Answer
The particle would have a mass that is $~~1.4\times 10^{36}~~$ times a proton's mass.
Work Step by Step
The total energy of the two protons is $13~TeV$
We can convert this energy to units of joules:
$(13\times 10^{12}~eV)(\frac{1.6\times 10^{-19}~C}{1~eV}) = 2.08\times 10^{-6}~J$
We can find the mass of a particle with this rest energy:
$mc^2 = E$
$m = \frac{E}{c^2}$
$m = \frac{2.08\times 10^{-6}~J}{(3.0\times 10^8~m/s)^2}$
$m = 2.31\times 10^9~kg$
We can express this mass as a multiple of a proton's mass:
$\frac{2.31\times 10^9~kg}{1.67\times 10^{-27}~kg} = 1.4\times 10^{36}$
The particle would have a mass that is $~~1.4\times 10^{36}~~$ times a proton's mass.
