Measurement of the polarization parameter in small angle proton-proton elastic scattering at 6 GeV/c

The polarization parameter in pp elastic scattering was measured at 6 GeV/c with fine t resolution for 0.02 < ?t < 0.5 GeV² using a polarized proton beam with Effective Mass Spectrometer at the Zero Gradient Synchrotron. The polarization rises like √?t in the interval 0.02 < ?t < 0.1 GeV², No statistical significant structure was found in this region of momentum transfer.     

Spinpolarisation und Winkelverteilung der Elektronen nach Anregung verschiedener Zustände des Hg-Atoms

At energies above ～ 50 eV, electrons scattered inelastically from mercury atoms show a similarity to elastically scattered electrons in both spin polarization and angular distribution. This similarity vanishes at primary energies below ～ 30 eV for the 6p′³ P ₁-channel (11.0 eV energy loss) and below～ 25 eV for the 6¹ P ₁-channel (6.7 eV energy loss).     

Die Ortsverteilung mittelschneller Elektronen bei Mehrfachstreuung

Several authors have investigated the angular distribution of plurally scattered electrons, but no experimental investigations in the range of plural scattering are known about the distribution of linear displacements. Therefore electrons (40 keV... 130 keV) have been shot in extended gaseous targets (He, Ne, A, Kr, Xe and O₂) of low pressure and the resultant distribution of the current density at the end of the target has been measured by means of thep?n junction of a gallium arsenide cell. The measurements in argon are compared with theoretical calculations. It is shown by some examples how to get from the measurements at the end of the target the electron distribution inside the target, too.     

Dissociation energies of six NO2 isotopologues by laser induced fluorescence spectroscopy and zero point energy of some triatomic molecules

We have measured the rotationless photodissociation threshold of six isotopologues of NO2 containing 14N, 15N, 16O, and 18O isotopes using laser induced fluorescence detection and jet cooled NO2 (to avoid rotational congestion). For each isotopologue, the spectrum is very dense below the dissociation energy while fluorescence disappears abruptly above it. The six dissociation energies ranged from 25 128.56 cm(-1) for 14N16O2 to 25 171.80 cm(-1) for 15N18O2. The zero point energy for the NO2 isotopologues was determined from experimental vibrational energies, application of the Dunham expansion, and from canonical perturbation theory using several potential energy surfaces. Using the experimentally determined dissociation energies and the calculated zero point energies of the parent NO2 isotopologue and of the NO product(s) we determined that there is a common De = 26 051.17+/-0.70 cm(-1) using the Born-Oppenheimer approximation. The canonical perturbation theory was then used to calculate the zero point energy of all stable isotopologues of SO2, CO2, and O3, which are compared with previous determinations.     

An automated method for volumetric quantification of magnetization transfer of the brain

Cerebral white matter damages can be detected and characterized using magnetization transfer (MT) imaging. In this study a fully automated method of measuring and analyzing the MT of the whole human brain is presented and assessed. A 3D-FLASH sequence with off-resonance RF pulse was optimized for fast, volumetric MT measurements. The postprocessing software developed for this purpose includes a SPM99-based segmentation algorithm, a visualization tool, and a histogram-based MT parameter analysis. The reproducibility of the method was tested with phantom measures and in studies on nine healthy volunteers. Small variances (0-1.6%) and therefore, a high reproducibility of MT parameter measurements were found in vitro, slightly higher variances in volunteer investigations (0.7-4.0%). With our technique, we expect to be able to better recognize and follow up the progression of white matter diseases. Due to the high reproducibility, this volumetric approach is specifically suitable for longitudinal MT studies.     

Analytic aspects of the Toda system: I. A Moser‐Trudinger inequality

In this paper, we analyze solutions of the open Toda system and establish an optimal Moser‐Trudinger type inequality for this system. Let Σ be a closed surface with area 1 and K = (a_ij)_{N × N} the Cartan matrix for SU(N + 1), i.e., We show that has a lower bound in (H¹(Σ))^N if and only if This inequality is optimal. As a direct consequence, if M_j < for 4π for j = 1, 2, …, N, Φ_M has a minimizer u that satisfies © 2001 John Wiley & Sons, Inc.     

Search for weakly interacting sub-eV particles with the OSQAR laser-based experiment: results and perspectives

Recent Planck measurements show some CMB anomalies on large angular scales, which confirms the early observations by WMAP. We show that an inflationary model, in which before the slow-roll inflation the Universe is in a superinflationary phase, can generate a large-scale cutoff in the primordial power spectrum, which may account for not only the power suppression on large angular scales, but also a large dipole power asymmetry in the CMB. We discuss an implementation of our model in string theory.