Energy Level Displacement of Excited np State of Kaonic Deuterium In Faddeev Equation Approach

TL;DR

This paper calculates the energy level displacement of excited kaonic deuterium states using Faddeev equations, providing theoretical predictions for experimental planning and understanding strong interaction effects.

Contribution

It introduces a Faddeev equation approach to determine the P-wave scattering length and energy level displacement of kaonic deuterium, including uncertainty estimates.

Findings

Calculated width of 2p state: 10.203 meV

Estimated yield of X-rays: 0.27%

Using known scattering lengths, width is 2.675 meV and yield is 1.90%

Abstract

We calculate the energy level displacement of the excited $np$ state of kaonic deuterium in terms of the P-wave scattering length of $K^-d$ scattering. We solve the Faddeev equations for the amplitude of $K^-d$ scattering in the fixed centre approximation and derive the complex P-wave scattering length of $K^-d$ scattering in terms of the S-wave and P-wave scattering lengths of $\bar{K}N$ scattering. The estimated uncertainty of the complex P-wave scattering length is of about $15\,%$. For the calculated width $\Gamma_{2p} = 10.203\,{\rm meV}$ of the excited $2p$ state of kaonic deuterium we evaluate the yield $Y_{K^-d} = 0.27\,%$ of $X$-rays for the $K_{\alpha}$ emission line of kaonic deuterium. Using the complex S-wave and P-wave scattering lengths of $\bar{K}N$ scattering, calculated in \cite{ECL1,Weise1}, we get the width $\Gamma_{2p} = 2.675\,{\rm meV}$ of the excited $2p$ state and the yield $Y_{K^-d} = 1.90 \,%$ of $X$-rays for the $K_{\alpha}$ emission line of kaonic deuterium. The results, obtained in this paper, can be used for the planning of experiments on the measurements of the energy level displacement of the ground state of kaonic deuterium, caused by strong low-energy interactions.