Gauge invariance, radiative interferences and properties of vector mesons

We state the implications on the properties of vector mesons due to gauge invariance. In particular, we find that polarized vector mesons exhibit a property in the radiation distribution of order $\omega^{-1}$ in the photon energy, namely it is null when the gyromagnetic ratio becomes $g=2$. Therefore, the generalization of the Burnett-Kroll theorem for polarized vector-meson states is held only if $g=2$. In addition, radiative interferences between the electric charge and any gauge invariant term is found to be parametrized by a common global factor which can be used to extract information of the involved states by a proper choice of the kinematical region, where they could be relevant.Comment: 5 pages, 1 figure. To appear in the Proceedings of the IX Mexican Workshop on Particles and Fields, Colima Mexico. Uses RevTex

Binary Decay of Light Nuclear Systems

A review of the characteristic features found in fully energy-damped, binarydecay yields from light heavy-ion reactions with $20\leq A_{target} + A_{projectile}\leq 80$ is presented. The different aspects of these yields that have been used to support models of compound-nucleus (CN) fission and deep-inelastic dinucleus orbiting are highlighted. Cross section calculations based on the statistical phase space at different stages of the reaction are presented and compared to the experimental results. Although the statistical models are found to reproduce most of the observed experimental behaviors, an additional reaction component corresponding to a heavy-ion resonance or orbiting mechanism is also evident in certain systems. The system dependence of this second component is discussed. The extent to which the binary yields in very light systems $(A_{CN} \leq 32)$ can be viewed as resulting from a fusion-fission mechanism is explored. A number of unresolved questions, such as whether the different observed behaviors reflect characteristically different reaction times, are discussed.Comment: 79 pages REVTeX file, 39 ps Figures included - to be publihed in Physics Report

The Renewed Need for Guidance Addressing Partnership 754 Election Revocations

The section 754 election of the Internal Revenue Code allows partnerships to make basis adjustments to avoid potentials for double taxation that can arise following transfers of partnership interests and distributions of partnership property. Once made, a 754 election applies to all future tax years and is revocable only with the consent of the Internal Revenue Service (Service). One subsection of the Treasury Regulations addresses when the Service might approve or deny a partnership’s request to revoke a 754 election. Despite the process contemplated in this regulation, until recently, partnerships could default out of a 754 election without Service approval through a technical termination. The lack of recorded application of the regulation implies that partnerships have largely not needed to rely on—and the Service has not needed to apply—the 754 election revocation regulation. The repeal of technical terminations under the 2017 Tax Cuts and Jobs Act, however, foreclosed the ability of partnerships to default out of a 754 election, creating not only a renewed permanence of 754 elections but also a new need for guidance concerning requests for revocation. In anticipation of both partnerships’ and the Service’s need to rely more heavily on requests for 754 election revocation, this Note provides potential factors the Service might use to consider such requests and highlights other ways partnerships might still effect a 754 election revocation without Service approval

Stern-Gerlach Entanglement in Spinor Bose-Einstein Condensates

Entanglement of spin and position variables produced by spatially inhomogeneous magnetic fields of Stern-Gerlach type acting on spinor Bose-Einstein condensates may lead to interference effects at the level of one-boson densities. A model is worked out for these effects which is amenable to analytical calculation for gaussian shaped condensates. The resulting interference effects are sensitive to the spin polarization properties of the condensate.Comment: 9 pages, 2 figure