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Spokesperson

Search for diabolic pair transfer at higher angular momentum states by using heavy-ion induced reaction. Spokesperson. Dr. Samit Kr. Mandal Department of Physics & Astrophysics Delhi University. H. J. Wollersheim GSI.

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Spokesperson

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  1. Search for diabolic pair transfer at higher angular momentum states by using heavy-ion induced reaction Spokesperson Dr. Samit Kr. Mandal Department of Physics & Astrophysics Delhi University H. J. Wollersheim GSI

  2. Pair transfer as a function of spin Spectroscopic quantities Intrinsic quantities pair transfer amplitude Parameters 238U 40Ar

  3. Nuclear Josephson Effects: Enhanced transfer of nucleon pairs between two superfluid heavy nuclei in a cold reaction correspond to a super-current. alternating current JE: Strong coupling situation Flux oscillation in particular mass partition Characteristic dependences on incident energy or reaction angle Transfer probability values larger than 0.5 direct super current JE: Weak coupling situation Enhanced transfer of several nucleon pairs Transfer probability values less than 0.5 G.Eckert et al. Z.Phys. A343 (1992), 276 I.Peter,W.von Oertzen et al., Eur.Phys. J.A16(2003),509

  4. Berry's Phase, Diabolic Pair Transfer Berry's phase is a simple mathematical fact. Berry considers a Hamiltonian, which depends on external parameters E2(λ,ω) En(λ,ω) V Φ 0 C Φ 1 E1(λ,ω) ω Φ 1=eiγΦ0 λ Examples: (a) Nilsson Model R=β (b) Cranked Shell Model R=(λ,Δ,ω) Φ1= -Φ0 A diabolical point, where two energy surfaces touch and a closed path on the lower surface encircling this point chemical potential λ, angular velocity ω, pairing gap Δ

  5. Berry's Phase and the Backbending Effect <A+2,J/(a+a+)l=0/A,J> J(ђ) Two different paths around a diabolic point The oscillating behavior of the pair transfer matrix element has a close analogy to the oscillating behavior of the electric current in Superconducting Quantum Interference Devices as a function of the magnetic field, the DC-Josephson effect

  6. Berry's Phase in Nuclear Physics • open problem for experimentalist Pair transfer matrix Full horizontal arrow indicates pair transfer matrix elements with positive sign and dashed arrows indicate those with negative sign . K quantum number for j=13/2 is shown.

  7. Proposed Systems: 172,174Yb on 206Pb 174,176Hf on 206Pb The Hf and Yb-chain : The interaction strength in the level crossing between the ground state band and the s-band characterized by the minimal distance between the yrast band and the first excited band ΔEmin. Connected lines correspond to minimal distances for the angular momenta I= 10-16ħ. Full dot symbols indicate the even mass Yb-isotopes. The position of the deformed single-particle energies of the v i13/2 levels for the nucleus 166Yb and 170Hf are given on the abscissa. Y. Sun et al, Z. Phys. A339 (1991) 51

  8. 2n-transfer probability as a function of spin yrast-states yrare-states 174Hf(206Pb,208Pb)172Hf The calculation show the diabolic effect for 206Pb on 174Hf. This calculation assumes 174Hf transfers to 172Hf. The symbol o’s are non diabolic case and Δ’s are diabolic cases. L F Canto et al PRC 47,2836(1993).

  9. Experimental Setup Beam:174,176Hf and 172,174Yb, Target :206Pb (500μg/cm2 thick), • The experiment will be performed at X7 beam line • The ion beam from UNILAC facility. • Annular proportional counter for • particle detection • Cluster Ge–detector from EUROBALL and segmented Super Clover will be used for gamma-ray detection

  10. Experimental Setup & Beam time request Beam:174,176Hf and 172,174Yb, Target :206Pb (500μg/cm2 thick), Beam Energy: 5-8 MeV/A . Beam Current: 109 pps. Estimated cross-sect ion (Coupled Channels Calculations- FRESCO)~ 1 μb for excited state of interest Yield ~ 200 counts/hr. Gamma detection efficiency ~ 4% For each isotope, shifts required = 14 shifts. Setting up detectors & particle-γ coincidence = 2 shifts. Total shift require : 30 for each experiment with two isotopes 50% of duty cycle of accelerator has been taken into account.

  11. Beam Time Request Two Experiments Each experiment: 30 Shifts Total : 60 Shifts.

  12. Collaborators : Sunil Kalkal , Mansi Saxsena Department of Physics & Astrophysics, University of Delhi, India & Punita Verma Kalindi College, University of Delhi, India & Jürgen Gerl, Magdalena Gorska, Henning Schaffner,Ivan Kojouharov, Jurek Grebosz, R. Hoischen Gesellschaft für Schwerionenforschung, Darmstad, Germany

  13. Thanks

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