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Recent experiments on three nucleon systems and problems to be solved Kenshi Sagara Kyushu U., Fukuoka, Japan FB19.

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Presentation on theme: "Recent experiments on three nucleon systems and problems to be solved Kenshi Sagara Kyushu U., Fukuoka, Japan FB19."— Presentation transcript:

1 Recent experiments on three nucleon systems and problems to be solved Kenshi Sagara Kyushu U., Fukuoka, Japan FB19

2 + + ++ +  Basic process High momentum transfer Various configurations QFS, FSI, Star, Collinear,.. Experiments in Nd system 3-nucleon forces 3-body effects Systematic experiments Calculatons with 2NF+3NF +

3 Ay puzzle 1986 Ay puzzle pd CS discrepancy 1994-1996-1997 (Sagara discrepancy) 3N BE problem 1980’s  3NF(FM) was found 1998 pd breakup discrepancy pd capture Ajj anomaly  3NF?  3NF? relativity? Space Star anomaly 1989 -- higher energy discrepancies -- pd sactt. discrepancy -- lower energy discrepancies -- Off-plane Sar anomaly QFS anomaly ??? Discrepancies in 3N systems and their origins FM-3NF 1957 Systematic measurements We are here. Faddeev eqs. 1960

4 Ay at E N =5-18 MeV (~1994) ++ Ay puzzle

5 nd Ay & pd Ay E N =10MeV pd Ay Ep=22.7MeV Modification factors H. Witala and W. Gloeckle, NPA528 (1991)48 NN forces 3P03P0 3P13P1 3P23P2 np1.041.071.03 pp0.861.051.02 nn0.751.081.03 A suggestion to solve Ay puzzle Modified calculations Original calculation

6 Ay puzzle Modification of LS force in 2NF Modification of 3PJ forces in 2NF Addition of LS force in 3NF Adjusting of forces in  PT 3NF effects? Relativistic effects? or ……….. Origin(s) Ay puzzle is a long-standing problem since 1986 (FB11).

7 Shortage of 3 H binding energy (1980’s) (Experiment) 8.482MeV (Theory) 2NF ~1MeV shortage 3 H B.E. can be reproduced by adjusting a parameter  in 2  3NF Another evidence was necessary to confirm 2  3NF

8 Systematic measurement of pd scattering cross section (1994) Here are discrepancies 18MeV 10MeV 5MeV 12MeV + +

9 pd cross section (RIKEN 1996) + + nd calculation by Koike 30% difference

10 + + RIKEN data (1996) Kyushu data (1994) Koike’s talk at FB15 (KVI)

11 H.Witala et al., Phys Rev Lett. 81 1183(1998) 8.482MeV (exp.) 2NF 2  3NF Binding energy + + 2  3NF Fujita-Miyazawa (1957) 41 years 2p3NF was found (1998) Scattering cross section

12 Ay puzzle 1986 Ay puzzle pd CS discrepancy 1994-1996-1997 (Sagara discrepancy) 3N BE problem 1980’s  3NF(FM) was found 1998 pd breakup discrepancy pd capture Ajj anomaly  3NF?  3NF? relativity? Space Star anomaly 1989 -- higher energy discrepancies -- pd sactt. discrepancy -- lower energy discrepancies -- Off-plane Sar anomaly QFS anomaly ??? Discrepancies in 3N systems and their origins FM-3NF 1957 Systematic measurements We are here. Faddeev eqs. 1960

13 pd capture experiment + +  ○ high momentum transfer → short-range 3NF × Reaction cross section is very small (< 1  barn). Experimental techniques thick target & low BG → liquid hydrogen target high-efficiency detection → one-shot measurement of whole angular distribution

14 Liquid Hydrogen Target 精密実験に不可欠 mm

15

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

17 Y BG level was low

18 Axx anomaly in pd capture at E d = 200 MeV from RCNP exp. (Yagita et al. 2002) 2 NF 2 NF +3 NF Calc. by Witala et al. 050100150 0.2 0.0  0.2  0.4  0.6 A xx C.M angle (deg.) 050100150 0.2 0.0  0.2  0.4 A yy C.M angle (deg.) 050100150 0.2 0.1 0.0  0.1  0.2 AyAy C.M angle (deg.) 050100150 0.5 0.4 0.3 0.2 0.1 Cross section (mb/sr) 0.0 C.M angle (deg.) Axx anomaly? Axx~Ayy?

19 Ajj of pd-capture were measured also at KVI, and KVI data agreed with calculations. A xx A yy A zz ● ○ RCNP(200MeV) ■ □ KVI ( 180MeV) RCNP data at 137MeV also disagreed with KVI data at 133MeV.

