Spin-dependent Pomeron and Odderon in elastic proton–proton scattering
Yoshikazu Hagiwara, Yoshitaka Hatta, Roman Pasechnik, Jian Zhou
Abstract
Abstract We introduce a new model of near-forward elastic proton–(anti)proton scattering at high energy based on the modern formulation of Pomeron and Odderon in terms of Wilson lines and generalized transverse momentum dependent distributions. We compute the helicity-dependent elastic amplitudes $$\phi _{1,2,3,4,5}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>ϕ</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>,</mml:mo><mml:mn>2</mml:mn><mml:mo>,</mml:mo><mml:mn>3</mml:mn><mml:mo>,</mml:mo><mml:mn>4</mml:mn><mml:mo>,</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:msub></mml:math> in this model and study their energy dependence from the nonlinear small- x evolution equations. While both Pomeron and Odderon contribute to helicity-flip processes in general, in the forward limit $$t=0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>t</mml:mi><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:mrow></mml:math> only the double helicity-flip amplitude $$\phi _2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>ϕ</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> , dominated by the spin-dependent Odderon, survives. This may affect the extraction of the $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ρ</mml:mi></mml:math> parameter as well as the total cross section in the LHC energy domain and beyond.