1. Torino, October 23-28, 2000 FINUDA @ DA  NE PRESENT STATUS AND POSSIBLE UPGRADES The FINUDA idea; DA  NE machine status; FINUDA detector: characteristics, performances and status; FINUDA possible upgrades! The FINUDA idea; DA  NE machine status; FINUDA detector: characteristics, performances and status; FINUDA possible upgrades!

2. FI.NU.DA. FIsica NUcleare a DA  NE FI.NU.DA. FIsica NUcleare a DA  NE A fixed target experiment carried out at a collider Main physics idea Non-mesonic decay High resolution spectroscopy High resolution spectroscopy low energy (16 MeV) monochromatic tagged low energy (16 MeV) monochromatic tagged  Target thicknessVery thin (0.1g/cm 2 )Thick(some g/cm 2 ) Resolution on hypernuclear levels~700 KeV~1-2 MeV AcceptanceLarge (Collider exp.)Small (Fixed target) Hypernuclei characteristics Many hyp. levels as for (  +, K + ) Only substitutional levels DA  NE K - beam K - extracted beams Projectile momentum P lab (GeV/c) Hyperon momentum (MeV/c)  L = 0 o    n      n    p   K - at rest is equivalent to  + K - at rest is equivalent to  + Momentum resolution 1.63 MeV FWHM

3. Both hypernucleus spectroscopy and hypernucleus decay can be studied in the same experiment Non-mesonic decay n p  Scintillator barrel neutron detector Low mass drift chambers Straw tube array Microvertex silicon  strips 1.1 Tesla solenoid He bags KK KK 270 MeV/c

4. KLOE CP, CPT violation chiral dynamics... and more FINUDA Hypernuclear physics FINUDA Hypernuclear physics DEAR   N scattering     (49%)   S   L (34%)  (13%) Source of monochromatic, collinear and taggable background free neutral and charged kaons Source of monochromatic, collinear and taggable background free neutral and charged kaons DA  NE Hall

5. Machine Design Parameters Single beam energy0.51 GeV Horizontal crossing angle10 – 15 mrad Beta function @ IP (V/H)4.5/450 cm Max num. of particles per bunch8.9 10 10 Beam-beam tune shift (Max)(V/H)0.04/0.04 bunch legth (r.m.s.)3 cm Hor. beam size @ crossing (r.m.s.)2 mm Vert. beam size @ crossing (r.m.s.) 20  m Max number of bunches120 Ring length97.69 m Crossing frequency368.263 MHz Machine layout To get HIGH LUMINOSITY !! n1 n2n1 n2  x  y L 0 = f

6. 1998 In November commissioning was completed with two temporary IR. 1999 At the beginning of the year KLOE and DEAR were rolled-in. The first physics events were observed at IR1 in mid April. 1 month of run ~ 2.5 pb -1. Few collision also in IR2 for DEAR. DA  NE Chronicle 2000 Vacuum accident! After reparation only machine development trying to improve luminosity and to reduce background. Main background source is Touscheck effect Big instabilities Beams blow-up L 0 = 2·10 29 cm -2 s -1 L 0 = 10 30 cm -2 s -1 coupling ~.002% Design param. were achieved N lost  n2n2  3  V Number of particles per bunch EmittanceRelativistic factor Beam volume 2000 DAFNE Integrated Luminosity

7. DA  NE present situation DA  NE history 9-10-2000 Single bunch luminosity: L 0 = 4·10 29 cm -2 s -1 Top multibunch luminosity: L = 1.3·10 31 cm -2 s -1 (with 45 bunches) Per day luminosity: 200  300 nbarn -1 Collisions are made in only one IR at time. DA  NE machine design is similar to PEP-II and KEKB but Energy is lowerdimension is smaller magnetic lattice has less elements e  .51 GeV 9 GeV 8 GeV e  .51 GeV 3 GeV 3.5 GeV 97.7m 2.2Km 3Km 53 ~450 ~300 quad./ring

8. DA  NE perspectives The injection kickers have been rebuild with damping antennas for the offending parasitic modes. New RF cavities are under study as well as a transverse feedback to cope with instabilities due to the high currents. Coupling at the IR is under study in order to overcome present limitations on single bunch luminosity. A lot of work is in progress…

9. The FINUDA apparatus

10. Bari University and INFN Brescia University INFN Frascati National Laboratories Pavia University and INFN Torino University, Politecnico, CNR and INFN Trieste University and INFN TRIUMF Vancouver Victoria University Shahid Beheshty University, Teheran National Center for Physics, Islamabad

