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The Antiproton-Ion Collider

The Antiproton-Ion Collider. R. Krücken Technische Universität München for the Antiproton Ion Collider Collaboration. EC, 500 KV. NESR. Neutron-skin thickness in Sn isotopes. AIC range and error estimate. (1&2) RHB/NL3. (3) RHB/NLSH. (3 He,t). antiprotons. (p,p). AIC range.

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The Antiproton-Ion Collider

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  1. The Antiproton-Ion Collider R. Krücken Technische Universität München for the Antiproton Ion Collider Collaboration EC, 500 KV NESR

  2. Neutron-skin thickness in Sn isotopes AIC range and error estimate (1&2) RHB/NL3 (3) RHB/NLSH (3He,t) antiprotons (p,p) AIC range (4) HFB/SLy4 (5) HFB/SkP M. Bender, P.H. Heenen, P.G. Reinhard Rev. Mod. Phys. 75 (2003) 122

  3. Why the antiproton ion collider? • charge radii can reliably be measured (Lasers, (e,e)) • several methods available for matter / neutron radii • (p,p), (,’), (3He,t), reaction cross section, antiprotonic atoms • results • for different methods are not consistent • are partly model dependent • are partly normalized to theory • We need a method that determines proton and neutron radii • using the same method in the same experiment • independently at the same time • with low statistical and systematic errors • EXO-pbar measures higher moments of the density distribution • AIC measures rms radii •  combination provides information on shape of density distribution

  4. Antiproton Ion Collider (pbarA) • Antiprotons collected in RESR • cooled and slowed to 30 MeV • transferred to pbar-ring • AIC specific equipment: • 70kV electron cooler RESR • 70kV electron cooler pbar-ring • transfer line RESR – pbar-ring (detailed ring design by Novosibirsk group)

  5. At lower energies one is more sensitive to the periphery of the density distribution ( energy scan) Antiproton-Nucleus Partial Absorption Cross Section 78Ni 120 50 MeV 100 MeV 200 MeV 100 300 MeV 400 MeV 80 sigABS(b) [mb] 60 40 20 0 0 5 10 15 20 Impact Parameter b [fm] Theoretical cross-sections AIC range AIC range Calculations by H.Lenske

  6. p A A-1 Nuclear density Pmiss(z): probability that pions miss the residual A-1 nucleus Pdh: probability that residual nucleus is cold (E*< Sn,p) z=4fm z=-4fm impact parameter b [fm] About 30% of produced A-1 nuclei survive Theoretical calculations – example 58Ni Lenske, Wycech

  7. p 132Sn A A-1 Acceptance limit of NESR Measured momentum distribution is consistent with quasi-free scattering LEAR data on Ne F. Balestra et al., NPA491, 541 (1989) Measured momentum distribution gives insight into angular momenta of annihilated nucleons Simulations of the reaction kinematics About 30% of produced A-1 nuclei survive

  8. Schottky method for identification and counting of A-1 nuclei von P. Kienle

  9. p A A-1 Simulated momentum distributions 132Sn 131Sn 132Sn 131In • A~130: • A & both A-1 nuclei in the acceptance • Schottky method using one ring setting • recoil detection 132Sn 72Ni 71Co 72Ni 71Ni • A~70: • A & and one A-1 nucleus in the acceptance • Schottky method using zwo ring settings • recoil detection 72Ni 40Ca 39Ca 40Ca 39K • A<60: • A-1 nucleus not in the acceptance • recoil detection 40Ca z

  10. Recoil Detection after NESR dipole section Staged set of recoil detectors covers large momentum range 0.5 m +7% -6% Existing ESR detector (TUM) 5 m

  11. Luminosity measurementusing elastically scattered antiprotons detector 106 104 102 Diff. Cross-section [b/sr] 0 1 2 3 4 5 6 lab [degrees]

  12. Examples Ion T1/2 yield Lumin. stotal meas. Counts stat. error [s] [pps] [cm-2s-1] [barn] time Drnp 55Ni 0.5 8·107 4·1024 1.2 ~60 h 105 0.02 fm 72Ni 4.1 9·106 4·1024 1.3 ~60 h 105 0.02 fm 104Sn 51 1·106 5·1024 1.8 ~60 h 105 0.025 fm ~12 h 2·104 0.055 fm 132Sn 93 1·108 9·1026 2.1 ~8 min 106 0.008 fm 134Sn 2.7 8·105 2·1023 2.1 ~60 h 105 0.025 fm ~12 h 2·104 0.055 fm 187Pb 34 1·107 3·1025 2.7 ~20 min 105 0.03 fm required beam time for 104-134Sn: (even-even only, min. 1 shift per isotope): 1-2 weeks

  13. AIC physics program • benchmarking: radii for the Sn isotopic chain • stable isotopes, measured with different techniques • plan: extending from 104Sn to 134Sn • radii along other closed-shell isotopic and isotonic chains • behavior of radii across a shape transition • e.g. from 80Zr to 104Zr • Odd-even effects in nuclear radii • study the antiproton-neutron interaction • radii in light nuclei (22O, 23,24F) (transition from halos to skins)

