You don't want (capturing) parentheses, you want square brackets (a character class, see perlre):

my $string = "foo / bar & etc";
my @parts = split(m# [&/] #,$string);
print join("\n",@parts,"");
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(Note the extra null string to tack a newline onto the "etc", and the use of a different matching delimiter to avoid the need to escape the forward slash -- the ampersand never needed to be escaped )