Sterile neutrino oscillations

Sterile neutrino oscillations after first MiniBooNE results GDR Neutrino, APC Paris, 22 June 2007 Thomas Schwetz CERN T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.1

Outline Introduction to the LSND problem Recent results from MiniBooNE Talk at Fermilab, April 11, 2007 A.A. Aguilar-Arevalo et al., arxiv:0704.1500 [hep-ex] Short-baseline data and sterile neutrino oscillation 4-neutrinos, 5-neutrinos, 6-neutrinos M. Maltoni, T. Schwetz, arxiv:0705.0107 [hep-ph] Comments on exotic solutions Summary and outlook T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.2

The LSND puzzle T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.3

The LSND signal π + µ + + ν µ e + + ν e + ν µ oscillations ν e 10 12 ν/cm 2 /MeV 7 6 5 4 3 2 1 ν µ ( 20) ν _ µ L 35 m signal: ν e + p e + + n 10 12 ν/cm 2 /MeV 0 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 10 20 30 40 50 60 MeV ν _ e ( 500) 0 0 10 20 30 40 50 60 MeV ν e T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.4

The LSND signal π + µ + + ν µ e + + ν e + ν µ oscillations ν e Beam Excess 17.5 15 12.5 10 7.5 Beam Excess p(ν _ µ ν_ e,e+ )n p(ν _ e,e+ )n other L 35 m evidence for ν µ ν e oscillations A. Aguilar et al., PRD 64 (2001) 112007 5 2.5 0 0.4 0.6 0.8 1 1.2 1.4 L/E ν (meters/mev) 87.9 ± 22.4 ± 6.0 excess events P = (0.264 ± 0.067 ± 0.045)% 3.3σ away from zero T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.4

Oscillation interpretation of LSND several bounds from other no-evidence SBL experiments, (KARMEN) combined analysis of LSND and KARMEN: Church, Eitel, Mills, Steidl, PRD (2002) m 2 (ev 2 /c 4 ) 10 2 10 1 10-1 10-2 Karmen Bugey 90% (L max -L < 2.3) 99% (L max -L < 4.6) CCFR NOMAD 10-3 10-2 10-1 1 sin 2 2θ T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.5

Oscillation interpretation of LSND the problem: m 2 ev 2 not consistent with solar (8 10 5 ) and atmospheric (3 10 3 ) mass splittings for three neutrinos! m 2 (ev 2 /c 4 ) 10 2 10 1 10-1 10-2 Karmen Bugey 90% (L max -L < 2.3) 99% (L max -L < 4.6) CCFR NOMAD 10-3 10-2 10-1 1 sin 2 2θ T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.5

MiniBooNE T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.6

W. Louis, J. Conrad, talk @ Fermilab, April 11, 2007 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.7

MiniBooNE neutrino flux W. Louis, J. Conrad, talk @ Fermilab, April 11, 2007 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.8

MiniBooNE background process estimated background for 475 < E QE ν events < 1250 MeV ν µ CCQE 10 ± 2 ν µ e ν µ e 7 ± 2 misc. ν µ events 13 ± 5 NC π 0 62 ± 10 NC Nγ 20 ± 4 dirt events 17 ± 3 ν e from µ 132 ± 10 ν e from K + 71 ± 26 ν e from KL 0 23 ± 7 ν e from π 3 ± 1 total background 385 ± 35 signal for 0.26% ν µ ν e 163 ± 21 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.9

MiniBooNE background process estimated background for 475 < E QE ν events ν µ CCQE 10 ± 2 ν µ e ν µ e 7 ± 2 misc. ν µ events 13 ± 5 NC π 0 62 ± 10 NC Nγ 20 ± 4 dirt events 17 ± 3 ν e from µ 132 ± 10 ν e from K + 71 ± 26 ν e from KL 0 23 ± 7 ν e from π 3 ± 1 total background 385 ± 35 signal for 0.26% ν µ ν e 163 ± 21 < 1250 MeV signal error = 163 385 + 352 + 21 = 3.6 2 MB should see a 3.6σ effect T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.9

