News on the exotic hadron called pi_1(1600).

TUM scientists working with the COMPASS experiment at CERN have discovered details about the exotic hadron called π1(1600). Although this particle decays within a very short time span of about 10−24 seconds,
it leaves behind its unique fingerprints, which could be deciphered through very complex data analyses.
For the first time, the scientists were able to uniquely identify the details of its decay path, which leads to three charged light mesons called pions, that were measured by the experiment. They were also able to reconcile the different signals that the π1(1600) produced in previous experiments, which were often considered contradictory, and traced them back to the artifacts of the different analysis techniques. With the COMPASS result, the π1(1600) is now the best established hadron built from light quarks that cannot be classified as an ordinary meson but belongs to a new class of exotic mesons. This work has now been published in the journal Physical Review D (