Suppression of the S-wave production of (32)⁺+(12)^- heavy meson pairs in e+^e- annihilation

The heavy meson-antimeson pairs, where one is an excited (32)⁺ meson and the other is a ground state (12)^- meson, namely, the pairs (D₁(2420)D̄+c.c.), (D₁(2420)D^{̄ *}+c.c.), (D₂(2460)D^{̄ *}+c.c.) in the charm sector and (B₁(5721)B̄+c. c.), (B₁(5721)B^̄*+c.c.), (B ₂(5747)B^̄*+c.c.) in the bottom sector, are allowed, by the quantum numbers, to be produced in the S wave in e⁺e^- annihilation. We show, however, that such S-wave production is forbidden by the heavy quark spin symmetry. Thus, the yield of the considered meson pairs in e⁺e^- annihilation should be significantly suppressed near the respective thresholds. In our view, this substantially weakens the arguments for considering the Y(4260) charmoniumlike resonance as a D₁D̄ molecular state.