MiniBooNE results obs. events minus background: 475 < Eν QE < 1250 MeV: 22 ± 19 ± 35 events (consistent with zero) 300 < Eν QE < 475 MeV: 96 ± 17 ± 20 events (excess at 3.6σ) events / MeV excess events / MeV 2.5 2.0 1.5 1.0 0.5 0.8 0.6 0.4 0.2 0.0 2ν oscillation analysis threshold MiniBooNE datay expected backgroundgν µ BG + best-fit ν µ ν e ν µ ν µ background background ν e data - expected background best-fit ν µ ν e 2 2 2 sin (2θ)=0.004, m =1.0 ev ν µ 2 2 2 sin (2θ)=0.2, m =0.1 ev ν µ 300 600 900 1200 1500 reconstructed E ν (MeV) 3000 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.10

The event excess at low energies Two-neutrino oscillations cannot account for the sharp rise of the spectrum. Before fully opening the box they found that the full range gives a very poor fit of the E vis distribution (< 1%). Decided to restrict the two-neutrino analysis to > 475 MeV. E QE ν T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.11

The event excess at low energies Two-neutrino oscillations cannot account for the sharp rise of the spectrum. Before fully opening the box they found that the full range gives a very poor fit of the E vis distribution (< 1%). Decided to restrict the two-neutrino analysis to > 475 MeV. E QE ν Backgrounds are difficult to estimate in the low energy region, all possible sources are under investigation. T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.11

The event excess at low energies Two-neutrino oscillations cannot account for the sharp rise of the spectrum. Before fully opening the box they found that the full range gives a very poor fit of the E vis distribution (< 1%). Decided to restrict the two-neutrino analysis to > 475 MeV. E QE ν Backgrounds are difficult to estimate in the low energy region, all possible sources are under investigation. The decision not to use the low energy bins is based on the hypothesis of two-flavour oscillations! T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.11

The MiniBooNE 2-neutrino limit 2 10 2 sin (2θ) upper limit 10 MiniBooNE 90% C.L.y MiniBooNE 90% C.L. sensitivity BDT analysis 90% C.L. m 2 2 (ev /c 4 ) 1-1 10 LSND 90% C.L. LSND 99% C.L. -2 10-3 10-2 10 2 sin (2θ) -1 10 1 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.12

MiniBooNE - LSND compatibility W. Louis, J. Conrad, talk @ Fermilab, April 11, 2007 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.13

Going beyond simple 2-neutrino oscillations T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.14

Going beyond simple 2-neutrino oscillations 4-neutrino oscillations? T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.14

Adding a sterile neutrino 4-neutrino mass schemes: m 2 i (2+2) (3+1) m 2 atm m 2 LSND m 2 LSND m 2 atm m 2 sol m 2 sol ν e ν µ ν τ ν s T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.15

(2+2): ruled out by solar and atmospheric data Maltoni, Schwetz, Tortola, Valle, hep-ph/0207157, hep-ph/0405172 50 χ 2 40 30 20 10 solar solar + KamLAND solar pre-sno salt 0 0 0.2 0.4 0.6 0.8 1 η s T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.16

(2+2): ruled out by solar and atmospheric data Maltoni, Schwetz, Tortola, Valle, hep-ph/0207157, hep-ph/0405172 50 χ 2 40 30 20 solar + KamLAND χ 2 PC 10 atm + K2K + SBL 0 0 0.2 0.4 0.6 0.8 1 η s T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.16

(2+2): ruled out by solar and atmospheric data Maltoni, Schwetz, Tortola, Valle, hep-ph/0207157, hep-ph/0405172 50 χ 2 40 30 20 global solar + KamLAND χ 2 PG χ 2 PC 10 atm + K2K + SBL 0 0 0.2 0.4 0.6 0.8 1 η s χ 2 = 26 (2+2) ruled out at the 5σ level T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.16

MB vs LSND in (3+1) In (3+1) schemes the SBL appearance probability is effectively 2-ν oscillations: with P µe = sin 2 2θ SBL sin 2 m2 41L 4E sin 2 2θ SBL = 4 U e4 2 U µ4 2 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.17

MB vs LSND in (3+1) In (3+1) schemes the SBL appearance probability is effectively 2-ν oscillations: with P µe = sin 2 2θ SBL sin 2 m2 41L 4E sin 2 2θ SBL = 4 U e4 2 U µ4 2 LSND / MiniBooNE inconsistency is the same as in the 2-flavour analysis presented by the MiniBooNE collaboration (98% CL) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.17

