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Theoretical Particle Physics


Forward neutron production by polarized protons


Forward neutron production by polarized protons

Research areas:

Física Teórica de Partículas



Type of Publication:

Technical Report



The transverse single-spin asymmetry of neutrons produced at forward rapidities in polarized pp collisions is calculated and compared with the recent measurements at RHIC. Absorptive corrections to the pion pole generating a relative phase between the spin-flip and non-flip amplitudes, lead to a transverse spin asymmetry, which however, is found to be far too small to explain the data. A larger contribution, comes from the interference of the pion and effective L1-Reggeon, which includes the a1 pole and the (dominant) II Regge cut. Assuming that this state saturates the spectral function of the axial current we determined its coupling to the nucleons applying the PCAC and the second Weinberg sum rule. The results of the parameter-free calculation of AN well agree with the data.