Cross section and double helicity asymmetry for {eta} mesons and their comparison to {pi}{sup 0} production in p+p collisions at {radical}(s)=200 GeV

Measurements of double-helicity asymmetries in inclusive hadron production in polarized p+p collisions are sensitive to helicity-dependent parton distribution functions, in particular, to the gluon helicity distribution, {Delta}g. This study focuses on the extraction of the double-helicity asymmetry in {eta} production (p-vector sign+p-vector sign{yields}{eta}+X), the {eta} cross section, and the {eta}/{pi}{sup 0} cross section ratio. The cross section and ratio measurements provide essential input for the extraction of fragmentation functions that are needed to access the helicity-dependent parton distribution functions.