Context: astroparticle physics, non-accelerator physics, low energy physics, natural sources physics, let’s-understand-the-Universe physics mainly looking for dark matter and neutrinos coupled to astrophysics and cosmology M. Di Marco Queen’s University (Canada) CERN School of Computing Vico Equense (Italy) 2004 Neutrinos physics What is that, why should we care ?

Crash course for computer science people our everyday world is made out of: neutrons (n) protons (p) and electrons (e-) for this talk, two more particles are needed: muon (µ) and neutrinos ( ) muon (µ) : fat twin of the e- produced by cosmic ray showers neutrino ( ) : almost massless produced by the sun, SNe, ect astroparticle physics: keV – MeV energies  HEP (GeV) 

… what is the problem with the neutrinos ? solar model works very well … but half of the are missing ! solution: oscillation are changing flavors since the 60’s, physicists are measuring the flux Presently: 4 large-scale experiments based on the Cerenkov effect particles travelling faster than light in water (impossible in vacuum) produce a shock wave, creating a blue light cone detected with a photomultiplier

Super-Kamiokande Kamioka mine (Japan) AMANDA / IceCube South Pole ANTARES Mediterranée

Sudbury Neutrino Observatory (SNO) 1700 tonnes Inner Shielding H 2 O 1000 tonnes D 2 O 5300 tonnes Outer Shield H 2 O 12 m Diameter Acrylic Vessel Support Structure for 9500 PMTs, 60% coverage Urylon Liner and Radon Seal

One million pieces transported and assembled under ultra-clean conditions. More than 60,000 showers and counting…

Unique Signatures in SNO (D 2 O) Charged-Current (CC) e +d  e - +p+p E thresh = 1.4 MeV e only e only Neutral-Current (NC) x + d  x + n+p E thresh = 2.2 MeV Equally sensitive to e   3 ways to detect neutrons Results: clear evidence for oscillation by a change of appearance measurement for other active neutrino types

0  : (A,Z)  (A,Z+2) + 2e- d d u u e-e- e-e- W-W- W-W- e e  L=2 m ee = |  i U ei ² m i | effective neutrino mass: oscillation  m ≠ 0 only plausible way to measure m : neutrinoless double beta decay extremely rare process … if it’s a majorana particle (if it’s Dirac, tritium experiment is the only way)

Multi-site energy deposition inside HP-Ge diode    Co-60 Energy deposition in surrounding medium HP Ge-diodes enriched in 76 Ge in (optional active) cryogenic fluid shield Line search at Q ββ = 2039 keV … how to detect 0  ?

Problem: natural radioactivity design takes backgrounds into consideration A. Dörr and H.V. Klapdor-Kleingrothaus NIMA 513 Backgrounds dominated by external sources Count rate at Q ββ : ~ / keV kg y Th-232 chain (ext.) U-238 chain (ext.) cosmogenic (ext.) Q ββ

H.V. Klapdor-Kleingrothaus, A. Dietz, O. Chkvorets, I.V. Krivosheina, NIM A, in press simulations are essential to take all sources of background into account geometry design prove that an eventual signal is “real” will help decide on the best technology for the next generation experiment

same issue as for HEP: a tiny signal in a plethora of signal

very positive collaboration developing between Majorana (USA) and “Gerda” (Germany) : agreed to share technical development information pursue the best technology for a next generation experiment at about 120 to 200 kg Status note: there is not even enough Ge in the world to provide 50 kg at the moment

signal extremely rare: detectors to be installed in underground laboratories large mass  international collaborations million dollar experiment tools like CVS and POOL, and software engineering skills (design, testing, validation, etc) become critical to split the work into bits for scientists in different countries to avoid duplicating the work SNOlab to be built next to SNO Conclusion