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<div><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Dear e+ program and SoLID supporters:</span><br>
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<span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Many thanks to those who signed up for the C3q proposal (since v1), those who provided proofreading, and those who did further calculations on tracking and DAQ deadtime. We are now
within one-week of submission (though maybe one decade of having the positron beam on SoLID).
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<span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">I have posted an updated version (now #2) at
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<a href="https://drive.google.com/file/d/1Uy7NrlHGzfYyoYYyYTJwg_syYhF55cXl/view?usp=sharing" id="LPlnk"><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">https://drive.google.com/file/d/1Uy7NrlHGzfYyoYYyYTJwg_syYhF55cXl/view?usp=sharing</span></a><br>
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<div dir="ltr"><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">A summary of changes is given below:</span></div>
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<font face="Liberation Serif, serif"><font style="font-size:12pt" size="3"><span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">1) rewrote
</span><span style="font-weight:normal"><font face="Liberation Serif, serif"><font style="font-size:12pt" size="3"><span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">e+ source section</span></span></font></font></span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">s
3.1 and 3.2. (shortened but nothing was moved to the appendix);</span><span style="font-weight:normal"></p>
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<font face="Liberation Serif, serif"><font style="font-size:12pt" size="3"><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">2) added tracking and DAQ deadtime, section 3.8 (thanks to Hanjie and Weizhi for the
calculations and/or measurements);</span><br>
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<font face="Liberation Serif, serif"><font style="font-size:12pt" size="3"><span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">3</span></span><span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">)
add target endcap calculation, section 3.9.3 -- it was nice to deal with some more "ordinary" systematic effects;</span><span style="font-weight:normal"></p>
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<font face="Liberation Serif, serif"><font style="font-size:12pt" size="3"><span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">4) added section 4.1 to outline the analysis procedure;</span><span style="font-weight:normal"></p>
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<font face="Liberation Serif, serif"><font style="font-size:12pt" size="3"><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">5) provided table on F3gammaZ uncertainties assuming 1% uncertainty on the calculation
of QED contribution. Estimation using 5% and 10% QED uncertainty was also done (but not provided as tables so as not to crowd the section);</span><br>
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</span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">6) in Appendix A,</span></span><span><span style="font-weight: normal; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; line-height: normal;">
under Eq.(55), clarified we are deriving for pure states (h=+1 or -1), then apply the result to real beams with polarizations. Without this, many people may be confused "where did the lambda^2 term go?".
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<div dir="ltr"><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Further more, the following is already on my to-do list. I am waiting for inputs to accommodate the change prior to submission (May 24th):</span></div>
<div dir="ltr"><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">-- remake Fig.11.</span><br>
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<span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Once again, please be critical and send me comments and suggestions.
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<span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">If you have not already subscribed to the pwg or solid mailing list, please sign up.</span><br>
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<span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Please also feel free to forward this to anyone who may be interested in the physics, or simply point them to this
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author signup form</a>.<br>
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<span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Best regards,</span><br>
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Xiaochao<br>
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