1. Double Anti-kaon Production in Nuclei by Stopped Anti-proton Annihilation F.Sakuma, RIKEN 1 International Workshop on ”Physics and Upgrade of the J-PARC Hadron Facility” (post Hyp-X workshop), Sep. 18-19, 2009

2. 2 This talk is based on the LoI submitted in June, 2009.

3. 3 Introduction of “Kaonic Nuclear Cluster” Possibility of “Double-Kaonic Nuclear Cluster” by Stopped-p bar Annihilation Experimental Approach Summary and Outlook Contents of this talk

4. 4 Introduction of “Kaonic Nuclear Cluster”

5. Mass-less Quark Higgs Mechanism Chiral Symmetry Breaking QGP neutron star SPS, RHIC, LHC KEK-PS W.Weise NPA553, 59 (1993). J-PARC? The Origin of Mass the missing piece is exploring hadron properties in dense matter most of the mass of matter are given by M u,d =0MeV M u,d ~300MeV M u,d ~3MeV 5

6. 6 Neutron Star high-density matter above the nuclear density? core material of neutron stars Outer Crust Inner Crust  0.3-0.5  0 Outer Core  0.5-2  0 Inner Core 2-15  0  2-15  0 possibility of the existence of a kaon condensed phase --- the structure of neutron stars ---  0 =0.17fm -3 =2.8x10 17 kg m -3 the highest density matter in our familiar material is a nucleus n ~ 10 -14 m p

7. 7 KN interaction Y.Akaishi & T.Yamazaki, PLB535, 70 (2002). The possibility of kaon condensation is supported by … experimental results theoretical investigations various models predict kaon condensation (mean field theories, effective interaction theories, …) Kaonic atom data indicates a strongly attractive KN interaction (KpX@KEK, DEAR@DA  NE) this suggests “the existence of deeply- bound K − -nuclei states”

8. we will open new door to the condensed matter physics, like the inside of neutron stars Kaonic Nuclear Cluster (KNC) 8 if deeply-bound kaonic nuclear states exist … Kaonic Nuclei Binding Energy [MeV] Width [MeV] Central Density KpKp2740 3.5  0 K  pp4861 3.1  0 K  ppp9713 9.2  0 K  ppn11821 8.8  0 T.Yamazaki, A.Dote, Y.Akiaishi, PLB587, 167 (2004). the density of kaonic nuclei is predicted to be extreme high density

9. Method Binding Energy (MeV) Width (MeV) Akaishi, Yamazaki PLB533, 70 (2002). ATMS4861 Shevchenko, Gal, Mares PRL98, 082301 (2007). Faddeev55-7090-110 Ikeda, Sato PRC76, 035203 (2007). Faddeev7974 Dote, Hyodo, Weise NPA804,197(2008). chiral SU(3)19+/-3 40-70 (  N-decay) 9 Theoretical Situation of KNC theoretical predictions for kaonic nuclei, e.g., K - pp Koike, Harada PLB652, 262 (2007). DWIA whether the binding energy deepshallow is deep or shallow broad how broad is the width ? 3 He(K-,n)

10. no “narrow” structure PLB 659:107,2008 10 Experimental Situation of KNC 4 He （ stopped K-,p) E549@KEK-PS 12 C(K -,n) 12 C(K -,p) missing mass E548@KEK-PS Prog.Theor.Phys.118:181-186,2007. arXiv:0711.4943 unknown strength between Q.F. & 2N abs. deep K-nucleus potential of ~200MeV - K - pnn? K - pp/ K - pnn? K - pn/ K - ppn? 4 He （ stopped K-,  N) E549@KEK-PS

11. 11 Experimental Situation of KNC (Cont’d) FINUDA@DA  NE OBELIX@CERN-LEAR We need conclusive evidence formationanddecay with observation of formation and decay ! DISTO@SATUREN  -p invariant mass PRL, 94, 212303 (2005) NP, A789, 222 (2007) the situation is still controversial, because of no conclusive evidence yet! because of no conclusive evidence yet! peak structure  signature of kaonic nuclei ? K - pp? arXiv:0810.5182 K - pp?