11. FINUDA Detector High resolution magnetic spectrometer with cylindrical geometry, optimized for: large  (~ 2p sr) good  p/p (~ 0.3%) dedicated Triggers FINUDA Components S.C. solenoid: (r=146 cm, L=211 cm) B = 1.1 T field homogeneous within 2% inside the tracking volume. Interaction/target region: makes the selection of K + - K - pairs, produces and detects hypernuclei. External tracking device: measures charged particles trajectories and momenta with high precision. External scintillator barrel: cooperate to trigger and detect neutrons. Helium gas chamber: reduce particles multiple scattering.

12. TOF: (Time Of Flight) 12 NE102A scintillator slabs (200  31  2.3) mm 3 topological and dE/dx trigger on (     ) and ( e +, e   slow down   to be stopped in the target time resolution 250 ps FWHM ISIM & OSIM: (Inner/Outer Silicon Module) double sided 300  m thick microstrip modules spatial resolution 30  m energy resolution 20% FWHM TARGET: 12 C, 6 Li thin targets (  0.1 g  cm -2 ) BEAM PIPE: Be 400  m thick  /p 408 MeV/c  ~ MIP; p ~ 6 MIP  /p 408 MeV/c  ~ MIP; p ~ 6 MIP The Interaction/Target Region OSIM ISIM TARGET TOF BEAM PIPE K  K +      BEAM PIPE ISIM OSIMInteraction vertex TOF TARGET   KK KK

13. The Tracking Device ee ee OSIM LMDC ST TOF Bhabha event LMDC: (Low Mass Drift Chambers) planar chambers with an He based gas mixture (He-C 4 H 10 70-30) spatial resolutions:  ( ,  )  150  m;  z 1% wire length ST: (Straw Tubes) 6 layers of 30  m mylar ST filled with Ar-Eth (50-50) spatial resolutions:  ( ,  )  100  m;  z = 500  m TOF: (Time of Flight) 72 scintillator slabs with mainly trigger duties will be used to detect neutron from n.m. decay with efficiency ~ 10 % and energy resolution 8 MeV 2424 straw tubes  = 15 mm, L = 255 cm  p/p 0.3% FWHM He atmosphere

14. Low Mass Drift Chamber 123 cm (187 cm) 39.6 cm (68.6 cm) Anode wire 3.00  0.05 Cathode wires Field wire Cathode wires Aluminised mylar (12  m) 6.00  0.05 External mylar (50  m) External mylar (6  m) 6.00  0.05 50.00  0.03 Drift cell layout Mean resolution of all cells over all angles and over all z

15. Straw Tube Signal/HV cable Pre-amplifier Feed-trough assembly DMEAr+C 2 H 6 50 + 50 Ar+CO 2 50 + 50 Max. Lorentz angle (1.1 T) Negligible Saturated drift velocity NoYes FlammableYes No Material ageingYesNo HV plateau length (V) 100030050 Space resolution (  m) 40100150 DME Ar 50 – CO 2 50 Ar 50 – Eth 50

16. The He-gas chamber The whole tracking volume of FINUDA (8m 3 ) is filled with an Helium atmosphere FINUDA momentum resolution  p/p is: 0.3% in He  1.5% in air FINUDA momentum resolution  p/p is: 0.3% in He  1.5% in air gas leak avoided by o-ring sealing, adhesive mylar tape and silicone gas leak avoided by o-ring sealing, adhesive mylar tape and silicone 14 12 10 8 6 4 2 0 He-chamber test 51015202530 0 time [h] Oxygen % in He PET, PA, PC, EVOH layers PET, PA, PC, EVOH layers With an He flow rate 900l/h leak rate < 130ml/s

17. External scintillator barrel Acceptance 29%; Energy resolution 1.3 MeV at 80 MeV; Time Of Flight acc. (FWHM) 700 ps Neutron reconstruction efficiency: Detection efficiency GeV Fit  = 2.6 MeV E ric - E gen -0.02-0.0100.010.02 160 140 120 100 80 60 40 20 0 Entries Neutron energy reconstruction Proton reconstruction efficiency: 72 slabs of BC408 mainly used to improve trigger capability

