[A1n_d2n] Fwd: [External] Abstract for APS April meeting

[Meziani, Zein-Eddine]

Hi Xiaochao,

Great that you are advertising the experiment in the APS meeting. Please find below my comments.

1- At 6 GeV there is more than one A1n result. Diana Parno (PLB) and David Flay (PRD) have publications from the d2n experiment that show the same trend. Perhaps you could change “The 6 GeV JLab result…” to the 6 GeV JLab results…”


2- The turn over to "positive territory” for delta d/d was still open in the 6 GeV era because 0.6 was too far from 1 and due in part to OAM contributions in the extraction according to the paper by Harut, Stan, Alexandre and Feng. Phys.Rev.Lett.99:082001,2007. That is why we wanted to go to 11 GeV.


3-“...fundamental quantities which can provide information about the spin structure of the nucleon.”  Instead of “ ...which can provide…" perhaps  “which provides..” otherwise, it sounds weaker in my opinion.

4- I would use “helicity” rather than “polarization” and add "in the proton”. My understanding is that “ polarization” in this context would mean “total angular momentum” of the object that has some mass and since the down quark has large orbital angular momentum that cancels its helicity according to lattice QCD, I would choose “ helicity”.


Zein-Eddine


On Dec 20, 2021, at 10:08 AM, Xiaochao Zheng <xiaochao at jlab.org<mailto:xiaochao at jlab.org>> wrote:

Dear All:

I have been invited to give a talk at the APS April meeting, session "Nucleon Structure at Large x", and today is the deadline for submitting abstracts.  I drafted a short one below, please comment before 4pm if possible:

The virtual photon asymmetry of the neutron $A_1^n$ is one of the fundamental quantities which can provide information about the spin structure of the nucleon.  Value of $A_1^n$ at high $x_{Bj}$ is of particular interest because valence quark dominate in this region, making it a relatively clean region to study the nucleon spin structure.  The 6 GeV JLab result on $A_1^n$ showed that the down quark polarization is negative up to $x=0.61$, in contrast with pQCD predictions that it must turn positive and approaches 1 at $x\to 1$.  In this talk I will report on a recently completed $A_1^n$ measurement using JLab 11 GeV beam and an upgraded polarized $^3$He target, that provided data up to $x=0.75$.

Thanks in advance.

Xiaochao
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