Beam-Target Helicity Asymmetry for γ→n→→π−

Beam-target helicity asymmetry E in K0Λ and K0Σ0Ho1, Schumacher2, D’Angelo3 et al. 2018Phys. Rev. CSelf Cite12040View full textAdd to dashboardCite

“…This setup has been used for several studies of K + photoproduction of hyperonic final states on a proton target [29-31, 33, 34, 43-45] and on an effective neutron (deuteron) target [26,27]. The present results stem from the socalled "g14" run period between December 2011 and May 2012, from which non-strange results have been previously reported [46]. The CEBAF accelerator provided longitudinally polarized electron beams with energies of E e = 2.281 GeV, 2.257 GeV, and 2.541 GeV, and an average electron beam polarization for the present study of P e = 0.82 ± 0.04, which was measured routinely by the Hall-B Möller polarimeter [47].…”

“…The performance of the system was extensively studied for a reaction with much higher count-rates than the present one. The non-strange reaction γd → π − p(X) was investigated using many of the same analysis steps and methods discussed in this article to extract the E observable for γn → π − p [46]. The analysis steps outlined below were all tested on that reaction.…”

“…This was studied using data for the γn → π − p reaction and reported in our previous publication Ref. [46]. It was found that for spectator recoil momenta of less than 100 MeV/c the correction was negligible.…”

N $$^*$$ ∗ Experiments and Their Impact on Strong QCD Physics

“…This has led to a major experimental effort at Jefferson Lab, ELSA, GRAAL, and MAMI to chart differential cross sections and polarization observables for a variety of meson photoproduction channels. At JLab with CLAS, many different final states have been measured with high precision on the proton [21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37], many of them are now employed in single-and in multi-channel analyses [38]. Recently, the first measurements of open strangeness processes on neutron targets have been published [39,40].…”

Photo- and Electro-excitation of Bound Neutrons and Protons

“…2 and 3, we find that the FSI effects on the γd → π 0 pn cross sections are significantly canceled in the ratio E. Now we extract cross sections (including polarization observables) for quasifree γn → πN from those for γd → πN N in a conventional manner. A set of kinematical cuts is applied to the γd → πN N cross sections generated with the DCC-based model, and then further correction is made for the Fermi mo- Table 1 The kinematical cuts used in the experimental analyses [4,5] for extracting unpolarized cross sections (dσ/dΩπ ) and the polarization asymmetry E for γn → π − p from those for γd → π − pp. The azimuthal angle difference between π − and the faster proton is denoted by ∆φ.…”