Question

which subtomaic particle has the least mas

Answer 1

The proton, if you just look one level down. However, If we are going even deeper, it might be the quarks

Answer 2

There are several types of quarks. It seems that u-quarks has the lowest mass : 1,5 to 4,0 MeV.c^-2.

Answer 3

and 1 MeV = 10^6 eV, 1 eV = 1,783*10^-36 kg. But the quarks have not the least mass. I know that the Neutrino "Ve" have less than 2,5 eV*c^-2, and the Photon have less than 1 ×10^−18 eV*c^-2 !!! So the photon should be the elementary particule which have the lowest mass

Answer 4

Boson I expect.

Answer 5

It should be an electron.

Answer 6

@Dean.Shyy I don't agree with you, an electron have a mass around 9,109×10-31 kg
(511 keV) so it's around 511 000 eV, the photon have less than 1 ×10−18 eV !!!