Sentence; considerations; determination; contents.

The panel of judges for the sentencing determination proceeding shall either unanimously fix the sentence at death or, if the sentence of death was not unanimously agreed upon by the panel, fix the sentence at life imprisonment. Such sentence determination shall be based upon the following considerations: (1) Whether the aggravating circumstances as determined to exist justify imposition of a sentence of death; (2) Whether sufficient mitigating circumstances exist which approach or exceed the weight given to the aggravating circumstances; or (3) Whether the sentence of death is excessive or disproportionate to the penalty imposed in similar cases, considering both the crime and the defendant. In each case, the determination of the panel of judges shall be in writing and refer to the aggravating and mitigating circumstances weighed in the determination of the panel. If an order is entered sentencing the defendant to death, a date for execution shall not be fixed until after the conclusion of the appeal provided for by section 29-2525.