<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Dear all,<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>Thank you Jackson, for putting this incredibly detailed and well-written note together. I've finished going through it. Basically I have two concerns before we unblind. I hope you can address them easily. Let's discuss in tomorrow's meeting. </div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">1) etas produced downstream</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>My biggest fear is that we'll "discover" an ALP that is actually the peak from etas produced on some downstream material. Can you convince me that this cannot happen? I don't know the best way to study it but some ideas are:</div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>- Figure out the total thickness of any foils or windows after the target ladder and where they occur. (I don't care about air, since it will not make a bump) </div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>- Simulate a fake signal with an eta mass, but a displaced vertex. </div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>Eventually this effect must limit our sensitivity to ALPs. I would be very satisfied if you could show where this limit ought to be, especially if it's 4 orders of magnitude from our expected sensitivity.</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">2) Effective # of searches</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>My second concern is about your data-driven method of using up-crossings to estimate the effective number of independent searches. If I understand things correctly, the effective number of search regions should really only be a function of your resolution. Maybe the shape of the smooth background comes in as a second order effect, but really it's an effect of the width of any bumps you might find. </div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>However, for any given random data set, the precise number of up crossings might fluctuate due to statistics. With 10% of the data, we see 3 up-crossings. When we unblind we expect to still see 3, plus or minus one. My question to you is: what should we do if we see many many more?</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>In some sense, we could study this by looking at only 1% of the data. Or in simulation. But I don't want to waste time on this. I just would like to hear your thoughts. Is there anyway to do a sanity check on the full data set before we look for bumps? Would our seeing 27 up crossings invalidate a discovery?</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">If you can give answers to these concerns, I would feel comfortable unblinding. </div><div class="">Looking forward to discussing tomorrow,</div><div class="">Axel</div><div class=""><br class=""></div><div class=""><br class=""><div class="">
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<div><br class=""></div><div>Typos to fix whenever you are bored in the next few months:</div><div><br class=""></div><div><div>Line 89</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>! GeV</div><div><br class=""></div><div>Line 106</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Three criteria vs four criteria</div><div><br class=""></div><div>Line 192</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>a -> an</div><div><br class=""></div><div>________________</div></div><div><br class=""><blockquote type="cite" class=""><div class="">On Dec 5, 2022, at 15:00 , Jackson Reeves Pybus via halld_src <<a href="mailto:halld_src@jlab.org" class="">halld_src@jlab.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hello all,<br class=""><br class="">As discussed in today’s SRC-CT analysis meeting, I am now distributing our internal analysis note for the ongoing Axion-Like Particle search using our Carbon data. As we hope to unblind the data from our current 10% soon to examine our full statistics, we would ask that anyone with interest in the analysis read over the note and provide comments in the following week, before next SRC-CT meeting. Comments relevant to the decision to unblind are the priority at this time. Next week, an overall description of the analysis will be presented to the group.<br class=""><br class="">Any comments should be added to the following Google Doc, which will be addressed Monday:<br class=""><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__docs.google.com_document_d_1LxsqEbn4JKX9AqlFElJ59TWd-2DN09to4w6Xj833Tv3cA_edit-3Fusp-3Dsharing&d=DwMFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=66Sb4pp0d4diwFuNQ_jTiKyZDsB_FG2X3Hlmk9_wuSY&m=N1TqBAlSCOi_HY3Ublw9Syo_-QbsiFIAlZoRAatnsA4yBIYMpkVO0TZaxmOD3aSv&s=C7WSuOX1eWH7BEYtQQMxCLtqL0Se2-6SaxEXuL1_b-0&e=" class="">https://docs.google.com/document/d/1LxsqEbn4JKX9AqlFElJ59TWd-N09to4w6Xj833Tv3cA/edit?usp=sharing</a><br class=""><br class="">Thank you,<br class="">Jackson<br class=""><br class=""></div><span id="cid:79F7B18C-66EF-4EF0-9228-A1B29F50C010@mynetworksettings.com"><SRC_CT_Analysis_Note_for_ALP_Search.pdf></span><meta http-equiv="Content-Type" content="text/html; charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""></div>_______________________________________________<br class="">halld_src mailing list<br class=""><a href="mailto:halld_src@jlab.org" class="">halld_src@jlab.org</a><br class="">https://mailman.jlab.org/mailman/listinfo/halld_src<br class=""></div></blockquote></div><br class=""></div></body></html>