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Measurement of 2 H( p,pp )n cross sections at E p = 250 MeV

Measurement of 2 H( p,pp )n cross sections at E p = 250 MeV. Sho Kuroita 1 , K. Sagara 1 , Y. Eguchi 1 , K. Yashima 1 , T. Shishido 1 , T. Yabe 1 , M. Dozono 1 , Y. Yamada 1 , T. Wakasa 1 , T. Noro 1 , H. Matsubara 2 J. Zenihiro 2 , A. Tamii 2 , H. Okamura 2 , K. Hatanaka 2 , T. Saito 3

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Measurement of 2 H( p,pp )n cross sections at E p = 250 MeV

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  1. Measurement of 2H(p,pp)n cross sections at Ep = 250 MeV Sho Kuroita1, K. Sagara1, Y. Eguchi1, K. Yashima1, T. Shishido1, T. Yabe1, M. Dozono1, Y. Yamada1, T. Wakasa1, T. Noro1, H. Matsubara2 J. Zenihiro2, A. Tamii2, H. Okamura2, K. Hatanaka2, T. Saito3 Y. Maeda3, H. Kamada4, Y. Tameshige5 1: Department of Physics, Kyushu University 2: Research Center for Nuclear Physics (RCNP), Osaka University 3: Department of Applied Physics, University of Miyazaki 4; Department of Physics, Faculty of Engineering, Kyushu Institute of Technology 5: National Institute of Radiological Sciences

  2. Introduction 1 • 1957 Fujita – Miyazawa suggested the existence of three nucleon force. • Then 2p-exchange three nucleon force (2p3NF) models were created, and these 2p3NF well described binding energies of nuclei were constructed by few nucleon. • Differential cross sections of pd scattering below EN = 140 MeVwere well described by including 2p3NF in Faddeev calculations. Cross sections of pd elastic scattering at Ep = 65, 140 MeV NN + TM3NF NN only H. Witalaet al., PRL81 (1998) 1183. 65 MeV 140 MeV FB19 - Bonn University, Germany

  3. Introduction 2 • Besides 2p-exchange 3NF, heavy-meson exchange 3NF are predicted in cPT. • These heavy-meson exchange 3NFs are expected that the effects become larger at high energy region. FB19 - Bonn University, Germany

  4. Study by elastic scattering • Above EN = 140 MeV, cross section of pd elastic scattering does not described by Faddeev calculation with 2π3NF. EN = 250 MeVNd elastic scattering K. Hatanakaet al., PRC66 044002 (2002). Y. Maeda et al., PRC76 014004 (2007). NN + TM3NF NN only ＊The disagreement of pd elastic scattering become larger at higher incident energy. ＊And the disagreements are not related to π-threshold p-threshold FB19 - Bonn University, Germany

  5. Study by pd breakup – 2H(p,p)pn reaction -- • So we have measured cross section of pd breakup reaction in order to investigate origins of the disagreement on Nd scattering cross section. • We measured cross section and analyzing power Ay of inclusive pd breakup 2H(p,p)pn reaction at Ep = 247 MeV to study the global feature of pd breakup reaction at intermediate energy region. At intermediate energies, Nd breakup reaction is main reaction process in 3N systems. J. Kuros-Zoluierczuket al.,PRC66, 024003 (2002). Observable : cross section, Ay (E = 70 ~ 230 MeV) Angle : 10, 15, 20 deg. Detector : Spectrometer (LAS@RCNP) VDC, Scintillator Target : Liquid Deuterium Calc. by H. Witala, private communication Angle is free ! detected p1 FB19 - Bonn University, Germany

  6. Study by pd breakup – 2H(p,p)pn reaction -- • Even after inclusion of 2π3NF , large disagreements remain. • The experimental cross section is about 1.8 times larger than calc. at 15 deg . • First, we pay attention to only the disagreement of cross sections. nd calculation by Prof. H. Witala FB19 - Bonn University, Germany

  7. Study by pd breakup – 2H(p,p)pn reaction -- • pd calculation indicate Coulomb effect slightly decreases cross section. • To sum up, the orign(s) of the disagreement is not Coulomb effcet. pd calculation by A. Deltuva FB19 - Bonn University, Germany

  8. Relations between 2H(p,p)pn and 2H(p,pp)n • 2H(p,p1)pn reaction== previous experiment == • 2H(p,p1p2)n reaction == New experiment == Angle is free ! detected p1 q2 q1 = 15°fixed E1 = 150 MeV FB19 - Bonn University, Germany

