Solar Neutrinos & Homestake or Something new under the Sun

1. Solar Neutrinos & Homestakeor Something new under the Sun Kevin T. Lesko Lawrence Berkeley National Laboratory Berkeley, CA

2. Why are Solar Neutrinos in the News? • Discoveries about neutrinos • Key, Critical Piece of the Universe we understand very little about • Neutrinos have Mass (as much all the stars) • Mix between different species (neutrinos are complicated) • 30 year old problem (missing neutrinos) solved! Kevin Lesko

3. p-p Chain “…to see into the interior of a star and thus verify directly the hypothesis of nuclear energy generation in stars.” Phys. Rev. Lett. 12, 300 (1964); Phys. Rev. Lett. 12, 303 (1964) Bahcall and Davis Solar Neutrinos p + p 2H + e+ + ne p+ e- + p 2H +ne 2H + p 3He + g 15% 85% 3He + 3He 4He + 2p 3He + 4He 7Be + g 0.02% 7Be + e- 7Li + ne 7Li + p 4He + 4He 7Be + p 8B + g 8B 8Be* + e+ + ne 8Be* 4He + 4He 3He + p 4He + e+ +ne 4p --> 4He + 2ne + 2e+ + ~25 MeV Kevin Lesko

4. Solar Neutrino Experiments (pre-SNO) GALLEX(Gran Sasso, Italy) SAGE(Baksan, Russia) Super-Kamiokande (Japan) Homestake (S Dakota, USA) Only ne directly observed Kevin Lesko

5. Subsequent 35 years have seen 5 experiments, all measure a deficiency of solar neutrinos The Solar Neutrino Problem Either Solar Models are Incomplete or Incorrect Or Neutrinos Undergo Flavor Changing Oscillations Kevin Lesko

6. 1.0 0.8 n 0.6 m Probabilty n e 0.4 0.2 0.0 0 1 2 3 4 5 6 7 x/losc Example of Two Flavor Oscillations In general, oscillations could explain the missing ns In the example here, sin2 is 0.7. One can solve for values of  and m2 which produce fluxes consistent with measured fluxes on Earth. Kevin Lesko

7. Charged Current • e+de-+p+p • just one flavor of n • Elastic Scattering x+e-x+e- • Neutral Current x+dx+n+p • All flavors of n The Sudbury Neutrino Observatory Large Deep Clean Sensitive

8. Neutrino Appearance Experiment! SSM: BPB Astrophy J 555, 990 2001 fmt (106 cm-2 s-1) fe (106 cm-2 s-1) Kevin Lesko

9. What does this mean? • Neutrinos are massive, solved SNP • Confirmed Solar Model • Neutrinos mix • But not like quarks • Strong Evidence for MSW effects • Found some of the dark matter • As much mass as all luminous matter • New physics • Neutrinos are a new physics frontier • SNO + KamLAND are a beachheads Kevin Lesko

10. No! Are we done? • Absolute mass, what is the mass of a neutrino? • How many neutrinos are there? 3 or more? • Sterile neutrinos? • Are neutrinos their own anti-particle or not? • Neutrinoless double beta decay? • Understanding the full mixing of neutrinos? • Precision Measurements of parameters • q13 of particular interest • CP violation in Leptons? • Extend the Standard Model • Hints for new symmetries & understanding origins of mass Kevin Lesko

11. Physics using the Sun • Oscillation Parameter q12 Are there only 3 neutrinos? How do the neutrinos relate to each other? Why do they mix in the unusual fashion they do? • Magnetic Moments Learn more about the neutrino’s fundamental properties • Solar Physics Learn precisely how the Sun works • Input to other experiments Kevin Lesko

12. Next Generation Solar Neutrino Experiments Low energy (pp) neutrino experiment: • En > 50 keV • Well known f • ES, CC expts • neutrino mb • solar physics Kevin Lesko

13. Connection to Homestake Further experiments are needed to understand neutrinos, some of these require: • Even better shielding from backgrounds (deeper, cleaner, better controlled environments) • Better known sources of neutrinos (Sun is still an excellent source, and it is still free) • Even more difficult experiments But a National Facility helps ALL these experiments Kevin Lesko

14. Why should you (we) care? • Not for Spin-offs - they are great, but not the real reason to do science • Not just because Japan/Europe are doing it - we should listen and watch, but guide ourselves • To understand the world/nature/universe • To ask why and be able to seek and find the answer • Education, next generation benefits from new tools, new ideas, better understanding of nature • To be able to compete in the next century (science and technology) Kevin Lesko

15. Why should we care? • Often big discoveries, big steps in new fields or at the overlap of fields - neutrinos are a good example of this • Economic sense - share site, technology, rather than having redundant sites • Tremendous synergism between experiments and fields not previously explored Kevin Lesko

16. Backup slides Kevin Lesko

17. Kevin Lesko

18. Kashiwazaki Takahama Ohi Why Kamioka? KamLAND uses the entire Japanese nuclear power industry as a Long-baseline source KamLAND 80% of flux from baselines 140 to 210 km Kevin Lesko

20. Solar Neutrinos in the News • 2002 Nobel Physics Prize: Koshiba + Davis (Sweden) • 2003 Fermi Prize: Davis + Bahcall (US) • 2003 Herzberg Prize: MacDonald (Canada) • 2003 Rutherford Prize: Wark (England) • Sudbury Neutrino Observatory • Top 2 discoveries in 2002 • Top 3 cited papers in all physics in 2003 • Generally heralded as proof of new physics Kevin Lesko

21. Hitoshi Murayama Neutrino Physics - Solar n Sudbury Neutrino Observatory - Canada • 5 s appearance experiment • flavor changing SSM Confirmation/ SNP Solution New Physics Kevin Lesko