8 Search Results
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NLO evolution of color dipoles in N=4 SYM
Here, high-energy behavior of amplitudes in a gauge theory can be reformulated in terms of the evolution of Wilson-line operators. In the leading logarithmic approximation it is given by the conformally invariant BK equation for the evolution of color dipoles. In QCD, the next-to-leading order BK equation has both conformal and non-conformal parts, the latter providing the running of the coupling constant. To separate the conformally invariant effects from the running-coupling effects, we calculate the NLO evolution of the color dipoles in the conformal $${\cal N}$$=4 SYM theory. We define the "composite dipole operator" with the rapidity cutoff preserving conformalmore » -
Structural Analysis of the SHMS Cosine Theta Superconducting Dipole Force Collar
Jefferson Laboratory is developing a set of innovative superconducting magnets for the 12 GeV upgrade in JLAB Hall C. Here, we will report on the finite element analysis (FEA) of the force collar for the Super High Momentum Spectrometer Cosine Theta Dipole magnet. The force collar is designed with an interference fit and intended to provide enough pressure after cool down to operating temperature to counteract Lorentz forces acting on the dipole coil during operation. By counteracting the Lorentz forces and keeping the coil pack in overall compression, movement of the coils is expected to be minimized. The dimensional geometrymore » -
Methods for field computations for the development of SSC superconducting magnets
The Superconducting Super Collider Program will require a large number of superconducting dipole and quadrupole magnets with a variety of designs. Analysis methods are being developed to facilitate rapid and accurate calculation of fields and optimization of design. 2-D and 3-D field computations are fully developed for analysis of coils in the straight section and ends. These are being linked to structural codes and CAD software for design optimization and studies. Other codes have been developed for coil errors, and for persistent and eddy current effects. The attempt is underway to integrate all the codes into a design software package.more » -
Higher-Order Terms in the Current-Current Theory of Weak Interactions
Here we examine the consequences of the hypothesis that, for some range of energies, the second-order terms in the perturbation expansion of the Fermi theory are small but non-negligible corrections to the first-order terms, and responsible for reactions which violate first-order selection rules. We compute matrix elements through second order in the weak coupling constant G and introduce subtraction constants which are necessary to render the matrix elements finite to this order. From this point of view we consider a number of weak-interaction problems, including the experimental parameters of μ decay, the universality of the μ-decay coupling constant and themore » -
Ground-State Energy Eigenvalues and Eigenfunctions for an Electron in an Electric-Dipole Field
Ground-state energy eigenvalues and eigenfunctions are obtained by a variational method for an electron in the field of a finite, stationary, permanent electric dipole. The dipole moments studied cover the range from the minimum value required for binding (Dmin =0.6393 ea0) to D =400 ea0, where the system is equivalent to the hydrogen atom perturbed slightly by a distant stationary negative charge. The eigenvalues obtained agree with those reported by Wallis, Herman, and Milnes, who determined them by another method in the range D =0.84ea0 to 30ea0. The normalized eigenfunctions display the manner in which the electronic charge density changesmore » -
The Dipole Moment of Thioacetoacetic Ester in Solution1
Values of the apparent dipole moment of 2.2 to 2.4 D were observed for thioacetoacetic ester dissolved in benzene, n-hexane, carbon tetrachloride and carbon disulfide. Structural configurations have been assigned to the thioenol and thione tautomeric forms of the ester and their dipole moments calculated from reported bond and group moments. Finally, on the basis of the observed and calculated values, it is postulated that a trans-thione and a trans-thioenol tautomer with the latter exhibiting intramolecular rotation are the predominant configurations of the ester in solution. -
Self-diffusion and Structure of Liquid Water. III. Measurement of the Self-diffusion of Liquid Water with H2, H3 and O18 as Tracers1
Measurements of the diffusion of small amounts of deuterium hydroxide and tritium hydroxide in ordinary water were made at several temperatures. Previous data on the diffusion of $$\text{H}^1_2\text{O}^{18}$$ in ordinary water have been revised. The results confirm previous conclusions regarding the structure of water and the mechanism of self-diffusion, dipole orientation and viscous flow in water. The effect of the differences in the moments of inertia of various water molecules is discussed.