1. NEUTRINOS: PAST PRESENT FUTURE Heidi Schellman @ Frank Merritt Fest 2015 1

2. What we knew in 1971 2  Neutrinos exist (Cowan, Reines 1956)  There are two kinds (Lederman, Schwartz, Steinberger - 1962 )  They may interact through W and Z boson exchange (Glashow, Weinberg, Salaam - 1968)

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4. FERMILAB NALCAL, July 1971 4  NAL, CALTECH JOIN IN NEUTRINO STUDIES (EXPERIMENT 21)  The Caltech-NAL researchers planned to carry their studies on neutrinos up to about 300 BeV. In July 1971, data existed only up to about 10 BeV.  Evidence suggests the W has a mass greater than that of two protons…  The Caltech-NAL experiment …, hoped to produce and detect the particle if its mass is less than about 20 proton masses.

5. Neutral currents observed 1973 5 Gargamelle hadronic neutral current event

6. Weinberg angle measurement: 1997 6

7. What we know now 7  Neutrinos Oscillate!  Solar – Davis 1960’s  Atmospheric – SuperK – 1998  + many others  Neutrinos have Mass (but what is it?)  The mixing angles are largish!   13 - Daya Bay, RENO, Chooz, T2K, MINOS - 2012

8. 8 23 13 12 Precision measurements

9. 9 Summary of experiments  m 2 23  m 2 12

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11. What’s left 11

12. Unknown: Mass hierarchy and mass offset 12 Normal Hierarchy Inverted Hierarchy  m 12  m 23 > 0  m 23 < 0 We know the absolute value of the mass differences but not the minimum mass or the sign of  m 2 23 ?? Interactions with matter can tell the difference.  m 2 12 > 0 is known from solar, sign of  m 2 23 is still unknown

13. By 2035: Mass Hierarchy and CP violating phase – DUNE + HyperK + reactor 13

14. Absolute mass scale may take longer! 14   m 2 13 =.0025 says at least 1 has m > 0.050 eV  Cosmology -  m < 0.23 eV - PLANCK 2015  Direct - m e < 0.200 eV – Katrin 2018?  Neutrino-less 2  decay  If Majorana  And inverted hierarchy Stolen from MR-M at NSAC Workshop

15. Surprises 15  Is there CP violation in the Majorana phases?  Are there more ‘sterile’ neutrino species?  Are there right handed ones?  Are they the dark matter?  Why don’t we know what 95% of the Universe is anyways?

16. Example: MSM 16  3 “light” R-handed neutrinos, keV and GeV mass scales  N 1 is dark matter candidate  N 2 N 3 may be visible in  CCFR/NuTeV  ATLAS/CMS  Beam dump experiments Phys.Rev.Lett. 110 (2013) 6, 061801

17. Neutrinos tell no lies 17  Neutrinos are hard to make  They are hard to find  But once you find them, every one tells you a lot