1. First observation of the heavy hyper-hydrogen isotope 6  H XIV International Conference on Hadron Spectroscopy Elena Botta INFN – Sezione di Torino & Universita’ di Torino for the FINUDA Collaboration

2. Talk outline n-rich hypernuclei FINUDA @ DA  NE LNF-INFN n-rich hypernuclei search with FINUDA Previous results (partial statistics) Present results (global statistics): preliminary production rate and binding energy determination (preliminary) XIV International Conference on Hadron Spectroscopy

3. n-rich hypernuclei: physics motivations  -hypernuclei: –nuclear core compression ( 7  Li vs 6 Li: H.Tamura et al., Phys.Rev.Lett. 84 (2000) 5963 –  extra binding energy good candidates to show n excess and n halo tool to obtain infos on b-b interaction in low-density nuclear matter  NN force rôle (increasing with N/Z) connections with nuclear astrophysics extension of the Strange Nuclei chart S. Ajimura et al. Proposal for P10 – J-PARC directly produced hyperfragments SCXDC X XIV International Conference on Hadron Spectroscopy

4. (K - stop,  + ) K - + p   +  0  0 + p  n +  + (2-step) K - + p    +  +   + p  n +  (1-step) K.Kubota et al, NPA 602 (1996) 327. 9  He ( 9 Be) U.L.=2.3 10 -4 /K - stop ; 12  Be( 12 C) U.L.=6.1 10 -5 /K - stop ; 16  C( 16 O) U.L.=6.2 10 -5 /K - stop T.Y.Tretyakova et al., Nucl. Phys. A 691 (2001) 51c (  -, K + )  - + p   0 + n  0 + p   + K + (2-step)  - + p  K 0 +  K 0 + p  n + K + (2-step)  - + p  K + +  -  - + p  n +  (1-step) P.K.Saha et al., PRL 94 (2005) 052502: 10  Li ( 10 B) d  /d  = 11.3±1.9 nb/sr T.Y.Tretyakova et al., Phys. At. Nucl. 66 (2003) 1651 n-rich hypernuclei (  np -2 states): production XIV International Conference on Hadron Spectroscopy

5. n-rich hypernuclei: 6  H L. Majling, NPA 585 (1995) 211c - binding energy - prod. rate ~ 10 -2 * hyp. prod. rate in (K - stop,  - ) Y. Akaishi et al., AIP Conf. Proc. 1011 (2008) 277 K.S. Myint, et al., Few Body Sys. Suppl. 12 (2000) 383 Y. Akaishi et al., Frascati Phys. Series XVI (1999) 16 “coherent”  coupling in 0+ states   NN three body force 5.8 MeV XIV International Conference on Hadron Spectroscopy 4.2 MeV

6. FINUDA @ DA  NE LNF-INFN Detector Detector capabilities: Selective trigger based on fast scintillation detectors (TOFINO, TOFONE) Clean K - vertex identification (ISIM P.ID.+ x,y,z resolution + K + tagging) , K, p, d, … P.I.D. (OSIM&LMDs dE/dx, TOF) High momentum resolution (6‰ FWHM for  - @270 MeV/c for spectroscopy) 1% FWHM for  + @250 MeV/c 2 % FWHM for  - @130 MeV/c for MWD study ( tracker resolution + He bag + thin targets) Solid angle ~ 2  srad Detector Detector capabilities: Selective trigger based on fast scintillation detectors (TOFINO, TOFONE) Clean K - vertex identification (ISIM P.ID.+ x,y,z resolution + K + tagging) , K, p, d, … P.I.D. (OSIM&LMDs dE/dx, TOF) High momentum resolution (6‰ FWHM for  - @270 MeV/c for spectroscopy) 1% FWHM for  + @250 MeV/c 2 % FWHM for  - @130 MeV/c for MWD study ( tracker resolution + He bag + thin targets) Solid angle ~ 2  srad 2003 data taking: 190 pb -1 (2 x 6 Li, 7 Li, 3 x 12 C, 27 Al, 51 V) 2006 data taking: 966 pb -1 (2 x 6 Li, 2 x 7 Li, 2 x 9 Be, 13 C, D 2 O) e + + e -   (1020)  K + + K - (127 MeV/c) K - stop + A Z  A  Z +  - Solenoid: B=1T XIV International Conference on Hadron Spectroscopy

