280
9. Deep Inelastic Electron–Nucleon Scattering and the Parton Model
FIGURE 9.7
Angular momentum balance for absorption of photon by helicity-conserving
spin1 parton.
2
FIGURE 9.8
The ratio 2xF 1 /F 2 : ◦, 1.5 < Q
2 < 4 GeV
2 ; •, 0.5 < Q
2 < 11 GeV
2 ; ×, 12 <
Q
2 < 16 GeV
2 . (Figure from D H Perkins Introduction to High Energy Physics
3rd edn, copyright 1987; reprinted by permission of Pearson Education, Inc.,
Upper Saddle River, NJ.)
These arguments therefore make clear the origin of the Callan–Gross relation. Experimentally, the Callan–Gross relation is reasonably well satisfied
in that R = σ S /σ T is small for most, if not all, of the deep inelastic regime
(figure 9.8). This leads us to suppose that the electrically charged partons
coupling to photons have spin1 .
2
9. Deep Inelastic Electron–Nucleon Scattering and the Parton Model
FIGURE 9.7
Angular momentum balance for absorption of photon by helicity-conserving
spin1 parton.
2
FIGURE 9.8
The ratio 2xF 1 /F 2 : ◦, 1.5 < Q
2 < 4 GeV
2 ; •, 0.5 < Q
2 < 11 GeV
2 ; ×, 12 <
Q
2 < 16 GeV
2 . (Figure from D H Perkins Introduction to High Energy Physics
3rd edn, copyright 1987; reprinted by permission of Pearson Education, Inc.,
Upper Saddle River, NJ.)
These arguments therefore make clear the origin of the Callan–Gross relation. Experimentally, the Callan–Gross relation is reasonably well satisfied
in that R = σ S /σ T is small for most, if not all, of the deep inelastic regime
(figure 9.8). This leads us to suppose that the electrically charged partons
coupling to photons have spin1 .
2