<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Hi All,</div><div class=""><br class=""></div><div class="">Thanks for weighing in Jo. We’ll look forward to debating the assignment of nearby states at a future DNP meeting, but for now this more of an exploration of the omega-pi final state.</div><div class=""><br class=""></div><div class=""><div class="">As for the abstract, rather than focusing on a specific resonance I would suggest something like below for the last sentences of Ahmed's abstract:</div><div class=""><br class=""></div><div class="">"This investigation will commence by inspecting the invariant mass spectra and Dalitz plots as a function of the Mandelstam variable $-t$, to investigate the production mechanism of the $b_1$ and serve as the first step in investigating the decays of heavier mesons to $\omega\pi^0$.”</div></div><div class=""><br class=""></div><div class="">-Justin</div><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 27, 2017, at 10:13 AM, Jozef Dudek <<a href="mailto:dudek@jlab.org" class="">dudek@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; -webkit-line-break: after-white-space;" class=""><div class="">Dear all,</div><div class=""><br class=""></div><div class="">I still get these emails, so let me briefly summarise what the lattice calcs have said about what you call the b_1(1650), the first excited isovector 1+- state. ( BTW where does the mass 1650 come from? )</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">The spectrum for the lightest quark mass (pion mass near 400 MeV) we’ve so far considered is shown below.</div><div class=""><br class=""></div><div class=""></div></div><span id="cid:10B4BBE6-2779-4479-B88A-9BBFCA4A8E85@jlab.org"><840_V24_spectrum.pdf></span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div class=""></div><div class=""><br class=""></div><div class="">Look at the blue boxes (isovector) in the 1+- column. The low-lying guy is the b_1(1235) — obviously it’s too heavy because the quarks are too heavy. Above that there are two boxes basically on top of each other and then another box above that. This indicates there might be two nearby states?</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Quark-model like assignments for these states are discussed in </div><div class=""><a href="https://journals.aps.org/prd/pdf/10.1103/PhysRevD.84.074023" class="">https://journals.aps.org/prd/pdf/10.1103/PhysRevD.84.074023</a></div><div class="">where the first excited state in the isovector 1+- channel is identified (as Curtis has it) as likely a radial excitation of the qqbar P-wave</div><div class=""><br class=""></div><div class="">With respect to the second 1+- state that is very close to the first excitation -- this guy isn’t identified in the paper referenced above. It wasn’t totally clear what this guy is. You can see from the quark mass dependence shown below (focus on the blue)</div><div class=""><br class=""></div><div class=""></div></div><span id="cid:38302CB3-6239-4E67-B8DE-AF4C039C0AF9@jlab.org"><PastedGraphic-1.png></span><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""></div><div class="">(figure 16 in <a href="https://journals.aps.org/prd/pdf/10.1103/PhysRevD.88.094505" class="">https://journals.aps.org/prd/pdf/10.1103/PhysRevD.88.094505</a>) </div><div class="">that the splitting with the state you’re interested in probably grows with increasing quark mass. </div><div class=""><br class=""></div><div class="">In a charmonium calculation (heavy quarks!) the splitting would have gotten quite large, and you’ll see in </div><div class="">figure 16 of <a href="https://link.springer.com/content/pdf/10.1007%2FJHEP07%282012%29126.pdf" class="">https://link.springer.com/content/pdf/10.1007%2FJHEP07%282012%29126.pdf</a></div><div class="">that there is a large splitting, but that the state can now be identified as a non-exotic hybrid meson, in the ‘first excited’ (quarks in a P-wave) set of hybrids. SO if you see two close-by states in your experiment, you might be seeing the radial excitation plus a non-exotic hybrid.</div><div class=""><br class=""></div><div class="">Hope this is helpful. If you have any questions, get in touch,</div><div class=""><br class=""></div><div class="">Thanks,</div><div class="">Jo.</div><div class=""><br class=""></div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Jun 27, 2017, at 9:49 AM, Curtis Meyer <<a href="mailto:cmeyer@cmu.edu" class="">cmeyer@cmu.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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With regard to the b2(1650) mentione din Ahmed’s abstract, this should be the b1(1650), which
<div class="">is a radial excitation of the b1(1235) and you can see it in the lattice calculation. A b2 is exotic, and</div>
<div class="">while expected, the mass is probably above 2GeV.</div>
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<div class="">Curtis<br class="">
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Ahmed Foda<br class="">
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- How are the b1(1235) and b2(1650) related? (Same branch modes?) What is the b2? Is it predicted by lattice?<br class="">
- Why is the -t dependence important in this context?<br class="">
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