Systematic measurement of pd breakup cross section at quasi-free scattering

1. Systematic measurement of pd breakupcross section at quasi-free scattering Y. Eguchia, K. Sagaraa, S. Kuroitaa, K. Yashimaa, T. Shishidoa, T. Yabea, and S. Ishikawab aDepartment of Physics, Kyushu University bDepartment of Physics, Science Research Center, Hosei University

2. π π π ρ N N N N N N Discrepancies in 3N system ① Higher energy discrepancies pd elastic scatt. discrepancy pr3NF ? rr3NF ? Relativity ? pd elastic scatt. C.S. discrepancy 1994-1996-1997 pp3NF(FM) was found 1998 pd capture Ajjdiscrepancy FM-3NF 1957 3N binding energy problem 1980’s pdbreakup discrepancy ② Lower energy discrepancies Ay puzzle 1986 Ay puzzle ??? Space Star Anomaly Quasi-Free Scatt. Anomaly ? Space Star Anomaly 1989 ??? 19th International IUPAP Conference on Few-Body Problems in Physics

3. Space Star (SS) Anomaly nd exp. Erlangen & TUNL （●）（○） EN=13 MeV Space Star (c.m. system) (1996) (1989) ~30% nd calc. pd exp. Koeln （1991） 90° Space Star equilateral triangle J.STRATE et al., Nucl. Phys. A501 (1989) 51H.R.Setzeet al., Physics Letters B388 (1996) 229 G.RAUPRICH et al., Nucl.Phys. A535 (1991) 313 • In Star configuration, outgoing 3 nucleons have the same energy and form an equilateral triangle. • In Space Star (SS), the star plane is perpendicular to the beam axis in c.m. system. SS Anomaly was first found in 1989 in nd breakup reaction at 13 MeV. 19th International IUPAP Conference on Few-Body Problems in Physics

4. Space Star (SS) Anomaly in pd breakup pdcalc. by Deltuvaet al. (2005) nd exp. Erlangen & TUNL （●）（○） EN=13 MeV nd calc. EN=13 MeV (1996) (1989) ~30% nd calc. ~15% pd exp. Koeln（□）& KUTL（■） pd exp. Koeln （1991） (2002) Space Star A.Deltuvaet al., PRC72,054004 (2005) • At pd SS, exp. cross section is smaller than pd calc. • At nd SS, exp. cross section is larger than nd calc. • Recently pd calc. have become available (by Deltuva et al. and by Ishikawa). 19th International IUPAP Conference on Few-Body Problems in Physics

5. Energy dependence of SS Anomaly 90° Space Star Erlangen TUNL Bochum Erlangen n + d ~30% TUNL Koeln Koeln ~15% KUTL G. Rauprich et al., Nucl. Phys. A 535, 313 (1991). G. Grossmann et al., Nucl. Phys. A 603, 161 (1996). H. Patberg et al., Phys. Rev. C 53, 1497 (1996). K. Gebharbt et al., Nucl. Phys. A 561, 232 (1993). H. R. Setze et al., Phys. Lett. B 388, 229 (1996). Z. Zhou et al., Nucl. Phys. A 684, 545 (2001). M. Stephan et al., Phys. Rev. C 39, 2133 (1989). TUNL Koeln p + d SS Anomaly has a maximum at around EN = 13 MeV. 19th International IUPAP Conference on Few-Body Problems in Physics

6. Off-plane Star • Systematic measurements ofpd breakup cross section have been started • at Off-plane Star • in 0°≦ α ≦ 180 ° • at Ep = 9.5 MeV (Ed = 19 MeV) and Ep = 13 MeV (Ed = 26 MeV). Off-plane Star (c.m. system) α • An angle between the star plane and the beam axis in c.m. system is defined as an inclined angle α. • α = 90 deg. at Space Star 19th International IUPAP Conference on Few-Body Problems in Physics

7. a dependence of Star Anomaly α=144º Space Star (α = 90 deg.) EN=13 MeV α=124º ~15% J. Ley et al, (Koeln) PRC73 (2006) 064001 ・　 Anomaly exists at forward angles.→ My talk • Star Anomaly has different αdependence between 9.5 MeV and 13 MeV. → Maeda’s talk (nuclear forces session) 19th International IUPAP Conference on Few-Body Problems in Physics

8. Discrepancy at Quasi-free Scattering 90° ～QFS α = 0 deg. Space Star (α = 90 deg.) ～QFS En At forward angles, star configuration is close to Quasi-free Scattering (QFS) configuration. Cross section become several times larger than SS cross section. Therefore, the anomaly at forward angles, is considered to be QFS anomaly than Star Anomaly. 19th International IUPAP Conference on Few-Body Problems in Physics

9. QFS condition We measure pd breakup C.S. at QFS configuration. p + d→ p1 + p2 + n QFS QFS Stara=0° 19th International IUPAP Conference on Few-Body Problems in Physics

