Fingerprints of disoriented chiral condensates in cosmic ray showers

Although the generation of disoriented chiral condensates (DCCs), where the order parameter for chiral symmetry breaking is misaligned with respect to the vacuum direction in isospin state, is quite natural in the theory of strong interactions, they have so far eluded experiments in accelerators and cosmic rays. If DCCs are formed in high-energy nuclear collisions, the relevant outcome are very large event-by-event fluctuations in the neutral-to-charged pion fraction. In this note we search for fingerprints of DCC formation in observables of ultra-high energy cosmic ray showers. We present simulation results for the depth of the maximum (XmaxXmax) and number of muons on the ground, evaluating their sensitivity to the neutral-to-charged pion fraction asymmetry produced in the primary interaction.

► We search for fingerprints of DCC in ultra high energy cosmic ray showers. ► DCC signatures are simulated via a change in the neutral-to-charged pion fraction f. ► We present results for the Xmax and number of muons on the ground. ► We evaluate the power of discrimination of a DCC signal as a function of f. ► Very asymmetric shower (wrt f = 1/3) have distinctive Xmax and NμNμ signatures.