First analysis of world polarized SIDIS data with small-$x$ helicity evolution
ORAL
Abstract
We use small-$x$ helicity evolution equations to analyze the world polarized DIS and Semi-inclusive DIS (SIDIS) data. After successfully describing the $g_1$ structure function extracted from polarized DIS, we extend this analysis to the small-$x$ $g^h_1$ structure function measured in polarized SIDIS. The fit is performed through a Monte-Carlo analysis within the JAM global framework. Combining the DIS and SIDIS data we are able to extract the individual helicity PDFs for both the light quarks and light anti-quarks. The advantage of our approach is that our evolution predicts the small-$x$ behavior of these helicity distributions, allowing for a precise extrapolation of our helicity PDFs to smaller values of $x$, in the region that cannot be accessed experimentally. This brings us one step closer to resolving the proton spin problem.
*This work has been supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award Number DE-SC0004286 (DA and YK), No. DE-AC05-06OR23177 (WM and NS) under which Jefferson Science Associates, LLC, manages and operates Jefferson Lab, the National Science Foundation under Grant No. PHY-2011763 (DP), and within the framework of the TMD Topical Collaboration. The work of NS was supported by the DOE, Office of Science, Office of Nuclear Physics in the Early Career Program.
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Presenters
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Daniel M Adamiak
- Ohio State University