[Qweak_transverse_prl_comments] Fwd: [Q-weak] First draft of the Qweak elastic transverse asymmetry paper

[Buddhini Waidyawansa]

---------- Forwarded message ----------
From: Dave Mack <mack at jlab.org>
Date: Sat, Sep 6, 2014 at 3:43 PM
Subject: Re: [Q-weak] First draft of the Qweak elastic transverse asymmetry
paper
To: Buddhini Waidyawansa <buddhini at jlab.org>


 Buddhini,

So is Table I without polarization correction? If the point of the table is
to convince people that we measured the same result 3 times, then don't we
have to divide by 1/P first? You quote an average polarization so you could
easily correct these experimental asymmetries by 1/<P>.

However, I assume there were 1-2% polarization differences between Run I
and Run II. Today I've decided to be worried about problems that might
arise from the averaging. Inputting some guesses into a calculator it looks
like the correct average for 3 datapoints

<Aphys> = ( (Aexp_1/P1)*W1 + (Aexp_2/P2)*W2 + (Aexp_3/P3)*W3 )/(W1+W2+W3)

will be extremely close to the approximation you apparently used

<Aphys> = (1/<P>)*(Aexp_1*W1 + Aexp_2*W2 + Aexp_3*W3 )/(W1+W2+W3)

The difference is less than 0.1%. So we're good.

I'm printing up your data release talk and your old tech note so I can
remember all this stuff.

Dave




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Buddhini Waidyawansa
Postdoctoral Fellow
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