393 research outputs found

    Meissner effect, Spin Meissner effect and charge expulsion in superconductors

    Full text link
    The Meissner effect and the Spin Meissner effect are the spontaneous generation of charge and spin current respectively near the surface of a metal making a transition to the superconducting state. The Meissner effect is well known but, I argue, not explained by the conventional theory, the Spin Meissner effect has yet to be detected. I propose that both effects take place in all superconductors, the first one in the presence of an applied magnetostatic field, the second one even in the absence of applied external fields. Both effects can be understood under the assumption that electrons expand their orbits and thereby lower their quantum kinetic energy in the transition to superconductivity. Associated with this process, the metal expels negative charge from the interior to the surface and an electric field is generated in the interior. The resulting charge current can be understood as arising from the magnetic Lorentz force on radially outgoing electrons, and the resulting spin current can be understood as arising from a spin Hall effect originating in the Rashba-like coupling of the electron magnetic moment to the internal electric field. The associated electrodynamics is qualitatively different from London electrodynamics, yet can be described by a small modification of the conventional London equations. The stability of the superconducting state and its macroscopic phase coherence hinge on the fact that the orbital angular momentum of the carriers of the spin current is found to be exactly ℏ/2\hbar/2, indicating a topological origin. The simplicity and universality of our theory argue for its validity, and the occurrence of superconductivity in many classes of materials can be understood within our theory.Comment: Submitted to SLAFES XX Proceeding

    Sneutrino-induced like sign dilepton signal with conserved R-parity

    Get PDF
    Lepton number violation could be manifest in the sneutrino sector of supersymmetric extensions of the standard model with conserved R-parity. Then sneutrinos decay partly into the ``wrong sign charged lepton'' final state, if kinematically accessible. In sneutrino pair production or associated single sneutrino production, the signal then is a like sign dilepton final state. Under favourable circumstances, such a signal could be visible at the LHC or a next generation linear collider for a relative sneutrino mass-splitting of order O(0.001){\cal O}(0.001) and sneutrino width of order O{\cal O}(1 GeV). On the other hand, the like sign dilepton event rate at the TEVATRON is probably too small to be observable.Comment: 19 pages, 14 Figures. Section about LSD at LHC and TEVATRON added. Previous Title "Single sneutrino production and the wrong charged lepton signal

    'Heaven starts at your parents' feet' : adolescent bowing to parents and associated spiritual attitudes

    Get PDF
    In a quantitative survey of religious attitudes and practices in a multi-religious sample of 369 school pupils aged between 13 and 15 in London, the practice of bowing to parents was found widespread in 22% of adolescents spanning several religious affiliations and ethnicities – especially Buddhists, Hindus and those of Indian, African and ‘Other Asian’ ethnicity. Whether an adolescent bowed correlated significantly with spiritual attitudes such as wanting to abstain from alcohol, hearing religious stories, being inspired by religious festivals and liking the idea of seeing God in everything. Findings suggest bowing to parents can have religious significance on all three levels of Jackson’s Interpretive Approach and therefore cannot be regarded as a ‘cultural accretion’ of religion. Study of bowing to parents could form a unifying exercise in shared values for study of religion in the plural classroom and facilitate community cohesion in certain religious membership groups

    Neutrino properties and the decay of the lightest supersymmetric particle

    Get PDF
    Supersymmetry with broken R-parity can explain the neutrino mass squared differences and mixing angles observed in neutrino oscillation experiments. In the minimal model, where R-parity is broken only by bilinear terms, certain decay properties of the lightest supersymmetric particle (LSP) are correlated with neutrino mixing angles. Here we consider charginos, squarks, gluinos and sneutrinos being the LSP and calculate their decay properties in bilinear R-parity breaking supersymmetry. Together with the decays of charged scalars and neutralinos calculated previously this completes the proof that bilinear R-parity breaking as the source of neutrino masses will be testable at future colliders. Moreover, we argue that in case of GMSB, the decays of the NLSP can be used to test the model.Comment: 15 pages, 8 figure

