Status of neutrino oscillations with a light sterile

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Status of neutrino oscillations with a light sterile

Christoph Andreas Ternes

IFIC, Universitat de València/CSIC

H2020 Oscillation Physics Workshop, IFIC

Paterna, November 28

^th

, 2018

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Standard model of particle physics

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Standard model of particle physics

3ν in SM

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Standard model of particle physics*

We know they have masses and they mix

3ν in SM

*with massive neutrinos

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Three-neutrino oscillations

Talk by Mariam Tórtola!

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Phys.Lett. B782 (2018) 633-640, P.F. de Salas, D.V. Forero, CAT, M. Tórtola, J.W.F. Valle https://globalfit.astroparticles.es/

See also: -Bari-group ( Prog.Part.Nucl.Phys. 102 (2018) 48-72 ) -Nu-fit ( 1811.05487 )

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Remaining unknowns are

Atmospheric octant Value of CP-phase

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Three-neutrino oscillations

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Neutrino mass ordering

JCAP 1803 (2018) no.03, 011, S. Gariazzo, M. Archidiacono, P.F. de Salas, O. Mena, CAT, M. Tórtola

Front. Astron. Space Sci. 5 (2018) 36, P.F. de Salas, S. Gariazzo, O. Mena, CAT, M. Tórtola

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Neutrino mass ordering

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Combine with data from decay experiments and cosmological observation using conservative priors to obtain 3.5σ preference for normal ordering

JCAP 1803 (2018) no.03, 011, S. Gariazzo, M. Archidiacono, P.F. de Salas, O. Mena, CAT, M. Tórtola

Front. Astron. Space Sci. 5 (2018) 36, P.F. de Salas, S. Gariazzo, O. Mena, CAT, M. Tórtola

3.4σ 3.5σ 3.2σ

3.2σ

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Anomalies in oscillations

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LSND

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Appearance of electron antineutrinos from a pure source of muon antineutrinos for energies 20 MeV < E < 52.8 MeV over 30m

LSND

PRL 75 (1995) 2650 PRC 54 (1996) 2685 PRL 77 (1996) 3082 PRD 64 (2001) 112007 Karmen

PRD 65 (2002) 112001

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LSND

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Appearance of electron antineutrinos from a pure source of muon antineutrinos for energies 20 MeV < E < 52.8 MeV over 30m

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LSND saw a 3.8σ excess

LSND

PRD 65 (2002) 112001

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LSND

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Appearance of electron antineutrinos from a pure source of muon antineutrinos for energies 20 MeV < E < 52.8 MeV over 30m

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LSND saw a 3.8σ excess

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No signal seen by Karmen at 18m (same technique)

LSND

PRD 65 (2002) 112001

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Gallium anomaly

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Gallium Radioactive Source Experiments Gallex and Sage

PRC 73 (2006) 045805, SAGE PRC 80 (2009) 015807, SAGE

Nucl.Phys.Proc.Suppl. 168 (2007) 344, Laveder et al

PRD 78 (2008) 073009 and PRC 83 (2011) 065504, C. Giunti et al

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Gallium anomaly

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Measure electron neutrinos

PRC 73 (2006) 045805, SAGE PRC 80 (2009) 015807, SAGE

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Gallium anomaly

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Measure electron neutrinos

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~3σ deficit of neutrinos

PRC 73 (2006) 045805, SAGE PRC 80 (2009) 015807, SAGE

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Reactor Antineutrino Anomaly

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New reactor antineutrino fluxes, again ~3σ deficit

PRD 83 (2011) 073006, Mention et al PRC 83 (2011) 054615, Mueller et al PRC 84 (2011) 024617, Huber

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Beyond three-neutrino oscillations

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We can add a forth neutrino

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This neutrino must be sterile, which means it is a

singlet under all standard model gauge groups

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This neutrino must be sterile, which means it is a singlet under all standard model gauge groups

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A forth active neutrino is excluded by observations of invisible Z-decays

Phys. Rept. 427 (2006) 257, LEP

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Effective 3+1 oscillations

We extend the mixing matrix

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Effective 3+1 oscillations

DISappearance

@Reactors and Gallium

@atmospherics and accelerators

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DISappearance

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We extend the mixing matrix

DISappearance

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APPearance DISappearance

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APPearance

@LSND, Karmen, MiniBoone, Opera

DISappearance

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APPearance

@LSND, Karmen, MiniBoone, Opera

Quadratically suppressed

DISappearance

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Current status of 3+1 oscillations

