  I propose a new evaluation of $\psi'(2S)$ and $\chi_c(1P)$ branching ratios
which avoids the correlations affecting the current Particle Data Group
evaluation.
  These correlations explain the apparent technique-dependent discrepancies
between the available determinations of the ${\cal B}(\chi_c(1P)\to p\bar p)$
and $\Gamma(\chi_c(1P)\to \gamma\gamma)$ under the hypotesis that the current
values of the $\psi'(2S)\to\chi_c(1P)\gamma$ branching ratios are
overestimated.
  In the process I also noticed that Particle Data Group has not restated many
of the older measurements, when necessary, for the new value of ${\cal
B}(J/\psi\to l^+l^-)$, which significantly affects the evaluation of some
relevant $\psi'(2S)$ and $\chi_c(1P)$ exclusive branching ratios.
