33Mg: determination of a negative parity intruder ground state via nuclear moments Leuven - Mainz - ISOLDE collaboration at CERN D. T. Yordanov1, M. Kowalska2,3, K. Blaum2, M. De. Rydt1, K. Flanagan1, P. Lievens4, R. Neugart2, Wilfried Nörtershäuser2, H. H. Stroke5 and G. Neyens1 1 Instituut voor Kern- en Stralingsfysica, K.U.Leuven, Leuven, Belgium 2 Insititut für Physik, Universität Mainz, Mainz, Germany 3 CERN, Physics Department – IS, Geneva, Switzerland 4 Laboratorium voor Vaste-Stoffysica en Magnetisme, K.U.Leuven, Leuven, Belgium 5 Department of Physics, New York University ISOLDE Workshop 2007

Table of Isotopes in the vicinity of The Island of Inversion Measured Intruder This Work Normal or not measured 4 4 4 4 1 2 1 2 1 2 1 1 1 1 3 3 1. Laser spectroscopy + NMR; 3. Inelastic scattering; 2. Coulomb excitation; 4. NMR; ISOLDE Workshop 2007

Former experimental studies of 33Mg b decay: 33Na, (3/2+) → 33Mg, (3/2+) S. Nummela et al., Phys. Rev. C 64, (2001) 33Mg 33Na (3/2+) b - Intermediate energy Coulomb excitation: 484keV: (5/2+) → (7/2+), bC = 0.52(12) B. V. Pritychenko et al., Phys. Rev. C 65, (2002) Proton inelastic scattering: 484keV, 546keV – parities relative to the ground state, bM = 0.47(8) Z. Elekes et al., Phys. Rev. C 73, (2006) ISOLDE Workshop 2007

Experimental results g = -0.4971(4) I = 3/2 NMR 33Mg, MgO |A| (I+1/2) NMR HFS 33Mg A/g ≈ const Experimental results g = -0.4971(4) I = 3/2 preliminary |A| (I+1/2) ≈ A (I+1)/2<0 ≈ -AI/2>0 ISOLDE Workshop 2007

n pf sd 8 20 1d5/2 2s1/2 1d3/2 1f7/2 2p3/2 33Mg (Z=12, N=21) 1p1h WBMB [1] SD – PF [2] n w Ip g Q(mb) 3/2- -1.47 -83 -1.35 -91 1 3/2+ 0.75 135 0.78 140 2 -0.45 147 -0.47 157 I=3/2 g = -0.4971(4) QS(bC) = 151(38) mb experiment theory [1] E. K. Warburton, J. A. Becker and B. A. Brown, Phys. Rev. C 41, (1990) [2] S. Nummela et al., Phys. Rev. C 63, (2001) ISOLDE Workshop 2007

n pf sd 8 20 1d5/2 2s1/2 1d3/2 1f7/2 2p3/2 33Mg (Z=12, N=21) 2p2h WBMB [1] SD – PF [2] n w Ip g Q(mb) 3/2- -1.47 -83 -1.35 -91 1 3/2+ 0.75 135 0.78 140 2 -0.45 147 -0.47 157 I=3/2 g = -0.4971(4) QS(bC) = 151(38) mb experiment theory [1] E. K. Warburton, J. A. Becker and B. A. Brown, Phys. Rev. C 41, (1990) [2] S. Nummela et al., Phys. Rev. C 63, (2001) ISOLDE Workshop 2007

n pf sd 8 20 1d5/2 2s1/2 1d3/2 1f7/2 2p3/2 33Mg (Z=12, N=21) 2p2h WBMB [1] SD – PF [2] n w Ip g Q(mb) 3/2- -1.47 -83 -1.35 -91 1 3/2+ 0.75 135 0.78 140 2 -0.45 147 -0.47 157 I=3/2 g = -0.4971(4) QS(bC) = 151(38) mb experiment theory [1] E. K. Warburton, J. A. Becker and B. A. Brown, Phys. Rev. C 41, (1990) [2] S. Nummela et al., Phys. Rev. C 63, (2001) ISOLDE Workshop 2007

33Mg 2/2 = 137.7 keV a (b = 0.4) = -0.615 2/2 = 96.8 keV PARTICLE PLUS ROTOR Kp = 1/2+ 1/2[200] 2/2 = 137.7 keV a (b = 0.4) = -0.615 -1.7 ≤ m / mN ≤ -0.17 m (31Mg) = -0.88355(15) mN Kp = 3/2- 3/2[321] 2/2 = 96.8 keV -0.93 ≤ m / mN ≤ -0.27 m (33Mg) = -0.7456(5) mN ISOLDE Workshop 2007

Conclusions Outlook 33Mg (Ip = 3/2-) has a 2p2h intruder ground state The first exited states also have intruder nature Outlook Investigate the neutron deficient 21Mg Access the deformation through rms charge radii ISOLDE Workshop 2007

ISOLDE - CERN 1.4 GeV protons from PSB 1.4 GeV protons from PSB GPS Target GPS Target Radioactive Laboratory Robots GPS GPS HRS Target RILIS Laser Ion Source HRS RILIS Laser Ion Source Control Room COLLAPS REX - ISOLDE COLLAPS ISOLTRAP ISOLDE Workshop 2007

COLLAPS @ ISOLDE b Detectors b Detectors Magnet B┴ → Magnet B┴ → N X1+ Ion Beam X1+ Ion Beam PM - Optical Detection PM - Optical Detection b Detectors Electrostatic Deflection Electrostatic Deflection B װ → Coils – Weak Field B װ → Coils – Weak Field RF Coil RF Coil Post Acceleration Lenses UV Laser Beam Post Acceleration Lenses UV Laser Beam F=0 32P3/2 D2 -2 -1 1 2 32S1/2 F=1 F=2 mF S b Detectors I=1/2 mI = +1/2 mI = -1/2 ISOLDE Workshop 2007