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pd 捕獲反応のテンソル偏極量の異常

pd 捕獲反応のテンソル偏極量の異常. K. Sagara 1 , Y. Tameshige 2 , K. Hatanaka 2 , S. Kuroita 1 , H. Matsubara 2 , K. Fujita1, Y. Shimizu 2 , T. Kawabata 3 , Y. Maeda 5 , Y. Sakemi, H. Okamura 2 , K. Sekiguchi 4 , Tamii 2 , and T. Wakasa 1 1 Dept. of Physics, Kyushu University 2 RCNP, Osaka University

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pd 捕獲反応のテンソル偏極量の異常

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  1. pd捕獲反応のテンソル偏極量の異常 • K. Sagara1, Y. Tameshige2, K. Hatanaka2, S. Kuroita1, • H. Matsubara2, K. Fujita1, Y. Shimizu2, T. Kawabata3, • Y. Maeda5, Y. Sakemi, H. Okamura2, K. Sekiguchi4, • Tamii2, and T. Wakasa1 • 1Dept. of Physics, Kyushu University • 2RCNP, Osaka University • 3CNS, University of Tokyo • 4RIKEN, • 5CYLIC, Tohoku University • 6Dept. of Engineering, Miyazaki University

  2. Discrepancies in 3N systems and their origins lower energy discrepancies Ay puzzle 1986 Ay puzzle ??? higher energy discrepancies pd CS discrepancy 1994-1996-1997 (Sagara discrepancy) pd sactt. discrepancy pp3NF(FM) was found 1998 pr3NF? rr3NF? relativity? FM-3NF 1957 pd breakup discrepancy 3N BE problem 1980’s pd capture Ajj anomaly lower energy discrepancies Space Star anomaly 1980’s Off-plane star anomaly ???

  3. By Koike’s talk at Few-Body Conf. at KVI (1997), CS minimum discrepancy was widely recognized.

  4. + g + + + Experiments in pd system pp3NF found High momentum transfer + Wide phase space

  5. pd capture experiment g + + ○Short-range forces may play important roles. (→new 3NF) ×Reaction cross section is very small (< 1 m barn). • Experimental techniques • thick target & low BG 　　→　liquid hydrogen target • high-efficiency detection → one-shot measurement of whole • angular distribution

  6. Side View (enlargement) Front View f12 Liquid Hydrogen Target 精密実験に不可欠 mm

  7. q(3He) < 4.7 Vertical plane for Axx Horizontal plane for Ayy & Ay Whole angular distribution was measured in one shot.

  8. 0.2 0.2 0.0 0.0 Ayy Axx -0.2 -0.2 -0.4 -0.4 -0.6 0 50 100 150 0 50 100 150 C.M angle (deg.) C.M angle (deg.) 0.2 0.5 0.4 0.1 0.3 Crosssection (mb/sr) Ay 0.0 0.2 -0.1 0.1 -0.2 0.0 0 50 100 150 0 50 100 150 C.M angle (deg.) C.M angle (deg.) Axx anomaly in pd capture at Ed = 200 MeV from RCNP exp. (Yagita et al. 2002) ２NF Calc. by Witala et al. ２NF＋３NF Axx anomaly? Axx~Ayy?

  9. Ajj of pd-capture were measured also at KVI, and KVI data agreed with calculations. Axx Ayy ● ○RCNP(200MeV) ■ □KVI 　（180MeV) Azz RCNP data at 137MeV also disagreed with KVI data at 133MeV.

  10. KVIでの測定, Ayy & Azz(=-Axx-Ayy ) KVI • Aｙｙ, Aｚｚ • 散乱平面はPBで決定 • 3He-gのコインシデンス測定 　　綺麗に測定（統計が少ない） Azz→実際は-(Axx+Ayy)を測定 共通点 • 液体水素標的 • pyyビーム Big-Bite spectrometer (BBS) & Plastic Ball detector (PB) 検出角度 Azz :45±10度 Ayy : 0±15度 Azz= -Axx-Ayy ビーム軸 から見たPB検出器

  11. d+p → 3He + g Ed = 140 MeV at RCNP BG多く、データ解析進まず preliminary Axx Ayy

  12. We made a new experiment (present exp.) at RCNP. Beam : 197 MeV (same as before) Target : Liquid Hydrogen (same as before) Detection: 3He (same as before) Observables: Axx (same as before) Ayy (same as before) Azz (= -Axx-Ayy) (similar to KVI)

  13. d +p→3He+g Ed =200 MeV q(3He) < 4.7deg Slit in front of LAS Beam polarization Azz=(Axx-Ayy) Ayy Axx

  14. Background subtraction y polarized beam True Liuqid target BG y unpol. beam Empty target

  15. In previous exp. BG level was low. Y

  16. Data at 140 MeV, BG多い LAS 0° Data Analysis projection

  17. A = [ (Ytrue)pol / (Ytrue)unpol – 1 ] / pbeam = [ (Ytot-YBG)pol / (Ytot-YBG)unpol – 1] / pbeam Y = (Ncount /Qbeam) /efficiency Efficiency should be high to obtain reliable data.

  18. Detection efficiency

  19. Detection efficiency was much improved by a multi-II method. Single cluster X1 ~83% Efficiency =.834 =0.48 Standard data analysis Multiple cluster X1 ~14% Efficiency =.974 =0.88 X1 Overlapped cluster & single cluster ~2% X2 Efficiency =.994 =0.96 Multi-II data analysis X1 Overlapped–overlapped cluster Other rays ~1% X2 Total 100%

  20. Single cluster data analysis vs. Multi-cluster II data analysis 2002 exp.

  21. d+p→3He+g New data and previous data (Multi-II) present 2002

  22. d+p→3He+g New data and previous data (Multi-II) present 2002

  23. pd radiative capture at Ed = 137 MeV (multi-II analysis)

  24. Summary Axx, Ayy, and Azz (= -Axx-Ayy) of pd radiative capture at Ed = 196 MeV were measured again at RCNP. Data were analyzed with 96% detection efficiency by multi-cluster-II method. Also previous RCNP data at 196 MeV were re-analyzed by multi-cluster-II method. New and previous data agree well, and Axx (Azz) anomaly in pd capture was confirmed. Also at 137 MeV, Axx anomaly in pd capture was confirmed. Axx ≈Ayy relation was also confirmed. The Axx (Azz) anomaly can not be explained by pp3NF, and new forces or mechanisms may be necessary.

  25. Discrepancies in 3N systems and their origins lower energy discrepancies Ay puzzle 1986 Ay puzzle ??? higher energy discrepancies pd CS discrepancy 1994-1996-1997 (Sagara discrepancy) pd sactt. discrepancy pp3NF(FM) was found 1998 pr3NF? rr3NF? relativity? FM-3NF 1957 pd breakup discrepancy 3N BE problem 1980’s pd capture Ajj anomaly lower energy discrepancies Space Star anomaly 1980’s Off-plane star anomaly QFS anomaly? ???

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