Illustration of correlations in the azimuthal angle relative to the direction
of the leading "calorimeter jet", jet1, in the event or relative to the
direction of the leading "charged particle jet" in the event, chgjet1.
The "toward" region is defined by || < 60o
and |eta| < 1 (includes particles in the leading jet), while the "away" region is defined by
|| > 120o
and |eta| < 1. The "transverse" region is defined by
60o <|| <120o
and |eta| < 1. Each region has an area in eta-phi space of 4pi/3.