FTS Regex query

I have a requirement to FTS a group of words - eg: “elon musk” as the searched word.

This phrase should match document field let us say - full name with the value “South African-born business magnate, investor, engineer, and inventor elon musk is a visionary that the world needs today.”

I used the expression \Welon musk\w

My java code snippet looks as follows:
String regexpFullName = "\W " + fullName + “\w”;
RegexpQuery regexFullNameQuery = new RegexpQuery(regexpFullName).field(CASE_INFO_FULL_NAME);

I created an index by full name and used the query above to fetch results.

The query is fetching 0 results.

Any help is appreciated.