BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Study of CP violation in Dalitz-plot analyses of B-0 -> K+ K- K-s(0), B+ -> K+ K- K+, and B+ -> (KsKsK+)-K-0-K-0. Phys. Rev. D, 85(11), 112010–31pp.
Abstract: We perform amplitude analyses of the decays B-0 -> K+ K- K-s(0), B+ -> K+ K- K+, and B+ -> K-s(0) K-s(0) K+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470 x 10(6) B (B) over bar decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B+ -> K+ K- K+, we find a direct CP asymmetry in B+ -> phi(1020)K+ of A(CP) = (12.8 +/- 4.4 +/- 1.3)%, which differs from zero by 2.8 sigma. For B-0 -> K+ K- K-s(0), we measure the CP-violating phase ss(eff)(phi(1020)K-s(0)) = (21 +/- 6 +/- 2)degrees. For B+ -> K-s(0) K-s(0) K+, we measure an overall direct CP asymmetry of A(CP) = (4(-5)(+4) +/- 2)%. We also perform an angular-moment analysis of the three channels and determine that the f(X()1500) state can be described well by the sum of the resonances f(0)(1500), f(2)'(1525), and f(0)(1710).
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Bottoni, S. et al, & Gadea, A. (2012). Reaction dynamics and nuclear structure of moderately neutron-rich Ne isotopes by heavy-ion reactions. Phys. Rev. C, 85(6), 064621–7pp.
Abstract: The heavy-ion reaction Ne-22+Pb-208 at 128 MeV beam energy has been studied using the PRISMA-CLARA experimental setup at Legnaro National Laboratories. Elastic, inelastic, and one-nucleon transfer differential cross sections are measured and global agreement is obtained with semiclassical and distorted-wave Born approximation (DWBA) calculations. In particular, the angular distribution of the 2(+) state of Ne-22 is analyzed by DWBA and a similar calculation is performed for the unstable Ne-24 nucleus, using existing data from the reaction Ne-24+Pb-208 at 182 MeV (measured at SPIRAL with the VAMOS-EXOGAM setup). In both cases the DWBA model gives a good reproduction of the experiment, pointing to a strong reduction of the beta(C)(2) charge deformation parameter in Ne-24. This follows the trend predicted for the evolution of the quadrupole deformation along the Ne isotopic chain.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Initial-state radiation measurement of the e(+)e(-) -> pi(+)pi(-)pi(+)pi(-) cross section. Phys. Rev. D, 85(11), 112009–17pp.
Abstract: We study the process e(+)e(-) -> pi(+)pi(-)pi(+)pi(-)gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb(-1) of data collected with the BABAR detector at SLAC, corresponding to approximately 260 000 signal events. We use these data to extract the nonradiative sigma(e(+)e(-) -> pi(+)pi(-)pi(+)pi(-)) cross section in the energy range from 0.6 to 4.5 GeV. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
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Filipuzzi, A., Portoles, J., & Gonzalez-Alonso, M. (2012). U(2)^5 flavor symmetry and lepton universality violation in W -> tau(nu)over-bar(tau). Phys. Rev. D, 85(11), 116010–10pp.
Abstract: The seeming violation of universality in the tau lepton coupling to the W boson suggested by LEP-II data is studied using an effective field theory (EFT) approach. Within this framework we explore how this feature fits into the current constraints from electroweak precision observables using different assumptions about the flavor structure of New Physics, namely [U(2) x U(1)](5) and U(2)(5). We show the importance of leptonic and semileptonic tau decay measurements, giving 3-4 TeV bounds on the New Physics effective scale at 90% C.L. We conclude under very general assumptions that it is not possible to accommodate this deviation from universality in the EFT framework, and thus such a signal could only be explained by the introduction of light degrees of freedom or New Physics strongly coupled at the electroweak scale.
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Hirsch, M., Staub, F., & Vicente, A. (2012). Enhancing l(i) -> 3l(j) with the Z(0)-penguin. Phys. Rev. D, 85(11), 113013–5pp.
Abstract: Lepton flavor violation has been observed in neutrino oscillations. For charged lepton flavor violation decays only upper limits are known, but sizable branching ratios are expected in many neutrino mass models. High-scale models, such as the classical supersymmetric seesaw, usually predict that decays l(i) -> 3l(j) are roughly a factor alpha smaller than the corresponding decays l(i) -> l(j)gamma. Here we demonstrate that the Z(0)-penguin diagram can give an enhancement for decays l(i) -> 3l(j) in many extensions of the minimal supersymmetric standard model (MSSM). We first discuss why the Z(0)-penguin is not dominant in the MSSM with seesaw and show that much larger contributions from the Z(0)-penguin are expected in general. We then demonstrate the effect numerically in two example models, namely, the supersymmetric inverse seesaw and R-parity violating supersymmetry.
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