Background: The structure of the semimagic Sn50 isotopes were previously studied via measurements of B(E2;21+→01+) and g factors of 21+ states. The values of the B(E2;21+) in the isotopes below midshell at N = 66 show an enhancement in collectivity, contrary to predictions from shell-model calculations. Purpose: This work presents the first measurement of the 21+ and 41+ states' magnetic moments in the unstable neutron-deficient Sn110. The g factors provide complementary structure information to the interpretation of the observed B(E2) values. Methods: The Sn110 nuclei have been produced in inverse kinematics in an α-particle transfer reaction from C12 to Cd106 projectiles at 390, 400, and 410 MeV. The g factors have been measured with the transient field technique. Lifetimes have been determined from line shapes using the Doppler-shift attenuation method. Results: The g factors of the 21+ and 41+ states in Sn110 are g(21+) = +0.29(11) and g(41+) = +0.05(14), respectively. In addition, the g(41+) = +0.27(6) in Cd106 has been measured for the first time. A line-shape analysis yielded τ(110Sn;21+) = 0.81(10) ps and a lifetime of τ(110Sn;31-) = 0.25(5) ps was calculated from the fully Doppler-shifted γ line. Conclusions: No evidence has been found in Sn110 that would require excitation of protons from the closed Z=50 core.

Background: The Cd isotopes are well studied, but experimental data for the rare isotopes are sparse. At energies above the Coulomb barrier, higher states become accessible. Purpose: Remeasure and supplement existing lifetimes and magnetic moments of low-lying states in Cd106. Methods: In an inverse kinematics reaction, a Cd106 beam impinging on a C12 target was used to Coulomb excite the projectiles. The high recoil velocities provide a unique opportunity to measure g factors with the transient-field technique and to determine lifetimes from lineshapes by using the Doppler-shift-attenuation method. Large-scale shell-model calculations were carried out for Cd106. Results: The g factors of the 21+ and 41+ states in Cd106 were measured to be g(21+)=+0.398(22) and g(41+)=+0.23(5). A lineshape analysis yielded lifetimes in disagreement with published values. The new results are τ(Cd106;21+)=7.0(3)ps and τ(Cd106;41+)=2.5(2)ps. The mean life τ(Cd106;22+)=0.28(2)ps was determined from the fully-Doppler-shifted γ line. Mean lives of τ(Cd106;43+)=1.1(1)ps and τ(Cd106;31-)=0.16(1)ps were determined for the first time. Conclusions: The newly measured g(41+) of Cd106 is found to be only 59% of the g(21+). This difference cannot be explained by either shell-model or collective-model calculations.

A model-independent technique was used to determine the γ-ray strength function (γSF) of Fe56 down to γ-ray energies less than 1 MeV for the first time with GRETINA using the (p,p′) reaction at 16 MeV. No difference was observed in the energy dependence of the γSF built on 2+ and 4+ final states, supporting the Brink hypothesis. In addition, angular distribution and polarization measurements were performed. The angular distributions are consistent with dipole radiation. The polarization results show a small bias towards magnetic character in the region of the enhancement.

We report a search for narrow resonances, produced in p p̄ collisions at √ s=1.96 TeV, that decay into muon pairs with invariant mass between 6.3 and 9.0 GeV/c 2. The data, collected with the CDF II detector at the Fermilab Tevatron collider, correspond to an integrated luminosity of 630 pb -1. We use the dimuon invariant mass distribution to set 90% upper credible limits of about 1% to the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the Υ(1S) meson. © 2009 Springer-Verlag.