12. 12 Experimental Principle of J-PARC E15 search for K-pp bound state using 3 He(K -,n) reaction K-K- 3 He Formation exclusive measurement by Missing mass spectroscopy and Invariant mass reconstruction Decay K - pp cluster neutron  p p -- Mode to decay charged particles Missing mass Spectroscopy via neutron Invariant mass reconstruction

13. 13 J-PARC E15 Setup 1GeV/c K- beam p  p n Neutron ToF Wall Cylindrical Detector System Beam Sweeping Magnet K1.8BR Beam Line flight length = 15m neutron Beam trajectory CDS & target Sweeping Magnet Neutron Counter Beam Line Spectrometer E15 will provide the conclusive evidence of K - pp

14. 14 Possibility of “Double-Kaonic Nuclear Cluster” by Stopped-p bar Annihilation What will happen to put one more kaon in the kaonic nuclear cluster?

15. 15 Double-Kaonic Nuclear Cluster The double-kaonic nuclear clusters have been predicted theoretically. The double-kaonic clusters have much stronger binding energy and a much higher density than single ones. B.E. [MeV] Width [MeV] Central- Density K-K-pp-11735 K-K-ppn-22137 17  0 K-K-ppp-103- K-K-pppn-23061 14  0 K-K-pppp-109- How to produce the double-kaonic nuclear cluster?  heavy ion collision  (K -,K + ) reaction  p bar A annihilation We use p bar A annihilation PL,B587,167 (2004). & NP, A754, 391c (2005).

16. The elementary p bar -p annihilation reaction: is forbidden for stopped p bar, because of a negative Q-value of 98MeV Double-Strangeness Production with p bar However, if multi kaonic nuclear exists with deep bound energy, following p bar annihilation reactions will be possible !  98MeV 16 theoreticalprediction B.E.=117MeV  =35MeV B.E.=221MeV  =37MeV

17. 17 Double-Strangeness Production Yield by Stopped-p bar Annihilation From several stopped-p bar experiments, the inclusive production yields are: Naively, the double-strangeness production yield would be considered as:  : reduction factor ~ 10 -2

18. 18 Past Experiments of Double-Strangeness Production in Stopped-p bar Annihilation only 2 groups Observations of the double-strangeness production in stopped p bar annihilation have been reported by only 2 groups, DIANA@ITEP and OBELIX@CERN/LEAR. experimentchanneleventsyield (10 -4 ) DIANAK+K+XK+K+X40.31+/-0.16 [p bar +Xe]K+K0XK+K0X32.1+/-1.2 K+K+--psK+K+--ps 34+/-80.17+/-0.04 OBELIX K+K+-+n-K+K+-+n- 36+/-62.71+/-0.47 [p bar + 4 He] K+K+-nK+K+-n 16+/-41.21+/-0.29 K + K + K -  nn 4+/-20.28+/-0.14 Although observed statistics are very small, their results have indicated a high yield of ~10 -4

19. 19 Past Experiments (Cont’d) DIANA [Phys.Lett., B464, 323 (1999).] p bar Xe annihilation p=<1GeV/c p bar -beam @ ITEP 10GeV-PS 700-liter Xenon bubble chamber, w/o B-field 10 6 pictures  7.8x10 5 p bar Xe inelastic  2.8x10 5 p bar Xe @ 0-0.4GeV/c Channeleventsyield (10 -4 ) K+K+XK+K+X40.31+/-0.16 K+K0XK+K0X32.1+/-1.2

20. channeleventsyield (10 -4 ) K+K+--psK+K+--ps 34+/-80.17+/-0.04 K+K+-+n-K+K+-+n- 36+/-62.71+/-0.47 K+K+-nK+K+-n 16+/-41.21+/-0.29 K + K + K -  nn 4+/-20.28+/-0.14 20 Past Experiments (Cont’d) OBELIX (’86~’96) [Nucl. Phys., A797, 109 (2007).] p bar4 He annihilation stopped p bar @ CERN/LEAR gas target ( 4 He@NTP, H 2 @3atm) cylindrical spectrometer w/ B-field spiral projection chamber, scintillator barrels, jet-drift chambers 2.4x10 5 /4.7x10 4 events of 4/5-prong in 4 He p min = 100/150/300MeV/c for  /K/p they discuss the possibility of formation and decay of K - K - nn and K - K - pnn bound system

