  The decorrelation in the azimuthal angle between the most forward and the
most backward jets (Mueller-Navelet jets) is measured in data collected in pp
collisions with the CMS detector at the LHC at sqrt(s) = 7 TeV. The measurement
is presented in the form of distributions of azimuthal-angle differences,
Delta(phi), between the Mueller-Navelet jets, the average cosines of (pi -
Delta(phi)), 2(pi - Delta(phi)), and 3(pi - Delta(phi)), and ratios of these
cosines. The jets are required to have transverse momenta, pT, in excess of 35
GeV and rapidities, |y|, of less than 4.7. The results are presented as a
function of the rapidity separation, Delta(y), between the Mueller-Navelet
jets, reaching Delta(y) up to 9.4 for the first time. The results are compared
to predictions of various Monte Carlo event generators and to analytical
predictions based on the DGLAP and BFKL parton evolution schemes.
