# Ultracold collisions of Cs in excited hyperfine and Zeeman states

## TL;DR

This paper studies ultracold cesium atom collisions in excited hyperfine and Zeeman states, calculating scattering properties to identify conditions for stable Bose-Einstein condensation and long-lived high-density atomic clouds.

## Contribution

It provides detailed calculations of scattering lengths and loss rates for Cs in excited states, revealing magnetic field regions suitable for stable ultracold gases.

## Key findings

- Identified magnetic field regions where Cs in specific states can be stable.
- Calculated scattering lengths and inelastic loss rates for excited Cs states.
- Suggested conditions for long-lived high-density cesium clouds.

## Abstract

We investigate Cs+Cs scattering in excited Zeeman and hyperfine states. We calculate the real and imaginary parts of the s-wave scattering length; the imaginary part directly provides the rate coefficient for 2-body inelastic loss, while the real part allows us to identify regions of magnetic field where 3-body recombination will be slow. We identify field regions where Cs in its $(f,m_f)=(3,+2)$ and $(3,+1)$ states may be stable enough to allow Bose-Einstein condensation, and additional regions for these and the $(3,0)$ and $(3,-3)$ states where high-density clouds should be long-lived.