By Council, CERN Theory is not allowed to support PhD students, and thus there is no PhD program in place. However, we allow staff members to host students locally if supported from outside funds. Some of them have access to grants and may be asked individually if they agree to supervise and/or support external students. Each staff member can host one full-time student at a given time, but exceptions can be negociated with the TH Head.
Note that generally, visitors are not entitled to bring PhD students along. Only Scientific Associates who spend several months at CERN can ask special permission from the TH Head to have students visiting. Such visits must be one at a time and only for a few weeks and outside the busy summer months, as well as desk space permitting. Financial support cannot be granted.