1 Neutrinos: Past, Present and Future Robert C. Webb Physics Department Texas A&M University Robert C. Webb Physics Department Texas A&M University

May 16, 2007RCW PPC A Brief History of the Neutrino The Early Years……  1930 Pauli proposes a massless neutral particle.  1932 Fermi names the “neutrino”.  1956 The first observation of electron anti- neutrinos by Reines and Cowan.  Possibility that neutrinos oscillate proposed by Pontecorvo and Sakata.  1961 The muon neutrino is observed at BNL. The Early Years……  1930 Pauli proposes a massless neutral particle.  1932 Fermi names the “neutrino”.  1956 The first observation of electron anti- neutrinos by Reines and Cowan.  Possibility that neutrinos oscillate proposed by Pontecorvo and Sakata.  1961 The muon neutrino is observed at BNL.

May 16, 2007RCW PPC Discovering the Neutrino

May 16, 2007RCW PPC Neutrino Physics  The observation of neutrinos by Reines and Cowan ushered in a new era of the study of these elusive “beasts”  Accelerator based measurements undertaken in the US and Europe.  Solar neutrino experiments begun underground.  The observation of neutrinos by Reines and Cowan ushered in a new era of the study of these elusive “beasts”  Accelerator based measurements undertaken in the US and Europe.  Solar neutrino experiments begun underground.

May 16, 2007RCW PPC The triumph of the Electro-Weak Unification While experimentalists set out to study the neutrino, the theorist were busy trying to find a theory for the weak interactions of the neutrino that fit… Weinberg and Salam develop a possible candidate, but it requires a “neutral” weak current as the charged current already seen. While experimentalists set out to study the neutrino, the theorist were busy trying to find a theory for the weak interactions of the neutrino that fit… Weinberg and Salam develop a possible candidate, but it requires a “neutral” weak current as the charged current already seen.

May 16, 2007RCW PPC Theory is working fine..but  The Solar Neutrino problem emerges.  Ray Davis and collaborators with encouragement from John Bachall search for neutrinos from the sun using a giant tank of “cleaning fluid”. (1968)  However, they “see” too few!!  What’s wrong, the theory or the experiment?? or both!!  The Solar Neutrino problem emerges.  Ray Davis and collaborators with encouragement from John Bachall search for neutrinos from the sun using a giant tank of “cleaning fluid”. (1968)  However, they “see” too few!!  What’s wrong, the theory or the experiment?? or both!!

May 16, 2007RCW PPC New experiments emerge to study this question.  All of these measurements found too few solar neutrinos!!  This question will get the ultimate answer in 2003 from the SNO Collaboration!  All of these measurements found too few solar neutrinos!!  This question will get the ultimate answer in 2003 from the SNO Collaboration!

May 16, 2007RCW PPC It’s not just the solar neutrinos that are mis-behaving..  There is an anomaly in the atmospheric neutrino flux as well.  SuperK along with several other undergound experiments see too few muon neutrinos!!  There is an anomaly in the atmospheric neutrino flux as well.  SuperK along with several other undergound experiments see too few muon neutrinos!!

May 16, 2007RCW PPC Super K’s results (1998)  Things make sense if we allow for neutrinos to “oscillate”…

May 16, 2007RCW PPC Two neutrino mixing

May 16, 2007RCW PPC But neutrinos still aren’t cooperating  If there are only 3 neutrinos then there should only be two mass differences!!

May 16, 2007RCW PPC Neutrino mass and mixing

May 16, 2007RCW PPC “precision” experiments to the rescue  NuMI/MINOS at Fermilab  K2K at KEK and in the future… T2K and NOVA  NuMI/MINOS at Fermilab  K2K at KEK and in the future… T2K and NOVA

May 16, 2007RCW PPC MINOS overview  NUMI Beam Line  Near Detector  Far Detector  Beam running  Data Analysis  NUMI Beam Line  Near Detector  Far Detector  Beam running  Data Analysis

May 16, 2007RCW PPC The NuMI beam : MI protons

May 16, 2007RCW PPC NuMI Beam Protons Delivered

May 16, 2007RCW PPC NuMI Beam Performance  Total Integrated POT as of now: >3 10 20, have run at up to 310kW, and up to 4.0 10 13 protons per pulse

May 16, 2007RCW PPC The 3 NuMI Beam Configurations

May 16, 2007RCW PPC MINOS Near Detector  Faster electronics  Partially instrumented:  282 planes of steel  153 planes of scintillator  (Rear part of detector  only used to track muons )  +…..  1 kton total mass  Same basic design steel, scintillator, etc  Some differences, e.g.:

May 16, 2007RCW PPC Typical Neutrino Beam Event

May 16, 2007RCW PPC Near Detector Events (showing multiple events in spill window)

May 16, 2007RCW PPC

May 16, 2007RCW PPC Near Detector CC events

May 16, 2007RCW PPC MINOS Far Detector Running since 2003!!

