First …. Hyper-meeting Who we are? (alphabetical order) Michelangelo Agnello (Turin Politechnic, FP) Ilaria Aimo (Turin Politechnic, PhD st.) Elena Botta (Turin University, AP) Stefania Bufalino (INFN-Torino/CERN Fellow) Alessandro Feliciello (INFN-Torino) Stefano Trogolo (Turin University, MTS)

FINUDA: FIsica NUcleare a DAFNE What did we do before? FINUDA: FIsica NUcleare a DAFNE The very first example of a (hyper)nuclear physics fixed-target experiment carried on at a collider (DAFNE @ LNF) Optimized to produce hypernuclei ALZ in a completely new way FINUDA

Hypernuclear Physics @FINUDA e+ + e-  f (1020)  K+ + K- (127 MeV/c) K-stop + AZ  ALZ + p- ALZ A(Z+1) + p- ALZ A-2(Z-1) + p + n ALZ A-3(Z-1) + p + n + n Spectroscopy Gp- MWD 1N induced Gp NMWD 2N induced Gnp FINUDA key features - different targets in the same run ➥ high degree of flexibility - simultaneous tracking of μ+ from the K+ decay ➥ energy and rate calibration transparency ➥ “high” resolution spectroscopy - very thin targets (0.1 ÷ 0.3 g/cm2) - coincidence measurement with large acceptance complete event ➥ decay mode study

The FINUDA detector e+ e- Detector capabilities: Selective trigger based on fast scintilla- tion detectors (TOFINO, TOFONE) precise K- vertex identification (~ 1 mm3) (ISIM P.ID.+ x,y,z resolution + K+ tagging) p, K, p, d, … P.ID. (OSIM and LMDC dE/dx) High momentum resolution (6‰ FWHM for π- @270 MeV/c for spectroscopy) (1% FWHM for p- @270 MeV/c for decay study) (6% FWHM for π- @110 MeV/c for decay study) (2% FWHM for p @400 MeV/c for decay study) (tracker resolution + He bag + thin targets) Neutron detection TOF (TOFONE-TOFINO) Outer scintillator barrel – 72 slabs (TOFONE) e+ e- Super- conducting Coil Mechanical support (clepsydra) For: 2424 Straw Tubes (longitudinal + stereo) 16 Low-Mass Drift Chambers (LMDC) 18 m-strip vertex detectors (ISIM/OSIM) Inner scintillator barrel – 12 slabs (TOFINO) 8 Targets Simultaneous study of formation and decay of strange hadronic systems by full event reconstruction Apparatus designed for a typical collider experiment: Cylindrical geometry large solid angle (~ 2p sr) multi-tracks analysis

And now … in ALICE Analysis strategy for hypernuclei search-> to study the 3LH via its mesonic weak decay 3LH -> 3He + p- Particle identification Track selections Topological cuts

Analysis Selections Track Selection • TPC refit; •( (ITS refit … in the future ..) • # TPC cluster >= 70 • Chi2/NDF < 4; •|HeEta|<0.8; •|PionEta|<0.8; •|zPrimaryVertex|<10 cm; PID with TPC information stored in the OADB Helium tracks -2<=ns<=3; Pions tracks |ns|<=2; Topological cuts He DAC from primary vertex > 0.02 cm; Pion DCA from primary vertex > 0.4 cm; DCA tracks < 0.7 cm; • Cos(Pointing angle)>0.99

(3He+p-) Invariant mass spectrum WORK IN (SLOW) PROGRESS!!!!

To do and to think about … more systematics …. background fitting/treatment new PID not yet used ….. cut on regenerated 3He non applied … vtx2 finding and fitting: V0 code copied in the task …. better solution? Asymmetry in nuclei/antinuclei production (only material regeneration?) 4LH? Other “strange” nuclei?