Classical music isn’t usually thought of as a competitive sport. But if it was, Arvo Pärt would be the equivalent of the Yankees in the 1950s – completely dominant. The Estonian composer is, in fact, the most-performed living composer in the world. And it’s easy to hear why, when his meditative work is interpreted by an ensemble like Vox Clamantis, also from Estonia. On Sunday, they'll add to Pärt’s dominance in the “most-performed” category with an all-Pärt program at Saint Francis Xavier Church near Union Square. Admission is free.