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

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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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 :

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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

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

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

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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June Evento fujoka 2 d d

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June d d

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June d d 

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June 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

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

De Mori Francesca,Turin University and INFN DAFNE04 Frascati, June

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