Sterile Neutrino Mixing NOW and in the Next Years Carlo Giunti INFN, Sezione di Torino NOW 06 Neutrino Oscillation Workshop 4- September 06 Otranto, Lecce, Italy C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5
Indications of SBL Oscillations Beyond 3ν C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 3/5 LSND [PRL 75 (995) 650; PRC 54 (996) 685; PRL 77 (996) 308; PRD 64 (00) 07] ν µ ν e 0 MeV E 60 MeV Well-known source of ν µ µ at rest e ν e ν µ L 30 m ν e p n e Well-known detection process of ν e But signal not seen by KARMEN at L 8 m with the same method [PRD 65 (00) 0] 3.8σ excess m SBL 0. ev m ATM m SOL
Gallium Anomaly C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 4/5 Gallium Radioactive Source Experiments: GALLEX and SAGE ν e Sources: e 5 Cr 5 V ν e e 37 Ar 37 Cl ν e E 0.75 MeV E 0.8 MeV Test of Solar ν e Detection: ν e 7 Ga 7 Ge e R =N exp N cal 0.7 0.8 0.9.0. GALLEX SAGE Cr Cr R = 0.84 ± 0.05 GALLEX SAGE Cr Ar L GALLEX =.9 m L SAGE = 0.6 m.9σ deficit m SBL ev m ATM m SOL [SAGE, PRC 73 (006) 045805; PRC 80 (009) 05807] [Laveder et al, Nucl.Phys.Proc.Suppl. 68 (007) 344; MPLA (007) 499; PRD 78 (008) 073009; PRC 83 (0) 065504] 3 He 7 Ga 7 Ge 3 H cross section measurement [Frekers et al., PLB 706 (0) 34] E th (ν e 7 Ga 7 Ge e ) = 33.5 ±. kev [Frekers et al., PLB 7 (03) 33]
Reactor Electron Antineutrino Anomaly C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 5/5 [Mention et al, PRD 83 (0) 073006] New reactor ν e fluxes [Mueller et al, PRC 83 (0) 05465; Huber, PRC 84 (0) 0467] R = N exp N cal 0.5 0.6 0.7 0.8 0.9.0.. Bugey 3 Bugey 4 Rovno9 Gosgen ILL Krasno Rovno88 SRP Chooz Palo Verde Double Chooz Daya Bay R = 0.936 ± 0.0 Nucifer Neutrino 4 RENO 3 L [m] 3.σ deficit m SBL 0.5 ev m ATM m SOL
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 6/5 Effective 3 SBL Oscillation Probabilities Appearance (α β) ( ) m P SBL ( ) sin ϑ ν ( ) αβ sin 4 L α ν β 4E Disappearance ( ) m P SBL ( ) sin ϑ ν ( ) αα sin 4 L α ν α 4E sin ϑ αβ = 4 U α4 U β4 sin ϑ αα = 4 U α4 ( U α4 ) U e U e U e3 U e4 U µ U µ U µ3 U µ4 U = U τ U τ U τ3 U τ4 U s U s U s3 U s4 SBL 6 mixing angles 3 Dirac CP phases 3 Majorana CP phases CP violation is not observable in SBL experiments! Observable in LBL accelerator exp. sensitive to matm [de Gouvea et al, PRD 9 (05) 053005, PRD 9 (05) 0730, arxiv:605.09376; Palazzo et al, PRD 9 (05) 07307, PLB 757 (06) 4; Gandhi et al, JHEP 5 (05) 039] and solar exp. sensitive to m SOL [Long, Li, CG, PRD 87, 3004 (03) 3004]
Rea Gal νec Sun TK Global ν e and ν e Disappearance νe & νe DIS β decay [ev ] [ev ] m 4 m 4 νe & νe DIS νe & νe DIS β 90% CL 95% CL 90% CL 95% CL sin ϑ ee KARMEN LSND ν e C N g.s. e [Conrad, Shaevitz, PRD 85 (0) 0307] [CG, Laveder, PLB 706 (0) 00] solar ν e KamLAND ν e ϑ 3 [CG, Li, PRD 80 (009) 3007] [Palazzo, PRD 83 (0) 303; PRD 85 (0) 07730] [CG, Laveder, Li, Liu, Long, PRD 86 (0) 304] TK Near Detector ν e disappearance [TK, PRD 9 (05) 05] sin ϑ ee Mainz Troitsk Tritium β decay [Mainz, EPJC 73 (03) 33] [Troitsk, JETPL 97 (03) 67; JPG 4 (04) 0500] No Osc. excluded at.8σ ( χ /NDF =.8/) 6 cm Losc 4 E [MeV] 6 m C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 7/5 (σ)