21. 21 Interpretation of the Experimental Results  Although observed statistics are very small, the results have indicated a high yield of ~10 -4, which is naively estimated to be ~10 -5.  Possible candidates of the double-strangeness production mechanism are:  rescattering cascades,  exotic B>0 annihilation (multi-nucleon annihilation) formation of a cold QGP, deeply-bound kaonic nuclei, H-particle, and so on single-nucleon annihilation rescattering cascades multi-nucleon annihilation B=0 B>0 B>0 the mechanism is NOT known well because of low statistics of the experimental results!

22. 22 Experimental Approach Anyway, the double-strangeness production yield of ~10 -4 makes it possible to explore the exotic systems, if exist.

23. 23 How to Measure? In the following discussion, we limit the reaction: (although K - K - pp decay modes are not known,) we assume the most energetic favored decay mode: We can measure the K - K - pp signal exclusively by detection of:  all particles, K + K 0 , using K 0   +  - mode  3 particles, and the other one is identified by missing mass final state = K + K 0  We need wide-acceptance detectors.

24. 24 K + K 0  Final State & Background This exclusive channel study is equivalent to the unbound (excited) H-dibaryon search! Q-valueX momentum  mass  angle K - K - ppvery small~ at restM  > 2xM  back to back H-dibaryonlargeboostedM  ~ 2xM  ~ 0 Possible background channels direct K + K 0  production channels, like:  0   contaminations, like: be eliminated by the kinematical constraint be distinguished by inv.-mass only  major background source

25. 25 Expected Kinematics assumptions: widths of K - K - pp/H = 0 many-body decay = isotropic decay B.E=109MeV B.E=150MeV B.E=200MeV (threshold) In the K - K - pp production channel, the kaons have very small momentum of up to 300MeV/c, even if B.E.=200MeV. We have to construct low mass material detectors. K + K 0 X momentum spectra

26. 26 Expected Kinematics (Cont’d) M H = 2M   momentum  inv. mass  spectra  opening-angle strong correlation of  opening-angle in K - K - pp/H productions

27. 27 Beam-Line We would like to perform the proposed experiment at K1.1 or K1.8BR beam line at K1.1 or K1.8BR beam line p bar stopping-rate  30GeV-9  A,  6.0degrees  Ni-target p bar production yield with a Sanford-Wang 1.3x10 3 stopped p bar /spill @ 0.65GeV/c, l degrader  14cm Incident Beam momentum bite : +/-2.5% (flat) incident beam distribution : ideal Detectors Carbon Degrader : 1.99*g/cm 3 Plastic Scintillator : l=1cm, 1.032*g/cm 3 Liquid He3 target :  7cm, l=12cm, 0.080*g/cm 3 p bar stopping-rate evaluation by GEANT4

28. 28 Expected Double-Strangeness Yield pbar beam momentum : 0.65GeV/c beam intensity : 3.4x10 4 /spill/3.5s pbar stopping rate : 3.9%  9.6x10 4 double-strangeness/month  9.6x10 3 K + K 0  /month branching ratio to K + K 0  final state : 0.1 stopped-p bar yield : 1.3x10 3 /spill/3.5s Double-strangeness production : 1x10 -4 /stopped-p bar a mere assumption!

