Enigmatic quarks

Standard Model of fundamental interactions and particles

INTERACTION	SOURCE	PARTICLES MEDIATING	MASS	POWER
Gravitational	mass	graviton G	0	10^-39
Electromagnetic	charge	foton g	0	10^-2
Strong	colour	gluon g	0	1
Weak	weak charge	bosons W^± Z⁰	80 GeV 91 GeV	10^-7

LEPTONS SPIN = 1/2			QUARKS SPIN = 1/2
FLAVOR	MASS GeV/c²	ELECTRIC CHARGE	FLAVOR	MASS GeV/c²	ELECTRIC CHARGE
n_e	< 7x10^-8	0	u	≈0.003	2/3
e^-	0.000511	-1	d	≈0.006	-1/3
n_m	< 0.0003	0	c	1.5	2/3
m^-	0.106	-1	s	≈0.1	-1/3
n_t	< 0.03	0	t	170	2/3
t ^-	1.7771	-1	b	4.7	-1/3

Masses of light quarks are known with almost 50% error bar.
These best data are following : 1/2(m_u+m_d)=4.2 MeV/c²; 1.5<m_u<5 MeV; 5<m_d<9 MeV/c²
and for strange quark m_s=0.105±0.033 GeV/c² [Manohor 2002]
Quarks are, after all, quite light particles: the u quark is only six times heavier than electron.