How to make parentheses bigger (to fit the size of an expression inide of them) in an R plot label?

Question

For example. Consider the code

plot(rnorm(10), xlab = NA, ylab = NA)
mtext(side=1, expression( paste("Log"["10"], ( frac( "x","y") ) ))) 

I would like to make the parentheses in the expression larger, to fit the size of the expression inside them. Note the expression is actually much more complicated in my actual script, but this is a minimal reproducible example that captures the essence of the problem.

Answer 1

From the demo pointed out by @Pascal, the answer is to use bgroup

mtext(side=1, expression( paste("Log"["10"], bgroup("(", frac( "x","y"), ")" ) )))