Constant unit 
or 
, or 
electromagnetic energy, h, boson
6.62606957(29) × 10−3 J×s, 1 Hz, known
0
0
Not applicable
neutron, elemental mass, strong force, fermion
939.565378(21) × 106 MeV/c2, 2.2718590(01) × 1023 Hz
1
1
Not applicable
Rydberg constant, R, EM energy, boson
13.60569(07) × eV/c2, 3.28984196(17) × 1015 Hz
−3
2/3, 1 − (1/3)
Not applicable
Bohr radius, α0, distance
5.2917721092(17) × 10−11 m, 5.66525639(28) × 1018 Hz
−5
4/5, 1 − (1/5), (2 × 2)/5
Not applicable
electron, e−, mass, matter, fermion
5.10998925(20) × 105 eV/c2, 1.23558996(05) × 1020 Hz
−7
6/7, 1 − (1/7), (2 × 3)/7
Not applicable
up quark, u, matter, fermion
2.3 + 0.7 − 0.5 MeV/c2, known
3.0 × 106 eV/c2, 7.253 × 1020 Hz to
1.8 × 106 eV/c2, 4.352 × 1020 Hz
derived 2.350968 × 106 eV/c2, 5.684615 × 1020 Hz
to
−10
9/10, 1 − (1/10), (3 × 3)/(2 × 5)
3
top quark, u, matter, fermion
173.34 ± 0.27 (stat) ± 0.71 (syst)100 GeV/c2, known
172.36 × 109 eV/c2, 4.2097 × 1025 Hz to
174.32 × 109 eV/c2, 4.1759 × 1025 Hz
derived 172.190 × 109 eV/c2, 4.16354 × 1025 Hz
to
+10
11/10,
1 + (1/10), 11/(2 × 5)
1
down quark, d, matter, fermion
4.8 + 0.5 − 0.3 MeV/c2, known
5.5 × 106 eV/c2, 1.328 × 1021 Hz to
4.5 × 106 eV/c2, 1.088 × 1021 Hz
derived 4.71763× 106 eV/c2, 1.14072 × 1021 Hz
to
−11
10/11,
1 − (1/11), (2 × 5)/11
2
strange quark, matter, fermion
95 + 5 − 5 MeV/c2, known
100 × 106 eV/c2, 2.418 × 1022 Hz to
90 × 106 eV/c2, 2.176 × 1022 Hz
derived 93.7075 × 106 eV/c2, 2.26584 × 1022 Hz
to
−28
27/28, 1 − (1/28), (3 × 3 × 3)/(2 × 2 × 7)
2