answer:From Wikipedia: “According to Michio Kaku (1994: 124–27), the Standard Model of particle physics contains nineteen arbitrary dimensionless constants that describe the masses of the particles and the strengths of the various interactions. This was before it was discovered that neutrinos can have nonzero mass, and his list includes a quantity called the theta angle which seems to be zero. After the discovery of neutrino mass, and leaving out the theta angle, John Baez (2002) noted that the new Standard Model requires twenty-five arbitrary fundamental constants, namely the: * Fine structure constant; * Strong coupling constant; * Masses of the fundamental particles (represented in terms of the Planck mass or some other natural unit of mass), namely the six quarks, the six leptons, the Higgs boson, the W boson and the Z boson; * Four parameters of the CKM matrix, which describe how quarks oscillate between different forms; * Four parameters of the Maki-Nakagawa-Sakata matrix, which does the same thing for neutrinos. Gravity requires one more fundamental constant, namely the: * cosmological constant (represented in terms of Planck units) of Einstein’s equations for general relativity. This makes for a current total of 26 dimensionless fundamental physical constants. More constants presumably await discovery, to describe the properties of dark matter. If the description of dark energy turns out to be more complicated than can be modelled by the cosmological constant, yet more constants will be needed.”