29. 29 Detector Design design concept low material detector system wide acceptance with pID useful for other experiments E15 setup @ K1.8BR CDC TypeAA’AUU’VV’AA’UU’VV’AA’ Layer123456789101112131415 radius190.5204.0217.5248.5262.0293.0306.5337.5351.0382.0395.5426.5440.0471.0484.5 ZTPC Layer1234 radius92.597.5102.5107.5 B = 0.5T CDC resolution :  r  = 0.2mm  z ’s depend on the tilt angles (~3mm) ZTPC resolution :  z = 1mm  r  is not used for present setup We are considering 2-types of detector

30. 30 Detector Design (Cont’d) new dipole setup @ K1.1 CDC TypeAA’AUU’VV’AA’UU’VV’AA’ Layer123456789101112131415 radius500525550575600625650675700725750775800825850 INC (wire chamber) TypeAA’AUU’VV’AA’AUU’VV’AA’A Layer1234567891011121314151617 radius100120140160180200220240260280300320340360380400420 The design goal is to become the common setup for the  -nuclei experiment with in-flight p bar -beam B = 0.5T Double Cylindrical-Drift-Chamber setup pID is performed with dE/dx measurement by the INC INC resolution :  r  = 0.2mm,  z = 2mm (UV) CDC resolution :  r  = 0.2mm,  z = 2mm (UV) CDC is NOT used for the stopped-p bar experiment

31. 31 Trigger Scheme p bar3 He charged particle multiplicity at rest CERN LEAR, streamer chamber exp. NPA518,683 91990). NcBranch (%) 15.14 +/- 0.04 339.38 +/- 0.88 548.22 +/- 0.91 77.06 +/- 0.46 90.19 +/- 0.08 4.16 +/- 0.06 expected stopped-p bar yield = 1.3x10 3 /spill All events with a scintillator hit can be accumulated

32. 32 Expected Signals assumptions: widths of K - K 0 pp/H = 0 B.E. of K - K - pp = 200MeV M H = 2xM  branching ratio to K + K 0  final state = 0.1 DAQ & analysis efficiency = 0.7  6.7x10 3 K + K 0  /month Generated ratio  K - K - pp:H:  = 0.1:0.1:0.8 KKpp   and H   decay branches are assumed to be 100%  0   contribution is NOT considered for the inclusive measurements  p bar + 3 He  K + K 0 S + X (X=KKpp/H/  ) events are generated isotropically at the center of the detector system  # of generated events is 200k for each case  obtained yields are scaled by the estimated K + K 0  yield  chamber resolution, multiple scattering and energy losses are fully took into account using GEANT4 toolkit  charged particles are traced with spiral fit  invariant mass with (K + or K 0 ) reconstruction K + K 0 missing mass with one more  reconstruction

33. 33 Expected Signals (Cont’d) E15 K + K 0 miss-mass with E15 setup NEW K + K 0 miss-mass with NEW setup  K-K-pp = 12MeV  H = 45MeV  K-K-pp = 8MeV  H = 25MeV NEW  inv-mass with NEW setup  K-K-pp = 27MeV  H = 0.7MeV 24 K - K - pp events/month 19 K - K - pp events/month 27 K - K - pp events/month E15  inv-mass with E15 setup  K-K-pp = 34MeV  H = 14MeV 25 K - K - pp events/month

34. 34 Summary and Outlook

35. 35 Summary Outlook We are investigating further realistic estimation of the K + K 0  yield and the backgrounds. We are now preparing the proposal for J-PARC based on the LoI. We propose to search for double strangeness production by p bar annihilation on helium nuclei at rest. The proposed experiment will provide significant information on double strangeness production and double strangeness cluster states, like K - K - pp.

36. 36

37. 37 Back-Up

38. 38 Decay Particle Momenta K - K - pp (B.E.=200MeV) H (M H =2*M  )  K0-+K0-+ K0--K0-- ---- -p-p E15 setup case K 0 S   +  - :206MeV/c at rest   p  - :101MeV/c at rest  c  (K+) = 0.75m @100MeV/c

39. 39 Time Schedule Year (JFY)K1.8BR K1.1 (  N) 2009beam-tuneproposal 2010E17R&D, design 2011E15R&D, design 2012E15construction 2013  (1405) commissioning 2014…data taking The proposed experiment will be scheduled in around JFY2014, whether we conduct the experiment at K1.8BR or K1.1 beam-line. K1.8BR : after E17/E15/  (1405)? K1.1 : joint project with the  N experiment?