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Isospin Symmetry test on the semimagic 44 Cr

Isospin Symmetry test on the semimagic 44 Cr. Toward the dripline in the f7/2 shell. 44 Cr. N=20, 40Ca +4 protons Mid mass, Tz=-2 36 Ca@RISING. N=Z. T=1 and T=2 mirror nuclei. Shell evolution Gaps Z=14 and N=14 No cross shell excitations. f7/2. f7/2. N,Z=20. N,Z=20. d3/2. d3/2.

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Isospin Symmetry test on the semimagic 44 Cr

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  1. Isospin Symmetry test on the semimagic 44Cr Toward the dripline in the f7/2 shell

  2. 44Cr • N=20, 40Ca +4 protons • Mid mass, Tz=-2 • 36Ca@RISING N=Z

  3. T=1 and T=2 mirror nuclei Shell evolution Gaps Z=14 and N=14 No cross shell excitations f7/2 f7/2 N,Z=20 N,Z=20 d3/2 d3/2 s1/2 s1/2 d5/2 d5/2 π π ν ν 36Ca 36S

  4. Cross conjugate nuclei f7/2 f7/2 N,Z=20 N,Z=20 d3/2 d3/2 s1/2 s1/2 d5/2 d5/2 π π ν ν 44Cr 44Ca f7/2 f7/2 N,Z=20 N,Z=20 d3/2 d3/2 s1/2 s1/2 d5/2 d5/2 π π ν ν 36Ca 36S

  5. 44Cr f5/2 f5/2 p1/2 p1/2 p3/2 p3/2 f7/2 f7/2 N,Z=20 N,Z=20 π π ν ν 44Cr 44Ca 1360 2+ 1248 1157 2+ 2+ 0+ 0+ 0+ 44Ca Exp kb3g gxpf1a 104 9.8 10.3 B(E2)[e2fm4]

  6. 44Cr p3/2 p3/2 f7/2 f7/2 N,Z=20 N,Z=20 d3/2 d3/2 s1/2 s1/2 π π ν ν 44Cr 44Ca 1571 2+ 1360 2+ 1248 1157 2+ 2+ 0+ 0+ 0+ 0+ 44Ca Exp kb3g gxpf1a sdfp 104 9.8 10.3 105.6 B(E2)[e2fm4]

  7. Particle-hole cross-shell excitations 1571 2+ 1360 2+ 1248 1157 2+ 2+ 0+ 0+ 0+ 0+ 44Ca Exp kb3g gxpf1a sdfp 104 9.8 10.3 105.6 B(E2)[e2fm4]

  8. 44Cr • Isospin symmetric: 44Ca 3307 3- 3285 6+ Sp = 2800 keV (SY) 2283 4+ 1157 2+ 0+ 0+ 44Cr 44Ca

  9. 49 49 25Mn24 24Cr25 f7/2 shell and INC nuclear forces VCm, VCM VB From the MED we extract information of nuclear structure properties • How the nucleus generates its angular momentum • Evolution of the deformation along a rotational band • Isospin non-conserving terms in the nuclear interaction • Learn about the configuration of the states

  10. 36Ca from 40Ca Fragmentation: 40Ca → 37Ca 38 µbarn Knock-out:37Ca → 36Ca 2 mbarn

  11. 44Cr from 50Cr Fragmentation: 50Cr → 45Cr 1.5 µbarn Knock-out:45Cr → 44Cr 2 mbarn

  12. 44Cr from 58Ni Fragmentation: 58Ni → 45Cr 0.6 µbarn Knock-out:45Cr → 44Cr 2 mbarn

  13. Feasibility: fragmentation + knock-out • Comparison to 36Ca: • Cross section: /50 • AGATA efficiency: x5 • AGATA resolution: x2 • Energy of the gamma (3.0→ 1.2 MeV): x3 • Beam current: x30 (3*108→1010) • 44Cr now is a factor 20 easier! P. Doornenbal et al. Physics Letters B 647 (2007) 237–242

  14. Feasibility: fragmentation + coulex • Directly produced 44Cr: 24 nbarn • More than an order of magnitude lost • Coulex on secondary target • 2+ predicted collective (2p2h, 4p4h) • Enhanced B(E2) • Good excitation cross section (~200 mbarn) • Factor of ~10 in statistics for the 2+

  15. B(E1) in T=2 • Janecke: EC (A,T,TZ)= EC0(A,T)- TzEC1(A,T)+ (3Tz2-T(T+1))EC2(A,T) • Warburton “Corresponding E1 transition in conjugate nuclei have equal strength” • T=2 Tz=-2 EC = EC0 + 2 EC1(A,2)+ 6EC2(A,T) • T=2 Tz=-1 EC = EC0 + 1 EC1(A,2)- 3EC2(A,T) • T=2 Tz=0 EC = EC0 + - 6EC2(A,T) • T=2 Tz=+1 EC = EC0 + 1 EC1(A,2)- 3EC2(A,T) • T=2 Tz=+2 EC = EC0 - 2 EC1(A,2)+ 6EC2(A,T) WILKINSON - ISOSPIN IN NUCLEAR PHYSICS

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