<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Richard,<div class=""><br class=""></div><div class="">As it was proposed in the LOI, the experiment is not intended to test any specific model. It would be sensitive to a difference in the proton form factor between electron and muon probes for Q2 between 5e-4 and 3e-1 GeV2. </div><div class=""><br class=""></div><div class="">I now understand that a scalar boson would modify the form factor for Q2 below the mass squared of the boson. The minimum observable mass would thus be about 20 MeV (MUSE is almost 40 MeV.) Very heavy masses appear to be ruled out, so If the boson were above 20 MeV it would produce a broad transition in the muon form factor at its M2. Observing such a transition would support this explanation as well and constrain the mass.</div><div class=""><br class=""></div><div class="">Having said that, some believe that the observation of a large radius in muonic 3He and 4He constrains the mass to be <2 MeV.</div><div class=""><br class=""><div class="">
<div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Best,<br class="">Mark Macrae Dalton</div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div><br class="Apple-interchange-newline">
</div>
<br class=""><div><blockquote type="cite" class=""><div class="">On Sep 15, 2016, at 11:00 AM, Richard Jones <<a href="mailto:richard.t.jones@uconn.edu" class="">richard.t.jones@uconn.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_quote"><div dir="ltr" class="">Hello all,<div class=""><br class=""></div><div class="">(Sorry Mr Moderator, will try not to send big attachments next time!)</div><div class=""><br class=""></div><div class="">Found this recent paper (linked below) interesting, not sure to what to make of it. Unlike most of these search plots, this one looks like the available mass/coupling space that would simultaneously explain muon g-2 and the proton radius puzzle is pretty narrow. I am curious whether GlueX might be able to close this window using the idea outlined in our June 2016 LOI?</div><div class=""><br class=""></div><div class=""><a href="https://drive.google.com/file/d/0B8giqd10L9kkay1nUkdvS1o2cVU/view?usp=sharing" class="">PhysRevLett 117 101801 (2016) Sept. 2.</a><br class=""></div><div class=""><br class=""></div><span class="gmail-HOEnZb"><font color="#888888" class=""><div class=""><br class=""></div><div class="">-Richard Jones</div><div class=""><br class=""></div></font></span></div>
</div><br class=""></div>
_______________________________________________<br class="">Halld-physics mailing list<br class=""><a href="mailto:Halld-physics@jlab.org" class="">Halld-physics@jlab.org</a><br class="">https://mailman.jlab.org/mailman/listinfo/halld-physics</div></blockquote></div><br class=""></div></body></html>