Positivity constraints on initial spin observables in inclusive reactions

Abstract

For any inclusive reaction of the type $A_1(spin1/2)+A_2(spin1/2)\to B+X$, we derive new positivity constraints on spin observables and study their implications for theoretical models in view, in particular, of accounting for future data from the polarized $pp$ collider at BNL-RHIC. We find that the single transverse spin asymmetry $A_N$ for several processes, in the central region for example jet production, direct photon production, lepton-pair production, must be such that $|A_N| \lappeq 1/2$, rather than the usual bound $|A_N|\le 1$.

6 pages, version to be published in Phys.Rev.Lett

References in corpus (3)

• Initial-State Interactions and Single-Spin Asymmetries in Drell-Yan Processes
• Transverse single spin asymmetries in Drell-Yan processes
• Next-to-leading order QCD corrections to A_TT for prompt photon production

Cited by in corpus (5)

• Do we understand the single-spin asymmetry for $p{i}^0$ inclusive production in pp collisions?
• Positivity Constraints on Spin Observables in Exclusive Pseudoscalar Meson Photoproduction
• General positivity bounds for spin observables in particle inclusive production
• Positivity bounds for Sivers functions
• Spin observables in antiproton-proton to AntiLambda-Lambda and density-matrix constraints