10. Experiment (pp-QFS) Si-SSD p-beam F.C. CD2foil M Monitor K. Sagara et al., Phys. Rev. C 50, 576 (1994) CD2foil (Rotary target) • p-beam : Ep=9.5 MeV, 13 MeV (~150 nA) @ KUTL • Target : CD2 foil (thickness : ~0.3mg/cm2) • Detector : Si-SSD (solid angle : ~0.4 msr) • Observable : cross section • Target thickness was monitored by using pd elastic scattering. • We used accurate pd elastic C.S. to obtain absolute pd breakup C.S.. 19th International IUPAP Conference on Few-Body Problems in Physics

11. Data analysis Raw data S curve E1 vs. E2 E1 vs. E2 B.G. subtracted TOF gate TOF data E1 vs. E2 background TOF gate ΔT2-ΔT1 vs. ΔT (E2,E1) background We measure Energy and Time of Flight of 2 proton. 19th International IUPAP Conference on Few-Body Problems in Physics

12. Result (pp-QFS) Ep= 13 MeV Ep= 9.5 MeV QFS QFS ~10% smaller ~13% smaller preliminary preliminary 19th International IUPAP Conference on Few-Body Problems in Physics

13. Energy dependence of QFS Anomaly Ep= 9.5 MeV QFS ~10% n + d Bochum ( 1992 ) ( ) Ep= 13 MeV 10 ~ 13% ~13% KUTL p + d 19th International IUPAP Conference on Few-Body Problems in Physics

14. Energy dependence of QFS Anomaly θ1= θ2= 42 deg. ～18% Bonn univ.（2002） En=26 MeV QFS n + d Bochum ( 1992 ) 16 ~ 18% ( ) A. Siepe et al., Phys. Rev. C 65, 034010 (2002) θ1= θ2= 42.2 deg. 10 ~ 13% ～16% CIAE（2007） En=25 MeV KUTL p + d X. C. Ruan et al., Phys. Rev. C 75, 057001 (2007) 19th International IUPAP Conference on Few-Body Problems in Physics

15. Energy dependence of QFS Anomaly 90° QFS Large charge asymmetry n + d Bochum ( 1992 ) Space Star 16 ~ 18% ( ) n + d ~30% 10 ~ 13% ~15% KUTL p + d p + d 19th International IUPAP Conference on Few-Body Problems in Physics

16. Systematic measurement of C.S. at around QFS p + d→ p1 + p2 + n Ep= 9.5 MeV Ep= 13 MeV Star α=0 Star α=0 QFS QFS θ1 = θ2 θ1 = θ2 19th International IUPAP Conference on Few-Body Problems in Physics

17. Angle dependence of QFS Anomaly Ep= 9.5 MeV QFS (9.5 MeV) θ1 = θ2 (9.5 MeV) ① ② ⑦ ② ① ④ ⑤ ⑥ ③ ③ ~10 % Ep= 13 MeV 1 QFS 13 MeV 2 θ1 = θ2 13 MeV 3 4 7 7 4 2 3 4 1 5 6 ~ 15% 6 5 19th International IUPAP Conference on Few-Body Problems in Physics

18. Summary • We performed systematic measurement of pd breakup cross section at around Quasi-free Scattering (QFS). • Those experimental results were compared with the calculation included coulomb force by Deltuva et al.. • Both at 9.5 MeV and 13 MeV , pd experimental data are smaller than pd calculation generally. • Large charge asymmetry was found both in SS Anomaly and in QFS Anomaly; experiment > calculation at nd breakup and experiment < calculation at pd breakup. • We will continue systematic experiment of pd breakup cross section to find the origin of Star Anomaly and QFS Anomaly. 19th International IUPAP Conference on Few-Body Problems in Physics

19. 19th International IUPAP Conference on Few-Body Problems in Physics

20. π π π ρ N N N N N N Discrepancies in 3N system ① Higher energy discrepancies pd elastic scatt. discrepancy pr3NF ? rr3NF ? Relativity ? pd elastic scatt. C.S. discrepancy 1994-1996-1997 pp3NF(FM) was found 1998 pd capture Ajjdiscrepancy FM-3NF 1957 3N binding energy problem 1980’s pdbreakup discrepancy ② Lower energy discrepancies Ay puzzle 1986 Ay puzzle ??? Space Star Anomaly Quasi-Free Scatt. Anomaly Space Star Anomaly 1989 ??? 19th International IUPAP Conference on Few-Body Problems in Physics

21. Space Star (SS) Space Star (c.m. system) Relative energy = 0 90° FSI equilateral triangle p d • In Star configuration, outgoing 3 nucleons have the same energy and form an equilateral triangle. • In Space Star (SS), the star plane is perpendicular to the beam axis in c.m. system. • Star configuration is most far from Final State Interaction (FSI) configuration. • In FSI configuration, one of relative energy = 0. • FSI enhances Cross Section. • It is expected that small effects are seen in Star configuration. 19th International IUPAP Conference on Few-Body Problems in Physics