Appearance vs disappearance in (3+1) Tension between SBL appearance and disappearance experiments Bilenky, Giunti, Grimus, 96, 98; Okada, Yasuda, 1997; Barger et al., 1998, 2000; Giunti, Laveder, 2001; Peres, Smirnov, 2001; Grimus, Schwetz, 2001 appearance amplitude sin 2 2θ SBL = 4 U e4 2 U µ4 2 no-evidence (NEV) ν e and ν µ disappearance experiements bound U e4 2 and U µ4 2 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.18

Disappearance bounds in (3+1) 10 2 Bugey, Chooz 10 1 CDHS m 2 41 [ev2 ] 10 0 10-1 atmospheric 10-2 10-3 10-2 10-1 U e4 2 10-3 10-2 10-1 U µ4 2 atm. neutrinos give an important constraint on U µ4 2 for low m 2 Bilenky, Giunti, Grimus, Schwetz, 1999; Maltoni, Schwetz, Valle, 2002 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.19

(3+1) global 90%, 99% CL m 2 41 [ev2 ] 10 1 10 0 LSND before MB: χ 2 PG = 20.9 (2 dof) MB incl.: χ 2 PG = 24.7 (2 dof) 10-1 NEV (incl. MB475) 10-4 10-3 10-2 10-1 10 0 disagreement at about 4σ sin 2 2θ SBL T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.20

More sterile neutrinos? T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.21

5-neutrino oscillations m 2 i (3+2) scheme m 2 LSND m 2 LSND ν e ν µ ν τ ν s m 2 atm m 2 sol Sorel, Conrad, Shaevitz, hep-ph/0305255 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.22

(3+2) appearance probability P νµ ν e = 4 U e4 2 U µ4 2 sin 2 φ 41 + 4 U e5 2 U µ5 2 sin 2 φ 51 + 8 U e4 U µ4 U e5 U µ5 sin φ 41 sin φ 51 cos(φ 54 δ) with the definitions φ ij m2 ij L 4E, δ arg ( ) Ue4U µ4 U e5 Uµ5. T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.23

(3+2) appearance probability P νµ ν e = 4 U e4 2 U µ4 2 sin 2 φ 41 + 4 U e5 2 U µ5 2 sin 2 φ 51 + 8 U e4 U µ4 U e5 U µ5 sin φ 41 sin φ 51 cos(φ 54 δ) with the definitions φ ij m2 ij L 4E, δ arg ( ) Ue4U µ4 U e5 Uµ5. (3+2) osc. include the possibility of CP violation! remember: MiniBooNE: neutrinos, LSND: anti-neutrinos T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.23

(3+2) appearance data best fit point spectra: 1 MiniBooNE 15 LSND 0.8 475 MeV MB300 MB475 MB data app data incl. MB best fit LSND only excess events per MeV 0.6 0.4 0.2 excess events 10 5 0 0.3 0.6 0.9 1.2 1.5 3 CCQE E ν [GeV] 0 background 0.4 0.6 0.8 1 1.2 1.4 L/E ν [m/mev] Perfect fit to appearance data (MB with or without the low energy excess) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.24

(3+2) appearance data 10 1 10 1 m 2 51 [ev 2 ] 10 0 m 2 51 [ev 2 ] 10 0 10-1 (3+2) fit: 10-1 (3+2) fit: 10-2 MB475 + LSND + KARMEN + NOMAD 10-2 10-1 10 0 10 1 m 2 41 [ev2 ] 10-2 MB300 + LSND + KARMEN + NOMAD 10-2 10-1 10 0 10 1 m 2 41 [ev2 ] χ 2 min = 16.9/(29 5) χ2 min = 18.5/(31 5) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.25

(3+2) disappearance data what about the disappearance data? ( P να ν α = 1 4 1 i=4,5 U αi 2 ) i=4,5 U αi 2 sin 2 φ i1 4 U α4 2 U α5 2 sin 2 φ 54 bound U ei and U µi (i = 4, 5), similar as in (3+1) to be reconciled with appearance amplitudes U ei U µi T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.26

