Split by non-escaped colons

I want to split a string by colons that do not have backslashes in front of them.

Example:

"this:is: a\\:cool : test" should return ["this", "is", " a\\:cool ", " test"]

My code so far:

Code:

String s = "this:is: a\\:cool  : test";
String[] split = s.split("(?!\\\\):");

I tested the regex "(?!\\\\):" and it matches ":" but not "\:". For some reason, the value of split is [this, is, a\, cool , test]. How can I do what I want?