Kinematic surprises in twisted-particle collisions

Abstract

Twisted particles" refer to non-plane-wave states of photons, electrons, hadrons, or any other particle which carry non-zero, adjustable orbital angular momentum with respect to their average propagation direction. Twisted photons and electrons have already been experimentally demonstrated, and one can expect creation of twisted states of other particles in future. Such states can be brought in collisions, offering a completely new degree of freedom in collider experiments and, especially, a novel tool for hadronic physics. We recently showed that 2 → 1 processes with two twisted particles such as resonance production in twisted e + e − annihilation give access to observables which are difficult or impossible to probe in the usual plane-wave collisions. In this paper, we discuss in detail surprising kinematic features of this process, focusing on spinless particle annihilation. They include (1) a new dimension in the final momentum space available in twisted annihilation, (2) interference fringes emerging in the cross section as a function of the total energy, and (3) the builtin mass spectrometric capability of this process, that is, simultaneous production and automatic angular separation of several resonances with different masses in monochromatic twisted particle annihilation experiment running at fixed energy. All these features cannot be obtained in the usual plane wave collision setting.

Double‐Twisted Spectroscopy with Delocalized Atoms

“…The number, height, location and contrast of these fringes depend on the OAM values $$m_i$$, on the absolute values of the transverse momenta $$\varkappa _i$$, and, for $${\cal M}_a \not= {\cal M}_b$$, on the relative phase between these two amplitudes. These are the atomic physics counterparts of the fringes derived for high‐energy particle collisions in [31].…”

“…Collisions of two initial particles in twisted states lead to novel effects, which so far have been theoretically explored only in particle physics realm. They can be purely kinematical [ 28–31 ] or can involve spin degrees of freedom in a novel way. [ 32 ] The origin of these effects can be tracked to the famous Young's two slit experiment but now seen in momentum space.…”

Double-twisted spectroscopy with delocalized atoms

“…Collisions of two initial particles in twisted states lead to novel effects, which so far have been theoretically explored only in particle physics realm. They can be purely kinematical [28,29,30,31] or can involve spin degrees of freedom in a novel way [32]. The origin of these effects can be tracked to the famous Young's two slit experiment but now seen in momentum space [33].…”

Twisted particles in heavy-ion collisions

“…Since it manifests in processes studied in Ref. [15], it can in principle be discovered. The vorticity of nuclear matter is another reason of a production of not only charged but also uncharged twisted particles [31].…”