Relativistic and non-relativistic scattering by short-range potentials is investigated for selected problems. Scattering by the δ' potential in the Schrödinger equation and δ potentials in the Dirac equation must be solved by regularization, efficiently carried out by a perturbation technique involving a stretched variable. Asymmetric regularizations yield non-unique scattering coefficients. Re...

Spectral and scattering theory at low energy for the relativistic Schrödinger operator are investigated. Some striking properties at thresholds of this operator are exhibited, as for example the absence of 0-energy resonance. Low energy behavior of the wave operators and of the scattering operator are studied, and stationary expressions in terms of generalized eigenfunctions are proved for the ...

This article gives an overview of many of the recent developments in understanding the structure of relativistic scattering amplitudes in gauge theories ranging from QCD to N = 4 super-Yang-Mills theory, as well as (super)gravity. I also provide a pedagogical introduction to some of the basic tools used to organize and illuminate the color and kinematic structure of amplitudes. This article is ...

We review a three-dimensional formalism that provides a systematic way to include relativistic effects including relativistic kinematics, the effects of negativeenergy states, and the boosts of the two-body system in calculations of two-body bound-states. We then explain how to construct a conserved current within this relativistic three-dimensional approach. This general theoretical framework ...

A bstract We present a general method for deriving the energy shift of an interacting system N spinless particles in finite volume. To this end, we use nonrelativistic effective field theory (NREFT), and match pertinent low-energy constants to scattering amplitudes. Relativistic corrections are explicitly included up given order 1/ L expansion. apply obtain ground state particles, first excited...

In 1999, F.A.B. Coutinho, Y.Nogami and Lauro Tomio published a paper entitled “Two definitions of the electric polarizability of a bound system in relativistic quantum theory”. The authors of ref.(1), dicussed the possibility of two definitions of the relativistic electric polarizability and the difference between the two definitions. In addition, the authors relate their definitions to the ele...

We give a brief overview about theory development of spin polarization in relativistic heavy ion collisions, which includes how the could be generated by single scattering, what equilibrium, to address some recent puzzles collisions and much progress we have made hydrodynamics kinetic theory. will also discuss possible helicity collisions.

.Over the past few years it has been shown that the use of an “infinite momentum’7 Lorentz frame1 has remarkable advantages for calculations in elementary particle physics and field theory, especially in the areas of current algebra sum rules, 2 parton models, 3, 4 and eikonal scattering.5,6 One important advantage is that it allows a straightforward application of the impulse and incoherence a...

The high density effective theory recently introduced by Hong and Hsu to describe ultradense relativistic fermionic matter is used to calculate the tree-level forward scattering amplitude between two particles at the Fermi surface. While the direct term correctly reproduces that of the underlying gauge theory, the exchange term has the wrong sign. The physical consequences are discussed in the ...