    Evidence for hadronic deconfinement in pˉ\bar{p}-p collisions at 1.8 TeV

    Get PDF
    We have measured deconfined hadronic volumes, 4.4<V<13.04.4 < V < 13.0 fm3^{3}, produced by a one dimensional (1D) expansion. These volumes are directly proportional to the charged particle pseudorapidity densities 6.75<dNc/dη<20.26.75 < dN_{c}/d\eta < 20.2. The hadronization temperature is T=179.5±5T = 179.5 \pm 5 (syst) MeV. Using Bjorken's 1D model,the hadronization energy density is ϔF=1.10±0.26\epsilon_{F} = 1.10 \pm 0.26 (stat) GeV/fm3^{3} corresponding to an excitation of 24.8±6.224.8 \pm 6.2 (stat) quark-gluon degrees of freedom.Comment: 15 pages, 3 figures, 2 table

    Neutrino masses in R-parity violating supersymmetric models

    Full text link
    We study neutrino masses and mixing in R-parity violating supersymmetric models with generic soft supersymmetry breaking terms. Neutrinos acquire masses from various sources: Tree level neutrino--neutralino mixing and loop effects proportional to bilinear and/or trilinear R-parity violating parameters. Each of these contributions is controlled by different parameters and have different suppression or enhancement factors which we identified. Within an Abelian horizontal symmetry framework these factors are related and specific predictions can be made. We found that the main contributions to the neutrino masses are from the tree level and the bilinear loops and that the observed neutrino data can be accommodated once mild fine-tuning is allowed.Comment: 18 pages; minor typos corrected. To be published in Physical Review

    Solar Neutrino Masses and Mixing from Bilinear R-Parity Broken Supersymmetry: Analytical versus Numerical Results

    Get PDF
    We give an analytical calculation of solar neutrino masses and mixing at one-loop order within bilinear R-parity breaking supersymmetry, and compare our results to the exact numerical calculation. Our method is based on a systematic perturbative expansion of R-parity violating vertices to leading order. We find in general quite good agreement between approximate and full numerical calculation, but the approximate expressions are much simpler to implement. Our formalism works especially well for the case of the large mixing angle MSW solution (LMA-MSW), now strongly favoured by the recent KamLAND reactor neutrino data.Comment: 34 pages, 14 ps figs, some clarifying comments adde

    Reconstructing Neutrino Properties from Collider Experiments in a Higgs Triplet Neutrino Mass Model

    Get PDF
    We extend the minimal supersymmetric standard model with bilinear R-parity violation to include a pair of Higgs triplet superfields. The neutral components of the Higgs triplets develop small vacuum expectation values (VEVs) quadratic in the bilinear R-parity breaking parameters. In this scheme the atmospheric neutrino mass scale arises from bilinear R-parity breaking while for reasonable values of parameters the solar neutrino mass scale is generated from the small Higgs triplet VEVs. We calculate neutrino masses and mixing angles in this model and show how the model can be tested at future colliders. The branching ratios of the doubly charged triplet decays are related to the solar neutrino angle via a simple formula.Comment: 19 pages, 4 figures; one formula corrected, two author's names corrected; some explanatory comments adde

    A study of single sneutrino production in association with fermion pairs at polarised photon colliders

    Get PDF
    We investigate single sneutrino production in the context of R-parity-violating Supersymmetry at future γγ\gamma\gamma linear colliders. The sneutrino is produced in association with fermion pairs and it is shown that its decays into two further fermions will lead to a clean signal. We also discuss possible backgrounds and the effects of beam polarisation.Comment: 31 pages, LaTeX, 10 postscript figures. Title has been modified. Two new figures and one appendix added. Detailed SM background estimations were made. A new reference added. Version to appear in PR
    • 

    corecore