Current quark

Current quarks (also called naked quarks or bare quarks) are defined as the constituent quark cores (constituent quarks with no covering) of a valence quark.^[1]:150-151

If, in one constituent quark, the current quark is hit inside the covering with large force, it accelerates through the covering and leaves it behind. In addition, current quarks possess one asymptotic freedom within the perturbation theory described limits. In quantum chromodynamics, the mass of the current quarks carries the designation current quark mass.

The local term plays no more role for the description of the hadrons with the light current quarks:

Current quark	Mass	Δx
Up quark	5–10 MeV/c^2	20–40 fm
Down quark	5–10 MeV/c^2	20–40 fm
Strange quark
Charm quark
Bottom quark
Top quark

A description is only possible with the help of relativistic quantum mechanics.

Current quark mass

The current quark mass is also called the mass of the 'naked' quarks. The mass of the current quark is reduced by the term of the constituent quark covering mass.

The current quark mass is a logical consequence of the mathematical formalism of the QFT, thus it is from a not descriptive origin. The current quark masses of the light current quarks are much smaller than the constituent quark masses. Reason for this is the missing of the mass of the constituent quark covering.

The current quark mass is a parameter to compute sufficiently small color charges.

Definition: The current quark mass means the mass of the constituent quark mass reduced by the mass of the respective constituent quark covering.

There is almost no difference between current quark mass and constituent quark mass for the heavy quarks (c,b,t).This is not so for the light quarks (u, d, s).

The comparison of the results of the computations with the experimental data supplies the values for the current quark masses.

Masses of the current quarks:
$m_u$ = 2 - 8 MeV/c^2	$m_c$ = 1.0 - 1.6 GeV/c^2	$m_t$ = 168 - 192 GeV/c^2
$m_d$ = 5 - 15 MeV/c^2	$m_s$ = 0.1 - 0.3 GeV/c^2	$m_b$ = 4.1 - 4.5 GeV/c^2

References

1. Timothy Paul Smith (2003). Hidden Worlds: Hunting for Quarks in Ordinary Matter. Princeton University Press. ISBN 0-691-05773-7.