[G12] Notes on Moment Analysis

[Saini, Mukesh]

Hi all,

I have updated and uploaded the pdf we saw earlier to include the Partial Wave decomposition from the E852 eta pi paper for 2 pseudoscalr mesons.

Find it at:
http://clasweb.jlab.org/rungroups/g12/wiki/images/c/c4/Phi_moments_comp.pdf

At the top of each page you can now see the particular moments expanded in terms of their Partial Waves contributions.

Note:
1. If we look at the H20 and H22 Moments (page 2)  we can make a few observations. The H20 moment distribution for P0 wave is positive and for the P- and P+ wave, the distribution is negative - As one would expect from the H20 formula stated above the page. This along with the H22 GMC moments, where P- distribution is +ve whereas P+ distribution is -ve, implies that the procedure followed for generating P0, P-, P+ Waves and calculating Moments is consistent with the physics distributions expected.

When we compare the data's H20 moment distribution to the Accepted moments, we observe that P0 wave contribution to the g12 phi meson data is significant.

2. Strong H21 moment distribution in the phi region for H21 data moment implies the interference for -ve reflectivity waves in g12 data.

3. From the interfering Moments terms like (H11 for P0 wave, H31 and H32 for all waves), We can observe that even when a moment is absent in the generated data, CLAS acceptance can create an illusion of the presence of certain waves (P0,P+,P- in H40,H41,H42) where there should be none.

Let me know if you have questions or suggestions,
Mukesh.
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