Nucleon structure in a light-front quark model consistent with quark counting rules and data

Using global fits of valence $u$ and $d$ quark parton distributions and data on quark and nucleon form factors in the Euclidean region, we derive a light-front quark model for the nucleon structure consistent with quark counting rules.

Figure 1

$u_v(x)$ at scale $\mu =1\mathrm{GeV}$ in models I and II.

Figure 2

$u_v(x)$ at scale $\mu =10\mathrm{GeV}$ in models I and II.

Figure 3

$d_v(x)$ at scale $\mu =1\mathrm{GeV}$ in models I and II.

Figure 4

$d_v(x)$ at scale $\mu =10\mathrm{GeV}$ in models I and II.

Figure 5

${\mathcal{E}}_u(x)$ at scale $\mu =1\mathrm{GeV}$ in models I and II.

Figure 6

${\mathcal{E}}_u(x)$ at scale $\mu =10\mathrm{GeV}$ in models I and II.

Figure 7

${\mathcal{E}}_d(x)$ at scale $\mu =1\mathrm{GeV}$ in models I and II.

Figure 8

${\mathcal{E}}_d(x)$ at scale $\mu =10\mathrm{GeV}$ in models I and II.

Figure 9

Dirac $u$ quark form factor multiplied by $Q^4$.

Figure 10

Dirac $d$ quark form factor multiplied by $Q^4$.

Figure 11

Pauli $u$ quark form factor multiplied by $Q^4$.

Figure 12

Pauli $d$ quark form factor multiplied by $Q^4$.

Figure 13

Dirac proton form factor multiplied by $Q^4$.

Figure 14

Dirac neutron form factor multiplied by $Q^4$.

Figure 15

Ratio $Q^2{F}_2^p(Q^2)/F_1^p(Q^2)$.

Figure 16

Ratio $G_E^p(Q^2)/G_D(Q^2)$.

Figure 17

Charge neutron form factor $G_E^n(Q^2)$.

Figure 18

Ratio ${\mu }_p{G}_E^p(Q^2)/G_M^p(Q^2)$.

Figure 19

Ratio $G_M^p(Q^2)/({\mu }_p{G}_D(Q^2))$.

Figure 20

Ratio $G_M^n(Q^2)/({\mu }_n{G}_D(Q^2))$.

Figure 21

Ratio ${\mu }_n{G}_E^n(Q^2)/G_M^n(Q^2)$.