LOS ANGELES (AP) – Oh “Mama” — Jessica Chastain dominates the weekend box office. Chastain has the top two movies this weekend. Her supernatural horror film “Mama” opens at number one with more than $28 million. “Zero Dark Thirty” falls to second, with 17.6 mil. “Silver Linings Playbook” is third. Arnold Schwarzenegger’s return to top-billing is off to a weak start. Schwarzenegger’s new film “The Last Stand” barely cracks the weekend top 10. It brings a little over 6 million — one of his worst openings ever.