U-Spin Tests of the Standard Model and New Physics

Within the standard model, a relation involving branching ratios and direct CP asymmetries holds for the B-decay pairs that are related by U-spin. The violation of this relation indicates new physics (NP). In this paper, we assume that the NP affects only the Delta S = 1 decays, and show that the NP operators are generally the same as those appearing in B -> pi K decays. The fit to the latest B -> pi K data shows that only one NP operator is sizeable. As a consequence, the relation is expected to be violated for only one decay pair: Bd -> K0 pi0 and Bs -> Kbar0 pi0.Comment: 12 pages, latex, no figures. References changed to follow MPL guidelines; info added about U-spin breaking and small NP strong phases; discussion added about final-state pi-K rescattering; analysis and conclusions unaltere

Systematic study of nuclear matrix elements in neutrinoless double-beta decay with a beyond mean-field covariant density functional theory

We report a systematic study of nuclear matrix elements (NMEs) in neutrinoless double-beta decays with a state-of-the-art beyond mean-field covariant density functional theory. The dynamic effects of particle-number and angular-momentum conservations as well as quadrupole shape fluctuations are taken into account with projections and generator coordinate method for both initial and final nuclei. The full relativistic transition operator is adopted to calculate the NMEs. The present systematic studies show that in most of the cases there is a much better agreement with the previous non-relativistic calculation based on the Gogny force than in the case of the nucleus $^{150}$Nd found in Song et al. [Phys. Rev. C 90, 054309 (2014)]. In particular, we find that the total NMEs can be well approximated by the pure axial-vector coupling term with a considerable reduction of the computational effort.Comment: 9 pages with 7 figures and 3 table

Coulomb Drag of Massless Fermions in Graphene

Using a novel structure, consisting of two, independently contacted graphene single layers separated by an ultra-thin dielectric, we experimentally measure the Coulomb drag of massless fermions in graphene. At temperatures higher than 50 K, the Coulomb drag follows a temperature and carrier density dependence consistent with the Fermi liquid regime. As the temperature is reduced, the Coulomb drag exhibits giant fluctuations with an increasing amplitude, thanks to the interplay between coherent transport in the graphene layer and interaction between the two layers.Comment: 5 pages, 5 figure

Radiative penguin Bs decays at Belle

We report searches for the radiative penguin decays Bs to phi gamma and Bs to gamma gamma based on a 23.6 fb-1 data sample collected with the Belle detector at the KEKB e+e- energy-asymmetric collider operating at the Upsilon(5S) resonance.Comment: On behalf of the Belle Collaboration. To appear in the proceedings of the International Europhysics Conference on High Energy Physics (EPS-HEP2007), Manchester, England, 19-25 July 2007. 3 pages, 2 figure

Phase equilibrium in two orbital model under magnetic field

The phase equilibrium in manganites under magnetic field is studied using a two orbital model, based on the equivalent chemical potential principle for the competitive phases. We focus on the magnetic field induced melting process of CE phase in half-doped manganites. It is predicted that the homogenous CE phase begins to decompose into coexisting ferromagnetic phase and CE phase once the magnetic field exceeds the threshold field. In a more quantitative way, the volume fractions of the two competitive phases in the phase separation regime are evaluated.Comment: 4 pages, 4 figure

CP asymmetries at D0

Using two independent measurements of the semileptonic CP asymmetry in the $B_s$ system, we constrain the CP violating phase of the $B_s$ system to be $\phi_s = -0.70^{+0.47}_{-0.39}$. The data sample corresponds to an integrated luminosity of 1.1 fb$^{-1}$ accumulated with D0 detector at the Fermilab Tevatron collider. We also measure the direct CP violating asymmetry in the decay $B^+ \to J/\psi K^+$ to be $A_{CP}(B^+ \to J/\psi K^+) = +0.0067 \pm 0.0074$(stat)$\pm0.0026$(syst). The data corresponds to an integrated luminosity of 1.6 fb$^{-1}$.Comment: contributed paper to EPS07, Manchester, UK, manuscript number EPSHEPP17

Gap Equations and Electroweak Symmetry Breaking

Recently a new dynamical symmetry breaking model of electroweak interactions was proposed based on interacting fermions. Two fermions of different SU(2) representations form a symmetry breaking condensate and generate the lepton and quark masses. The weak gauge bosons get their usual standard model masses from a gauge invariant Lagrangian of a composite doublet scalar field. The new fermion fields become massive by condensation. In this note the gap equations are given in the linearized (mean field) approximation and the conditions for symmetry breaking and mass generation are presented. Perturbative unitarity constrains the self-couplings and the masses of the new fermions, a raw spectrum is given.Comment: 10 pages, 4 figure