❚✇♦✲♣❤♦t♦♥ ❡①❝❤❛♥❣❡ ❝♦♥tr✐❜✉t✐♦♥ ✐♥ ❡❧❛st✐❝ ❡❧❡❝tr♦♥✲♣r♦t♦♥ s❝❛tt❡r✐♥❣✿ ♠❡❛s✉r❡♠❡♥ts ❛t ❱❊PP✲✸ ■✳ ❆✳ ❘❛❝❤❡❦✱ ✶ ❏✳ ❆rr✐♥❣t♦♥✱ ✷ ▲✳ ▼✳ ❇❛r❦♦✈✱ ✶ ❱✳ ❋✳ ❉♠✐tr✐❡✈✱ ✶ , ✸ ❱✳ ❱✳ ●❛✉③s❤t❡✐♥✱ ✹ ❘✳ ❆✳ ●♦❧♦✈✐♥✱ ✶ , ✸ ❆✳ ❱✳ ●r❛♠♦❧✐♥✱ ✶ ❘✳ ❏✳ ❍♦❧t✱ ✷ ❱✳ ❱✳ ❑❛♠✐♥s❦②✱ ✶ ❇✳ ❆✳ ▲❛③❛r❡♥❦♦✱ ✶ ❙✳ ■✳ ▼✐s❤♥❡✈✱ ✶ ◆✳ ❨✉✳ ▼✉❝❤♥♦✐✱ ✶ , ✸ ❱✳ ❱✳ ◆❡✉❢❡❧❞✱ ✶ ❉✳ ▼✳ ◆✐❦♦❧❡♥❦♦✱ ✶ ❘✳ ❙❤✳ ❙❛❞②❦♦✈✱ ✶ ❨✉✳ ❱✳ ❙❤❡st❛❦♦✈✱ ✶ , ✸ ❱✳ ◆✳ ❙t✐❜✉♥♦✈✱ ✸ ❉✳ ❑✳ ❚♦♣♦r❦♦✈✱ ✶ , ✸ ❍✳ ❞❡ ❱r✐❡s✱ ✹ ❙✳ ❆✳ ❩❡✈❛❦♦✈✱ ✶ ❛♥❞ ❱✳ ◆✳ ❩❤✐❧✐❝❤ ✶ ✶ ❇✉❞❦❡r ■♥st✐t✉t❡ ♦❢ ◆✉❝❧❡❛r P❤②s✐❝s ❙❇ ❘❆❙✱ ◆♦✈♦s✐❜✐rs❦✱ ❘✉ss✐❛ ✷ ❆r❣♦♥♥❡ ◆❛t✐♦♥❛❧ ▲❛❜♦r❛t♦r②✱ ❆r❣♦♥♥❡✱ ❯❙❆ ✸ ◆♦✈♦s✐❜✐rs❦ ❙t❛t❡ ❯♥✐✈❡rs✐t②✱ ◆♦✈♦s✐❜✐rs❦✱ ❘✉ss✐❛ ✹ ◆✉❝❧❡❛r P❤②s✐❝s ■♥st✐t✉t❡ ❛t ❚♦♠s❦ P♦❧②t❡❝❤♥✐❝❛❧ ❯♥✐✈❡rs✐t②✱ ❚♦♠s❦✱ ❘✉ss✐❛ ✺ ◆■❑❍❊❋✱ ❆♠st❡r❞❛♠✱ ❚❤❡ ◆❡t❤❡r❧❛♥❞s ❊▼■◆✲✷✵✶✷ ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✶
Pr♦t♦♥ ❡❧❡❝tr♦♠❛❣♥❡t✐❝ ❢♦r♠ ❢❛❝t♦rs ❚❤❡ ❊▼ ❢♦r♠ ❢❛❝t♦rs ❛r❡ ❡ss❡♥t✐❛❧ ✐♥❣r❡❞✐❡♥ts ♦❢ ♦✉r ❦♥♦✇❧❡❣❞❡ ♦❢ t❤❡ ♥✉❝❧❡♦♥ str✉❝t✉r❡ ❛♥❞ t❤✐s ❥✉st✐✜❡s t❤❡ ❡✛♦rts ❞❡✈♦t❡❞ t♦ t❤❡✐r ❡①♣❡r✐♠❡♥t❛❧ ❞❡t❡r♠✐♥❛t✐♦♥ ■♥ ♦♥❡✲♣❤♦t♦♥ ✭❇♦r♥✮ ❛♣♣r♦①✐♠❛t✐♦♥✿ ◆✉❝❧❡♦♥ ❈✉rr❡♥t ❖♣❡r❛t♦r Γ µ ( q ) ❙❛❝❤s ❋♦r♠ ❋❛❝t♦rs Γ µ ( q ) = γ µ ❋ ✶ ( q ✷ ) + ✐ σ µν q ν ❋ ✷ ( q ✷ ) ✷ ▼ ❊❧❡❝tr✐❝ ❋♦r♠ ❋❛❝t♦r ❋ ✶ ( q ✷ ) ✕ ♥♦♥ s♣✐♥ ✢✐♣ ❉✐r❛❝ ❋♦r♠ ❋❛❝t♦r ● ❊ ( ◗ ✷ ) = ❋ ✶ ( ◗ ✷ ) − ◗ ✷ ✹ ▼ ❋ ✷ ( ◗ ✷ ) ❋ ✷ ( q ✷ ) ✕ s♣✐♥ ✢✐♣ P❛✉❧✐ ❋♦r♠ ❋❛❝t♦r ▼❛❣♥❡t✐❝ ❋♦r♠ ❋❛❝t♦r ● ▼ ( ◗ ✷ ) = ❋ ✶ ( ◗ ✷ ) + ❋ ✷ ( ◗ ✷ ) ● ❊ ≈ ● ▼ /µ ♣ ≈ ● ❉ ≡ ( ✶ + ◗ ✷ / ✵ . ✼✶ ) − ✷ ✐♥ ♥♦♥✲r❡❧❛t✐✈✐st✐❝ ❧✐♠✐t ● ❊ ❛♥❞ ● ▼ ❞❡s❝r✐❜❡ ❝❤❛r❣❡ ❛♥❞ ♠❛❣♥❡t✐③❛t✐♦♥ ❞✐str✐❜✉t✐♦♥ ✐♥ ♥✉❝❧❡♦♥ ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✷
▼❡❛s✉r❡♠❡♥ts ♦❢ Pr♦t♦♥ ❢♦r♠ ❢❛❝t♦rs ❙t✉❞② ✇✐t❤ ❡❧❛st✐❝ ❡♣ s❝❛tt❡r✐♥❣ ❚❤❡ ❘♦s❡♥❜❧✉t❤ s❡♣❛r❛t✐♦♥ ♠❡t❤♦❞ ❛t ❝♦♥st❛♥t ◗ ✷ ❘♦s❡♥❜❧✉t❤ ❋♦r♠✉❧❛ ❘♦s❡♥❜❧✉t❤✱ ✶✾✺✵ � ❞ σ � ǫ ❞ σ � τ � τ ● ✷ ❊ + ● ✷ ❞ Ω = · ǫ ( ✶ + τ ) · ▼ ❞ Ω ▼♦tt ✇❤❡r❡ τ = ◗ ✷ / ✹ ▼ ✷ ❛♥❞ ǫ = � − ✶ � ✶ + ✷ ( ✶ + τ ) t❛♥ ✷ ( θ/ ✷ ) P♦❧❛r✐③❡❞ ❜❡❛♠s ❛♥❞ t❛r❣❡ts ❛♥❞ r❡❝♦✐❧ ♣♦❧❛r✐♠❡t❡rs ❋♦r♠ ❢❛❝t♦r r❛t✐♦ ❢r♦♠ ♣♦❧❛r✐③❛t✐♦♥ tr❛♥s❢❡r ❆❦❤✐❡③❡r✱❘❡❦❛❧♦✱ ✶✾✻✽ ● ❊ = P ❚ × ❑ ● ▼ P ▲ ✇❤❡r❡ P ❚ ❛♥❞ P ▲ ✲ tr❛♥s✈❡rs❡ ❛♥❞ ❧♦♥❣✐t✉❞✐♥❛❧ ♣♦❧❛r✐③❛t✐♦♥ ❝♦♠♣♦♥❡♥ts ♦❢ ♣r♦t♦♥✱ � ❑ = − τ ( ✶ + ǫ ) / ✷ ǫ ✕ ❦✐♥❡♠❛t✐❝ ❢❛❝t♦r ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✸
