No, and she won't be retried. The new jury will consider only the "death v. life" question--they will be instructed to accept the verdicts of premeditated 1st degree murder and cruelty.
I thought (see my previous comments) that a new jury would not be personally "attached" to the prior verdicts and therefore would be likely to vote for life, but my law partner directed me to a recent AZ Republic article:
http://www.azcentral.com/news/arizona/articles/20130522arizona-juries-that-couldnt-decide-on-death-penalty-prog.html.
Apparently this situation has come up 5 times in Maricopa County. In 4 of the cases, the state asked for a new jury (rather than just asking for a life sentence). In 3 out of those 4 cases, the new jury gave death. In the other case, the second jury was also hung, so the defendant got life.
ETA: One caveat. Although the retrial will "only" concern the penalty phase, don't expect it to go as quickly next time. The new jury will have to hear a lot more evidence than this one, because (1) mitigation evidence was presented during the guilt phase to the old jury, including evidence of mental disorders, and (2) it is impossible to balance mitigating evidence against aggravating evidence and the nature of the crime without knowing the aggravating evidence and the nature of the crime first.
