The Antiproton-Ion Collider

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

2. The Antiproton-Ion Collider • Why another technique for nuclear radii? • The Antiproton-Ion collider • Simulations and rate estimates • Summary and Outlook EC, 500 KV NESR

3. Drnp from antiprotonic atoms

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

5. Why the antiproton ion collider? • charge radii can reliably measured (Lasers, (e,e’)) • several methods available for matter / neutron radii • (p,p), (,’), (3He,t) reaction cross section, antiprotonic atoms • results are • not always consitent • partly model dependent • We need a method that determines proton and neutron radii • using the same method • in the same experiment • at the same time • independently

6. Antiproton Ion Collider (pbarA) • Additional equipment: • 70kV electron cooler RESR • 70kV electron cooler pbar-ring • transfer line RESR – pbar-ring • Rate estimate • 109 stored antiprotons • Luminosity of 1023 cm-2 s-1 for • 106 stored ions • Typical total absorption cross-section: • 1 barn • 0.1 counts per second • 1000 counts in 3 hours • 0.01 fm stat. accuracy of Drnp • Antiprotons collected in RESR • cooled and slowed to 30 MeV • transferred to pbar-ring (Ring design by Novosibirsk group)

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

8. 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 Calculations by H.Lenske

9. 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

10. 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

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

12. 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

13. 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

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

15. AIC physics program • benchmarking: radii for the Sn isotopic chain • stable isotopes, measured with different techniques • plan: extending from 105Sn to 135Sn • radii along other closed-shell isotopic and isotonic chains • radii for nuclei near the drip-line in light nuclei • transition from halo nuclei to neutron skins • behaviour of radii across a shape transition • e.g. from 80Zr to 104Zr • Odd-even effects in nuclear radii • study the antiproton-neutron interaction

16. Summary and Outlook • 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 • Simple counting experiment using Schottky method or recoil detectors (once the collider runs) • 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

17. 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)