Research says that people imprint on music in their dating years, and carry those tastes with them through the rest of their lives. Lately, this has spelled trouble for jazz music, which is failing to attract new and younger fans in a competitive musical landscape. With its listenership in steep decline, jazz legend Wynton Marsalis is looking to rebrand the genre and engineer its comeback, with the help of Harvard Business School professor Rohit Deshpande, author of the case, “Wynton Marsalis and Jazz at Lincoln Center.”