  Multidimensional two-particle Bose-Einstein correlation functions of charged
hadrons are reported for pp collisions at 2.76 and 7 TeV in terms of different
components of the pair relative momentum, extending the previous
one-dimensional (1-D) analyses of CMS. This allows for investigating the
extension of the source accessible to the femtoscopic correlation technique in
different directions, revealing a more detailed picture of the emitting source
in these collisions at increasing energies. The measurements are performed for
different intervals of the pair average transverse momentum, kT, and for
increasing charged particle multiplicitiy, Nch. Results in 1-D, 2-D and 3-D
show a decrease of the fit radius parameters with kT, whereas a clear rise with
Nch is observed in all cases. In addition, the fit radius parameters at both
energies show close similarity in size and behavior within the same intervals
of (Nch,kT).
