Main Image
Volume 346 - 23rd International Spin Physics Symposium (SPIN2018) - Parallel Session: Nucleon helicity structure (F. Kunne, W. Melnitchouk and B. Page)
Theoretical predictions on polarization asymmetry for Drell-Yan process with spin- one deuteron and tensor-polarized structure function $b_1$
Q.T. Song,* S. Kumano
*corresponding author
Full text: pdf
Pre-published on: 2019 August 19
Published on: 2019 August 23
We report recent theoretical progress on
a polarization asymmetry in the proton-deuteron Drell-Yan process
with a polarized-deuteron target and the tensor-polarized structure
function $b_1$. Experimental measurements are possible
at JLab for $b_1$ and at Fermilab for the Drell-Yan process.
First, we show a theoretical estimate for the proton-deuteron Drell-Yan
asymmetry in the Fermilab-E1039 experiment. We evolved
tensor-polarized parton distribution functions,
which explain existing HERMES $b_1$ data,
at $Q^2=2.5$ GeV$^2$ to the $Q^2$ range of the Fermilab Drell-Yan
measurements. Then, we predicted that the asymmetry is
of the order of a few percent. The Drell-Yan experiment
has an advantage to probe the tensor-polarized antiquark distributions,
which were suggested by the HERMES experiment as a finite sum for $b_1$
($\int dx b_1 (x) \ne 0$).
Second, we predicted $b_1$ for the JLab experiment by the standard
convolution model of the deuteron. Our theoretical $b_1$ structure function
seems to be much different from the HERMES data. Furthermore,
a significant distribution exists at very large $x$ ($>1$) beyond
the kinematical limit $x_{max}=1$ for the proton. Because the standard
deuteron-model estimate is much different from the HERMES data,
there could be an interesting development as a new hadron-physics field
if future JLab data will be much different from our conventional prediction.
Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.