stack overflow error with regex for parsing

I know that there has already been some postings about the stack overflow error with regex and long strings, but they didn't help me and never concern my type of parsing problem.

I just try to find the string in parentheses from a mathematical function e.g.

 funktionsstring  
  =SIN(3.141592653589793238462643383279502884197169399375105820974944592307816406
   286208998628034825342117067982148086513282306647093844609550582231725359408
   12848111745028410270193852110555964462294895493038196);

Using the following code with a pattern to find the string x which is in parentheses eg. ( x ) :

Pattern pattern = Pattern.compile("\\([^(]*?\\)");
Matcher matcher = pattern.matcher(funktionsstring);

I get the following error

    Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at java.util.regex.Pattern.bitsOrSingle(Pattern.java:2553)
at java.util.regex.Pattern.range(Pattern.java:2601)
at java.util.regex.Pattern.clazz(Pattern.java:2507)
at java.util.regex.Pattern.sequence(Pattern.java:2030)
at java.util.regex.Pattern.expr(Pattern.java:1964)
at java.util.regex.Pattern.compile(Pattern.java:1665)
at java.util.regex.Pattern.<init>(Pattern.java:1337)
at java.util.regex.Pattern.compile(Pattern.java:1022)
at classes.Parser.Klammerauswertung(Parser.java:104)
at classes.Parser.Klammerauswertung(Parser.java:119)
at classes.Parser.Klammerauswertung(Parser.java:119)

I don't see if I can improve the pattern in some way to prevent iteration which seems to cause the stack overflow. Obviously the split function doesn't work here.

Also - as the string is very long - I would like to allow n\ as character. I want to work generally with big decimal numbers (using apfloat) to obtain at least some 100 to 1000 exact decimals for scientific reasons, is it possible to keep regex changing the pattern?

If not, how do I have to rewrite regex?

Is there a better tool?