The Race for ν e and ν e Disappearance CeSOX shape (95% CL) STEREO (yr, 95% CL) PROSPECT phase (3yr, 3σ) CeSOX rate (95% CL) SoLiD phase (yr, 95% CL) PROSPECT phase (3yr, 3σ) CeSOX rateshape (95% CL) SoLiD phase (3yr, 3σ) DANSS (yr, 95% CL) BEST (95% CL) Neutrino 4 (yr, 95% CL) NEOS (0.5yr, 95% CL) IsoDAR@KamLAND (5yr, 3σ) IsoDAR@C ADS (5yr, 3σ) KATRIN σ KATRIN σ [ev ] [ev ] m 4 m 4 νe & νe DIS β νe & νe DIS β 90% CL 95% CL 90% CL 95% CL sin ϑ ee CeSOX (Gran Sasso, Italy) 44 Ce ν e BOREXINO: L 5-m [Vivier@TAUP05] BEST (Baksan, Russia) 5 Cr ν e L 5-m [PRD 93 (06) 07300] IsoDAR@KamLAND (Kamioka, Japan) 8 Li ν e L 6m [arxiv:5.0530] IsoDAR@C-ADS (Guangdong, China) 8 Li ν e L 5m [JHEP 60 (06) 004] sin ϑ ee STEREO (ILL, France) L 8-m [arxiv:60.00568] SoLid (SCK-CEN, Belgium) L 5-8m [arxiv:5.07835] Neutrino-4 (RIAR, Russia) L 6-m [JETP (05) 578] PROSPECT (ORNL, USA) L 7-m [arxiv:5.00] DANSS (Kalinin, Russia) L -m [arxiv:606.0896] NEOS (Hanbit, Korea) L 4m [Oh@WIN05] KATRIN (Karlsruhe, Germany) 3 H ν e [Mertens@TAUP05] C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 8/5
NEOS@ICHEP06 C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 9/5
data / (H M) 0.90 0.94 0.98.0.06. Our Analysis of NEOS@ICHEP06 Spectrum Best Fit: m 4 =. ev, sin ϑ ee = 0.9.0.0 3.0 4.0 5.0 6.0 7.0 8.0 Prompt Energy [MeV] We did not use the NEOS spectrum data in the 5 MeV bump region. The calculated spectrum may need corrections also elsewhere. To be safe we added 5% uncorrelated uncertainties to all the bins. [CG & Marco Laveder] [ev ] m 4 NEOS Spectrum 68.7% CL (σ) 95.45% CL (σ) 99.73% CL (3σ) sin ϑ ee We fitted the NEOS spectrum with a free normalization constant determined by the fit. χ null χ osc = 3.44 C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5 (.3σ)
Reactor Rates Bugey-3 and NEOS Spectra C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5 Combined Without NEOS 90% CL 95% CL Combined 90% CL 95% CL With NEOS [ev ] m 4 [ev ] m 4 Reactor Rates Bugey 3 Spectrum 3 Best Fit: sin ϑ ee χ null χ osc =. { m 4 =.7 ev sin ϑ ee = 0.3 (.7σ) Reactor Rates Bugey 3 Spectrum NEOS Spectrum 3 Best Fit: sin ϑ ee χ null χ osc =.9 { m 4 = 3.0 ev sin ϑ ee = 0.3 (.9σ)
ν µ ν e and ν µ ν e Appearance LSND MiniBooNE KARMEN NOMAD BNL E776 ICARUS OPERA [ev ] m 4 ν µ ν e 90% CL 95% CL 3 sin ϑ eµ C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5
ν µ and ν µ Disappearance CDHSW: ν µ ATM: ν µ ν µ SciBooNE MiniBooNE: ν µ SciBooNE MiniBooNE: ν µ MINOS: ν µ IceCube: ν µ ν µ m 4 [ev ] 3 sin ϑ µµ C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 3/5
