Does the p-Ps lifetime agree with expectations from magnetic quenching?

Magnetic quenching experiments with naphthalene give small value of density parameter η. Corresponding lifetime of p-Ps should be equal or close to that of free annihilation. Contrary to expectations, we obtained the lifetime of short-lived component τ1=180ps (its intensity is larger than predicted by statistical weight rule). Generally, the experiments with the use of magnetic field give smaller η value than these using zero-field methods.