Physics Commons^™

Kobayashi-Maskawa Angles And Su(3) Breaking In Hyperon Beta-Decay, Jf Donoghue, Br Holstein, Sw Klimt

Barry R Holstein

The determination of the Kobayashi-Maskawa matrix element Vus from hyperon β decays has long had a hidden uncertainty due to the almost universal assumption of SU(3) invariance in Cabibbo-type fits, especially since the data definitely indicate the presence of SU(3) breaking. We have reanalyzed the hyperon-decay data using the pattern of symmetry breaking predicted by the quark model including the center-of-mass correction. We find that the SU(3)-broken picture is far superior to the assumption of perfect SU(3), and provides a good fit to experiment. The sensitivity of Vus to the breaking is not large and we find Vus=0.220+/-0.001+/-0.003 (the errors …

Implications Of Atmospheric Test Fallout Data For Nuclear Winter, George H. Baker

George H Baker

Atmospheric test fallout data have been used to determine admissible dust particle size distributions for nuclear winter and nuclear fallout studies. The research was originally motivated by extreme differences noted in the magnitude and longevity of dust effects predicted by particle size distributions routinely used in fallout predictions versus those used for nuclear winter studies. Three different sets of historical data have been analyzed:

1. Stratospheric burden of Strontium-90 and Tungsten-185, 1954-1967 (97 contributing events) 2. Continental U.S Strontium-90 fallout through 1958 (75 contributing events) 3. Local Fallout from selected Nevada tests (16 events)

The contribution of dust to possible …

Weak Decays Of The H-Dibaryon, Jf Donoghue, E Golowich, Br Holstein

Barry R Holstein

We calculate decay rates and branching fractions for the postulated S=-2 H dibaryon, both for the expected ΔS=1 channels (nΛ,nΣ0,pΣ-) and for the possible ΔS=2 mode (nn). For ΔS=1 decays we find the S waves are dominated by ΔI=(3/2) transitions due to the Pauli principle, which forces the six-quark final state to be in a SU(3) 27-plet. If observed, this would be the first breakdown of the ΔI=1/2 rule. The lifetime is long, of order 10-8 sec, which should be considered in planning experiments. In the ΔS=2 case, we add a consideration of dispersive effects to our previous calculation of …

Gravitational Coupling At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett

Barry R Holstein

We discuss a thermodynamic identity which helps explain why ≠ at finite temperature. In addition we complete the discussion of the gravitational force by including the gravitational variation of the temperature. Gradients in the temperature induce extra forces not accounted for by the usual coupling to the energy-momentum tensor.

Rigid Backbone: A New Geometry For Percolation, Anthony Roy Day, R. R. Tremblay, A.-M. S. Tremblay

Anthony Roy Day

It is shown that the diluted two-dimensional central-force problem belongs to a new class of percolation problems. Geometric properties such as the fractal dimension of the backbone, the correlation-length exponent, and the connectivity are completely different from those of previously studied percolation problems. Explicit calculations of the backbone and the construction of an algorithm which identifies the infinite rigid cluster clearly demonstrate the absence of singly connected bonds, the overwhelming importance of loops, and the long-range nature of the rigidity.

G. N. Lewis' Atom And Quantum Monte Carlo Studies Of Liquids, Randall W. Hall, Peter G. Wolynes

Randall W. Hall

Auger Analysis Of Si–H Bonding And Hydrogen Concentration In Hydrogenated Amorphous Silicon, Nancy Burnham, Aj Nelson, Ab Schwartzlander, Se Asher, Ll Kazmerski

Nancy A. Burnham

Auger electron spectroscopy line‐shape analysis of the Si‐L 2 3 V V peak has been performed on hydrogenated amorphous silicon (a‐Si:H). Both a‐Si:H produced by hydrogen implantation of siliconsingle crystals (for analytical standards) and thin films (fabricated for solar cell applications) were examined in these studies. Hydrogen concentrations were confirmed by secondary ion mass spectrometry, and samples having hydrogen content over the range 101 6–102 2 cm− 3 were evaluated. Correlations between the area under the deconvoluted L 2 3 V V transition peak and the known hydrogen content have resulted in a semiquantitative method of determining hydrogen concentration using …

Scanning Auger Microprobe Studies Of Ball Cratered Cds/Cuinse2 Solar Cells, Nancy Burnham, Ll Levenson, Rj Matson, R Noufi, Ll Kazmerski

