Positronium negative ion experiments – formation, photodetachment and production of an energy tunable positronium beam–

Anomalous magnetic moment of the positronium ion

“…These observables have been precisely predicted [5][6][7][8][9][10][11]. The recent progress has occurred thanks to the prospect of intense positron sources on the experimental side [12][13][14] and by improved variational calculations of the three-body wave function and incorporation of relativistic and some radiative effects on the theory side.…”

Magnetic moment of the positronium ion and virial relations

“…The binding correction becomes Agbound / gfree 11 \ 2gfree a 2 (14) The error in the coefficient of a2 is dominated by the comparison of g factors of free electrons and positrons, known to be equal to better than three parts per trillion [ 11 ]. Of course, providing that coefficient with more than four or five decimal places is, at present, only of academic interest because of the unknown a4 effects.…”

“…Equation (13) is but one example of hypervirial relations that can be used to check the accuracy of variational calculations. This is a welcome development, now that Pshas become more accessible to precise measurements [14], where we have included the actual value of the free-positron g factor, using the result of [4] (rather than approximating 8free 2 as in [3]). Taking the recently measured gtree of the electron [10] and the values of A and B from [7], we confirm and improve the result of [4], as well as the less precise result [3], Abound --0.510551 028 187 6(6)a2 + 0 ( a 4).…”

Polarizability of negatively charged helium‐like ions interacting with Coulomb and screened Coulomb potentials

“…The Ps – has been observed first by Mills and he subsequently measured its annihilation rate . Due to experimental advancements in positron trapping and accumulation technology, it is of great interest to study several properties of Ps – . The static and dynamic dipole polarizabilities of the Ps – were reported in the literature besides several structural properties .…”