We present an analytic two-loop calculation within the scalar diquark model of potential linear and angular momenta, defined as difference between Jaffe-Manohar Ji notions momenta. As expected by parity time-reversal symmetries, a direct confirms that transverse momentum coincides with (or canonical) definition average quark momentum, also known Sivers shift. examine whether initial/final-state...

The six-degree equations of flight in their classic form do not provide a proper physical perception due to a number of interferences. Nor do they render visible the important role of attack angles. In this study, attempts have been made to develop a complete set of 3D acceleration equations from the equations of normal and tangential acceleration αN=vωv, αt=v ̇. For this purpose, a coordinate s...

We study actions in (2 + 1)-dimensions associated with null curves whose Lagrangians are arbitrary functions f on the curvature of the particle path, showing that null helices are always possible trajectories of the particles for every function f . The vector field P , obtained from the Euler-Lagrange equation, can be interpreted as the linear momentum of the particle since it is constant along...

We show that it is possible to perturb arbitrary vacuum asymptotically flat spacetimes to new ones having exactly the same energy and linear momentum, but with center of mass and angular momentum equal to any preassigned values measured with respect to a fixed affine frame at infinity. This is in contrast to the axisymmetric situation where a bound on the angular momentum by the mass has been s...