7. n-rich hypernuclei search with FINUDA: previous results XIV International Conference on Hadron Spectroscopy M.Agnello et al., PLB 640 (2006) 145 2003-2004 data sample background: K - + p   + +  -  +  n  + (~130-250 MeV/c) K - + pp   + + n  +  n  + (~100-320 MeV/c) cut on K - /  + distance production rate/stopped K - : U.L. (90% CL) 6  H: (2.5 ± 0.4 stat +0.4 -0.1sys ) 10 -5 7  H: (4.5 ± 0.9 stat +0.4 -0.1sys ) 10 -5 K - stop + 6 Li  6  H +  + K - stop + 7 Li  7  H +  +

8. 6  H search with FINUDA from: “Proposal for a new FINUDA data taking” FINUDA Collaboration February 2008 2006-2007 data sample: 5x statistics K - stop + 6 Li  6  H +  + (251-254 MeV/c) INCLUSIVE MEASUREMENT K - stop + 6 Li  6  H +  + (251-254 MeV/c) 6  H  6 He +  - (60-160 MeV/c) COINCIDENCE MEASUREMENT XIV International Conference on Hadron Spectroscopy

9. 6  H search with FINUDA K - stop + 6 Li  6  H +  + (250-254 MeV/c) 6  H  6 He +  - (60-160 MeV/c) no evident signal/structure low production rate  new strategy XIV International Conference on Hadron Spectroscopy

10. K - stop + 6 Li  6  H +  + 6  H  6 He +  - M(K - ) + 3 M(n) + 3M(p) – B( 6 Li) = M( 6  H) + T( 6  H) + M(  + ) + T(  + ) M( 6  H) = 4 M(n) + 2M(p) – B( 6 He) + T( 6 He) + M(  - ) + T(  - ) T(  + ) + T(  - ) = M(K - ) + M(p) – M(n) – B( 6 Li) + B( 6 He) –T( 6 He) – T( 6  H) – M(  + ) – M(  - ) = 203 ± 1.3 MeV (203.5÷203.2 MeV with B  = 0÷6 MeV) cut on T(  + ) + T(  - ): 202÷204 MeV independent reactions: decay at rest 6  H search with FINUDA XIV International Conference on Hadron Spectroscopy

11. selection: T(  + )+T(  - ) = 202÷204 MeV XIV International Conference on Hadron Spectroscopy Preliminary absolute energy scale:  +(235 MeV/c) from K  2  p = 0.2 MeV/c

12.  - momentum (MeV/c)  + momentum (MeV/c) 3 candidate events 2.7 10 7 K - stop events 249÷255 MeV/c (  p =1.1 MeV/c) 130÷138 MeV/c (  p =1.2 MeV/c) XIV International Conference on Hadron Spectroscopy Preliminary

13. 1 candidate event ++ -- XIV International Conference on Hadron Spectroscopy Preliminary (251.3±1.1 MeV/c) (135.1±1.2 MeV/c)

14. Background sources: fake coincidences:  +(249÷255 MeV/c) &  - (130÷138 MeV/c) K - stop + 6 Li   + +  - + 4 He + n (end point ~190 MeV/c)  +  n +  + (end point ~282 MeV/c) K - stop + 6 Li  4  H + n + n +  + (end point ~252 MeV/c) 4 He +  - (p(  - ) = 133 MeV/c) K - stop + 6 Li   0 + 6  He different 6  He  6 Li +  - (p(  -) = 108.5 MeV/c) 6 Li  0 + 6 Li  6  He +  + (end point 278 MeV/c) nuclei (  (  0 )) K - stop + 6 Li  3  H +  + + n + n + n (end point 242 MeV/c) 3  H  3 He +  - (p(  -) = 115 MeV/c) K - stop + 6 Li  3 He + n + n +  +  + (T tot < 182 MeV)   n  - K - stop + 6 Li  3 He +  + + n + n +  - (T tot < 180 MeV)  +  n +  + 6  H/K - stop production rate XIV International Conference on Hadron Spectroscopy

