4,340 research outputs found

    Propagation of Vortex Electron Wave Functions in a Magnetic Field

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    The physics of coherent beams of photons carrying axial orbital angular momentum (OAM) is well understood and such beams, sometimes known as vortex beams, have found applications in optics and microscopy. Recently electron beams carrying very large values of axial OAM have been generated. In the absence of coupling to an external electromagnetic field the propagation of such vortex electron beams is virtually identical mathematically to that of vortex photon beams propagating in a medium with a homogeneous index of refraction. But when coupled to an external electromagnetic field the propagation of vortex electron beams is distinctly different from photons. Here we use the exact path integral solution to Schrodingers equation to examine the time evolution of an electron wave function carrying axial OAM. Interestingly we find that the nonzero OAM wave function can be obtained from the zero OAM wave function, in the case considered here, simply by multipling it by an appropriate time and position dependent prefactor. Hence adding OAM and propagating can in this case be replaced by first propagating then adding OAM. Also, the results shown provide an explicit illustration of the fact that the gyromagnetic ratio for OAM is unity. We also propose a novel version of the Bohm-Aharonov effect using vortex electron beams.Comment: 14 pages, 2 figures, submitted to Phys Rev

    Charge breaking bounds in the Zee model

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    We study the possibility that charge breaking minima occur in the Zee model. We reach very different conclusions from those attained in simpler, two Higgs doublet models, and the reason for this is traced back to the existence of cubic terms in the potential. A scan of the Zee model's parameter space shows that CB is restricted to a narrow region of values of the parameters

    Fully self-consistent calculations of nuclear Schiff moments

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    We calculate the Schiff moments of the nuclei 199Hg and 211Ra in completely self-consistent odd-nucleus mean-field theory by modifying the Hartree-Fock-Bogoliubov code HFODD. We allow for arbitrary shape deformation, and include the effects of nucleon dipole moments alongside those of a CP-violating pion-exchange nucleon-nucleon interaction. The results for 199Hg differ significantly from those of previous calculations when the CP-violating interaction is of isovector character.Comment: 7 pages, 2 figure

    Charmonia from Lattice QCD

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    Recent lattice QCD results on charmonium properties are reviewed. I comment on molecules and hybrid states as well as on future studies of states near strong decay thresholds.Comment: 8 pages, 5 figures, Invited talk presented at ``Charm 2006'', Beijing, 5-7 June 200

    Aspects of Neutrino Mass Matrices

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    After an Introduction briefly describing the rise and fall of the three-zero texture of the Zee model, we discuss still-allowed two-zero textures for the Majorana three-neutrino mass matrix. Finally, a model with two right-handed neutrinos and two Dirac texture zeros is described (FGY model) which can relate CP violation in leptogenesis to CP violation in long-baseline neutrino oscillations.Comment: 9 pages latex. Talk at Coral Gables 2003. Added reference

    A Search for Low Surface Brightness Structure Around Compact Narrow Emission Line Galaxies

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    As the most extreme members of the rapidly evolving faint blue galaxy population at intermediate redshift, the compact narrow emission line galaxies (CNELGs) are intrinsically luminous (-22 < M_B < -18) with narrow emission linewidths (30 < \sigma < 125 km/s). Their nature is heavily debated: they may be low-mass starbursting galaxies that will fade to present-day dwarf galaxies or bursts of star formation temporarily dominating the flux of more massive galaxies, possibly related to in situ bulge formation or the formation of cores of galaxies. We present deep, high-quality (~0.6 - 0.8 arcsec) images with CFHT of 27 CNELGs. One galaxy shows clear evidence for a tidal tail; the others are not unambiguously embedded in galactic disks. Approximately 55% of the CNELGS have sizes consistent with local dwarfs of small-to-intermediate sizes, while 45% have sizes consistent with large dwarfs or disks galaxies. At least 4 CNELGs cannot harbor substantial underlying disk material; they are low-luminosity galaxies at the present epoch (M_B > -18). Conversely, 15 are not blue enough to fade to low-luminosity dwarfs (M_B > -15.2). The majority of the CNELGs are consistent with progenitors of intermediate-luminosity dwarfs and low-luminosity spiral galaxies with small disks. CNELGs are a heterogeneous progenitor population with significant fractions (up to 44%) capable of fading into today's faint dwarfs (M_B > -15.2), while 15 to 85% may only experience an apparently extremely compact CNELG phase at intermediate redshift but remain more luminous galaxies at the present epoch.Comment: 16 pages, 14 figures, emulateapj, published in Ap
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