Infinite loop of aritmetic expression

I have my parser generator that will generate the Earley Chart parser,
I got not idea when I gave this input it will go infinite loop, my
processor working at maximum speed and then hang. Is my grammar
correct ?

Input : 6 ^ 2 + 1 - 4 * 3 / 2

art  -> art PLUS term
art  -> art MINUS term
art  -> term
term -> term TIMES factor
term -> term DEVIDE factor
term -> factor
factor -> factor EXPONENT primary
factor -> primary
primary -> LPAREN art RPAREN
primary -> NUMBER


^ : EXPONENT
+ : PLUS
- : MINUS
* : TIMES
/ : DEVIDE
[0-9]+ : NUMBER

Any idea why ? Thanks.