View source for Measurement of the beam asymmetry Σ for π^0 and η photoproduction on the proton at E sub γ=9 GeV

{{DISPLAYTITLE:Measurement of the beam asymmetry &Sigma; for &pi;<span style="position:absolute; top: -9999px">^</span ><sup>0</sup> and &eta; photoproduction on the proton at E<span style="position:absolute; top: -9999px"> sub </span ><sub>&gamma;</sub>=9 GeV}}
== Publication Information ==
* H. Al Ghoul et al. [GlueX Collaboration], Phys. Rev. C95, 042201 (2107), [https://doi.org/10.1103/PhysRevC.95.042201 DOI:10.1103/PhysRevC.95.042201]. 
* [https://arxiv.org/abs/1701.08123 arXiv:1701.08123] [nucl-ex] (2017).
* [https://www.hepdata.net/record/76745 HEPData].

== Abstract ==

<span style="font-family:Times;"> We report measurements of the photon beam asymmetry &Sigma; for the reactions &gamma;&#8407;p&rarr;&pi;<sup>0</sup>p and &gamma;&#8407;p&rarr;&eta;p from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous &pi;<sup>0</sup> measurements, and are the first &eta; measurements in this energy regime. The results are compared with theoretical predictions based on ''t''-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models. </span>

== Figures and captions ==

{| border="1" cellpadding="2" valign="top" style="text-align: center;"
!width="400"| Caption
!width="200"| Figures
|-
| (a) Photon beam intensity versus energy as measured by the pair spectrometer (not corrected for instrumental acceptance).  (b) Photon beam polarization as a function of beam energy, as measured by the triplet polarimeter, with data points offset horizontally by &pm;0.015 GeV for clarity. || <span class="plainlinks">[https://halldweb.jlab.org/DocDB/0031/003102/036/fig0_beam.pdf pdf]</span>
|-
|}