18. neutron kinetic energy 00.050.150.1 GeV 0 300 100 200 proton kinetic energy 00.050.150.1 GeV 0 70 10 20 30 40 50 60 FINUDA Physics program Study of non-mesonic decay: - evaluation of  p,  n - possibility to select exclusive states 6  Li  5  He + p - measurement of the energy spectra of non- mesonic decay products Light hypernuclei mesonic decay study Energy res. 1.45 MeV FWHM Energy res. 0.7 MeV FWHM Measurement of the excitation spectrum with resolution < 1 MeV C 12  High statistic study of p-shell hypernuclei,   and ( using a 6 Li target) Li 7  Be 9  B 10  He 5 

19. FINUDA capabilities This reaction produce the same particles of the n.m channel  p  np but the  and the p are emitted back-to-back  cutting on angular distribution can be eliminated main source of backgroung K  (np)    p n    E ~ 700 KeV Only forward pions correction for energy lost in the target Only forward pions correction for energy lost in the target All pions

20.  +p  p+n non-mesonic decay signal background  0.6 Main background:     from K +            - without any selection - selection on n (candidate) tof p-n (candidate) angular corr. p-n (candidate) total energy signal reduction to 80% background reduction to 2.5% signal background  20 n  p    A neutron is an isolated hit not connected to charged signals A neutron is an isolated hit not connected to charged signals

21. signal background  0.17 A neutron is an isolated hit not connected to charged signals A neutron is an isolated hit not connected to charged signals  +n  n+n non-mesonic decay  n    Main background:     from K +            - without any selection - selection on n (candidate) tof n-n (candidate) angular corr. n-n (candidate) total energy signal reduction to 93% background reduction to 1.5% signal background  11 n

22. Summary of the FINUDA expected performances @ L = 10 31 cm -2 s -1 Hypernuclear spectroscopy Hypernuclear decay Results comparable with the present ones (in a unique data taking) ground state at 10 -3 capture rate excited state at 2x10 -3 capture rate ground state at 10 -3 capture rate excited state at 2x10 -3 capture rate Observableevent/hour Data taking time Collected events High resolution hyp. Spectros. 30  - /h two states 5  10 3  - in the spectrum  hyp (  tot ) 2 p/h in coinc. with  - 120 p  p /   proton seen 2 p/h not in coinc. with neutron 120 p ~ 10% error  p /   proton and neutron seen 0.2 (pn)/h p and n coinc. 1 month (~ 10 pb -1 ) 50 (pn) ~ 15% error  n /   2 neutrons seen 0.04 (nn)/h 2 neutrons in coinc. 12 (nn) ~ 30% error n/pn/p ~ 35% error   - /   40  - ~ 15% error

23. Summary of the FINUDA expected performances @ L = 10 32 cm -2 s -1 ground state at 10 -3 capture rate excited state at 2x10 -3 capture rate ground state at 10 -3 capture rate excited state at 2x10 -3 capture rate Hypernuclear spectroscopy Hypernuclear decay World class results

24. FINUDA upgrades FINUDA is a powerful detector with very good capabilities low energy kaons can be stopped ~ 100 mg/cm 2 ; big solid angle 4  detectors; best events rate for L ~ 10 32 80 ev/h; possibility to study hyp. production and decays; both ( K    ) and ( K    ) are accessible. low energy kaons can be stopped ~ 100 mg/cm 2 ; big solid angle 4  detectors; best events rate for L ~ 10 32 80 ev/h; possibility to study hyp. production and decays; both ( K    ) and ( K    ) are accessible. The idea of studying hypernuclei on a  -factory has many advantages: high momentum resolution  p/p ~ 0.3%; efficient trigger system; high momentum resolution  p/p ~ 0.3%; efficient trigger system; Upgrades are foreseen to overcome experimental limitation; Upgrades are foreseen to overcome experimental limitation; Where is FINUDA main limitation? The only reasonable upgrade that can be foreseen for FINUDA is to find a good-working   -factory

25. Novosibirsk  -factory Mainz  -factory UCLA  -factory In 1991 at the first DA  NE workshop 4  –factory projects were presented together with LNF one KEK  –factory Only DA  NE was approved and founded “…Strange particles offer us important clues to the nature of matter and the character of the forces that shape the word…”. [C.Quigg- DA  NE 99 workshop summary talk] If one of those project is still alive or someone is planning to build a  –factory we have a very nice detector that can be rolled-in immediately!! If one of those project is still alive or someone is planning to build a  –factory we have a very nice detector that can be rolled-in immediately!! Circumference120 m Num. of bunches600 Num. of part/bunch3 10 10 Frequency1.428 GHz Conclusions