Find lines matching regex and select a different part of the line

I have two lines like below:

/pace =builtin\administrators Type=0x0 Flags=0x13 AccessMask=0x1f01ff

/pace =domain\user Type=0x0 Flags=0x13 AccessMask=0x1f01ff

Need to create a regular expression where it only select 0x1f01ff where the line have domain\user.

This is what I have created but it select /pace =domain\user Type=0x0 Flags=0x13 AccessMask=:

^(.+domain(.*开发者_开发问答)accessmask=)

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try this:

^.+domain\\user.+AccessMask=([^\s]+)

It matches any line that has domain\user and then get the value of accessmask (any character that is not a whitespace)