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Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target

Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target. C. Monrozeau (Ph. D), E. Khan, Y. Blumenfeld. Motivations: exotic modes ?. Few measurements on GR in unstable nuclei IVGDR. GQR and GMR soft modes are predicted !.

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Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target

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  1. Measurement of the GMR and the GQR in unstable nuclei using the MAYA active target C. Monrozeau (Ph. D), E. Khan,Y. Blumenfeld

  2. Motivations: exotic modes ? • Few measurements on GR in unstable nuclei IVGDR • GQR and GMR soft modes are predicted ! Terasaki et al, Phys. Rev. C71 (2006) 34310

  3. : density and neutron excess • GMR breathing mode density variation around r0 (few %) Neutron stars evolution of incompressibility with asymmetry EISGMR along anisotopic chain (unstable nuclei) determination of K (symmetry energy term) D.T.Khoa et al. Nucl. Phys. A602 (1996) 98 Motivations: equation of state Nuclear equation of state

  4. GMR GQR GR in 58Ni : analysis mixing 0+ and 2+ Experimental probes for isoscalar giant resonances Inelastic scattering : (d,d’) (a,a’) @ E  25 A.MeV 58Ni (a,a’) Ea=240 MeV D.H. Younblood et al, Phys. Rev. Lett 76, 1429 (1996)

  5. low energy threshold reverse kinematics thin target large solid angular coverage low intensity beam good detection efficiency Active target = target+ detector thick target deuteron kinematics 56Ni(d,d’) @ 50 MeV/A deuterium gas : 1,6 mg/cm2 (6,3 mg/cm2 CD2 ) Time and Charge Projection Chamber cathod active zone Frisch grid beam detection zone amplification wires pads (cathod) ISGMR in unstable nuclei unstable nuclei

  6. Experimental setup 56Ni @ 50 MeV/A 5.104 pps • July 2005, GANIL • SISSI beam Ionisation chamber Drift chamber Si wall Moving flap CsI wall Au foil Diamond 56Ni (5.104 pps) 50 A.MeV + contaminants MAYA

  7. Results 56Ni excitation energy spectrum recoiling d kinematics d breakup

  8. Analysis with gaussian fit Counts/MeV E* (MeV) Reaction :DWBA with double folding using HF and RPA 56Ni gs and transition densities

  9. Multipole Decomposition Analysis

  10. first (p,p’) experiment in inverse kinematics ! G. Kraus et al. Phys Rev. Lett. 73 (1994) 1773 Summary & outlooks • Isoscalar GMR and GQR measured in the 56Ni unstable nucleus • Use of MAYA active target with d gas • 16h of 104 pps beam • Results compatible with the 58Ni (stable) data • The method works ! • Improvements : identification & d breakup, reaction model • Next : neutron rich Ni isotopes, 132Sn • ACTAR active target

  11. Collaboration C.Monrozeau1, E.Khan1, Y. Blumenfeld1, W. Mittig5, D.Beaumel1, M.Caamaño2,D.Cortina-Gil2, C-E.Demonchy3, N.Frascaria1, U.Garg4, M.Gelin5, A.Gillibert6, D.Gupta1, N. Keeley6, F.Maréchal7, A.Obertelli6, P.Roussel-Chomaz5, J-A.Scarpaci1 1 Institut de Physique Nucléaire (IN2P3/CNRS), 91406 Orsay Cedex, France 2 Univ. Santiago de Compostela, E-15706 Santiago de Compostela, Spain 3 Univ. of Liverpool, Dep. of Physics, Olivier Lodge Lab., Liverpool L69 7ZE, U.K. 4 Univ. of Notre-Dame, Dep. of Physics, Notre Dame, IN 46556 USA 5 GANIL (DSM/CEA, IN2P3/CNRS), BP 5027, 14076 Caen Cedex 5, France 6 CEA/DSM/DAPNIA/SPhN, Saclay, 91191 Gif-sur-Yvette Cedex, France 7 Institut de Recherches Subatomiques (IN2P3/CNRS), BP 28, 67037 Strasbourg, France

  12. K∞ in nuclear matter (analytic) (N=Z and no Coulomb interaction) Energy Functional E[ρ] E(r,d) = E(r,0) + asym(r) d2 +... EISGMR (self-consistent CHF) 208Pb neutron excess nucleus G. Colò et al. (Phys. Rev. C70 (2004) 024307) measure EISGMR along an isotopic chain (unstable nuclei) probe the effect of the symmetry term Motivations: K∞ Microscopic method Skyrme & Gogny K = 235  12 MeV Relativistic MF K = 250 – 270 MeV N.B. : macroscopic method needs data on the nuclear chart

  13. 20cm He gas 25cm 28cm 56Ni(d,d’) with the active target MAYA 56Ni unstable (106 pps @ GANIL) A NEW EXPERIMENTAL METHOD 2H gas 2H gas

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