Elong-15-02-26

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Deuteron Form Factors Parameterization

Abbot Parameterization

Best as I've found, the most recent deuteron form factor parameterization comes from Abbot, et al (2000), who give parameter equations but not the parameters. They are also using world data from 2001, which is missing a number of new points.

2015-02-26-d-em-ff.png 2015-02-26-d-t20.png

2012 World Data

I talked with Ron Gilman, who has kindly passed on world data from 2012 as summarized in Holt & Gilman (2012). In particular, he noted that low Q^2 t20 measurements could be invaluable for confirming that we understand the target tensor polarization, as <math>t_{20}</math> is best known experimentally and theoretically in the 0<Q2<0.16 (GeV/c)2 region, which coincides with what will likely be the "cheapest" points.

2015-02-26-d-2012-data.png

Long Parameterization

Donal sent me parameterizations of A and B that M. Petratos put together, of the form <math>F=10^{([0]+[1]*x+[2]*x^2)}</math> where x=Q^2 and F=A or B.

For A, he used [0]=-2.5275, [1]=-1.5704, [2]=0.09667.

For B, he used [0]=-2.1870, [1]=-3.4066, [2]=0.44380.

I calculated the chi^2/ndf of both of these, and created new parameters for the 2012 world data.

For B, I used the same form as Petratos above but with [0]=-2.26938, [1]=-3.18194, [2]=0.147926

For A, I used the equation

<math>A=10^{([0]+[1]*x+[2]*x^2+[3]*x^3)}+10^{(-2.68235-1.47849*x+0.0782541*x^2)}</math>

where x=Q^2 and [0]=-1.85931e-02, [1]=-1.37215e+01, [2]=3.23622e+01, [3]=-4.29740e+01. The reason I used two added functions is due to there being a "kink" region around Q^2~0.6.

Results from both are shown below.

2015-02-26-A fit.png 2015-02-26-B fit.png

Very very preliminary t20 fit:

2015-02-26-t20 basic fit.png (Note: Extremely preliminary, overly simplistic fit)