Hi,
The near to be release 2019.3 RC with HDRP 7.1.5 (and near to be release 7.1.6 for the RC), add the support of Raytracing in Preview.
Before there was a dedicated experimental version from March that we have used to do our GDC raytracing demo. Now raytracing is part of Unity product. Documentation can be found here: Redirecting to latest version of com.unity.render-pipelines.high-definition
The experimental forum previously used for raytracing is now moved in this forum.