❘❛❞✐❛t✐✈❡ ❝♦rr❡❝t✐♦♥s✱ ✐♥ ♣❛rt✐❝✉❧❛r✱ ❛ s❤♦rt✲r❛♥❣❡ ❚✇♦✲P❤♦t♦♥ ❊①❝❤❛♥❣❡ ✭❚P❊✮ ✐s ❛ ❧✐❦❡❧② ♦r✐❣✐♥ ♦❢ t❤❡ ❞✐s❝r❡♣❛♥❝② ■♥❝♦♥s✐st❡♥❝② ❄ 1.6 Unpolarized data: Walker (1994), 1.4 global analysis 1.2 Qattan (2005) 1 M G 0.8 ⁄ E G 0.6 µ Polarized data: 0.4 Jones (2000), Punjabi (2005) 0.2 Gayou (2002), Puckett (2011) 0 Puckett (2010) 0 1 2 3 4 5 6 7 8 9 2 2 Q , GeV ❈❧❡❛r ❞✐s❝r❡♣❛♥❝② ❜❡t✇❡❡♥ ✉♥♣♦❧❛r✐③❡❞ ❛♥❞ ♣♦❧❛r✐③❡❞ ❞❛t❛ ✐s ♦❜s❡r✈❡❞✳ ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✹
■♥❝♦♥s✐st❡♥❝② ❄ 1.6 Unpolarized data: Walker (1994), 1.4 global analysis 1.2 Qattan (2005) 1 M G 0.8 ⁄ E G 0.6 µ Polarized data: 0.4 Jones (2000), Punjabi (2005) 0.2 Gayou (2002), Puckett (2011) 0 Puckett (2010) 0 1 2 3 4 5 6 7 8 9 2 2 Q , GeV ❈❧❡❛r ❞✐s❝r❡♣❛♥❝② ❜❡t✇❡❡♥ ✉♥♣♦❧❛r✐③❡❞ ❛♥❞ ♣♦❧❛r✐③❡❞ ❞❛t❛ ✐s ♦❜s❡r✈❡❞✳ ❘❛❞✐❛t✐✈❡ ❝♦rr❡❝t✐♦♥s✱ ✐♥ ♣❛rt✐❝✉❧❛r✱ ❛ s❤♦rt✲r❛♥❣❡ ❚✇♦✲P❤♦t♦♥ ❊①❝❤❛♥❣❡ ✭❚P❊✮ ✐s ❛ ❧✐❦❡❧② ♦r✐❣✐♥ ♦❢ t❤❡ ❞✐s❝r❡♣❛♥❝② ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✹
∆ ∆ ❍❛r❞ ♣❤♦t♦♥s ✐♥ ❜♦① ❛♥❞ ✲❜♦①✿ ✐♥t❡❣r❛❧ ♦✈❡r ♦✛✲s❤❡❧❧ ♣r♦t♦♥ ✐♥t❡r♠✐❞✐❛t❡ st❛t❡ ❝♦♥tr✐❜✉t✐♦♥s ♠✉st ❜❡ ♠❛❞❡✳ ❘❛❞✐❛t✐✈❡ ❈♦rr❡❝t✐♦♥s t♦ ❡❧❛st✐❝ ✭❡♣✮ s❝❛tt❡r✐♥❣ ✏❊❧❛st✐❝✑ s❝❛tt❡r✐♥❣ ✭ ❡ ± ♣ → ❡ ± ♣ ✮✿ M ♣ M ♣ M ❡ M ❡ M ❇♦r♥ M ✷ γ M ✈❛❝ ✈❡rt ✈❡rt s❡❧❢ s❡❧❢ ❇r❡♠sstr❛❤❧✉♥❣ ✭ ❡ ± ♣ → ❡ ± ♣ γ ✮✿ M ♣ M ❡ ❜r❡♠ ❜r❡♠ σ ( ❡ ± ♣ ) = |M ❇♦r♥ | ✷ ± ✷ R ❡ � � M † ❇♦r♥ M ✷ γ + � � � � � � M † M † M † ❇♦r♥ M ♣ ❇♦r♥ M ❡ + ✷ R ❡ ❇♦r♥ M ✈❛❝ + ✷ R ❡ + ✷ R ❡ + . . . ✈❡rt ✈❡rt ❜r❡♠ | ✷ + |M ♣ ❜r❡♠ | ✷ ± ✷ R ❡ � � M ❡ † ❜r❡♠ M ♣ + |M ❡ + . . . ✭✶✮ ❜r❡♠ • ❙t❛♥❞❛r❞ ✭s♦❢t ♣❤♦t♦♥s✮ ❘❈✿ ❞♦♠✐♥❛♥t ✭✐♥❢r❛✲r❡❞✮ ♣❛rt ❝❛♥ ❜❡ ❢❛❝t♦r✐③❡❞ ✐♥ t❤❡ ♦❜s❡r✈❛❜❧❡s✳ ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✺
∆ ∆ ❘❛❞✐❛t✐✈❡ ❈♦rr❡❝t✐♦♥s t♦ ❡❧❛st✐❝ ✭❡♣✮ s❝❛tt❡r✐♥❣ ✏❊❧❛st✐❝✑ s❝❛tt❡r✐♥❣ ✭ ❡ ± ♣ → ❡ ± ♣ ✮✿ M ♣ M ♣ M ❡ M ❡ M ❇♦r♥ M ✷ γ M ✈❛❝ ✈❡rt ✈❡rt s❡❧❢ s❡❧❢ ❇r❡♠sstr❛❤❧✉♥❣ ✭ ❡ ± ♣ → ❡ ± ♣ γ ✮✿ M ♣ M ❡ ❜r❡♠ ❜r❡♠ σ ( ❡ ± ♣ ) = |M ❇♦r♥ | ✷ ± ✷ R ❡ � � M † ❇♦r♥ M ✷ γ + � � � � � � M † M † M † ❇♦r♥ M ♣ ❇♦r♥ M ❡ + ✷ R ❡ ❇♦r♥ M ✈❛❝ + ✷ R ❡ + ✷ R ❡ + . . . ✈❡rt ✈❡rt ❜r❡♠ | ✷ + |M ♣ ❜r❡♠ | ✷ ± ✷ R ❡ � � M ❡ † ❜r❡♠ M ♣ + |M ❡ + . . . ✭✶✮ ❜r❡♠ • ❙t❛♥❞❛r❞ ✭s♦❢t ♣❤♦t♦♥s✮ ❘❈✿ ❞♦♠✐♥❛♥t ✭✐♥❢r❛✲r❡❞✮ ♣❛rt ❝❛♥ ❜❡ ❢❛❝t♦r✐③❡❞ ✐♥ t❤❡ ♦❜s❡r✈❛❜❧❡s✳ • ❍❛r❞ ♣❤♦t♦♥s ✐♥ ❜♦① ❛♥❞ × ✲❜♦①✿ ✐♥t❡❣r❛❧ ♦✈❡r ♦✛✲s❤❡❧❧ ♣r♦t♦♥ ✐♥t❡r♠✐❞✐❛t❡ st❛t❡ ❝♦♥tr✐❜✉t✐♦♥s ♠✉st ❜❡ ♠❛❞❡✳ ■✳❆✳ ❘❛❝❤❡❦ ❊▼■◆✲✷✵✶✷ ❙❡♣t❡♠❜❡r ✷✶✱ ✷✵✶✷ ✺
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