1 / 15

Systematic Study of Double Strangeness System with an Emulsion-Counter Hybrid Method

Jun.30,2006 J-PARC.PAC. E.Hayata, M.Hayata, M.Hirose, K.Imai , S.Kamigaito, N.Saito, K.Tanida, M.Togawa, T.Tsunemi, C.J.Yoon M.Kawasaki, H.Nakamura, K.Nakazawa , K.T.Tint, T.Watanabe K.Hosomi, T.Koike, Y.Ma, K.Shirotori, H.Tamura , M.Ukai R.Hasan R.E.Chrien

kfunk
Download Presentation

Systematic Study of Double Strangeness System with an Emulsion-Counter Hybrid Method

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Jun.30,2006 J-PARC.PAC E.Hayata, M.Hayata, M.Hirose, K.Imai, S.Kamigaito, N.Saito, K.Tanida, M.Togawa, T.Tsunemi, C.J.Yoon M.Kawasaki, H.Nakamura, K.Nakazawa, K.T.Tint, T.Watanabe K.Hosomi, T.Koike, Y.Ma, K.Shirotori, H.Tamura, M.Ukai R.Hasan R.E.Chrien Y.Y.Fu, C.P.Li, Z.M.Li, J.Zhou, S.H.Zhou, L.H.Zhu J.Y.Kim M.Y.Pac T.Yoshida K.S.Chung, S.H.Kim, J.S.Song, C.S.Yoon M.Ieiri, H.Noumi, M.Sekimoto, H.Takahashi K.Hoshino, T.Kawai, B.D.Park, T.Sato, T.Watabe N.Yasuda K.Yamamoto J.K.Ahn, S.Y.Ryu C.Fukushima, M.Kimura, S.Ogawa, H.Shibuya D.H.Davis, D.Tovee Ed.Hungerfold B.Bassalleck Kyoto: Gifu: Tohoku: AMU: BNL: CIAE: Chonnam: Dongshin: Fukui: Gyeongsang: KEK: Nagoya: NIRS: OsakaCity: Pusan: Toho: UCL: U.Houston: U.New-Mexico: Systematic Study of Double Strangeness System with an Emulsion-Counter Hybrid Method NAGARAevent (KEK-E373)

  2. Jun.30,2006 J-PARC.PAC Strange matter { L-L Interaction, H-dibaryon, X-Nucleus Interaction, Inside Neutron Stars (Quark-star?) Motivation of the proposed experiment * detection of102 or more candidate eventswith S = -2, → Discovery of 10or more nuclear species. Our goal is to produce a S=-2 nuclear chart, by observing nuclei with S=-2 as many as possible. More than 10 times statistics than previous E373.

  3. Jun.30,2006 J-PARC.PAC Direct process + K + K - K - K - X Λ Λ Λ H or Λ X - - p X Λ Λ + 2 8 M e V Λ Λ => 3 Cands. -> + K Λ X - - K Λ A Λ Λ Λ * X - - atom Λ A ( S = 2 ) Λ Λ Λ Λ o r π o H How to produce S=-2 Systems • via X atom (KEK-E373) Double-Hypernucleus Twin-Hypernucleus

  4. Jun.30,2006 J-PARC.PAC e m a c h i - y a n a g i e v e n t D - + N B + p + n 1 4 1 3 X → Λ Λ t w o b o d y ＊ c a s e a t p o i n t A - * C B e t o r B e t 1 2 1 0 1 0 → X + + + Λ Λ Λ Λ t h r e e b o d y ＊ c a s e a t p o i n t A A p r o t o n - Ξ C B Double-Hypernuclei found by KEK-E373 47single-hypernuclear events  ~ 600 eventsΞ-capture at rest ・ 6 double-hypernuclei ・ 2 twin-hypernuclei ・ 1 S-emission DBLL : LLInteraction Energy DBLL = BLL(LALZ)-2BL(A-1LZ) Found Weakly attractive LL Interaction ! Hybrid Method==>Reliable

  5. Jun.30,2006 J-PARC.PAC  ‘H’ L L L L DBLL& nuclear structure Theoretical prediction S=-2 nuclear system DBLL may NOTdepend on A BLL : LL binding energy in nucleus DBLL depends on A To determine LL interaction independent on the nuclear structure, we need to measure A-dependence of DBLL.

