[Halld-physics] Comments on all abstracts

Tue Jun 27 12:07:47 EDT 2017

Hi folks:

Thanks to all for chiming in.  This was a nice discussion and indeed I look forward to improving my “education” on this front.

Justin, I like your suggested phrase.  This keeps it in the general, “cautious” spirit of an abstract, giving us flexibility over the next few months before deciding what exactly to show at the meeting.

Cheers, Zisis...

> On Jun 27, 2017, at 9:17 AM, Justin Stevens <jrsteven at jlab.org> wrote:
> 
> Hi All,
> 
> 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.
> 
> 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:
> 
> "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 $\omega\pi^0$.”
> 
> -Justin
> 
>> On Jun 27, 2017, at 10:13 AM, Jozef Dudek <dudek at jlab.org <mailto:dudek at jlab.org>> wrote:
>> 
>> Dear all,
>> 
>> 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? )
>> 
>> 
>> The spectrum for the lightest quark mass (pion mass near 400 MeV) we’ve so far considered is shown below.
>> 
>> <840_V24_spectrum.pdf>
>> 
>> 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?
>> 
>> 
>> Quark-model like assignments for these states are discussed in  
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__journals.aps.org_prd_pdf_10.1103_PhysRevD.84.074023&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=FAn-hdsXbHBN7xoIuFdubsRqNYNQ5nnNUukGMiBlLdk&e=  <https://urldefense.proofpoint.com/v2/url?u=https-3A__journals.aps.org_prd_pdf_10.1103_PhysRevD.84.074023&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=FAn-hdsXbHBN7xoIuFdubsRqNYNQ5nnNUukGMiBlLdk&e= >
>> 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
>> 
>> 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)
>> 
>> <PastedGraphic-1.png>
>> (figure 16 in   https://urldefense.proofpoint.com/v2/url?u=https-3A__journals.aps.org_prd_pdf_10.1103_PhysRevD.88.094505&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=MQkljFNabP5cFX9LPU8rjFhngjyA8U9SM928-44aYqU&e=  <https://urldefense.proofpoint.com/v2/url?u=https-3A__journals.aps.org_prd_pdf_10.1103_PhysRevD.88.094505&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=MQkljFNabP5cFX9LPU8rjFhngjyA8U9SM928-44aYqU&e= >) 
>> that the splitting with the state you’re interested in probably grows with increasing quark mass. 
>> 
>> In a charmonium calculation (heavy quarks!) the splitting would have gotten quite large, and you’ll see in 
>> figure 16 of https://urldefense.proofpoint.com/v2/url?u=https-3A__link.springer.com_content_pdf_10.1007-252FJHEP07-25282012-2529126.pdf&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=cZ4bNHNOrWd7RNdW1AHcsQ4Oh44T2LZdF-i3Y0cR01w&e=  <https://urldefense.proofpoint.com/v2/url?u=https-3A__link.springer.com_content_pdf_10.1007-252FJHEP07-25282012-2529126.pdf&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=cZ4bNHNOrWd7RNdW1AHcsQ4Oh44T2LZdF-i3Y0cR01w&e= >
>> 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.
>> 
>> Hope this is helpful. If you have any questions, get in touch,
>> 
>> Thanks,
>> Jo.
>> 
>> 
>>> On Jun 27, 2017, at 9:49 AM, Curtis Meyer <cmeyer at cmu.edu <mailto:cmeyer at cmu.edu>> wrote:
>>> 
>>> With regard to the b2(1650) mentione din Ahmed’s abstract, this should be the b1(1650), which 
>>> is a radial excitation of the b1(1235) and you can see it in the lattice calculation. A b2 is exotic, and
>>> while expected, the mass is probably above 2GeV.
>>> 
>>> Curtis
>>> ---------
>>> Curtis A. Meyer MCS Associate Dean for Faculty and Graduate Affairs
>>> Wean:    (412) 268-2745  Professor of Physics
>>> Doherty: (412) 268-3090  Carnegie Mellon University
>>> Fax:         (412) 681-0648
>>> Pittsburgh, PA 15213
>>> cmeyer at cmu.edu <mailto:cmeyer at cmu.edu>
>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.curtismeyer.com_&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=agvCG8txxZXFiJPEDvvJ-_7MPtyKHzURsdkxndh86G8&e=  <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.curtismeyer.com_&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=tkzhhpt64rRw6UYYOiZUvX2EnoOb8Z04QVfRqLSRE8Q&m=xHHyz3sw4yOqVM732ApHpKnJMmZeJYM9uysDkWZgtlM&s=agvCG8txxZXFiJPEDvvJ-_7MPtyKHzURsdkxndh86G8&e= >
>>>> 
>>>> 
>>>> Ahmed Foda
>>>> 
>>>> - How are the b1(1235) and b2(1650) related? (Same branch modes?) What is the b2? Is it predicted by lattice?
>>>> - Why is the -t dependence important in this context?
>>>> 
>>>> 
>>>> 
>>>> 
>>>> -- 
>>>> Elton Smith
>>>> Jefferson Lab MS 12H3
>>>> 12000 Jefferson Ave STE 4
>>>> Newport News, VA 23606
>>>> (757)269-7625
>>>> (757)269-6331 fax
>>>> 
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Dr. Zisis Papandreou
Professor of Physics, Ph.D., P.Phys.
---------------------------------------------------------
Department of Physics   
University of Regina	    
3737 Wascana Parkway
Regina, SK  S4S 0A2	 CANADA

Phone: (306) 585-5379
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Email:  zisis at uregina.ca <mailto:zisis at uregina.ca>
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