First Evidence for B_s -> phi phi and Other Penguin B decays at CDF

We present the first evidence of the decay mode $B_s \to \phi \phi$ and a measurement of partial width and direct CP asymmetry for the $B^+ \to \phi K^+$ decay using $180 pb^{-1}$ of data collected by the CDFII experiment at the Fermilab Tevatron collider. We measure: BR (\phiphi) = (1.4 \pm 0.6(stat.) \pm 0.2(syst.) \pm 0.5(\BR)) \cdot 10^{-5}, where the last error is due to the uncertainty on the $B_s \to J/\psi\phi$ branching ratio used as normalization, $BR (\phi k) = (7.2 \pm 1.3(stat.) \pm 0.7(syst.)) \cdot 10^{-6}$ and \ACP(phi k) = -0.07 \pm 0.17 (stat.) \ase{0.06}{0.05} (syst.). We also briefly discuss prospects for studying other charmless $B \to VV$ decays at CDFComment: Talk given at the 32nd Internation Conference on High Energy Conferenc

Cross sections for short pulse single and double ionization of helium

In a previous publication, procedures were proposed for unambiguously extracting amplitudes for single and double ionization from a time-dependent wavepacket by effectively propagating for an infinite time following a radiation pulse. Here we demonstrate the accuracy and utility of those methods for describing two-photon single and one-photon double ionization of helium. In particular it is shown how narrow features corresponding to autoionizing states are easily resolved with these methods.Comment: 9 pages, 9 figure

Decoding sequential vs non-sequential two-photon double ionization of helium using nuclear recoil

Above 54.4 eV, two-photon double ionization of helium is dominated by a sequential absorption process, producing characteristic behavior in the single and triple differential cross sections. We show that the signature of this process is visible in the nuclear recoil cross section, integrated over all energy sharings of the ejected electrons, even below the threshold for the sequential process. Since nuclear recoil momentum imaging does not require coincident photoelectron measurement, the predicted images present a viable target for future experiments with new short-pulse VUV and soft X-ray sources.Comment: 4 pages, 3 figure

A relationship between the many-body theory of inelastic scattering and the distorted wave approximation

It is shown that the first-order results of the recent many-body theory of inelastic scattering (see abstr. A25430 of 1971) can be derived by a direct application of the distorted-wave and random phase approximations to the usual expression for the inelastic scattering amplitude. The result is derived both in the second quantized formalism and by the standard application of the distorted-wave approximation coupled with the random phase approximation (RPA). The RPA (or time-dependent Hartree-Fock theory) provides the transition density between the initial and inelastically excited states. Possible generalizations of the procedures are discussed

Photoabsorption cross sections of two-electron atoms by the coordinate rotation method: Application to H– and several states of He

The coordinate rotation method, recently extended by us to treat photoabsorption processes, is used to obtain photoabsorption cross sections for several two-electron atoms. The calculations are performed using standard configuration–interaction methods; the need for atomic continuum wavefunctions is completely avoided in this approach. We have computed the photodetachment cross section of H– and photoionization cross sections for He in its ground and 2 1S states. In all cases, the computed cross sections agree well with results obtained by numerical integration and with available experimental data