(3+2) global 10 m 2 51 [ev 2 ] 1 m 2 41 = 0.89 ev 2 m 2 51 = 6.49 ev 2 χ 2 min = 94.5/(107 7) 0.1 (3+2) fit to global data (MB475) 0.1 1 10 m 2 41 [ev 2 ] T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.27

(3+2) global testing consistency of disappearance and appearance (incl. MB475) data: χ 2 PG = 17.2 (4 dof) PG = 0.18% parameters in common U e4 U µ4, U e5 U µ5, m 2 41, m 2 51 inconsistency at about 3.1σ without MB: χ 2 PG = 17.5 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.28

(3+2) app vs disap 90%, 99% CL U e5 U µ5 10-1 10-2 appearance (MB475) 10-3 disappearance 10-3 10-2 10-1 U e4 U µ4 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.29

(3+2) vs (3+1) (3+2) (3+1) 10 m 2 51 [ev2 ] 1 0.1 (3+2) fit to global data (MB475) 0.1 1 10 m 2 41 [ev 2 ] 90 100 110 120 130 χ 2 χ 2 min, global (3+1) χ2 min, global (3+2) = 6.1/4 dof (81% CL) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.30

MB300 in (3+2) schemes including the full MB spectrum: 10 m 2 41 = 0.87 ev 2 m 2 51 = 1.91 ev 2 m 2 51 [ev2 ] 1 χ 2 min = 104.4/(109 7) (χ 2 min,mb475 = 94.5) 0.1 (3+2) fit to global data (MB300) χ 2 PG = 25.1/4 0.1 1 10 m 2 41 [ev2 ] PG = 4.8 10 5 (4σ) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.31

MB300 in (3+2) schemes including the full MB spectrum: 10-1 90%, 99% CL m 2 41 = 0.87 ev 2 m 2 51 = 1.91 ev 2 U e5 U µ5 10-2 appearance (MB300) χ 2 min = 104.4/(109 7) (χ 2 min,mb475 = 94.5) 10-3 disappearance 10-3 10-2 10-1 U e4 U µ4 χ 2 PG = 25.1/4 PG = 4.8 10 5 (4σ) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.31

MB300 in (3+2) schemes 1 excess events per MeV 0.8 0.6 0.4 0.2 475 MeV appearance data (MB300) global data (MB300) MB data 0 0.3 0.6 0.9 1.2 1.5 3 CCQE E ν [GeV] the MB low energy excess is not reproduced at the global best fit point T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.32

CP violation 110 MB300 100 MB475 χ 2 90 30 global data MB300 20 MB475 appearance data 10 0 0.5 1 1.5 2 δ [π] T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.33

adding another sterile: (3+3) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.34

(3+3) probabilities appearance prob.: P νµ ν e = 4 i U ei U µi 2 sin 2 φ i1 +8 i,j<i U ei U µi U ej U µj sin φ i1 sin φ j1 cos(φ ij δ ij ), i, j = 4, 5, 6, survival prob.: ( P να ν α = 1 4 1 i U αi 2 ) i U αi 2 sin 2 φ i1 4 i,j<i U αi 2 U αj 2 sin 2 φ ij, i, j = 4, 5, 6 with: φ ij m2 ijl 4E, δ ij arg ( ) UejU µj U ei Uµi T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.35

(3+3) global fit MB475 115 MB300 110 105 (3+2) χ 2 100 (3+2) (3+1) (3+3) 95 (3+3) 90 0.1 1 10 m 2 41 [ev2 ] 0.1 1 10 m 2 41 [ev2 ] m 2 41 m 2 51 m 2 61 χ 2 min χ 2 (3+2) χ2 (3+3) CL MB475 0.46 0.83 1.84 92.8 1.7/4 20% MB300 0.46 0.83 1.84 100.9 3.5/4 52% T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.36

All these sterile neutrino schemes have problems with cosmology T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.37

All these sterile neutrino schemes have problems with cosmology sterile states contribute to the relativistic degrees of freedom (CMB, BBN) conflict with bound on the sum of neutrino masses from various cosmological data sets (LSS) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.37

Cosmology SN Ia, LSS (2dF, SDSS), BAO, CMB (WMAP, BOOMERANG) 68%, 95%, 99% CL Hannestad, Raffelt, astro-ph/0607101 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.38