3 Appearance-Disappearance Tension ν e DIS sin ϑ ee 4 U e4 ν µ ν e APP ν µ DIS sin ϑ µµ 4 U µ4 sin ϑ eµ = 4 U e4 U µ4 4 sin ϑ ee sin ϑ µµ [Okada, Yasuda, IJMPA (997) 3669; Bilenky, CG, Grimus, EPJC (998) 47] 3σ ν e DIS ν µ DIS DIS APP ν µ ν e is quadratically suppressed! [ev ] m 4 Similar constraint in 3, 33,..., 3N s [CG, Zavanin, MPLA 3 (05) 650003] 3 GLO σ σ 3σ 4 3 Update of [Gariazzo, CG, Laveder, Li, Zavanin, JPG 43 (06) 03300] with improved treatment of the MiniBooNE background disappearance due to neutrino oscillations according to information from Bill Louis (thanks!) sin ϑ eµ C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 4/5
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 5/5 Collin, Arguelles, Conrad, Shaevitz [NPB 908 (06) 354] Our Fit Update of [Gariazzo, CG, Laveder, Li, Zavanin, JPG 43 (06) 03300] 3 GLO 90% CL [ev ] m 4 Best Fit: m 4 =.75 ev U e4 = 0.07 U µ4 = 0.04 GoF = 57% (χ min /NDF = 306.8/3) GoF null = 4.4% (χ /NDF = 359./35) χ /NDF = 5.3/3 ( 6.7σ) 4 3 sin ϑ eµ Best Fit: m 4 =.6 ev U e4 = 0.08 U µ4 = 0.04 GoF = 6% (χ min /NDF = 304.0/68) GoF null = 0.04% (χ /NDF = 355./7) χ /NDF = 5./3 ( 6.6σ)
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 6/5 Kopp, Machado, Maltoni, Schwetz [JHEP 305 (03) 050] Our Fit Update of [Gariazzo, CG, Laveder, Li, Zavanin, JPG 43 (06) 03300] APP 90.00% CL APP 99.00% CL APP 99.73% CL DIS 90.00% CL DIS 99.00% CL DIS 99.73% CL [ev ] m 4 4 3 Best Fit: m 4 = 0.93 ev U e4 = 0.03 U µ4 = 0.09 GoF = 9% (χ min /NDF = 7/680) GoF PG = 0.0% (χ PG /NDF = 8.0/) sin ϑ eµ Best Fit: m 4 =.6 ev U e4 = 0.08 U µ4 = 0.04 GoF = 6% (χ min /NDF = 304.0/68) GoF PG = 0.06% (χ /NDF = 5.0/)
MiniBooNE Low-Energy Anomaly C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 7/5 ν µ ν e [PRL (009) 80] ν µ ν e [PRL (03) 680] LSND signal LSND signal Fit of MB Low-Energy Excess requires small m 4 and large sin ϑ eµ, in contradiction with disappearance data MB low-energy excess is the main cause of bad APP-DIS GoF PG = 0.06% Multinucleon effects in neutrino energy reconstruction are not enough to solve the problem [Martini et al, PRD 85 (0) 0930; PRD 87 (03) 03009; PRD 93 (06) 073008] Pragmatic Approach: discard the Low-Energy Excess because it is likely not due to oscillations [CG, Laveder, Li, Long, PRD 88 (03) 073008] MicroBooNE is crucial for checking the MiniBooNE Low-Energy Anomaly and the consistency of different short-baseline data
Global Pragmatic C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 8/5 3σ DIS APP GLO APP PrGLO [ev ] m 4 4 3 sin ϑ eµ APP-GLO: all MiniBooNE data APP-PrGLO: only MiniBooNE E > 475 MeV data (Pragmatic)
