  Recent measurements have revealed a significant suppression of multipion
Bose-Einstein correlations in heavy-ion collisions at the LHC. The suppression
may be explained by postulating coherent pion emission. Typically, the
suppression of Bose-Einstein correlations due to coherence is taken into
account with the coherent state formalism in quantum optics. However, since
charged pion correlations are most often measured, the additional constraint of
isospin conservation, which is absent in quantum optics, needs to be taken into
account. As a consequence, correlations emerge between pions of opposite
charge. A calculation of the correlations induced by isospin conservation of
coherent emission is made for two, three- and four-pion correlation functions
and compared to the data from the LHC.