  9. Prediction from calculation Calc. by Prof. H. Kamada • Dependence of cross section for q2 d3s/dW1dW2dE(15f, 150 MeV, q2, 180f) • 3N calculation for 2H(p,p1p2)n reaction at 250 MeV suggests that 2H(p,pp)n cross section has the maximum at q2 ~ 35 deg. • Dependence of cross section for f12 d3s/dW1dW2dE(15f, 150 MeV, 35f, f12) • Also 3N calculation suggests that 2H(p,p1p2)n cross section has the maximum at f12 = 180 deg. • So we measure cross section at f12 = 180 deg. q2 f12 FB19 - Bonn University, Germany

  10. Experiment • 2H(p,pp)n breakup reactions at Ep = 250 MeV • 250 MeV proton beam from RING cyclotron @ RCNP • WS course in West exp. Room • Observable : Cross section • target : Liquid deuterium CD2 • Detector : GR (spectrometer) LAS (spectrometer) Scintillator • Luminosity monitor • dp elastic scattering (kinematical coincidence) • Configuration • 2H(p,p1p2)n reaction q1 (GR) = 15 deg fixed q2(LAS) = 35, 50, 65, 80 deg GR Scatt. Chamber * Liq. D2 LAS FB19 - Bonn University, Germany

  11. Target – Liquid deuterium -- • We used liquid deuterium target system as deuteron target . Liquid deuterium target is an almost pure and very thick deuteron target, and it enables low background experiments. • Thickness : ~ 220 mg/cm2, (target length = ~12 mm) • Cell temperature : ~ 18 K (cooled by Cryo – refrigerator) (monitored by Si diode thermometer) • The thickness of liquid deuterium (liq. D2) target is varied by condition of cell temperature and gas pressure e.t.c.. • So we monitored the thickness by using coincidence measurement of pd elastic scattering simultaneously. Cryo - refrigerator Liq. D2 target cell Heater expand ! FB19 - Bonn University, Germany

  12. Result -- 2H(p,p1)pn reaction -- • We have measured cross sections of 2H(p,p1)pn reaction to check the disagreement of the previous 2H(p,p)pn cross sections at 250 MeV in the same setup. • We have reconfirmed the large disagreement of 2H(p,p1)pn cross section between experimental data and Faddeev calculation including 2p3NF. Calc. by Prof. H. Witala expand preliminary preliminary FB19 - Bonn University, Germany

  13. Spectrum -- 2H(p,pp)n reaction -- • q1 (GR) = 15 deg, q2 (LAS) = 35 deg, f12 = 180 deg. B.G. event True + B.G. event q2 momentum q2 momentum q1 momentum q1 momentum Yield B.G. subtract E1[MeV] E1[MeV] FB19 - Bonn University, Germany

  14. Result 1 -- 2H(p,p1p2)n reaction -- Calc. by Prof. H. Kamada q2=50 deg q2=35 deg q1=15deg, E1=150 MeV q1=15deg, E1=150 MeV preliminary preliminary preliminary preliminary FB19 - Bonn University, Germany

  15. Result 2 -- 2H(p,p1p2)n reaction -- Calc. by Prof. H. Kamada q2=80 deg q2=65 deg q1=15deg, E1=150 MeV q1=15deg, E1=150 MeV preliminary preliminary preliminary preliminary FB19 - Bonn University, Germany

  16. Trend of 2H(p,p1p2)n cross sections • Dependence of cross section for q2 d3s/dW1dW2dE(15f, 150 MeV, q2, 180f) • The cross sections of 2H(p,p1p2)n reaction at 250 MeV have the maximum at q2 = 35 deg. • The ratio of the disagreement of 2H(p,p1p2)n cross section have also has the maximum at q2 = 35 deg. And the ration become smaller at backward angles. Calc. by Prof. H. Kamada preliminary q2 = 35°,50°, 65°,80° q1 = 15°fixed E1 = 150 MeV preliminary 16 FB19 - Bonn University, Germany

  17. Result 1 -- 2H(p,p1p2)n reaction -- Calc. by Prof. H. Kamada q2=50 deg q2=35 deg q1=15deg, E1=150 MeV q1=15deg, E1=150 MeV preliminary preliminary preliminary preliminary FB19 - Bonn University, Germany

