Notwithstanding rule 32 of the Federal Rules of Criminal Procedure, when a defendant is found guilty
or pleads guilty to an offense under section 3591, no presentence report shall be prepared. At the sentencing hearing, information may be presented as to any matter relevant to the sentence, including any mitigating or aggravating factor permitted or required to be considered under section 3592. Information presented may include the trial transcript and exhibits if the hearing is held before a jury or judge not present during the trial, or at the trial judge’s discretion. The defendant may present any information relevant to a mitigating factor. The government may present any information relevant to an aggravating factor for which notice has been provided under subsection (a). Information is admissible regardless of its admissibility under the rules governing admission of evidence at criminal trials except that information may be excluded if its probative value is outweighed by the danger of creating unfair prejudice, confusing the issues, or misleading the jury. For the purposes of the preceding sentence, the fact that a victim, as defined in section 3510, attended or observed the trial shall not be construed to pose a danger of creating unfair prejudice, confusing the issues, or misleading the jury. The government and the defendant shall be permitted to rebut any information received at the hearing, and shall be given fair opportunity to present argument as to the adequacy of the information to establish the existence of any aggravating or mitigating factor, and as to the appropriateness in the case of imposing a sentence of death. The government shall open the argument. The defendant shall be permitted to reply. The government shall then be permitted to reply in rebuttal. The burden of establishing the existence of any aggravating factor is on the government, and is not satisfied unless the existence of such a factor is established beyond a reasonable doubt. The burden of establishing the existence of any mitigating factor is on the defendant, and is not satisfied unless the existence of such a factor is established by a preponderance of the information.