Hydrogen and Helium Atoms and Molecules in an Intense Magnetic Field

We calculate the atomic structure of hydrogen and helium, atoms and molecules in an intense magnetic field, analytically and numerically with a judiciously chosen basis.Comment: 16 pages, 5 figures, to appear in Phys. Rev.

Hydrogen atom moving across a strong magnetic field: analytical approximations

Analytical approximations are constructed for binding energies, quantum-mechanical sizes and oscillator strengths of main radiative transitions of hydrogen atoms arbitrarily moving in magnetic fields 10^{12}-10^{13} G. Examples of using the obtained approximations for determination of maximum transverse velocity of an atom and for evaluation of absorption spectra in magnetic neutron star atmospheres are presented.Comment: 17 pages, 3 figures, 5 tables, LaTeX with IOP style files (included). In v.2, Fig.1 and Table 5 have been corrected. In v.3, a misprint in the fit for oscillator strengths, Eq.(21), has been correcte

Electronic States and Superconductivity in Multi-layer High-Tc Cuprates

We study electronic states of multilayer cuprates in the normal phases as functions of the number of CuO_2 planes and the doping rate. The resonating valence bond wave function and the Gutzwiller approximation are used for a two-dimensional multilayer t-t'-t''-J model. We calculate the electron-removal spectral functions at (\pi,0) in the CuO_2 plane next to the surface to understand the angle-resolved photoemission spectroscopy (ARPES) spectra. We find that the trilayer spectrum is narrower than the bilayer spectrum but is wider than the monolayer spectrum. In the tri- and tetralayer systems, the outer CuO_2 plane has different superconducting amplitude from the inner CuO_2 plane, while each layer in the bilayer systems has same amplitude. The recent ARPES and NMR experiments are discussed in the light of the present theory.Comment: 7 pages, 7 figure

The classification of irreducible admissible mod p representations of a p-adic GL_n

Let F be a finite extension of Q_p. Using the mod p Satake transform, we define what it means for an irreducible admissible smooth representation of an F-split p-adic reductive group over \bar F_p to be supersingular. We then give the classification of irreducible admissible smooth GL_n(F)-representations over \bar F_p in terms of supersingular representations. As a consequence we deduce that supersingular is the same as supercuspidal. These results generalise the work of Barthel-Livne for n = 2. For general split reductive groups we obtain similar results under stronger hypotheses.Comment: 55 pages, to appear in Inventiones Mathematica

Comparing and contrasting the νμ→ντ\nu_{\mu} \to \nu_{\tau} and νμ→νs\nu_{\mu} \to \nu_s solutions to the atmospheric neutrino problem with SuperKamiokande data

The $\nu_{\mu} \to \nu_{\tau}$ and $\nu_{\mu} \to \nu_s$ solutions to the atmospheric neutrino problem are compared with SuperKamiokande data. The differences between these solutions due to matter effects in the Earth are calculated for the ratio of $\mu$-like to $e$-like events and for up-down flux asymmetries. These quantities are chosen because they are relatively insensitive to theoretical uncertainties in the overall neutrino flux normalisation and detection cross-sections and efficiencies. A $\chi^2$ analysis using these quantities is performed yielding $3\sigma$ ranges which are approximately given by $(0.725 - 1.0, 4 \times 10^{-4} - 2 \times 10^{-2} eV^2)$ and $(0.74 - 1.0, 1 \times 10^{-3} - 2 \times 10^{-2} eV^2)$ for $(\sin^2 2\theta,\Delta m^2)$ for the $\nu_{\mu} \to \nu_{\tau}$ and $\nu_{\mu} \to \nu_s$ solutions, respectively. Values of $\Delta m^2$ smaller than about $2 \times 10^{-3}$ eV$^2$ are disfavoured for the $\nu_{\mu} \to \nu_s$ solution, suggesting that future long baseline experiments should see a positive signal if this scenario is the correct one.Comment: revtex, 22 pages, 12 figure

Tau Neutrinos Favored over Sterile Neutrinos in Atmospheric Muon Neutrino Oscillations

The previously published atmospheric neutrino data did not distinguish whether muon neutrinos were oscillating into tau neutrinos or sterile neutrinos, as both hypotheses fit the data. Using data recorded in 1100 live-days of the Super-Kamiokande detector, we use three complementary data samples to study the difference in zenith angle distribution due to neutral currents and matter effects. We find no evidence favoring sterile neutrinos, and reject the hypothesis at the 99% confidence level. On the other hand, we find that oscillation between muon and tau neutrinos suffices to explain all the results in hand.Comment: 9 pages with 2 figures, submitted to PR

Observation of the east-west anisotropy of the atmospheric neutrino flux

The east-west anisotropy, caused by the deflection of primary cosmic rays in the Earth's magnetic field, is observed for the first time in the flux of atmospheric neutrinos. Using a 45 kt-year exposure of the Super-Kamiokande detector, 552 e-like and 633 mu-like horizontally-going events are selected in the momentum range between 400 and 3000 MeV/c. The azimuthal distribution of e-like and mu-like events agrees with the expectation from atmospheric neutrino flux calculations that account for the geomagnetic field, verifying that the geomagnetic field effects in the production of atmospheric neutrinos in the GeV energy range are well understood.Comment: 8 pages,3 figures revtex, submitted to PR

Constraints on Neutrino Oscillations Using 1258 Days of Super-Kamiokande Solar Neutrino Data

We report the result of a search for neutrino oscillations using precise measurements of the recoil electron energy spectrum and zenith angle variations of the solar neutrino flux from 1258 days of neutrino-electron scattering data in Super-Kamiokande. The absence of significant zenith angle variation and spectrum distortion places strong constraints on neutrino mixing and mass difference in a flux-independent way. Using the Super-Kamiokande flux measurement in addition, two allowed regions at large mixing are found.Comment: 6 pages, 4 figures, submitted to PR

Implications of mirror neutrinos for early universe cosmology

The Exact Parity Model (EPM) is, in part, a theory of neutrino mass and mixing that can solve the atmospheric, solar and LSND anomalies. The central feature of the neutrino sector is three pairs of maximally mixed ordinary and mirror neutrinos. It has been shown that ordinary-mirror neutrino oscillations can generate large neutrino asymmetries in the epoch of the early universe immediately prior to Big Bang Nucleosynthesis (BBN). The large neutrino asymmetries generically suppress the production of mirror neutrinos, and a sufficiently large $\nu_e$ asymmetry can directly affect light element synthesis through nuclear reaction rates. In this paper we present a detailed calculation of neutrino asymmetry evolution driven by the six-flavour EPM neutrino sector, focusing on implications for BBN.Comment: Latex, about 55 pages long with some figure

Measurement of a small atmospheric νμ/νe\nu_\mu/\nu_e ratio

From an exposure of 25.5~kiloton-years of the Super-Kamiokande detector, 900 muon-like and 983 electron-like single-ring atmospheric neutrino interactions were detected with momentum $p_e > 100$ MeV/$c$, $p_\mu > 200$ MeV/$c$, and with visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, the ratio $(\mu/e)_{DATA}/(\mu/e)_{MC}$ was measured to be $0.61 \pm 0.03(stat.) \pm 0.05(sys.)$, consistent with previous results from the Kamiokande, IMB and Soudan-2 experiments, and smaller than expected from theoretical models of atmospheric neutrino production.Comment: 14 pages with 5 figure