Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in $\mathrm{Ba}{({}_{\mathrm{1-x}Cox})2}^{}{\mathrm{As}}_2$ single crystals with $x=0.057$, which is near the antiferromagnetic instability. Resistivity $\rho ={\rho }_0+A{T}^n$ was studied under applied pressure up to 7.90 GPa. The parameter $n$ approaches a minimum value of $n\approx 1$ at a critical pressure ${}_{\mathrm{Pc}}$$=3.65$ GPa. Near ${}_{\mathrm{Pc}}$, the superconducting transition temperature T${}_{\mathrm{c}}$ reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. These results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum T${}_{\mathrm{c}}$${}_{.}$

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