Pragmatic Global 3 Fit Update of [Gariazzo, CG, Laveder, Li, Zavanin, JPG 43 (06) 03300] ( ) ν e ( ) ν e 3 PrGLO σ σ 3σ ( ) ν µ ( ) ν e 3 PrGLO σ σ 3σ ( ) ν µ ( ) ν µ 3 PrGLO σ σ 3σ [ev ] m 4 [ev ] m 4 [ev ] m 4 3σ ν e DIS 3σ APP DIS 4 3 ν µ DIS (99.73% CL) IceCube () MINOS (95% CL) sin ϑ ee GoF = 4% PGoF = 7% No Osc. disfavored at 6.σ χ /NDF = 46.6/3 sin ϑ eµ Not yet included: IceCube, arxiv:605.0990 MINOS, arxiv:607.076 C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 9/5 sin ϑ µµ
SBL IceCube C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 0/5 [Collin, Arguelles, Conrad, Shaevitz, arxiv:607.000] SBL SBL IceCube Red: 90% CL Blue: 3 m 4 U e4 U µ4 U τ4 N bins χ min χ null χ (dof) SBL.75 0.63 0.7-35 306.8 359.5 5.34 (3) SBLIC.75 0.64 0.9 0.00 54 58.59 568.84 50.6 (4) IC 5.6-0.34-09 07. 09.69.58 ()
The Race for the Light Sterile ( ) ν e ( ) ν e KATRIN σ ( ) ν µ ( ) ν e SBN (3yr, 3σ) nuprism (3σ) JSNS (3σ) ( ) ν µ ( ) ν µ SBN (3yr, 3σ) KPipe (3yr, 3σ) [ev ] m 4 [ev ] m 4 [ev ] m 4 CeSOX (95% CL) Neutrino 4 (yr, 95% CL) BEST (95% CL) PROSPECT phase (3yr, 3σ) IsoDAR@KamLAND (5yr, 3σ) PROSPECT phase (3yr, 3σ) IsoDAR@C ADS (5yr, 3σ) SoLiD phase (yr, 95% CL) DANSS (yr, 95% CL) SoLiD phase (3yr, 3σ) NEOS (0.5yr, 95% CL) STEREO (yr, 95% CL) sin ϑ ee 3 PrGLO σ σ 3σ 4 3 sin ϑ eµ 3 PrGLO σ σ 3σ sin ϑ µµ C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 /5 Effects of light sterile neutrinos should also be seen in: β Decay Experiments [Hannestad et al, JCAP (0) 0, PRC 84 (0) 045503; Formaggio, Barrett, PLB 706 (0) 68; Esmaili, Peres, PRD 85 (0) 730; Gastaldo et al, JHEP 606 (06) 06] Neutrinoless Double-β Decay Experiments [Rodejohann et al, JHEP 7 (0) 09; Li, Liu, PLB 706 (0) 406; Meroni et al, JHEP 3 (03) 46, PRD 90 (04) 05300; Pascoli et al, PRD 90 (04) 093005; CG, Zavanin, JHEP 507 (05) 7; Guzowski et al, PRD 9 (05) 00] Long-baseline Neutrino Oscillation Experiments [de Gouvea et al, PRD 9 (05) 053005, PRD 9 (05) 0730, arxiv:605.09376; Palazzo et al, PRD 9 (05) 07307, PLB 757 (06) 4, arxiv:60.05995, arxiv:603.03759, arxiv:605.0499; Gandhi et al, JHEP 5 (05) 039; Pant et al, arxiv:509.04096, Choubey, Pramanik, arxiv:604.0473] Solar neutrinos [Dooling et al, PRD 6 (000) 0730, Gonzalez-Garcia et al, PRD 6 (000) 03005; Palazzo, PRD 83 (0) 303, PRD 85 (0) 07730; Li et al, PRD 80 (009) 3007, PRD 87, 3004 (03), JHEP 308 (03) 056; Kopp et al, JHEP 305 (03) 050] Atmospheric neutrinos [Goswami, PRD 55 (997) 93; Bilenky et al, PRD 60 (999) 073007; Maltoni et al, NPB 643 (00) 3, PRD 67 (003) 030; Choubey, JHEP 07 (007) 04; Razzaque, Smirnov, JHEP 7 (0) 084, PRD 85 (0) 0930; Gandhi, Ghoshal, PRD 86 (0) 03730; Barger et al, PRD 85 (0) 030; Esmaili et al, JCAP (0) 04, JCAP 307 (03) 048, JHEP 3 (03) 04; Rajpoot et al, EPJC 74 (04) 936; Lindner et al, JHEP 60 (06) 4; Behera et al, arxiv:605.08607] Supernova neutrinos [Caldwell, Fuller, Qian, PRD 6 (000) 3005; Peres, Smirnov, NPB 599 (00); Sorel, Conrad, PRD 66 (00) 033009; Tamborra et al, JCAP (0) 03; Wu et al, PRD 89 (04) 06303; Esmaili et al, PRD 90 (04) 03303] Cosmic neutrinos [Cirelli et al, NPB 708 (005) 5; Donini, Yasuda, arxiv:0806.309; Barry et al, PRD 83 (0) 30] Indirect dark matter detection [Esmaili, Peres, JCAP 5 (0) 00] Cosmology [see: Wong, ARNPS 6 (0) 69; Archidiacono et al, AHEP 03 (03) 947]