Cosmology one has to invoke some non-standard mechanism to prevent the equilibration of sterile neutrinos, e.g., primordial lepton asymmetry Foot, Volkas, 95 blocking active-sterile oscillations by some exotic particle physics Babu, Rothstein, 92; Bento, Berezhiani, 01 low reheating temperature Gelmini, Palomares-Riuz, Pascoli, 04 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.39

More exotic proposals T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.40

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 CPT viol. quantum decoherence Barenboim, Mavromatos 04 Lorentz violation Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; KamLAND+atmospheric antineutrino data Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 CPT viol. quantum decoherence Barenboim, Mavromatos 04 Lorentz violation Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; KamLAND+atmospheric antineutrino data Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 KARMEN, TWIST CPT viol. quantum decoherence Barenboim, Mavromatos 04 Lorentz violation Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; KamLAND+atmospheric antineutrino data Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 KARMEN, TWIST CPT viol. quantum decoherence Barenboim, Mavromatos 04 KamLAND spectral data Lorentz violation Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 CPT viol. quantum decoherence Barenboim, Mavromatos 04 Lorentz violation KamLAND+atmospheric antineutrino data KARMEN, TWIST KamLAND spectral data energy dependence, MiniBooNE? Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 CPT viol. quantum decoherence Barenboim, Mavromatos 04 Lorentz violation KamLAND+atmospheric antineutrino data Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos KARMEN, TWIST KamLAND spectral data energy dependence, MiniBooNE? CDHS+atmospheric data? Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

More exotic proposals 3-neutrinos and CPT violation Murayama, Yanagida 01; Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, Schwetz 03 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03 Exotic muon-decay Babu, Pakvasa 02 CPT viol. quantum decoherence Barenboim, Mavromatos 04 Lorentz violation KamLAND+atmospheric antineutrino data Kostelecky, Mews, 04; Gouvea, Grossman, 06; Katori, Kostelecky, Tayloe, 06 mass varying neutrinos KARMEN, TWIST KamLAND spectral data energy dependence, MiniBooNE? CDHS+atmospheric data? Kaplan, Nelson, Weiner 04; Zurek 04; Barger, Marfatia, Whisnant 05 shortcuts of sterile neutrinos in extra dimensions Paes, Pakvasa, Weiler 05 1 decaying sterile neutrino Palomares-Riuz, Pascoli, Schwetz 05 MiniBooNE 2 decaying sterile neutrinos with CPV T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.41

Non-standard models...... which seem to fit everything (incl. LSND and MB): A sterile neutrino with CPT violation different mixing for neutrinos and anti-neutrinos Barger, Marfatia, Whisnant 03 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.42

Non-standard models...... which seem to fit everything (incl. LSND and MB): A sterile neutrino with CPT violation different mixing for neutrinos and anti-neutrinos Barger, Marfatia, Whisnant 03 A sterile neutrino with Lorentz violation dispersion relation for sterile ν deviates from p = E 2 m 2 Barger, Huber, et al., in preparation; motivated by extra-dimension model of Paes, Pakvasa, Weiler 05 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.42

Non-standard models...... which seem to fit everything (incl. LSND and MB): A sterile neutrino with CPT violation different mixing for neutrinos and anti-neutrinos Barger, Marfatia, Whisnant 03 A sterile neutrino with Lorentz violation dispersion relation for sterile ν deviates from p = E 2 m 2 Barger, Huber, et al., in preparation; motivated by extra-dimension model of Paes, Pakvasa, Weiler 05 Two decaying sterile neutrinos (CP violation) Palomares-Riuz, Pascoli, Schwetz 05 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.42

Summary T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.43

Summary - sterile neutrino oscillations (3+1) schemes have been only marginally allowed before MB, and become even more disfavoured with recent data (4σ). T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.44

Summary - sterile neutrino oscillations (3+1) schemes have been only marginally allowed before MB, and become even more disfavoured with recent data (4σ). (3+2) schemes offer the possiblity of CP violation to reconcile LSND and MiniBooNE, can explain the low energy excess in MB, but there is tension between appearance and disappearance data (3σ, 4σ for MB300) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.44