  14. Antiproton-Ion Collider Collaboration • Spokesperson / Deputy: R. KrückenC / J. ZmeskalA • Project Manager / Deputy: P. KienleC / L. FabbiettiC Krücken, Reiner C Lenske, Horst E Litvinov, Yuri A Marton, Johann B Nolden,Fritz A Ring, Peter C Shatunov, Yuri F Skrinsky, Alexander N. F Suzuki Ken, C Vostrikov, Vladimir A. F Yamaguchi, Takayuki G Widmann,Eberhard B Wycech, Slawomir H Zmeskal, Johann B Beller, Peter A Bosch,FritzA Cargnelli, Michael B Fabbietti, Laura C Faestermann, Thomas C Frankze, Bernhard A Fuhrmann, Hermann B Hayano, Ryugo S.D Hirtl, AlbertB Homolka, Josef C Kienle, Paul B,C Kozhuharov, Christophor A Institute A, Gesellschaft für Schwerionenforschung, Darmstadt, Germany (GSI) Institute B, Stephan Meyer Institut, Vienna, Austria (SMI) Institute C, Technische Universität München, Munich, Germany (TUM) Institute D, University of Tokyo, Tokyo, Japan (UoT) Institute E, Justus-Liebig Universität Giessen., Giessen, Germany (JLU) Institute F, Budker Institute of Nuclear Physics, Novosibirsk, Russia (BINP) Institute G University of Saytama, Saytama, Japan.(UoS) Institute H, Andrzej Soltan Institute for Nuclear Studies, Warsaw, Poland (IPJ)

  15. Task Institutions involved Financial responsibilities Electron cooler BINP, GSI, SMI Transfer line, ring modifications BINP, GSI, SMI Schottky detection system GSI Luminosity detector TUM, SMI SMI Heavy ion detectors TUM TUM Responsibilities and financial contributions Two 70 kV electron coolers (incl. power supplies) 3.0 M€ transfer line from RESR to electron ring 0.5 M€ modifications of the electron storage ring design 0.3 M€ 8 DSSD & 32 PIN diodes for heavy ion detection 0.2 M€ readout electronics for DSSD and PIN diodes 0.2 M€ mechanical holding structures for HI detectors 0.1 M€ Luminosity detector, readout and electronics 0.1 M€ Total: 4.4 M€

  16. Summary • antiproton-nucleus cross section at 740 MeV/u is proportional to <r2> • detection of A-1 products allows • determination of proton and neutron radii • in the same experiment (same systematic uncert.) • in a model independent way • AIC is feasible in terms of technology and physics output • AIC allows systematic investigation of • Neutron skins • Transition from halos to skins • Odd-even staggering in radii • Shape coexistence and its effect on neutron and proton radii • Nucleon-antiproton interaction • Additional cost: 4,4 MEuro (2 x 1.5 MEuro for electron coolers)

  17. Optics of NESR and anitproton storage ring Antiproton Storage ring IP NESR IP

  18. BINP electron cooler

  19. Floor plan

  20. Luminosity

  21. Compare to (p,p) 132Sn 134Sn 1025cm-2s-1 1028cm-2s-1 102 101 100 134Sn: 2 per hour 50 hour experiment AIC: 105 annihilations in 60 hours  s(Drnp) = 0,025 fm

  22. Compare to (e,e) 134Sn 132Sn 1025cm-2s-1 1028cm-2s-1 102 101 100 0.15 fm 134Sn: 1 per week 10-1 10-2 10-3 5%

  23. Drnp from antiprotonic atoms

  24. Compare with EXO-pbar From EXO-pbar TP • EXO-pbar concentrates on tail of wave-function in short-lived near dripline nuclei  halo nuclei • AIC concentrates on systematic trends in p and n rms-radii •  skins, asymmetry energy, odd even effects • Both methods are complementary

  25. Limits due to T1/2 >1s and production yield (>104) Example: Z = 28-50 T1/2 =1s

  26. Determination of cross-sections and radii Luminosity from elastic scattering Total reaction cross-section from reduction of primary ions with mass A cross-section for production of A-1 nuclei: Detection efficiency for A-1 nuclei exp. determined loss-factor

  27. Optical potential 1/2 T-matrix: Scattering amplitude from optical theorem: With Gaussian Form-factor Very small real part of potential and

  28. Optical potential 2/2 Lenske: DWBA+RMF densities

  29. Cross-section

  30. Count-rate estimate for Luminosity detector Only elastic scattering Distance of closest approach: D > Rnucleus + Rpbar + 2fm  Luminosity detector at lab > 1º Count-rate estimate: For 132Sn at 3º : 100 s-1cm-2

  31. Identification of individual ions in storage ring bound Beta-decay D. Boutin (GSI) L. Maier (TUM) et al.

  32. Identification of antiprotons and pions

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