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 3/5 Effective 3 LBL Oscillation Probabilities [de Gouvea et al, PRD 9 (05) 053005, PRD 9 (05) 0730, arxiv:605.09376; Palazzo et al, PRD 9 (05) 07307, PLB 757 (06) 4, arxiv:60.05995, arxiv:603.03759, arxiv:605.0499; Gandhi et al, JHEP 5 (05) 039] U e3 sin ϑ 3 0.5 ε = ε 0.03 U e4 sin ϑ 4 0.7 ε U µ4 sin ϑ 4 0. ε α m m 3 7 5 0.03 ε.4 3 At order ε 3 : [Klop, Palazzo, PRD 9 (05) 07307] kj m kj L/4E P LBL ν µ ν e 4 sin ϑ 3 sin ϑ 3 sin 3 ε sin ϑ 3 sin ϑ sin ϑ 3 (α 3 ) sin 3 cos( 3 δ 3 ) ε 3 4 sin ϑ 3 sin ϑ 4 sin ϑ 4 sin ϑ 3 sin 3 sin( 3 δ 3 δ 4 ) ε 3
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 4/5.0 CP Violation in TK and NOνA [Capozzi, CG, Laveder, Palazzo, in preparation, with TK and NOνA data presented at Neutrino 06] 3ν 4ν.0 3ν 4ν δπ 3 δπ 3 0.5 0.0 0.5.0.0 0.5 0.0 0.5 Rea. θ 3 68% 90% 90% 0.095 0. 0.090.0 0.00 0.05 0. 0.5 0.0 0.00 0.05 0. 0.5 0.0 0.085 sin θ 3 sin θ3 0.08 sin 0.09 0.080 Normal hierarchy Inverted hierarchy 0.075.0 0.5 0.0 0.5.0.0 θ 3 sin δπ 3 0.5 0.0 0.5.0.0 0.5 δπ 3 0. 0.0 LBL Reactors.0 0.5 Normal hierarchy 68% 90% 0.09 68% 68%.0 0.07 0.08 0.09 0. 0.07 0.08 0.09 0. sin θ 90% 3 sin θ3 90% 0.08 0.07.0 0.5 0.0 0.5.0.0.0 Inverted hierarchy Normal hierarchy Inverted hierarchy 0.5 0.5 0.5 0.5 Normal Ordering δπ 3 0.0 0.5 0.0 δπ 3 0.0 0.5 0.5 0.0 0.5 Inverted Ordering.0.0.0.0.0 0.5 0.075 0.095 0.09 0.0 0.5.0.0 0.0800.08 0.5 0.085 0.09 0.090 0.5 0..0 0.07 0.08 δπ 4 sin θ 3 δπ 4 sin θ 3 Inverted Ordering: Better agreement of LBL & Reactors for δ 4 π/
C. Giunti Sterile Neutrino Mixing NOW 06 9 Sep 06 5/5 Conclusions Exciting indications of light sterile neutrinos at the ev scale: LSND νµ ν e signal. Gallium νe disappearance. Reactor νe disappearance. Vigorous experimental program to check conclusively in a few years: νe and ν e disappearance with reactors and radioactive sources. νµ ν e transitions with accelerator neutrinos. ν µ disappearance with accelerator neutrinos. Possibilities for the next years: Reactor and source experiments ν e and ν e observe SBL oscillations: big excitement and explosion of the field. Because of 5 MeV bump we know that the calculated spectrum must be corrected: oscillations must be observed as a function of distance! Otherwise: still marginal interest to check the LSND appearance signal. In any case the possibility of the existence of sterile neutrinos related to New Physics beyond the Standard Model will continue to be studied (e.g kev sterile neutrinos: see the talk by A. Merle). Sterile neutrinos will always be allowed at all mass scales below the existing mixing bounds.