Is the $A2$ meson split? Two experiments say no

Two recent experiments have brought new life to the argument about whether the $A2$ meson is split—that is, whether it exists as two particles having identical properties except for a 3% difference in mass. The experiments, one performed at CERN by a CERN–Munich group and the other at Brookhaven, both report data indicating the $A2$ is not split. S. J. Lindenbaum, the leader of the Brookhaven group, presented data at the annual APS meeting in New York that he claims have less than one chance in a million of being consistent with a two‐peak (dipole) mass formula. (The group has also published a letter in Physical Review Letters 26, 413, 1971.)