Conn. Gen. Stat. § 53a-20

A person in possession or control of premises, or a person who is licensed or privileged to be in or upon such premises, is justified in using reasonable physical force upon another person when and to the extent that he reasonably believes such to be necessary to prevent or terminate the commission or attempted commission of a criminal trespass by such other person in or upon such premises; but he may use deadly physical force under such circumstances only (1) in defense of a person as prescribed in section 53a-19 , or (2) when he reasonably believes such to be necessary to prevent an attempt by the trespasser to commit arson or any crime of violence, or (3) to the extent that he reasonably believes such to be necessary to prevent or terminate an unlawful entry by force into his dwelling as defined in section 53a-100 , or place of work, and for the sole purpose of such prevention or termination.