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, A.Tamii 2, and T. Wakasa 1 1 Dept. of Physics, Kyushu University 2 RCNP, Osaka University 3 CNS, University of Tokyo 4 RIKEN, 5 CYLIC, Tohoku University 6 Dept. of Engineering, Miyazaki University

Ay puzzle 1986 Ay puzzle pd CS discrepancy (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 1980’s higher energy discrepancies pd sactt. discrepancy lower energy discrepancies Off-plane star anomaly ??? Discrepancies in 3N systems and their origins FM-3NF 1957

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

  3NF found High momentum transfer Wide phase space Experiments in pd system

pd capture experiment + +  ○ Short-range forces may play important roles. (→new 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

Liquid Hydrogen Target 精密実験に不可欠 mm

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

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  0.2  0.4  0.6 A xx C.M angle (deg.)  0.2  0.4 A yy C.M angle (deg.)  0.1  0.2 AyAy C.M angle (deg.) Cross section (mb/sr) 0.0 C.M angle (deg.) Axx anomaly? Axx~Ayy?

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.

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

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

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)

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

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

Y In previous exp. BG level was low.

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

A = [ (Y true ) pol / (Y true ) unpol – 1 ] / p beam = [ (Y tot -Y BG ) pol / (Y tot -Y BG ) unpol – 1] / p beam Y = (N count /Q beam ) /efficiency Efficiency should be high to obtain reliable data.

Detection efficiency

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 Detection efficiency was much improved by a multi-II method. Total 100%

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

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

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

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

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  3NF, and new forces or mechanisms may be necessary.

Ay puzzle 1986 Ay puzzle pd CS discrepancy (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 1980’s higher energy discrepancies pd sactt. discrepancy lower energy discrepancies Off-plane star anomaly QFS anomaly? ??? Discrepancies in 3N systems and their origins FM-3NF 1957