How to exclude the lookahead part from colouring

[datatraveller1]

The input file "dictionary" has the entry:
Fascinating (p. pr. & vb. n.) of Fascinate

I'm searching this input file for the term beginning with "fascinating", a space and an opening round bracket like so:
rg.exe "^fascinating (?:[(])" dictionary -i --no-line-number --pcre2

The result line is correct:
Fascinating (p. pr. & vb. n.) of Fascinate

However, the red colour match for this result line is:
Fascinating (
but I want to omit the opening round bracket for the red colouring because this is only the lookahead part.
The lookahead part should not be part of the match. Can this be done?

[BurntSushi]

Yes, if you use look-ahead. You aren't actually using look-ahead. I didn't test it, but try ^fascinating(?= [(]).

See also: https://www.regular-expressions.info/lookaround.html

[datatraveller1]

Great, your solution works!
rg.exe "^fascinating(?= [(])" dictionary -i --no-line-number --pcre2

So,I have simply used look-ahead wrongly. Thank you so much!