Unnuclear physics: Conformal symmetry in nuclear reactions

Abstract

We investigate a nonrelativistic version of Georgi’s “unparticle physics.” We define the unnucleus as a field in a nonrelativistic conformal field theory. Such a field is characterized by a mass and a conformal dimension. We then consider the formal problem of scatterings to a final state consisting of a particle and an unnucleus and show that the differential cross-section, as a function of the recoil energy received by the particle, has a power-law singularity near the maximal recoil energy, where the power is determined by the conformal dimension of the unnucleus. We argue that unlike the relativistic unparticle, which remains a hypothetical object, the unnucleus is realized, to a good approximation, in nuclear reactions involving emission of a few neutrons, when the energy of the final-state neutrons in their center-of-mass frame lies in the range between about 0.1 MeV and 5 MeV. Combining this observation with the known universal properties of fermions at unitarity in a harmonic trap, we predict a power-law behavior of an inclusive cross-section in this kinematic regime. We verify our predictions with previous effective field theory and model calculations of the 6He(p,pα)2n, 3H(π−,γ)3n, and 3H(μ−,νμ)3n reactions and discuss opportunities to measure unnuclei at radioactive beam facilities.

Complex scaling flows in quench dynamics of interacting particles

“…This is consistent with a recent experiment which found that three-body correlations grow slower than two-body ones after an interaction quench [10]. If, instead, three bosons are already resonantly interacting in the two-body sector with s = 4.465 [34] in the initial state before the quench, we expect an anomalous growth law C (3) (t) ∼ t 8.93 reminiscent of unparticle physics [43,44].…”

Exotic spin-dependent interactions through unparticle exchange

“…Since then, the effects of unparticles have been explored in many subjects, including collider physics [2][3][4][5][6], neutrino physics [7,8], cosmology and astrophysics [9,10], quantum electrodynamics [11,12], dark energy [13][14][15][16], etc. The recent nonrelativistic extension of unparticle physics has led to a new concept of unnucleus [17] and provided an interpretation of neutral charm mesons near threshold [18].…”