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Discrepancy in pd Breakup Reaction at Ep = 13 MeV

Discrepancy in pd Breakup Reaction at Ep = 13 MeV K. Sagara , M. Tomiyama, S. Shimomoto, T. Ishida, T. Kudoh, S. Kuroita, T. Morikawa, M. Shiota, H. Ohira, *H. Kamada and **H. Witala Dept. of Physics, Kyushu University, Fukuoka, Japan

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Discrepancy in pd Breakup Reaction at Ep = 13 MeV

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  1. Discrepancy in pd Breakup Reaction at Ep = 13 MeV K. Sagara, M. Tomiyama, S. Shimomoto, T. Ishida, T. Kudoh, S. Kuroita, T. Morikawa, M. Shiota, H. Ohira, *H. Kamada and **H. Witala Dept. of Physics, Kyushu University, Fukuoka, Japan *Dept. of Physics, Kyushu Institute of Technology, Kita-Kyushu, Japan, **Dept. of Physics, Jagiellonian University, Cracow, Poland

  2. Outlook Backgrounds: Ay puzzle in pd and nd scattering exists at 0 < Ep and En < 30 MeV. Space Star (SS) anomaly in nd breakup is most prominent at En=13 MeV. 2p3NF effects are too small to explain these discrepancies. Questions: Does SS anomaly appear also in pd breakup at 13 MeV? Are there further discrepancies in pd breakup at 13 MeV? Experiments: We made three measurements at Ep =13 MeV 1) D(p,pp)n experiment at pp FSI 2) D(p,p)pn experiment at qp =10deg ~60 deg 3) D(p,pp)n experiment at many angle pairs around SS A new method to estimate Coulomb effects: Watson&Migdal-Faddeev approximation for pd breakup cross section is compared with pd calculation by Deltuva et al.

  3. Ay puzzle: Systematic measurement of pd scattering Ay at Ep =2-18 MeV at Kyushu University (1994) Tornow talked about nd Ay puzzle on Monday. Ay puzzle is still an open problem since 1986.

  4. Space Star anomaly D(n,nn)p at En =13 MeV D(p,pp)n at Ep =13 MeV nd exp. Erlangen & TUNL nd calc. pd exp. Koeln

  5. Energy Dependence of SS

  6. Questions: • Does SS anomaly existalso in pd breakup at 13 MeV? • Are there other discrepancies in pd breakup at 13 MeV? • We made three experiments at 13 MeV: • D(p,pp)n experiment at pp FSI • to study the treatment of Coulomb effects • 2) D(p,p)pn experiment at qp = 10deg ~60 deg • to see global feature of breakup cross section • 3) D(p,pp)n experiment at wide angular range around SS • to see angular dependence of SS anomaly

  7. Experiment (1)Ep =13 MeV D(p,p1p2)n near pp-FSI

  8. D(p,p1p2)n Ep=13MeV data 20 deg. FSI S-curve E1 vs. E2 E1 vs. E2 (TOF gated) ΔT1-ΔT2 vs. ΔT(E1,E2) back ground (Energy gated)

  9. D(p,pp)n at 13 MeV Comparisonwith nd-Faddeev calc. Watson-Migdal pp FSI calc. Faddeev calc. by H. Kamada

  10. Watson-Migdal FSI Formula nd breakupnn-FSI pd breakup pp-FSI Scattering length Effective range Coulomb penetration factor Sommerfeld parameter Slowly varying function

  11. F(nd) = f(n1n2) + f(n1p) + f(n2p) F(pd) ≈ f(n1n2)x(WMpp/WMnn) + f(n1p) + f(n2p) WMnn(Enn) WMpp(Epp) ENN(MeV) (WMpp/WMnn) (WMpp/WMnn) 4 40 0 ENN(MeV) 20 ENN(MeV) 2 0

  12. n+n+p calculation ↓ p+p+n calculation

  13. WM-Faddeev calculation gives nearly the same results as pd calculation by Deltuva et al. Calc. by Deltuva et al WM-Faddeev calculation

  14. Experiment (2): D(p,p)pn cross section at qp = 10~60 deg at Ep = 13 MeV D2 gas / vacuum For 20degree < qp 13 MeV p For qp ≤ 20degree D2 gas / vacuum / H2 gas 2.2mm Havar foil 13 MeV p 4mm Al foil

  15. D(p,p)pn at 10 degree D2 target vacuum target H2 target – vacuum target Ep (channel)

  16. Deltuva etal. WM+Faddeev

  17. Preliminary data 15 degree 10 degree 20 degree Tentative conclusion: In D(p,p)pn inclusive cross section at qp = 10 ~ 60 degree, no discrepancy has been found.

  18. Experiment (3): D(p,pp)n cross section at around Space Star at Ep = 13 MeV n p q2=50.5 f12=120 p q1=50.5 Lab. system CM system

  19. D(p,pp)n cross section was measured at 23 angle pairs around SS configuration (q1=50.5, q2=50.5 , f12=120 )

  20. Present data and Koeln data at SS agree well. Calc. by Deltuva nd calc pd calc

  21. 53.5-53.5 50.5-50.5 47.5-47.5 space star 56.0-56.0 59.5-59.5 63.0-63.0

  22. averaged cross section Calc. by Deltuva q1+q2 q2 q1 There is a discrepancy in pd breakup cross section around the space star.

  23. Summary Three experiments have been made on 1) D(p,pp)n cross section at pp FSI 2) D(p,p)pn cross section at qp =10deg ~60 deg 3) D(p,pp)n cross section at around the space star Cross section around pp-FSI and D(p,p)pn inclusive cross section are well reproduced by pd calculation by Deltuva et al. There is a discrepancy (10%-15%) in the cross section around the space star. Watson&Migdal-Faddeev approximation was found to be a simple and effective method to estimate pd breakup cross section.

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