Aschenauer, E.C.
nucl-ex
POL
Max results
Sort by Reverse order

Showing 3 of 3 results

Inclusive double-helicity asymmetries in neutral pion and eta meson production in $\vec{p}+\vec{p}$ collisions at $\sqrt{s}=200$ GeV

The PHENIX collaboration Adare, A. ; Aidala, C. ; Ajitanand, N.N. ; et al.
Phys.Rev.D 90 (2014) 012007, 2014.
Inspire Record 1282448 DOI 10.17182/hepdata.64716

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 $\pi^0$ and $\eta$ production in $\sqrt{s} = 200$ GeV polarized $p$$+$$p$ collisions. Comparison of the $\pi^0$ results with different theory expectations based on fits of other published data showed a preference for small positive values of gluon polarization, $\Delta G$, in the proton in the probed Bjorken $x$ range. The effect of adding the new 2009 \pz data to a recent global analysis of polarized scattering data is also shown, resulting in a best fit value $\Delta G^{[0.05,0.2]}_{\mbox{DSSV}} = 0.06^{+0.11}_{-0.15}$ in the range $0.05<x<0.2$, with the uncertainty at $\Delta \chi^2 = 9$ 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 $\Delta G^{[0.05,0.2]}_{\mbox{DSSV}}$ between $0.02$ and $0.12$, demonstrating the need for full treatment of the experimental systematic uncertainties in future global analyses.

9 data tables
Table 1

PI0 ASYM(LL) measurements from 2005.

Table 2

PI0 ASYM(LL) measurements from 2006.

Table 3

PI0 ASYM(LL) measurements from 2009.

More…

Polarization of Lambda and anti-Lambda produced by 800-GeV protons

Ramberg, E.J. ; Bock, G.J. ; Coleman, R. ; et al.
Phys.Lett.B 338 (1994) 403-408, 1994.
Inspire Record 372108 DOI 10.17182/hepdata.42451

We have measured the polarization of Λ and Λ hyperons produced by 800 GeV protons on a Be target at a fixed targeting angle of 4.8 mrad. Comparison with previous data at 400 GeV production energy and twice the targeting angle shows no significant energy dependence for the Λ polarization. This is in striking contrast to the energy dependence found for σ + and Ξ − polarizations. We find no evidence for Λ polarization at 800 GeV.

2 data tables
Table 1

Errors are combined statistics and systematics.

Table 2

No description provided.


Determination of Proton Nucleon Analyzing Powers and Spin Rotation Depolarization Parameters at 500-{MeV}

Marshall, J.A. ; Barlett, M.L. ; Fergerson, R.W. ; et al.
Phys.Rev.C 34 (1986) 1433-1438, 1986.
Inspire Record 240068 DOI 10.17182/hepdata.26283

500 MeV p→+p elastic and quasielastic, and p→+n quasielastic, analyzing powers (Ay) and spin-rotation-depolarization parameters (DSS, DSL, DLS, DLL, DNN) were determined for center-of-momentum angular ranges 6.8°–55.4° (elastic) and 22.4°–55.4° (quasielastic); liquid hydrogen and deuterium targets were used. The p→+p elastic and quasielastic results are in good agreement; both the p→+p and p→+n parameters are well described by current phase shift solutions.

6 data tables
Table 1

The elastic P P analysing power at 500 MeV incident proton energy. There is an additional overall normalization uncertainty of 1 PCT.

Table 2

The spin depolarization and spin rotation parameters in 500 MeV P P elastic interactions. Additional normalization uncertainty of 1 PCT (2 PCT for DLL and DLS).

Table 3

The elastic P P analysing power at 500 MeV incident proton energy. There is an additional overall normalization uncertainty of 1 PCT.

More…