Nancy A. Burnham

CdS/CuInSe2solar cell films are typically several micrometers thick. Composition profiles of these films are usually carried out on fracture cross sections by scanning Auger microscopy or by recording Auger spectra during ion milling. For fracture cross sections, the depth resolution depends on the electron beam diameter and the roughness of the fracture surface. Ion milling is time consuming, and artifacts are caused by ion beam faceting. Ball cratering requires only a fraction of an hour and provides significant magnification of the film cross section. There is sufficient contrast, both in optical and electron microscopy, to distinguish between CdS and CuInSe2 …

Chiral Symmetry, Nonleptonic Hyperon Decay, And The Feinberg-Kabir-Weinberg Theorem, Jf Donoghue, Br Holstein

Barry R Holstein

We demonstrate that additional (kaon-pole) diagrams must be appended to the traditional commutator-plus-baryon-pole approach to nonleptonic hyperon decay. The modified analysis satisfied the constraints of the Feinberg-Kabir-Weinberg theorem. The new terms are not numerically significant in the case of the usual current-current Hamiltonian, in the continuum limit, but can be important for work using lattice techniques or for other Hamiltonians.

The Rigid Backbone: A New Geometry For Percolation., Anthony Day, R. Tremblay, A.-M. Tremblay

Anthony Roy Day

It is shown that the diluted two-dimensional central-force problem belongs to a new class of percolation problems. Geometric properties such as the fractal dimension of the backbone, the correlation-length exponent, and the connectivity are completely different from those of previously studied percolation problems. Explicit calculations of the backbone and the construction of an algorithm which identifies the infinite rigid cluster clearly demonstrate the absence of singly connected bonds, the overwhelming importance of loops, and the long-range nature of the rigidity.

Electromagnetic And Isopin Breaking Effects Decrease Epsilon'/Epsilon, Jf Donoghue, E Golowich, Br Holstein, J Trampetic

Barry R Holstein

No abstract provided.

Chiral Perturbation-Theory Corrections To Kl-]-Gamma-Gamma, Jf Donoghue, Br Holstein, Ycr Lin

Barry R Holstein

No abstract provided.

Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay

Anthony Roy Day

A Comment on the Letter by Wang and Harris, Phys. Rev. Lett. 55, 2459 (1985).

Quantum Electrodynamics At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett

Barry R Holstein

We present a systematic examination of finite temperature effects in quantum electrodynamics at one loop order. We calculate mass, charge, and wavefunction renormalization, demonstrate the running of the coupling constant at high temperatures, and study the renormalized vertex function and the energy momentum tensor. The confusion in the literature concerning the finite temperature corrections to the electron's magnetic moment is resolved. We also present the finite temperature effects in scalar electrodynamics. Throughout we stress the need to provide a well-defined method to observe a given quantity when interpreting the results of a calculation, and we suggest new techniques which incorporate …

Spectral Properties Of Percolating Central Force Elastic Networks, Anthony Day, R. Tremblay, A.-M. Tremblay

Anthony Roy Day

The exponent describing the low frequency spectrum of vibrations for the central force universality class is computed with both the Coherent Potential Approximation and numerical simulations. The results of both calculations agree surprisingly well.

Reanalysis Of Higgs-Boson-Exchange Models Of Cp Violation, Jf Donoghue, Br Holstein

Barry R Holstein

We reexamine the value of ɛ'/ɛ in models where CP violation is due to the exchange of charged Higgs bosons. Previous work has been flawed by incorrect treatment of the chiral properties of weak amplitudes. We use the effective-chiral-Lagrangian framework to clear up these aspects. The resultant value of ɛ'/ɛ is estimated to be in the neighborhood of ɛ'/ɛ=-0.006, although this estimate could be off by a factor of two or three in either direction. This value is consistent with the present experimental bounds.

Behavior Of An Electron In Helium Gas, John Bartholomew, Randall W. Hall, Bruce J. Berne

Randall W. Hall

Gravitational Twins Revisited, Br Holstein

Barry R Holstein

No abstract provided.

Possible Weak Interaction Experiments With Polarized He-3, Br Holstein

Barry R Holstein

No abstract provided.

Forced Harmonic-Oscillator - A Path Integral Approach, Br Holstein

Barry R Holstein

The problem of the harmonic oscillator driven by an external force is explored using path integral techniques. The qualitative features of the solution are demonstrated.

