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<p style="margin-top:0;margin-bottom:0">Thanks for looking into this Sho.</p>
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<p style="margin-top:0;margin-bottom:0">I think bottom line, I just apply the truth x cut for the efficiency curves. I don't think this is cheating since we care about the truth for these.</p>
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<p style="margin-top:0;margin-bottom:0">Nan (a rotation student), did a quick and dirty study similar to this. He cut on the residual of both electron and positron momentum, decay z, and mass at 3 sigma for all these. Then he took the ratio between the efficiency
curves (as a function of z) of those curves and the curves without those cuts. Results are below (ratio vs z for several A' masses). I originally was curious in the affect of the recoil electron in the reconstruction (those cuts should get rid of most of them),
not the radiative tail as discussed this morning. The results are what I expected, a very large affect for low mass (which always has a large tail in mass), and a slightly larger affect neat the target where reconstructing with the recoil electron is more
likely. In our mass and z region of interest (~>30 mm and mass > 35 MeV), it seems like a 5-10% effect.</p>
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<p style="margin-top:0;margin-bottom:0"><img size="0" contenttype="image/png" style="max-width: 99.9%;" id="img330437" tabindex="0" data-outlook-trace="F:1|T:1" src="cid:572ab039-93d9-433d-ab75-634925e2a259"> at
<br>
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<p style="margin-top:0;margin-bottom:0">Same plot but with error bars</p>
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<p style="margin-top:0;margin-bottom:0"><img size="0" contenttype="image/png" style="max-width: 99.9%;" id="img405154" tabindex="0" data-outlook-trace="F:1|T:1" src="cid:700bafb6-2e6f-4e9f-a468-583c70a63e60"></p>
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<p style="margin-top:0;margin-bottom:0">More details are here if you want to see some of the tails he cut out: <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_nanw0321_HPS_tree_master_Plots_vertex-5Fcut&d=DwMFAg&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=J4PP6Zl8IyGHpsqWaKegORCYw8hoCHePTw5O95a5lqQ&m=og6EE5wGaYDOKMKrYDAojbELR7JksZG3kTpfqAhttG4&s=cjJ6618cWgwdV3I6mvTqDSH8wr9s-klt0yRjcyLUlLo&e=" class="OWAAutoLink" id="LPlnk58489" previewremoved="true">https://github.com/nanw0321/HPS/tree/master/Plots/vertex_cut</a></p>
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<p style="margin-top:0;margin-bottom:0">Matt Solt<br>
</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Hps-analysis <hps-analysis-bounces@jlab.org> on behalf of Sho Uemura <meeg@slac.stanford.edu><br>
<b>Sent:</b> Tuesday, June 26, 2018 1:44:52 PM<br>
<b>To:</b> Graham, Mathew Thomas<br>
<b>Cc:</b> hps-analysis@jlab.org<br>
<b>Subject:</b> Re: [Hps-analysis] HPS Analysis Meeting June 26 @ 10am/1pm PDT/EDT</font>
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<div class="PlainText">I read the note, it looks good so far. I've made a couple of typo fixes
<br>
and I'll put more substantive comments in a text file (in the Dropbox, <br>
comments_sho/comments.txt), but the only things I have there right now are <br>
things I screwed up in my thesis.<br>
<br>
I looked at the low-mass tail (pyroot macro and plots attached). See the <br>
comments in the macro for detail, but summary: I'd misremembered what the <br>
cut is that cleans it up: it's not the radiative cut on the recon vertex, <br>
it's a x>0.8 cut on the truth A'. So, that's obviously cheating (in my <br>
thesis I say I'm doing it, but completely sweep it under the rug). But the <br>
tail I saw (might not be the same tail you see) is definitely recoil e- <br>
misidentification in low-X A' events.<br>
<br>
On Tue, 26 Jun 2018, Graham, Mathew Thomas wrote:<br>
<br>
><br>
> Hi All,<br>
><br>
> We?ll meet tomorrow for an update on things in the run-up to ICHEP. We?ve got both the 2015 bump-hunt and vertexing analysis aiming for it and this Wednesday is the nominal deadline for presenting the results to the collaboration.<br>
><br>
> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__confluence.slac.stanford.edu_display_hpsg_June-2B26-252C-2B2018-2BDAWG-2BMeeting&d=DwIGaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=J4PP6Zl8IyGHpsqWaKegORCYw8hoCHePTw5O95a5lqQ&m=k4vmYUNmn_n-5PP-EHertr6XxvPSqcKO5XvWw2_iXGE&s=tfApseM4CjHLmQsSyzN2_qiQXCcyyhPiyBz4KuhbuJs&e=">
https://urldefense.proofpoint.com/v2/url?u=https-3A__confluence.slac.stanford.edu_display_hpsg_June-2B26-252C-2B2018-2BDAWG-2BMeeting&d=DwIGaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=J4PP6Zl8IyGHpsqWaKegORCYw8hoCHePTw5O95a5lqQ&m=k4vmYUNmn_n-5PP-EHertr6XxvPSqcKO5XvWw2_iXGE&s=tfApseM4CjHLmQsSyzN2_qiQXCcyyhPiyBz4KuhbuJs&e=</a>
<<a href=""></a>https://urldefense.proofpoint.com/v2/url?u=https-3A__confluence.slac.stanford.edu_display_hpsg_June-2B26-2C-2B2018-2BDAWG-2BMeeting&d=DwIGaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=J4PP6Zl8IyGHpsqWaKegORCYw8hoCHePTw5O95a5lqQ&m=k4vmYUNmn_n-5PP-EHertr6XxvPSqcKO5XvWw2_iXGE&s=0pcsXe14RWQBSJw6vopXDE59LApRfHspxGQ9MmL_W5o&e=
><br>
><br>
> Thanks, Matt & Nathan<br>
><br>
><br>
> * Browser: <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_722990411&d=DwIGaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=J4PP6Zl8IyGHpsqWaKegORCYw8hoCHePTw5O95a5lqQ&m=k4vmYUNmn_n-5PP-EHertr6XxvPSqcKO5XvWw2_iXGE&s=zv9zYKaJUIsEnSy69p9nhR411Ne36jaUOe7bumSNm8k&e=">
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