  A search for heavy resonances that decay to tau lepton pairs is performed
using proton-proton collisions at sqrt(s) = 13 TeV. The data were collected
with the CMS detector at the CERN LHC and correspond to an integrated
luminosity of 2.2 inverse femtobarns. The observations are in agreement with
standard model predictions. An upper limit at 95% confidence level on the
product of the production cross section and branching fraction into tau lepton
pairs is calculated as a function of the resonance mass. For the sequential
standard model, the presence of Z' bosons decaying into tau lepton pairs is
excluded for Z' masses below 2.1 TeV, extending previous limits for this final
state. For the topcolor-assisted technicolor model, which predicts Z' bosons
that preferentially couple to third-generation fermions, Z' masses below 1.7
TeV are excluded, representing the most stringent limit to date.
