (3+1) MES Ψ 1 } Ψ 2 Ψ 3 {{} seesaw/leptogenesis DM Breakdown U(1) Z N not a generic feature. Here: only accidental global U(1) 3 symmetry protecting Ψ j. Broken to U(1) by higher-dimensional operators φ 2 S 3 S c 4 /Λ, φ 2 S c 3S 6 /Λ, φ 2 S 2 S c 7 /Λ. Completely broken at even higher order, e.g. φ 6 S 5 ν c R /Λ5. Suppressed DM decay. Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 17 / 18

19 Summary Sterile Neutrinos Additional right-handed neutrinos with exotic charges under a broken U(1) can generate structure in neutral fermions. Here: generate seesaw-suppressed sterile neutrino. Magic numbers: anomaly-cancelling fermions form multicomponent WIMPs. Gauge interactions open new SM-DM portal through thermalized sterile neutrinos. Huge unexplored playground! Other charges: 3 + 2, 3 + 3, Majorana DM, unstable DM,... Julian Heeck - MPIK Exotic Charges, Multicomponent DM and Light Sterile Neutrinos 18 / 18

Neutrinos and Abelian Gauge Symmetries

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