JHEP 1706 (2017) 135, S. Gariazzo, C. Giunti, M. Laveder, Y.F. Li

Phys.Lett. B782 (2018) 13-21, S. Gariazzo, C. Giunti, M. Laveder, Y.F. Li PRELIMINARY, S. Gariazzo, C. Giunti, M. Laveder, Y.F. Li, CAT

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Reactor fluxes

Double Chooz, arxiv:1406.7763 Daya Bay, arxiv:1508.04233 RENO, arxiv:1511.05849

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Huber-Mueller-fluxes do not predict the “bump”

Reactor fluxes

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The “bump” cannot be explained by sterile neutrino oscillations, because they should be washed out at these distances

Reactor fluxes

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The “bump” cannot be explained by sterile neutrino oscillations, because they should be washed out at these distances

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We need a model-independent procedure, taking only ratios of fluxes at different distances

into account

Reactor fluxes

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Electron (anti)neutrino disappearance

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NEOS

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Single detector, taking ratio to Daya Bay

PRL 118 (2017) 121802

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DANSS

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Single movable detector, ~3σ preference for 3+1

arXiv:1804.04046

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Fit of disappearance data

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DANSS / NEOS

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Perfect agreement at

See also: JHEP 1711 (2017) 099, Dentler, M. et al Phys.Lett. B782 (2018) 13-21

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DANSS / NEOS + Gallium + RAA

Small tension between NEOS/DANSS and

Gallium and RAA

Phys.Lett. B782 (2018) 13-21

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All data:

Fit is dominated by NEOS/DANSS

Phys.Lett. B782 (2018) 13-21

Fit of disappearance data

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Muon (anti)neutrino disappearance

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IceCube and DeepCore

PRL 117 (2016) 071801

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High-energy regime

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0.3 TeV – 20 TeV

PRL 117 (2016) 071801

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High-energy regime

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0.3 TeV – 20 TeV

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Waiting for 7 yr update!

PRL 117 (2016) 071801

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High-energy regime

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0.3 TeV – 20 TeV

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PRL 117 (2016) 071801 PRD 95 (2017) 112002

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IceCube and DeepCore

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High-energy regime

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0.3 TeV – 20 TeV

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Low-energy regime

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6 GeV – 56 GeV

PRL 117 (2016) 071801 PRD 95 (2017) 112002

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IceCube and DeepCore

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High-energy regime

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0.3 TeV – 20 TeV

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Low-energy regime

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6 GeV – 56 GeV

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Also constraining

PRL 117 (2016) 071801 PRD 95 (2017) 112002

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MINOS/MINOS+

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Two analyses: far-over-near ratio, and two-detector fit

PRL 117 (2016) 151803 arxiv:1710.06488

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MINOS/MINOS+

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Two analyses: far-over-near ratio, and two-detector fit

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For large mass splittings: systematic dominated

PRL 117 (2016) 151803 arxiv:1710.06488

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All data:

MINOS/MINOS+

dominates at small mass splittings

PRELIMINARY

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Electron (anti)neutrino appearance

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MiniBoone

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MiniBoone was built to check the LSND results with a different baseline, but similar L/E

ArXiv:1805.12028

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MiniBoone

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MiniBoone has no near detector

ArXiv:1805.12028

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MiniBoone

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MiniBoone has no near detector

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MiniBoone sees an excess in neutrino and antineutrino mode, which cannot be explained with sterile oscillations

ArXiv:1805.12028

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All data:

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The best fit value of MiniBoone is

excluded by Icarus and Opera

PRELIMINARY

Fit of appearance data

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All data:

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The best fit value of MiniBoone is

excluded by Icarus and Opera

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LSND and

MiniBoone only partially agree

PRELIMINARY

Fit of appearance data

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Tension in APP vs DIS data

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Data before 2018

JHEP 1706 (2017) 135, S. Gariazzo, C. Giunti, M. Laveder, Y.F. Li

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PRELIMINARY

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Data 2018

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Data 2018

PRELIMINARY

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JHEP 08 (2018) 010, Dentler, M. et al

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A global 3+1 fit is unacceptable

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A global 3+1 fit is unacceptable

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Only removing either ALL -DIS-data or LSND

makes the fit acceptable

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Model-independent indication of light sterile neutrino oscillations in very short-baseline reactor experiments

Conclusions

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Model-independent indication of light sterile neutrino oscillations in very short-baseline reactor experiments

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Nothing seen in muon neutrino disappearance experiments

Conclusions

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This leads to very strong bounds on , but also to first bounds on

Conclusions

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APP-DIS tension makes the complete 3+1 global fit unacceptable

Conclusions

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APP-DIS tension makes the complete 3+1 global fit unacceptable

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What are LSND and MiniBoone observing?

Systematics or new physics?

Conclusions

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Thank you!