Cross section enhancement in pd reactions at higher energ ｙ

Cross section enhancement in pd reactions at higher energｙ 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

+ g + + + 3Nsystem Bound states Scattering & Reactions +

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. s discrepancy pp3NF(FM) was found 1998 pr3NF? rr3NF? relativity? FM-3NF 1957 pd breakup s discrepancy 3N BE problem 1980’s pd capture Ajj anomaly lower energy discrepancies nnp Space Star anomaly 1980’s ppn Space star anomaly QFS anomaly? ???

Nd scattering cross section 3H binding energy EN= 65 MeV (Theory) (Experiment) + + 2NF 8.482MeV 2p3NF ~1MeV 2p3NF EN= 140 MeV H.Witala et al. (1998) found that discrepancy in 3N binding energy, and discrepancy in Nd scattering cross section. are removed by including 2p3NF. 2p3NF

Nd scattering Analyzing Powers Axz Axx Ayd Ayy Ed=140MeV Ep= 70MeV + + Ed=200MeV Ep=100MeV Ed=270MeV Ep=135MeV K. Sekiguchi et al. Cross section is reproduced by 2p3NF, but Analyzing powers are not reproduced.

Nd scattering Ay at 250 MeV pd Ay & nd Ay at 250 MeV pd Ay & nd Ay at 250 MeV + + 2p3NF effects relativistic effects At 250 MeV also, Ay is not reproduced by 2p3NF orby relativity.

At 250 MeV, also cross section is not reproduced. K. Hatanaka et al., PRC66 044002(2002) Y. Maeda et al., PRC76 014004(2007) + + 2NF only 2NF+3NF Non-relativistic Relativistic

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

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

Our first BU experiment at 250 MeV p2 p1 n CS at 250 MeV GR Liq D2 Target p - beam LAS p1 Only p1 was detected to see global feature

p1 p2 n Only p1 detected CS at 250 MeV Cross section Cross section ~1.6 times E1 Cross section 2NF+3NF Only 2NF • nd calc.by H. Witala Cross Section Exp > Calc

p1 p2 n Ay at 250 MeV Only p1 detected Ay Ay E1 Ay 2NF+3NF Only 2NF • nd calc.by H. Witala Ay Exp ≠ Calc

Second experiment p1 and p2 detected (kinematically complete exp.) p2 p1 n CS at 250 MeV Microscopic study of CS enhancement.  find q2-dependence of CS emhance Undetected in the first exp. P2 detected P1 detected Configuration space is wide, and Magnetic spectrometers have narrow E-range  Select configurations

Selection of E1-range p2 p1 C A B E1 q1-dependence at different E1 We selected B, E1 = 150 MeV. B C A q1

First experiment free detected p1 Second experiment detected p2 detected p1

Selection of q2-range q2-dependence at E1 =150 MeV, q1 = 15 degree, and F12 = 180 degree. 2NF+3NF 2NF Calc by H. Kamada q2 Selection of F12 F12 q1 F12-dependence at E1 =150 MeV, q1 = 15 degree, and q2 = 35 degree. F12

p2 n p1 Cross Section at 250 MeV p1 and p2 detected p2 GR Liq D2 Target p - beam LAS p1

Liquid D2 target ~10mm thickness LD2 [ thick enough] 6 mm thick window foil [thin enough] “Empty” target easily made for BG run Low Background level True events BG events

New data were added for p1 detection. New and previous dara agree well p1 p2 n 2p3NF effects

Same data. Relativistic effects.

Same data. 3NF effects and relativistic effects.

p1 p2 n Raw data atq1 =15 ° and q2 =35 ° True+BG BG

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

p1 p2 n pp3NF effects Calc. by H. Witala 2NF+3NF Only 2NF

p1 p2 n Relativistic effects Calc. by H. Witala Relativistic Non-relativistic

p1 p2 n 3NF effects and relativistic effects Calculation by H. Witala

p1 p2 n Ep-beam = 250 MeV q2 dependence of BU cross section Systematic uncertainty q1= 15 deg E1=150 MeV ~1.6 1

x 5.8 If pp3NF effects are artificially 5.8 times increased, experimental CS data are roughly reproduced.

Possible enhancement of pp3NF at higher energy Arbitrary unit But, 5.8 times may be too large to explain by pp3NF enhance.  Effects of pr3NF and/or rr3NF?

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. pp3NF 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.

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. s discrepancy We are here. pp3NF(FM) was found 1998 pr3NF? rr3NF? relativity? FM-3NF 1957 pd breakup s discrepancy 3N BE problem 1980’s pd capture Ajj anomaly lower energy discrepancies nnp Space Star anomaly 1980’s ppn Space star anomaly QFS anomaly? ???

2012/ 8/20(Mon)-8/25(Sat) Come to FB20 in Fukuoka Hakatabay Fukuoka Convention Center (already reserved) Contact persons : sagara@phys.kyushu-u.ac.jp hiyama@riken.jp tamii@rcnp.osaka-u.ac.jp ishikawa@hosei.ac.jp kamada@mns.kyutech.ac.jp

Cross section enhancement in pd reactions at higher energ ｙ