20 Experiment at KVI, A yy & “A zz ” (=-A xx - A yy ) Big-Bite spectrometer (BBS) & Plastic Ball detector (PB)  -detection A zz : 45±10 degree A yy : 0 ±15 dergree Azz = -Axx-Ayy Beam axis

21 d + p → 3 He+  Ed  eV  ( 3 He) < 4.7deg Slit in front of LAS “A zz ” = (A xx -A yy ) A xx A yy Beam polarization is along y-axis. Re-measurement at RCNP at 200 MeV

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

23 Detection efficiency

24 Single cluster Multiple cluster Overlapped cluster & single cluster Overlapped–overlapped cluster Other rays ~83% ~2% ~14% ~1% Efficiency =.83 4 =0.48 Standard data analysis Efficiency =.97 4 =0.88 Efficiency =.99 4 =0.96 Multi-II data analysis X1 X2 X1 X2 Backgroun estimation was much improved by a multi-II method. Total 100% X1 X2

25 Single cluster data analysis vs. Multi-cluster II data analysis (new) 2002 exp.

26 d+p→3He+  New data and previous data (new multi-II analysis) 2002 present

27 d+p→3He+  New data and previous data (Multi-II) present 2002 -(Axx+Ayy) “Azz”

28

29 pd radiative capture at E d = 137 MeV (multi-II analysis)

30 Ajj in pd capture Axx anomaly (Azz anomaly) has been confirmed. Axx ~ Ayy ---> axial symmetry ? Azz > calculation ----> short range reaction? + + 

31 pd scattering CS at 250 MeV E-dependence of CS at 150 degree + + exp/cal at  = 150 ⁰ 2  3NF  =150 ⁰

32 J. Kuros-Zoluierczuk et al., PRC66, 024003 (2002).

33 D(p,pp)n CS at 250 MeV + ++

34 d p p detected un-detected d p p detected p Inclusive exp. at 250 MeV D(p,p)pn experiment (global feature) Exclusive exp. at 250 MeV D(p,pp)n experiment (microscopic study) --> Kuroita’s talk + ++

35 pd breakup CS at 250 MeV, inclusive & exclusive Large (~2 times) CS enhancement pd & nd scattering CS above 150 MeV Short-range 3NF? Relativity? ……..? + ++ ++

36 + ++ Space star anomaly around 10 MeV

37 α=144º α=124º

38 ~ QFS EnEn Is there QFS anomaly in addition to space star anomaly? + ++ QFS anomaly?

39 Result (pp-QFS) QFS E p = 9.5 MeV E p = 13 MeV QFS ~7% smaller ~9% smaller star

40 pd QFS E p = 9.5 MeV E p = 13 MeV

41 A. Siepe et al., Phys. Rev. C 65, 034010 (2002) ~ 18% θ 1 = θ 2 = 42 deg. θ 1 = θ 2 = 42.2 deg. ~ 16% X. C. Ruan et al., Phys. Rev. C 75, 057001 (2007) nd QFS pd QFS Also there are nd QFS (2002,2007), and CS of nd QFS is higher than calculation, CS of pd QFS is lower than calculation. + + +

42 ① ② ③ ④ ⑤ ⑥ ⑦ E p = 9.5 MeV E p = 13 MeV 1 5 4 2 3 6 7 Angular dependence of QFS anomaly

43 Nd breakup cross section at low energy Star anomaly appears only around space star (  = 90 °) at 13 MeV, and in a wide angular region at 9.5MeV. Large CSB occurs, nd CS> calc, and pd CS < calc. Star anomaly QFS anomaly CS anomaly also appears in pd QFS and nd QFS. QFS anomaly appear s in a wide angular region. Large CSB occurs, nd CS> calc, and pd CS < calc. What origin(s) Same origin or different ones?

44 Ay puzzle 1986 Ay puzzle pd CS discrepancy 1994-1996-1997 (Sagara discrepancy) 3N BE problem 1980’s  3NF(FM) was found 1998 pd breakup discrepancy pd capture Ajj anomaly  3NF?  3NF? relativity? Space Star anomaly 1989 -- higher energy discrepancies -- pd sactt. discrepancy -- lower energy discrepancies -- Off-plane Sar anomaly QFS anomaly ??? Discrepancies in 3N systems and their origins FM-3NF 1957 Systematic measurements We are here. Faddeev eqs. 1960

45 More systematic experiments on some reactions More challenging calculations with new 3NF, new frame, … remaining 3NF’s unknown 3-body effects ……. +


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