Personnel: Jeff Dean at Google DeepMind (Chief Scientist (Google Research / DeepMind))

NoteThe source directly confirms all key fields of the record: (1) Person: Jeff Dean ✓; (2) Organization: Google DeepMind ✓ (formed April 2023 from merger of Google Brain and DeepMind); (3) Role: Chief Scientist ✓ (explicitly stated 'Dean became Google's chief scientist'); (4) Start date: April 2023 ✓ (matches the claimed 2023-04). The Wikipedia article also states earlier 'He was appointed Google's chief scientist in 2023 after the merger of DeepMind and Google Brain into Google DeepMind.' All record fields are directly supported by the source text.