Cross section enhancement in pd reactions at higher energ ｙ K. Sagara, S. Kuroita, T. Sueta, H. Shimoda, Y. Eguchi, K. Yashima, T. Yabe, M. Dozono, Y. Yamada, T. Wakasa, T. Noro, H. Matsubara *, J. Zenihiro *, Y. Tameshige *, H. Okamura *, A. Tamii *, K. Hatanaka *, T. Saito #, Y. Maeda #, and H. Kamada + Dept. of Physics, Kyushu University *RCNP, Osaka University # Dept. of Engineering, Miyazaki University + Kyushu Institute of Technology

 3N system Scattering & Reactions Bound states

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? nnp Space Star anomaly 1980’s higher energy discrepancies pd sactt.  discrepancy lower energy discrepancies ppn Space star anomaly QFS anomaly? ??? Discrepancies in 3N systems and their origins FM-3NF 1957

3 H binding energy (Experiment) 8.482MeV (Theory) 2NF 2  3NF ~1MeV + + Nd scattering cross section H.Witala et al. (1998) found that discrepancy in 3N binding energy, and discrepancy in Nd scattering cross section. are removed by including 2  3NF. E N = 65 MeV E N = 140 MeV 2  3NF

Ed=140MeV Ep= 70MeV Ed=200MeV Ep=100MeV Ed=270MeV Ep=135MeV AydAyd A xz A yy A xx K. Sekiguchi et al. Cross section is reproduced by 2  3NF, but Analyzing powers are not reproduced. + + Nd scattering Analyzing Powers

At 250 MeV also, Ay is not reproduced by 2  3NF or by relativity. 2  3NF effects relativistic effects + + Nd scattering Ay at 250 MeV pd Ay & nd Ay at 250 MeV pd Ay & nd Ay at 250 MeV

2NF only 2NF+3NF Non-relativistic Relativistic K. Hatanaka et al., PRC (2002) Y. Maeda et al., PRC (2007) At 250 MeV, also cross section is not reproduced. + +

Enhancement of backward cross section starts around 100 MeV. Cross Section at 250 MeV Cross Section Ratio (Exp/Calc) at150º 150º  = 150 degree Cross section is more basic quantity than analyzing powers.

Elastic Break-up ~5 times At 250 MeV, break-up reaction is dominant. We investigate enhancement of break-up cross section n+d total reaction cross section total

GR LAS p - beam Liq D 2 Target CS at 250 MeV Only p 1 was detected to see global feature p1p1 p2p2 n p1p1 Our first BU experiment at 250 MeV

CS at 250 MeV Only p 1 detected 2NF+3NF Only 2NF nd calc.by H. Witala p2p2 n p1p1 Cross section ~1.6 times Cross Section Exp > Calc E1E1

2NF+3NF Only 2NF nd calc.by H. Witala Ay at 250 MeV Only p 1 detected Ay Exp ≠ Calc p2p2 n p1p1 E1E1

CS at 250 MeV p2p2 n p1p1 p 1 and p 2 detected (kinematically complete exp.) P 2 detected P 1 detected Second experiment Undetected in the first exp. Microscopic study of CS enhancement. Configuration space is wide, and Magnetic spectrometers have narrow E-range  find  2 -dependence of CS emhance  Select configurations

E1E1 A B C A C B  1 -dependence at different E 1 11 p2p2 p1p1 We selected B, E 1 = 150 MeV. Selection of E 1 -range

detected p 1 free detected p 1 detected p 2 Second experiment First experiment

2NF+3NF 2NF Calc by H. Kamada  2 -dependence at E 1 =150 MeV,  1 = 15 degree, and  12 = 180 degree.  12 -dependence at E 1 =150 MeV,  1 = 15 degree, and  2 = 35 degree.  12 22 11 Selection of  2 -range Selection of  12

GR LAS p - beam Liq D 2 Target p1p1 p2p2 Cross Section at 250 MeV p2p2 n p1p1 p 1 and p 2 detected

Liquid D 2 target True events BG events ~10mm thickness LD 2 [ thick enough] 6  m thick window foil [thin enough] “Empty” target easily made for BG run Low Background level

New data were added for p 1 detection. New and previous dara agree well 2  3NF effects p2p2 n p1p1

Same data. Relativistic effects.

Same data. 3NF effects and relativistic effects.

True+BG BG Raw data at  1 =15 ° and  2 =35 ° p2p2 n p1p1

Check of the absolute cross section using pd elastic scattering cross section pd scattering

Calc. by H. Witala  3NF effects 2NF+3NF Only 2NF p2p2 n p1p1

Calc. by H. Witala Relativistic effects Relativistic Non-relativistic p2p2 n p1p1

Calculation by H. Witala 3NF effects and relativistic effects p2p2 n p1p1

 2 dependence of BU cross section Systematic uncertainty p2p2 n p1p1    deg E 1 =150 MeV E p-beam = 250 MeV ~1.6 1

x 5.8 If  3NF effects are artificially 5.8 times increased, experimental CS data are roughly reproduced.

Arbitrary unit Possible enhancement of  3NF at higher energy But, 5.8 times may be too large to explain by  3NF enhance.  Effects of  3NF and/or  3NF?

Summary At 250 MeV, pd breakup cross section were measured by First, detecting 1-protons from p+d  p+p+n reaction, Second, detecting 2-protons in coincidence. Large discrepancy of about 2 times in CS was observed. The discrepancy was found to appear in a wide angular region.  3NF effects are too small (5.8 time) to explain the discrepancy, also relativistic effects are too small to explain the discrepancy. CS discrepancy monotonically increases with energy. New 3NF may be necessary to explain the discrepancy.

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? nnp Space Star anomaly 1980’s higher energy discrepancies pd sactt.  discrepancy lower energy discrepancies ppn Space star anomaly QFS anomaly? ??? Discrepancies in 3N systems and their origins FM-3NF 1957 We are here.

2012/ 8/20(Mon)-8/25(Sat) Fukuoka Convention Center (already reserved) Contact persons : Hakata bay Come to FB20 in Fukuoka