15. Preliminary Background evaluation: fake coincidences: T tot (202÷204 MeV) &  + (249÷255 MeV/c) &  - (130÷138 MeV/c) for targets other than 6 Li 1 event for all other targets  0.27±0.27 bgd events on 6 Li = BGD1 K - stop + 6 Li   + +  - + 4 He + n (end point 190 MeV/c)  +  n +  + (end point 282 MeV/c) Monte Carlo simulation of the process (detector acceptance, trigger, PR, reconstruction, PId, selections ) 1 event for 2.3 10 6 K - stop from MC * BR(K - stop p   +  - ) * [1 - (  + n  p)] * BR(  +  n  + ) * BR( 4 He + n)  0.48 ± 0.48 bgd events on 6 Li = BGD2 Vander Velde-Wilchet et al., Nucl.Phys. A241 (1975) 511 12 C Katz et al., Phys. Rev. D 1 (1970) 1267 4 He H.Outa, Ph.D. thesis: 4 He BR( 4 He + n ) = 100% 6  H/K - stop production rate XIV International Conference on Hadron Spectroscopy

16. 6  H/K - stop production rate Background evaluation: K - stop + 6 Li  4  H + n + n +  + (end point 252 MeV/c) 4  H  4 He +  - (p(  - ) = 133 MeV/c) Monte Carlo simulation of the process (detector acceptance, trigger, PR, reconstruction, Pid, selections ) 2 events for 1.6 10 6 K - stop from MC * BR( 4  H hyperfr. production on 7 Li) * (P CEX (  N)) 2  0.025 bgd events on 6 Li = BGD3 H.Tamura et al., Phys. Rev. C 40 (1989) R479 P CEX (  N) =  totCEX  nucl N A /A x = 0.16  totCEX = 30 mbarn Jenefsky et al., Nucl. Phys. A 290 (1977) 407 x= R 0 A 1/3 = 2.36 10 -13 cm 6 Li radius XIV International Conference on Hadron Spectroscopy Preliminary

17. 6  H/K - stop production rate XIV International Conference on Hadron Spectroscopy R = (events – BGD1 – BGD2 – BGD3) (  (  -)) -1 (  (  +)) -1 / (n. K - stop on 6 Li)  (  ) =  D  MC R = (1.2 ± 0.8) 10 -6 /K - stop BGD2: work in progress !! BGD3: work in progress … 6 Li target purity ~ 90%  R = (1.3 ± 0.9) 10 -6 /K - stop selection cut vs T res.  R = (2.3 ± 1.6) 10 -6 /K - stop (2.5 ± 0.4 +0.4 -0.1 ) 10 -5 /K - stop Systematic error: work in progress Very preliminary !!

18. kinematics T tot (MeV) T(  + ) (MeV) T(  - ) (MeV) p(  + ) (MeV/c) p(  - ) (MeV/c) M( 6  H) formation (MeV/c 2 ) M( 6  H) decay (MeV/c 2 ) 202.5±1.3147.86±0.9 6 54.67±0.84251.3±1.1135.1±1.25802.33±0.965801.41±0.84 202.7±1.3146.79±0.9 6 55.94±0.84250.0±1.1136.9±1.25803.45±0.965802.73±0.84 202.1±1.3150.11±0.9652.01±0.84253.8±1.1131.2±1.25799.97±0.965798.66±0.84 5799.64 5801.24 5801.70 5803.74 5805.44 MeV 5 H +  3 H + n + n +  4  H + n + n Majling Akaishi XIV International Conference on Hadron Spectroscopy mean value = 5801.43±0.74 Preliminary

19. …… thank you!