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

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

r np from antiprotonic atoms

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

Why the antiproton ion collider? charge radii can reliably measured (Lasers, (e,e)) several methods available for matter / neutron radii (p,p), (, ), ( 3 He,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

Antiproton Ion Collider (pbarA) Rate estimate 10 9 stored antiprotons Luminosity of cm -2 s -1 for 10 6 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 r np Additional equipment: 70kV electron cooler RESR 70kV electron cooler pbar-ring transfer line RESR – pbar-ring Antiprotons collected in RESR cooled and slowed to 30 MeV transferred to pbar-ring (Ring design by Novosibirsk group)

Limits due to T 1/2 >1s and production yield (>10 4 ) T 1/2 =1s Example: Z = 28-50

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

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

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

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

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

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

Luminosity measurement using elastically scattered antiprotons lab [degrees] Diff. Cross-section [b/sr] detector

AIC physics program benchmarking: radii for the Sn isotopic chain stable isotopes, measured with different techniques plan: extending from 105 Sn to 135 Sn 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 80 Zr to 104 Zr Odd-even effects in nuclear radii study the antiproton-neutron interaction

Summary and Outlook antiproton-nucleus cross section at 740 MeV/u is proportional to 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

Antiproton-Ion Collider Collaboration Spokesperson / Deputy:R. Krücken C / J. Zmeskal A Project Manager / Deputy:P. Kienle C / L. Fabbietti C Beller, Peter A Bosch, Fritz A Cargnelli, Michael B Fabbietti, Laura C Faestermann, Thomas C Frankze, Bernhard A Fuhrmann, Hermann B Hayano, Ryugo S. D Hirtl, Albert B Homolka, Josef C Kienle, Paul B,C Kozhuharov, Christophor A 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 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)

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

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

BINP electron cooler

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

Examples IonT 1/2 yieldLuminosityTime for 10 4 events 52 Ca12s 4·10 5 pps5 ·10 23 cm -2 s -1 ~300 min 55 Ni0.5s 8·10 7 pps4 ·10 24 cm -2 s -1 ~35 min 134 Sn2.7s 8·10 5 pps2 ·10 23 cm -2 s -1 ~360 min 187 Pb34s 1·10 7 pps3 ·10 25 cm -2 s -1 ~2 min

Luminosity

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

Optical potential 2/2 Lenske: DWBA+RMF densities

Cross-section

Count-rate estimate for Luminosity detector Only elastic scattering Distance of closest approach: D > R nucleus + R pbar + 2fm Luminosity detector at lab > 1º Count-rate estimate: For 132 Sn at 3º : 100 s -1 cm -2

Identification of antiprotons and pions