Semileptonic Hyperon Decay - A Problem For Chiral Perturbation-Theory, Jf Donoghue, Br Holstein

Barry R Holstein

We study the recently computed mk2lnm2k corrections to hyperton beta decay found in chiral perturbation theory. The inclusion of these effects is not compatible with the high precision hyperon data, yielding a fit much inferior to the standard assumption of SU(3) invariance. This incompatibility of data and theory is a problem for the application of chiral perturbation theory.

Viscosity Measurements In Dilute Helium-3-Helium-4 Mixtures, George Schmiedeshoff

George Schmiedeshoff

We have measured the viscosity of a dilute mixture of 3He in 4He at temperatures from 5 to 100 mK and in magnetic fields of 0.35, 2.01 and 8.76 T using a vibrating wire viscometer. Subject to our choice of calibration function, the data at 0.35 T is in good agreement with theory. Due to an interaction of our viscometer with the magnetic field the motion of the wire at 2.01 and 8.76 T is not understood; however, the 2.01 T data can be brought into agreement with the 0.35 T data by adjusting a geometrical constant. An increase in …

Renormalization Of The Energy-Momentum Tensor And The Validity Of The Equivalence Principle At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett

Barry R Holstein

Using the techniques of finite-temperature field theory we renormalize the electromagnetic and gravitational couplings of an electron which is immersed in a heat bath with T

Guage Invariant De Gennes Model, Anthony Day, T. Lubensky

Anthony Roy Day

A gauge-invariant formulation of the de Gennes model for the nematic—to—smectic-A transition is presented. In this formulation the energy associated with the gauge field A⃗ reduces to the Frank elastic energy with the application of the constraint n⃗0·A⃗=0 where n⃗0 is the uniform equilibrium director and A⃗ is to be identified with deviations δn⃗ of the director from equilibrium. It is shown that thermodynamic quantities and renormalization-group recursion relations are gauge invariant. All gauge dependence appears in the exponent η describing order-parameter correlations. The gauge invariance of a negative dielectric anisotropy smectic-A in an external electric field is also studied.

Possibilities For Finite Grand Unification With N = 2 Supersymmetry, Asim Gangopadhyaya

Asim Gangopadhyaya

Predicting The Proton Mass From Pi-Pi-Scattering Data, Jf Donoghue, E Golowich, Br Holstein

Barry R Holstein

We relate experimental information on ππ scattering to tree-level effective chiral Lagrangians. The result is of a form similar to that used in Skyrme-type models of the proton, where the nucleons are described as topologically stable solitons of the chiral fields. In such models, one can express the proton mass in terms of measured scattering data, with the result Mp=880±300 MeV. We interpret this as a consistency test for the Skyrme models.

Renormalization And Radiative-Corrections At Finite Temperature, Jf Donoghue, Br Holstein

Barry R Holstein

We discuss the renormalization prescription for fermions at finite temperature and describe the procedure for calculating radiative corrections. Novel features arise, such as a lack of explicit Lorentz invariance, 1k2 singularities, and the absorption of soft photons from the background heat bath. The methods are illustrated by explicit calculation of the electron renormalization and the radiative corrections to H-->e+e- (with H being spin zero) in finite-temperature QED.

Dislocations And The Nematic To Smectic-A Transition For Arbitrary Values Of K1, Anthony Day, T. Lubensky, A. Mckane

Anthony Roy Day

The de Gennes model is used to derive the energy of interacting dislocations in smectic-A liquid crystals. This energy reduces to the energy of interacting vortices in type-II superconductors when the splay elastic constant K1 is zero and to that derived from the Landau-Peierls elastic energy when spatial variations are slow on a scale of the bend and twist penetration depths. Furthermore, it has a well-defined K1→∞ limit. The dislocation energy is used to study the nematic—to—smectic-A transition as a function of K1 in two dimensions and in 4-ε dimensions. No evidence for the Nelson-Toner, anisotropic critical point is found …

Bound-States, Virtual States, And Non-Exponential Decay Via Path-Integrals, Br Holstein

Barry R Holstein

Using path integral techniques we demonstrate how three quantum-mechanical phenomena-alpha decay, nonexponential decay, and resonant scattering-can be treated. This procedure is an algebraic one yet reproduces the usual results obtained via solution of the Schrödinger equation via WKB methods.

Electro-Optics Applications For Alleviating Emi/Emc/Emp Problems, George H. Baker, Walter H. Hardwick

George H Baker

No abstract provided.