  6. Jun.30,2006 J-PARC.PAC  M(LL)thres. ‘H’ L L H-dibaryon resonance (?) near the LL threshold Recent result What is the ground state of S=-2 nuclei? KEK-PS E522 LL or H-dibaryon state or mixed in nuclei? |H> = √a |LL> + √b |XN> - √c |SS> 1. A-dependence of DBLL 2. Decay branching ratio [S=-2] => S-p, Ln 3. Higher statistics for LL spectrum is expected. LL invariant mass

  7. Jun.30,2006 J-PARC.PAC #1 #2 #3 Ａ Ξ- Ｂ First observation S-N weak decay of double strangeness nuclei • X- + (p) →X→S-+p Decay mode (X => S-+p)<…….Theoretical Prediction. X : LL(~10-3)、H-dibaryon(several tens’%). E373 data : One event for the Decay (X[S= -2]=> S-p ) Proposed experiment can provide Br(X[S= -2]=> S-p ) with more than 10 times higher statistics. また、 LLとHの質量差が小さい場合には、 <ダブルハイパー核> はLLとHの混合状態 である可能性もある。　 

  8. Jun.30,2006 J-PARC.PAC #1 #2 Ξ- A.Ichikawa et al., Phys. Lett.B (2001) X-nucleus potential 1) Level energy of X- hyperon in nucleus by twin-hypernuclei. • 2) The first measurement of X--atomic X rays • employing “Hyperball-J” (Ge detector array). • Energy shift -> X- nucleus potential -> X-N interaction High accuracy←P03 K. Tanida ~ 0.2 keV (FWHM) < Expected energy shift 0.3 － 3 keV (by Friedman, Gal) Very low background Clean X- stopping events identified in emulsion.

  9. Jun.30,2006 J-PARC.PAC Setup of the proposed experiment Almost same as E373 # Beam :K- (1.7GeV/c), 3 x 105K-/spill with K-/p- > 6 at K1.8 beam-line (~20% of 9mA) # Trigger :(K-, K+) => 104 X- stopping events (more than 10 times higher stat. than E373)

  10. Jun.30,2006 J-PARC.PAC Development #1Double-sided Si Strip Detector (DSSD) Silicon; 32 x 64mm area, 300mm thick 50mm strip pitch -> 16mm resolution readout; VA-chip Energy spectrum for b-ray (90Sr) Equivalent electron noise; 600~1000 S/N;23~34 for MIPS PS-T594 : + Track connection (DSSD ⇔ Emulsion) using the last beam at KEK-PS, on mid March + Analysis is going-on.

  11. Jun.30,2006 J-PARC.PAC arbitrary unit arbitrary unit Development #2 Upgraded Hyperball-J K.Tanida H.Tamura *Peak efficiency：×2 *Very low background X- atomic X-ray い

  12. Jun.30,2006 J-PARC.PAC Development #3 Emulsion scanning system New system Area：35×35 cm2 40×40cm2 Light：Halogen Lamp Ultra High-bright LED speed：×２ tracking eff.：× 1.5 # of System：6 (old, E373) 7 (new) + 3 (old) New system Old system Scanning for this experiment：more speed-up [ × 6 than old system ] (1) Develop scanning algorism(2) Optimize the area for scanning

  13. Jun.30,2006 J-PARC.PAC Development #4 Production method of emulsion New method of Emulsion gel. production For the proposed exp., amount of emulsion gel => 2.6 tons Fuji-film needs one year or more by conventional way. Conventional way by hand Using the production lines for commercial films Emulsion cost will be saved 50% Tested by particle beams with good results. Half of necessary emulsion has been made!

  14. Jun.30,2006 J-PARC.PAC Summary #Physics 1) S=-2 nuclear chartby ~102LLZvia 104 X--stopping events. =>DBLLof several nuclideswill providedefinitive information on LL interaction and structure of S=-2 nuclei. 2) H-dibaryon state in S=-2 system ? =>measure A-dependence ofDBLL &S-decay mode ofLLZ. 3) X--nucleus potential => detection of twin hypernuclei => First measurementof X-ray ofX-atom

  15. Jun.30,2006 J-PARC.PAC Summary # Readinessof the Experiment(‘Kakenhi / Tokubetsu-Suishin’ : $3M) +DSSD (Double-sided Si StripDetector ) +Scanning system(6=>10 systems : high speed and better efficiency) +Emulsion(50%) +Hyperball-J (other budgets) # Requested Beam and Time(K-, K+) trigger 3 x 105K-/spill withK-/p-> 6atK1.8 beam-line(~20%of 9mA) 150hoursfor detector tuning and600hoursfor beam exposure # Detector:DSSD, Emulsion, Hyperball, KURAMA spectrometer, etc. Almost Ready

More Related