Inclusive double-helicity asymmetries in neutral-pion and eta-meson production in p⃗ +p⃗ collisions at s√=200 GeV
Adare, A., Aidala, C., Ajitanand, N., Akiba, Y., Akimoto, R., Al-Ta'ani, H., . . . Rak, J. (2014). Inclusive double-helicity asymmetries in neutral-pion and eta-meson production in p⃗ +p⃗ collisions at s√=200 GeV. Physical Review D, 90 (1), 012007. doi:10.1103/PhysRevD.90.012007 Retrieved from http://arxiv.org/abs/1402.6296
Published in
Physical Review DAuthors
Aoki, K. |
Date
2014Discipline
FysiikkaCopyright
© 2014 American Physical Society. This is an article whose final and definitive form has been published by American Physical Society.
Abstract: Results are presented from data recorded in 2009 by the PHENIX experiment at the Relativistic Heavy
Ion Collider for the double-longitudinal spin asymmetry,
A
LL
, for
π
0
and
η
production in
ffiffiffi
s
p
¼
200
GeV
polarized
p
þ
p
collisions. Comparison of the
π
0
results with different theory expectations based on fits of
other published data showed a preference for small positive values of gluon polarization,
Δ
G
, in the proton
in the probed Bjorken
x
range. The effect of adding the new 2009
π
0
data to a recent global analysis of
polarized scattering data is also shown, resulting in a best fit value
Δ
G
½
0
.
05
;
0
.
2
DSSV
¼
0
.
06
þ
0
.
11
−
0
.
15
in the range
0
.
05
<x<
0
.
2
, with the uncertainty at
Δ
χ
2
¼
9
when considering only statistical experimental
uncertainties. Shifting the PHENIX data points by their systematic uncertainty leads to a variation of
the best-fit value of
Δ
G
½
0
.
05
;
0
.
2
DSSV
between 0.02 and 0.12, demonstrating the need for full treatment of the
experimental systematic uncertainties in future global analyses.
...


Publisher
American Physical SocietyISSN Search the Publication Forum
1550-7998