  18. Conclusion • We have measured cross sections of 2H(p,p1p2)n reaction at E1 = 150 MeV, q1 = 15 deg fixed, q2 = 35, 50, 65, 80 deg. (total 4 setup). • Simultaneously, we have measured cross section 2H(p,p)pn reaction and confirmed the large disagreement between experimental data and Faddeev calculations including 2p3NF. • The preliminary result of 2H(p,pp)n cross sections suggest large disagreements between experimental data and calculations as same as 2H(p,p)pn reaction. • We think that origin(s) of these discrepancy is • Heavy-meson exchange 3NF • pr3NF, rr3NF, e.g.. • Relativistic effect • So we will have to study relations between these disagreement and candidate of origin(s). preliminary ~ x 1.8 FB19 - Bonn University, Germany

  19. Others disagreement • Nd elastic scattering (s, Ay, Kij) … RCNP, RIKEN, KVI etc (EN > 140 MeV) • pd radiative capture (s?, Aij) … RCNP (Ed = 200 MeV) FB19 - Bonn University, Germany

  20. Motivation 2 -- 2H(p,p)pn reaction -- • The disagreements of cross sections for 2H(p,p1)pn at 250 MeV become larger at forward angles. Dose the disagreements vanish at backward angle ? Previous exp. 2H(p,p1)pn reaction detected p1 3 1 2 2 3 1 • So we have also measured cross sections of 2H(p,p)pn reaction at backward angles to see whether the discrepancy exist at backward angles. FB19 - Bonn University, Germany

  21. Collinear configuration • Why d3s/dW1dW2dE(15f, 150 MeV, ~35f, 180f) has a maximum ? • When q1 = 15 deg and E1 = 150 MeV, q2 =36 deg, 2H(p,p1p2)n reaction is in “Collinear configuration”. • 3N calculations predict cross section has maximum at Collinear configuration. • Whether SR3NF effects dominate in collinear configuration or not is also an interesting subject ? q1= 15 deg (lab.) E1 = 150 MeV FB19 - Bonn University, Germany

  22. Study by pd breakup – 2H(p,p)pn reaction -- • So we have measured cross section of pd breakup reaction in order to investigate origins of the disagreement on Nd scattering cross section. • We measured cross section and analyzing power Ay of inclusive pd breakup 2H(p,p)pn reaction at Ep = 247 MeV to study the global feature of pd breakup reaction at intermediate energy region. At intermediate energies, Nd breakup reaction is main reaction process in 3N systems. J. Kuros-Zoluierczuket al.,PRC66, 024003 (2002). Observable : cross section, Ay (E = 70 ~ 230 MeV) Angle : 10, 15, 20 deg. Detector : Spectrometer (LAS@RCNP) VDC, Scintillator Target : Liquid Deuterium Calc. by H. Witala, private communication measured FB19 - Bonn University, Germany

  23. Introduction 2 • So we maybe think that the strength / effects of 2p3NF are also understood by studies of binding energies of nuclei were constructed by few-nucleon and Nd elastic scattering. • But others of three-nucleon (3NF) is not found, for example, pr3NF, rr3NF that were the existence expected. • Effects of these 3NF may be found at higher energies because these 3NF are the model exchange heavier than p. • Besides 2p3-exchange NF, heavy-meson exchange 3NF are redicted in cPT.. FB19 - Bonn University, Germany

  24. 2H(p,n)pp @ IUCP • The disagreement of cross section exist at another energies, for example, 2H(p,n) reaction at Ep = 197 MeV by IUCF. • We have already systematic cross section data for 2H(p,p)pn reaction at 250 MeV in wide energy region of reaction protons. • If we would performed a experiment for 2H(p,pp)n reaction, we should measure cross section for 2H(p,p)pn to get information of global feature and pp-FSI. expand Cross section of 2H(p,n) at IUCF D.L. Proutet al., PRC65 034611 (2002). In this experiment, cross sections for 2H(p,n) was measured at q = 13, 24, 37, 48 deg, and concentrated to QFS. FB19 - Bonn University, Germany

  25. Motivation 1 -- 2H(p,pp)n reaction -- • The discrepancy of 2H(p,p1)pn is the largest at around E1 = 150 MeV . • So we have measured cross sections for 2H(p,p1p2)n reaction around E1 = 150 MeV at fixed q1 = 15 deg. in order to investigation origins for the disagreement of 2H(p,p1)pn. New exp. 2H(p,p1p2)n reaction (microscopic study) Previous exp. 2H(p,p1)pn reaction q2 q1 = 15°fixed E1 = 150 MeV detected p1 Angle is free ! FB19 - Bonn University, Germany

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