May 16, 2007RCW PPC The MINOS Far Detector Currently have ~20 kt-yr of Cosmic Ray data. Observing single and multiple muons. LOTS Observed upward going muons (neutrino interaction below the detector). ~300 events in current sample. First physics paper on beam neutrinos submitted to Phys. Rev. Lett. In operation with >2 E 20 Protons on the NuMI target Currently have ~20 kt-yr of Cosmic Ray data. Observing single and multiple muons. LOTS Observed upward going muons (neutrino interaction below the detector). ~300 events in current sample. First physics paper on beam neutrinos submitted to Phys. Rev. Lett. In operation with >2 E 20 Protons on the NuMI target

May 16, 2007RCW PPC A beam neutrino event in the MINOS Far Detector

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May 16, 2007RCW PPC Atmospheric neutrinos

May 16, 2007RCW PPC First results from MINOS

May 16, 2007RCW PPC MINOS data as a function of Energy

May 16, 2007RCW PPC MINOS Sensitivity

May 16, 2007RCW PPC The ultimate sensitivity

May 16, 2007RCW PPC Electron neutrino mixing.. the next target  NOVA and T2K..using accelerator neutrinos.  Daya Bay and Double Chooz…using reactor neutrinos.  NOVA and T2K..using accelerator neutrinos.  Daya Bay and Double Chooz…using reactor neutrinos.

May 16, 2007RCW PPC The Off-Axis concept

May 16, 2007RCW PPC

May 16, 2007RCW PPC Beam Location and Far Detector Siting

May 16, 2007RCW PPC NOvA Far Detector  25 ktons  1984 liquid scintillator planes, no additional absorber (~80% active)  Scintillator cells 3.8 x 6.0 x 1570 cm  Read out from one side per plane with APDs  Expected minimum signal 20pe  25 ktons  1984 liquid scintillator planes, no additional absorber (~80% active)  Scintillator cells 3.8 x 6.0 x 1570 cm  Read out from one side per plane with APDs  Expected minimum signal 20pe 15.7m 110 m

May 16, 2007RCW PPC NOvA Event Simulations One unit is 4.9 cm (horizonta l) 4.0 cm (vertical) One unit is 4.9 cm (horizonta l) 4.0 cm (vertical) + A -> p + 3  ± +  0 + e +A→p  +  - e -  + A -> p +  - Particle ID: particularly “fuzzy” e’s long track, not fuzzy  gaps in tracks (  o ?) large energy deposition (proton?)

May 16, 2007RCW PPC NOvA Near Detector  126 tons of scintillator, 83 tons of steel  23 ton fiducial mass  186 liquid scintillator planes in target, 10 in muon ranger, 1m of steel  Same cell size, same minimum signal  Read out from one side per plane with APDs plus faster electronics than in far detector  126 tons of scintillator, 83 tons of steel  23 ton fiducial mass  186 liquid scintillator planes in target, 10 in muon ranger, 1m of steel  Same cell size, same minimum signal  Read out from one side per plane with APDs plus faster electronics than in far detector

May 16, 2007RCW PPC The Far Detector Site

May 16, 2007RCW PPC Upgrading Proton Source for NOvA  Proton Plan goal (present FNAL accelerator upgrade program) is 390kW (have achieved 310kW with MINOS) Proton Plan 2 uses Recycler as a proton pre-injector  Post-collider era: Use Recycler to accumulate protons from Booster while MI is accelerating, saves time  Recycler momentum aperture is large enough to allow slip- stacking operation in Recycler for up to 12 Booster batches injected  Extracted to MI in a single turn and there re-captured and accelerated  Main Injector will run at its design acceleration rate of 240 GeV/s (1.333 s cycle time)  4.3×10 12 p/batch, 95% slip-stacking efficiency  4.9×10 13 ppp at 120 GeV every 1.333s  700 kW, or 6×10 20 protons per year Now part of NOvA Project!  Proton Plan goal (present FNAL accelerator upgrade program) is 390kW (have achieved 310kW with MINOS) Proton Plan 2 uses Recycler as a proton pre-injector  Post-collider era: Use Recycler to accumulate protons from Booster while MI is accelerating, saves time  Recycler momentum aperture is large enough to allow slip- stacking operation in Recycler for up to 12 Booster batches injected  Extracted to MI in a single turn and there re-captured and accelerated  Main Injector will run at its design acceleration rate of 240 GeV/s (1.333 s cycle time)  4.3×10 12 p/batch, 95% slip-stacking efficiency  4.9×10 13 ppp at 120 GeV every 1.333s  700 kW, or 6×10 20 protons per year Now part of NOvA Project!

May 16, 2007RCW PPC Neutrino Summary MINOS data show  disappearance at low energies at 6.21.27x10 20 Protons on Target) The best fit oscillation parameters are (hep-ex ) Systematic uncertainties on m 2 are ~40% of statistical MINOS continues to take data—still to come: cross sections, e appearance, sterile neutrino search MINOS data show  disappearance at low energies at 6.21.27x10 20 Protons on Target) The best fit oscillation parameters are (hep-ex ) Systematic uncertainties on m 2 are ~40% of statistical MINOS continues to take data—still to come: cross sections, e appearance, sterile neutrino search

May 16, 2007RCW PPC NOvA Prospects  NOA look for e /  transitions at m 2 atm  First hint of  13 being non-zero?  CP violation in absence of matter effects  Matter effects in absence of m sol 2  NOA look for e /  transitions at m 2 atm  First hint of  13 being non-zero?  CP violation in absence of matter effects  Matter effects in absence of m sol 2

May 16, 2007RCW PPC Neutrino future outlook what might we expect to see 50 years hence?  New group of precision experiments b eing planned to study electron neutrino-muon neutrino mixing..  Possibility that there is CP violation in the neutrino sector..  Is the neutrino a Majorana particle or not??  Large underground detectors will allow us to use neutrinos for the study of the earth, dark matter candidates, supernovae, and beyond…  New group of precision experiments b eing planned to study electron neutrino-muon neutrino mixing..  Possibility that there is CP violation in the neutrino sector..  Is the neutrino a Majorana particle or not??  Large underground detectors will allow us to use neutrinos for the study of the earth, dark matter candidates, supernovae, and beyond…