Can my employer say bad things about me to my new employer?
It depends. There is no general prohibition against a former employer “bad mouthing” you to new or prospective employers. Remember, it is a free country, and we all have a right to our opinions. Employers are free to express their opinions about you, including bad ones.
There are two specific laws that come into play in these circumstances; defamation and the Connecticut Personnel Files Act. Defamation is a false statement of fact that harms you in your reputation and is done with malice or at least with reckless disregard for the truth. An example would be if a former employer falsely told a new or prospective employer during a reference check that you stole from them when in fact you did not and they knew you did not. It would not be defamation if they honestly believed you stole.