Studies of CP violation in the decay Bs → J/ψφ at DØ

We report a measurement of the lifetime, decay rate difference and CP-violating phase for B0s mesons obtained from a flavour-tagged, time-dependent, angular analysis in a sample of 5598 ± 113 B0s → J/ψφ decays selected in a 8 fb−1 data sample of pp collisions at √s = 1.96TeV recorded with the DØ experiment at Fermilab

Spectrum of the Relativistic Particles in Various Potentials

We extend the notion of Dirac oscillator in two dimensions, to construct a set of potentials. These potentials becomes exactly and quasi-exactly solvable potentials of non-relativistic quantum mechanics when they are transformed into a Schr\"{o}dinger-like equation. For the exactly solvable potentials, eigenvalues are calculated and eigenfunctions are given by confluent hypergeometric functions. It is shown that, our formulation also leads to the study of those potentials in the framework of the supersymmetric quantum mechanics

Tropical–North Pacific Climate Linkages over the Past Four Centuries

Analyses of instrumental data demonstrate robust linkages between decadal-scale North Pacific and tropical Indo-Pacific climatic variability. These linkages encompass common regime shifts, including the noteworthy 1976 transition in Pacific climate. However, information on Pacific decadal variability and the tropical high-latitude climate connection is limited prior to the twentieth century. Herein tree-ring analysis is employed to extend the understanding of North Pacific climatic variability and related tropical linkages over the past four centuries. To this end, a tree-ring reconstruction of the December-May North Pacific index (NPI)-an index of the atmospheric circulation related to the Aleutian low pressure cell-is presented (1600-1983). The NPI reconstruction shows evidence for the three regime shifts seen in the instrumental NPI data, and for seven events in prior centuries. It correlates significantly with both instrumental tropical climate indices and a coral-based reconstruction of an optimal tropical Indo-Pacific climate index, supporting evidence for a tropical-North Pacific link extending as far west as the western Indian Ocean. The coral-based reconstruction (1781-1993) shows the twentieth-century regime shifts evident in the instrumental NPI and instrumental tropical Indo-Pacific climate index, and three previous shifts. Changes in the strength of correlation between the reconstructions over time, and the different identified shifts in both series prior to the twentieth century, suggest a varying tropical influence on North Pacific climate, with greater influence in the twentieth century. One likely mechanism is the low-frequency variability of the El Nino-Southern Oscillation (ENSO) and its varying impact on Indo-Pacific climate.</p

Calculation of the energy spectrum of a two-electron spherical quantum dot

We study the energy spectrum of the two-electron spherical parabolic quantum dot using the exact Schroedinger, the Hartree-Fock, and the Kohn-Sham equations. The results obtained by applying the shifted-1/N method are compared with those obtained by using an accurate numerical technique, showing that the relative error is reasonably small, although the first method consistently underestimates the correct values. The approximate ground-state Hartree-Fock and local-density Kohn-Sham energies, estimated using the shifted-1/N method, are compared with accurate numerical self-consistent solutions. We make some perturbative analyses of the exact energy in terms of the confinement strength, and we propose some interpolation formulae. Similar analysis is made for both mean-field approximations and interpolation formulae are also proposed for these exchange-only ground-state cases.Comment: 18 pages, LaTeX, 2 figures-ep

Bound states of scalar particles in the presence of a short range potential

We analyze the behavior of the energy spectrum of the Klein-Gordon equation in the presence of a truncated hyperbolic tangent potential. From our analysis we obtain that, for some values of the potential there is embedding of the bound states into the negative energy continuum, showing that, in opposition to the general belief, relativistic scalar particles in one-dimensional short range potentials can exhibit resonant behavior and not only the Schiff-Snyder effect.Comment: To appear in Modern Physics Letters

Scattering of a Klein-Gordon particle by a Woods-Saxon potential

We solve the Klein-Gordon equation in the presence of a spatially one-dimensional Woods-Saxon potential. The scattering solutions are obtained in terms of hypergeometric functions and the condition for the existence of transmission resonances is derived. It is shown how the zero-reflection condition depends on the shape of the potential.Comment: 10 pages, Revtex. To appear in Phys. Rev.

Exact solution of the two-dimensional Dirac oscillator

In the present article we have found the complete energy spectrum and the corresponding eigenfunctions of the Dirac oscillator in two spatial dimensions. We show that the energy spectrum depends on the spin of the Dirac particle.Comment: revtex, 6pp. IVIC-CFLE 93/0

Computation of inflationary cosmological perturbations in chaotic inflationary scenarios using the phase-integral method

The phase-integral approximation devised by Fr\"oman and Fr\"oman, is used for computing cosmological perturbations in the quadratic chaotic inflationary model. The phase-integral formulas for the scalar and tensor power spectra are explicitly obtained up to fifth order of the phase-integral approximation. We show that, the phase integral gives a very good approximation for the shape of the power spectra associated with scalar and tensor perturbations as well as the spectral indices. We find that the accuracy of the phase-integral approximation compares favorably with the numerical results and those obtained using the slow-roll and uniform approximation methods.Comment: 21 pages, RevTex, to appear in Phys. Rev