NEUTRINOS: PAST PRESENT FUTURE Heidi Frank Merritt Fest

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

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FERMILAB NALCAL, July  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.

Neutral currents observed Gargamelle hadronic neutral current event

Weinberg angle measurement:

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

Precision measurements

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

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What’s left 11

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

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

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

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?

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,

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