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Observation of Beam Spin Asymmetries in the Process $e p \rightarrow e \pi^{+}\pi^{-}X$ with CLAS12
- Source :
- Phys. Rev. Lett. 126, 152501 (2021)
- Publication Year :
- 2021
-
Abstract
- The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function $e(x)$, which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function $G_1^\perp$. A clear sign change is observed around the $\rho$ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark.<br />Comment: 6 pages, 5 figures
- Subjects :
- High Energy Physics - Experiment
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. Lett. 126, 152501 (2021)
- Publication Type :
- Report
- Accession number :
- edsarx.2101.04842
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevLett.126.152501