1. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Very preliminary results of Non Mesonic Weak Decays in FINUDA De Mori Francesca for the FINUDA Collaboration

2. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Outlook:  NMWD in hypernuclei  NMWD in FINUDA  Proton single nucleon spectra of various targets  Rare Decays of  Conclusions and prospects

3. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Non Mesonic Weak Decays In nuclear medium :  N  NN  NN  nNN (15%) Dominant in medium-heavy hypernuclei( A  12 ) Unique opportunity to study the four-baryons weak interaction

4. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 2 6 Li 1 7 Li 3 12 C 1 27 Al 1 51 V 5 cm OSIM ISIM TOF Target Beam pipe FINUDA allows in primis the measurement of emitted nucleon spectra from :

5. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Event selection of NMWD protons  Selected positive tracks from K - vertex with specific energy loss in the band of proton  Presence of pion track from K - vertex required with pion momentum corresponding to the production of the hypernucleus in the bound region

6. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 12 C target 7 Li target 51 V target 27 Al target Preliminary not acceptance-corrected -1.8<B  <11.MeV -3.3<B  <5.6 MeV -1.2<B  <16.8 MeV -0.2<B  <20.2 MeV

7. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Rare Decays of 4  He is unstable Pd~570 MeV/c Pt~510 MeV/c exploiting 6 Li target Some three-four body decay channels Possible 2-body decays of 4  He with charged particles

8. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Deuteron pair of rare decays selection ( 4  He d+d):  Looking for positive tracks from K - vertex  Looking for dE/dx over the proton band  Looking for a pair of tracks of this kind back to back with momentum greater than 400 MeV/c

9. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 PID (dE/dx in vertex silicon detectors) Momentum(MeV/c) dE/dx(OSIM)

10. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Angle between pairs of tracks P>400MeV/c sel.deuterons

11. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 First observation of 4  He d-d rare decay ten deuteron pairs observed

12. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Evento fujoka 2 d d

13. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 d d

14. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 d d 

15. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Conclusions & prospects  First very preliminary results of NMWD in FINUDA: single proton spectra from all 5 different targets  Clear evidence of rare non mesonic decay of 4  He never observed before  needed neutron identification: we are working on it  needed improved backtracking: we are working on it  needed better mass identification for back-tracking for deuteron momenta better reconstruction:we are working on it we are on the way to increase the number of good events

16. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 Contribute to the proton spectrum of the background reaction:

17. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004

18. De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 8 2004 O.Hashimoto et al. Phys.Rev.Lett.88:042503,2002 KEK-PS E307