Search for α\alpha-cluster states in even-even Cr isotopes

The $\alpha + \mathrm{core}$ structure is investigated in even-even Cr isotopes from the viewpoint of the local potential model. The comparison of $Q_{\alpha}/A$ values for even-even Cr isotopes and even-even $A = 46,54,56,58$ isobars indicates that $^{46}$Cr and $^{54}$Cr are the most favorable even-even Cr isotopes for $\alpha$-clustering. The ground state bands of the two Cr isotopes are calculated through a local $\alpha + \mathrm{core}$ potential with two variable parameters. The calculated spectra give a very good description of most experimental $^{46}$Cr and $^{54}$Cr levels. The reduced $\alpha$-widths, rms intercluster separations and $B(E2)$ transition rates are determined for the ground state bands. The calculations reproduce the order of magnitude of the available experimental $B(E2)$ values without using effective charges and indicate that the first members of the ground state bands present a stronger $\alpha$-cluster character. The volume integral per nucleon pair and rms radius obtained for the $\alpha+^{50}$Ti potential are consistent with those reported previously in the analysis of $\alpha$ elastic scattering on $^{50}$Ti

A theory of new type of heavy-electron superconductivity in PrOs_4Sb_12: quadrupolar-fluctuation mediated odd-parity pairings

It is shown that unconventional nature of superconducting state of PrOs_4Sb_12, a Pr-based heavy electron compound with the filled-Skutterudite structure, can be explained in a unified way by taking into account the structure of the crystalline-electric-field (CEF) level, the shape of the Fermi surface determined by the band structure calculation, and a picture of the quasiparticles in f$^{2}$-configuration with magnetically singlet CEF ground state. Possible types of pairing are narrowed down by consulting recent experimental results. In particular, the chiral "p"-wave states such as p_x+ip_y is favoured under the magnetic field due to the orbital Zeeman effect, while the "p"-wave states with two-fold symmetery such as p_x can be stabilized by a feedback effect without the magnetic field. It is also discussed that the double superconducting transition without the magnetic field is possible due to the spin-orbit coupling of the "triplet" Cooper pairs in the chiral state.Comment: 12 pages, 2 figures, submitted to J. Phys.: Condens. Matter Lette

Heavy-flavor physics at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron protonantiproton collider have been producing world’s leading results on many interesting heavy-flavor physics topics. We report here three recent CDF results on B0s meson dynamics. An updated search for ultra rare B0s meson decays into dimuon final states and new bounds on the B0s mixing phase and decay-width difference using B0s → J/ψφ decays are summarized, both based on the whole Run II dataset corresponding to 10 fb−1. A new measurement of the branching fractions of the B0s → D(∗)+ s D(∗)− s decays uses 6.8 fb−1 of data is also reported