Retarded penetrating particles in EAS

We present the results of long-term (1995–2006) exploitation of the underground scintillation MUON-T unit at the Tien-Shan mountain scientific station. In 2000, the unit was supplied with a chronotron. The time distribution of retarded (relative to the EAS front) penetrating particles at a depth of 20 m.w.e. was obtained with high statistical confidence. The effect of the geomagnetic field on retardation of penetrating EAS particles, leading to asymmetry of their registration relative to the North-South direction, is confirmed.