Effective radius of ground- and excited-state positronium in collisions with hard walls

Abstract

We determine effective collisional radii of positronium (Ps) by considering Ps states in hard-wall spherical cavities. $B$-spline basis sets of electron and positron states inside the cavity are used to construct the states of Ps. Accurate Ps energy eigenvalues are obtained by extrapolation with respect to the numbers of partial waves and radial states included in the bases. Comparison of the extrapolated energies with those of a pointlike particle provides values of the effective radius ${\rho }_{nl}$ of Ps($nl$) in collisions with a hard wall. We show that for $1s$, $2s$, and $2p$ states of Ps, the effective radius decreases with the increasing Ps center-of-mass momentum, and find ${\rho }_{1s}=1.65$ a.u., ${\rho }_{2s}=7.00$ a.u., and ${\rho }_{2p}=5.35$ a.u. in the zero-momentum limit.

arXiv comment13 pages, 11 figures, submitted to Physical Review A

References in corpus (7)

• High-precision determination of the electric and magnetic form factors of the proton
• Measurement of the ortho-positronium confinement energy in mesoporous thin films
• Many-body theory of positron-atom interactions
• Positron scattering and annihilation on noble gas atoms
• Ps-atom scattering at low energies
• Convergence of CI single center calculations of positron-atom interactions
• Positron scattering and annihilation in hydrogen-like ions

Cited by in corpus (5)

• Complexity of the AdS Soliton
• Many-body theory for positronium-atom interactions
• Calculations of positronium-atom scattering using a spherical cavity
• Many-body theory for positronium scattering and pickoff annihilation in noble-gas atoms
• Positronium density measurements using polaritonic effects