We show that pairs of widely separated interferometers are advantageous for
measuring the Stokes parameter V of a stochastic background of gravitational
waves. This parameter characterizes asymmetry of amplitudes of right- and
left-handed waves and generation of the asymmetry is closely related to parity
violation in the early universe. The advantageous pairs include
LIGO(Livingston)-LCGT and AIGO-Virgo that are relatively insensitive to
Omega_GW (the simple intensity of the background). Using at least three
detectors, information of the intensity Omega_GW and the degree of asymmetry V
can be separately measured.Comment: 6 pages, 3 figures, accepted for publication in PR