The leading term of the He$-\bar{p}\mbox{He}^+$ long-range interaction

TL;DR

This paper calculates the long-range interaction coefficients between antiprotonic helium and helium atoms, providing data crucial for precision spectroscopy and understanding collisional effects in these exotic systems.

Contribution

It introduces a method to compute dispersion coefficients for metastable antiprotonic helium states using CCR formalism, addressing their resonant nature.

Findings

Calculated dispersion coefficients $C_6$ for antiprotonic helium states.

Provided numerical data on static dipole polarizabilities.

Results can estimate collisional shifts and line broadening.

Abstract

The long range interaction between an antiprotonic helium atom $\bar{p}$He$^+$ and helium atom in its ground state is studied. We calculate the dispersion coefficients $C_6$ using the Complex Coordinate Rotation (CCR) formalism in order to comply with the resonant nature of metastable states of the antiprotonic helium. We present as well numerical data on static dipole polarizabilities of antiprotonic helium states. The obtained coefficients $C_6$ may be used to estimate the collisional shift and broadening of transition lines in a low density precision spectroscopy of the antiprotonic helium.