Asymmetric Momentum Research Articles

QCD corrections in an asymmetric momentum subtraction scheme

Numerical results for higher order QCD corrections for (a) e +e −-annihilation, (b) para-quarkonium decay and (c) deep-inelastic scattering are presented in the recently proposed asymmetric momentum subtraction renormalization scheme (AMOS). The corrections are comparable to those in the symmetric momentum subtraction scheme (SMOS) which has yielded the smallest numbers so far. It is also pointed out that AMOS is theoretically more appealing than SMOS.

Energy and momentum theorems in magnetospheric processes

This review deals with the several energy and momentum theorems that relate to magnetospheric processes that have been developed. The region of primary consideration in this paper is the magnetospheric domain that extends between the ionosphere and the interplanetary medium, although, for studying certain phenomena, ionospheric and solar wind properties are of central importance and must be included. Both energy theorems and momentum theorems with their applications are presented. Since energy is an integral property of the system variables, analytical results can be found without knowledge of detailed dynamical processes. Thus, relations are derived between particle and magnetic system energies, and application is made to the shape of the magnetopause and various phases of a magnetic storm. Particular attention is given to symmetric and asymmetric ring currents, including energy and momentum equilibrium conditions; a review of nonlinear self‐consistent models and a discussion of how charge exchange and energy diffusion participate in the recovery phase are presented. Comprehensive expressions for the storm time disturbance field are given in terms of both ring current and boundary current energies, and changes that occur during magnetospheric compressions are discussed. The momentum theorems center around the requirement of static force balance during geomagnetically quiet intervals. Whereas the energy theorems give expressions for the average disturbance field over the earth, the momentum theorems give the gradient in the disturbance field across the earth. The forces between earth and the boundary current, the ring current, and the tail current are derived for various models. It is noted that existing vacuum models of the geomagnetic tail are deficient in meeting the combined requirements of energetics and dynamics of the quiet time tail. Introducing the plasma sheet removes the difficulty by allowing an extra degree of freedom in adjusting the force between the earth and the tail. The role of the plasma sheet in making force adjustments is shown to be consistent with the observed thinning of the plasma sheet before sub storms.

Minimal and nonminimal gravitational interactions, and the asymmetric energy momentum tensor

Minimal and nonminimal gravitational couplings are discussed in terms of the translation gauge fields b k μ, which are necessary to describe the gravitational interaction of the spin 1/2 field. For this purpose we carry out the extension of the conventional tetrad formalism of general relativity. Our general framework contains four arbitrary parameters; one of them represents the asymmetry of the affine connection (or equivalently that of the energymomentum tensor) and the others measure possible deviations from Einstein's gravitational Lagrangian, which will be responsible for spin effects. We also discuss the physical meaning of the invariance requirement with respect to the Poincare gauge transformation that uniquely leads us within the present framework to Einstein's theory of gravity.