Summary - sterile neutrino oscillations (3+1) schemes have been only marginally allowed before MB, and become even more disfavoured with recent data (4σ). (3+2) schemes offer the possiblity of CP violation to reconcile LSND and MiniBooNE, can explain the low energy excess in MB, but there is tension between appearance and disappearance data (3σ, 4σ for MB300) (3+3) schemes do not offer qualitatively new features, and the fit does not improve significantly wrt (3+2) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.44

Summary - sterile neutrino oscillations (3+1) schemes have been only marginally allowed before MB, and become even more disfavoured with recent data (4σ). (3+2) schemes offer the possiblity of CP violation to reconcile LSND and MiniBooNE, can explain the low energy excess in MB, but there is tension between appearance and disappearance data (3σ, 4σ for MB300) (3+3) schemes do not offer qualitatively new features, and the fit does not improve significantly wrt (3+2) M. Maltoni, T. Schwetz, arxiv:0705.0107 [hep-ph] T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.44

Sterile neutrino oscillations - outlook CPV is being tested by MiniBooNE anti-neutrino data (problem of statistics) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.45

Sterile neutrino oscillations - outlook CPV is being tested by MiniBooNE anti-neutrino data (problem of statistics) an experiment at a stopped pion source exploring NC detection Garvey et al., hep-ph/0501013 T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.45

Sterile neutrino oscillations - outlook CPV is being tested by MiniBooNE anti-neutrino data (problem of statistics) an experiment at a stopped pion source exploring NC detection Garvey et al., hep-ph/0501013 the problem of (3+s) schemes heavily rely on SBL disappearance experiments Bugey ( ν e reactor) and CDHS (ν µ accelerator) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.45

Sterile neutrino oscillations - outlook CPV is being tested by MiniBooNE anti-neutrino data (problem of statistics) an experiment at a stopped pion source exploring NC detection Garvey et al., hep-ph/0501013 the problem of (3+s) schemes heavily rely on SBL disappearance experiments Bugey ( ν e reactor) and CDHS (ν µ accelerator) could be worth to look for disappearance at the m 2 1 ev 2 scale at future reactor, solar or LBL ND experiments T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.45

Sterile neutrino oscillations - outlook CPV is being tested by MiniBooNE anti-neutrino data (problem of statistics) an experiment at a stopped pion source exploring NC detection Garvey et al., hep-ph/0501013 the problem of (3+s) schemes heavily rely on SBL disappearance experiments Bugey ( ν e reactor) and CDHS (ν µ accelerator) could be worth to look for disappearance at the m 2 1 ev 2 scale at future reactor, solar or LBL ND experiments Thank you for your attention! T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.45

Additional slides T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.46

4-neutrino oscillation parameters 3 mass-squared differences + 6 mixing angles 9 parameters T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.47

4-neutrino oscillation parameters 3 mass-squared differences + 6 mixing angles 9 parameters η α = i U αi 2 with i solar mass states d α = 1 i U αi 2 with i atmospheric mass states note that in (2+2): η α = d α m 2 sol, m2 atm, m 2 LSND, θ sol, θ atm, θ LSND, η s, η e, d µ T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.47

4-neutrino oscillation parameters 3 mass-squared differences + 6 mixing angles 9 parameters η α = i U αi 2 with i solar mass states d α = 1 i U αi 2 with i atmospheric mass states note that in (2+2): η α = d α m 2 sol, m2 atm, m 2 LSND, θ sol, θ atm, θ LSND, η s, η e, d µ approximations: m 2 sol m2 atm m 2 LSND η e 1 for solar and atmospheric oscillations (reactor data) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.47

Coupling of the data sets m 2 SOL m 2 ATM m 2 LSND η s SOL ATM NEV d µ LSND θ SOL θ ATM θ LSND η e T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.48

Coupling of the data sets m 2 SOL m 2 ATM m 2 LSND η s SOL ATM NEV d µ LSND θ SOL θ ATM θ LSND η e important for (2+2) important for (3+1) T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.48

Compatibility of independent data sets parameter goodness-of-fit (PG) Maltoni, Schwetz, hep-ph/0304176 χ 2 PG χ 2 min,global i χ 2 min,i = i χ 2 i (best fit) i: data sets evaluate χ 2 PG for # dof = # of params in comon measure for the price one has to pay by the combination, relative to the fit of the sets individually T. Schwetz, GDR Neutrino, Paris, 22 June 2007 p.49