Scanning force microscopy on heavy-ion tracks in muscovite mica: track diameter versus energy loss and loading force


title: Experimental results of the betatron sum resonance
abstract: The experimental observations of motion near the betatron sum resonance, /spl nusub x/+2/spl nusub z/=13, are presented. A fast quadrupole (Panofsky-style ferrite picture-frame magnet with 8 pulsed power supplies) producing a betatron tune shift of the order of 0.03 at rise time of 1 /spl mu/s was used. This quadrupole was used to produce betatron tunes which jumped past and then crossed back through a betatron sum resonance line. The beam response as function of initial betatron amplitudes were recorded turn by turn. The correlated growth of the action variables, J/sub x/ and J/sub z/, was observed. The phase space plots in the resonance frame reveal the features of particle motion near the nonlinear sum resonance region.<<ETX>>

title: Dipole and spin-dipole resonances in charge-exchange reactions on 12C.
abstract: The [sup 12]C([ital n],[ital p])[sup 12]B reaction was studied using the white neutron source at the Los Alamos Meson Physics Facility/Weapon Neutron Research Center with a continuous incident neutron energy from 60 to 260 MeV. Double differential cross sections were measured in the angular range 11[degree][le][theta][sub lab][le]37[degree]. Using the neutron time-of-flight facility at the Indiana University Cyclotron Facility, we also studied the [sup 12]C([ital p],[ital n])[sup 12]N reaction at [ital E][sub [ital p]]=186 MeV and the [sup 12]C([ital [rvec p]],[ital [rvec n]])[sup 12]N reaction at [ital E][sub [ital [rvec p]]]=160 and 186 MeV. Double differential cross sections were measured between [theta][sub lab]=0[degree] and [theta][sub lab]=50[degree] in 5[degree] steps. Spin observables [ital D][sub [ital N][ital N]], [ital A][sub [ital Y]], and [ital P] were measured at [theta][sub lab]=5[degree],9[degree],13[degree] with [ital E][sub [ital [rvec p]]]=160 MeV and [theta][sub lab]=15[degree],20[degree] with [ital E][sub [ital [rvec p]]]=186 MeV. Angular distributions of differential cross section and spin observables for low-lying transitions in the residual nuclei are compared with disorted-wave impulse approximation (DWIA) calculations. A multipole decomposition analysis was performed to study the giant dipole and giant spin-dipole resonances. The contributions of the quasifree reaction in the giant resonance region was subtracted. The empirical results ofmore » energy distributions for dipole ([Delta][ital L]=1) transition are compared with DWIA calculations using nuclear structure information obtained with a conventional shell model and also with a random phase approximation.« less

title: Crystallization in the Thin and Ultrathin Films of Poly(ethylene-vinyl acetate) and Linear Low-Density Polyethylene
abstract: The crystallization of poly(ethylene−vinyl acetate) and linear low-density polyethylene (LLDPE) films spun-cast from the polymer/toluene solutions with as-cast thickness from 460 to 10 nm was studied. The lamellar thickness was measured using small-angle X-ray scattering (SAXS) and found to increase from 14 to 21 nm for films thinner than 100 nm. The morphology of LLDPE measured by scanning probe microscopy (SPM) showed an edge-on lamellae for the films thicker than 30 nm and flat-on lamellae for the films thinner than 15 nm. A pseudo-“shish-kebab” tiny crystal structure was observed in between the larger lamellae. Crystallinity was confirmed using attenuated total reflectance−Fourier transformed infrared spectroscopy (ATR-FTIR) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The shear modulation force microscopy technique (SMFM) was used to measure the melting point, Tm, which was found to decrease for films thinner than 100 nm. The rate of decrease was a function of the annealing pr...

title: Energetic electrons associated with magnetic reconnection in the magnetic cloud boundary layer.
abstract: Here is reported in situ observation of energetic electrons (∼100-500 keV) associated with magnetic reconnection in the solar wind by the ACE and Wind spacecraft. The properties of this magnetic cloud driving reconnection and the associated energetic electron acceleration problem are discussed. Further analyses indicate that the electric field acceleration and Fermi-type mechanism are two fundamental elements in the electron acceleration processes and the trapping effect of the specific magnetic field configuration maintains the acceleration status that increases the totally gained energy.

title: Clarification of the three-body decay of 12C (12.71 MeV).
abstract: Using beta decays of a clean source of 12N produced at the IGISOL facility, we have measured the breakup of the 12C (12.71 MeV) state into three alpha particles with a segmented particle detector setup. The high quality of the data permits solving the question of the breakup mechanism of the 12.71 MeV state, a longstanding problem in few-body nuclear physics. Among existing models, a modified sequential model fits the data best, but systematic deviations indicate that a three-body description is needed.

title: Experimental study of hadron inclusive production in J / psi energy region

title: A Universal Probability Distribution Function for Weak-lensing Amplification
abstract: We present an approximate form for the weak-lensing magnification distribution of standard candles, valid for all cosmological models, with arbitrary matter distributions, over all redshifts. Our results are based on a universal probability distribution function (UPDF), P(η), for the reduced convergence, η. For a given cosmological model, the magnification probability distribution, P(μ), at redshift z is related to the UPDF by P(μ) = P(η)/ , where η = 1 + (μ - 1)/(2|κmin|), and κmin (the minimum convergence) can be directly computed from the cosmological parameters (Ωm and ΩΛ). We show that the UPDF can be well approximated by a three-parameter stretched Gaussian distribution, where the values of the three parameters depend only on ξη, the variance of η. In short, all possible weak-lensing probability distributions can be well approximated by a one-parameter family. We establish this family, normalizing to the numerical ray-shooting results for a Λ cold dark matter (CDM) model by Wambsganss et al. (1997). Each alternative cosmological model is then described by a single function ξη(z). We find that this method gives P(μ) in excellent agreement with numerical ray-tracing and three-dimensional shear matrix calculations, and we provide numerical fits for three representative models (SCDM, ΛCDM, and OCDM). Our results provide an easy, accurate, and efficient method to calculate the weak-lensing magnification distribution of standard candles and should be useful in the analysis of future high-redshift supernova data.

title: Energy and centrality dependence of the contribution from leading particles to charged-particle pseudorapidity distribution

title: Robust constraints on dark energy and gravity from galaxy clustering data
abstract: Galaxy clustering data provide a powerful probe of dark energy. We examine how the constraints on the scaled expansion history of the Universe, xh(z) =H(z)s (with s denoting the sound horizon at the drag epoch), and the scaled angular diameter distance, xd(z) =DA(z)/s, depend on the methods used to analyse the galaxy clustering data. We find that using the observed galaxy power spectrum, Pobsg(k), xh(z) and xd(z) are measured more accurately and are significantly less correlated with each other, compared to using only the information from the baryon acoustic oscillations (BAO) in Pobsg(k). Using the {xh(z), xd(z)} from Pobsg(k) gives a Dark Energy Task Force (DETF) dark energy figure of merit (FoM) approximately a factor of 2 larger than using the {xh(z), xd(z)} from BAO only; this provides a robust conservative method to go beyond BAO only in extracting dark energy information from galaxy clustering data. 
 
 
 
We find that a Stage IV galaxy redshift survey, with 0.7 < z < 2 over 15 000 (deg)2, can measure with high precision [where fg(z) and G(z) are the linear growth rate and factor of large-scale structure, respectively, and is the dimensionless normalization of Pobsg(k)], when redshift-space distortion information is included. The measurement of provides a powerful test of gravity, and significantly boosts the dark energy FoM when general relativity is assumed.

title: Observation of the decay psi(2S) ---> K*(892)anti-K + c.c.