Most jazz musicians avoid repetition dogmatically. But when Ryan Keberle realized he’d been playing the same eight-note phrase in all his recent warm-ups, the trombonist embraced his inclination. “As I started playing it more and more, I realized I wasn’t thinking of anything else,” he says. “You can reach a real state of mindfulness through repetition.” Keberle built the phrase into “Without a Thought,” the complex but gracefully flowing centerpiece of his new album, Into the Zone. It’s his first for Greenleaf Music—and arguably the most personal document yet from a trombonist and bandleader better known for his soloist role in famed large ensembles.