[Frost] Updated my analysis page

[Michael Dugger]

Franz,

The nucleon Born term will give Czz = +1. Patrick is seeing negative 
values. So, Born term is not the issue.

The response related to the form factors is not very useful. I do not see 
how a vertex form factor will give rise to Czz in t-channel.

We were just trying to understand what Patrick is seeing. Just throwing 
out a bunch of physics terms does not help me understand.

I'm just going to assume it is complicated. This is getting to be a waste 
of time.

-Michael


On Sat, 11 Jun 2011, Franz Klein wrote:

>
> Mike,
> Nucleon pole always means the nucleon Born term (strongest u-channel 
> contribution near threshold).
> Dressed vertices can be described via from factor (e.g. Nicole D'Hose's 
> description of pion and sigma exchange in rho and omega production) or using 
> the dynamical reaction model (aka Sato-Lee) via loop over all rescattering 
> terms (mostly piN, piDelta).
> Yongseok Oh's code calculate all combinations of single and double pol. 
> observables (Oh's code has a sign error in the u-channel coupling).
>
> Greetings
> Franz
> On Fri, 10 Jun 2011, Michael Dugger wrote:
>
>> 
>> Franz,
>> 
>> I wanted to better understand what you wrote and have a few questions:
>> 
>> * When you say "nucleon pole" are you talking about the Nucleon Born term?
>> 
>> * When you say that the "Oh-Lee model it looks very similar to Patrick's 
>> results" are you talking about the Sigma data or Czz data? Is there 
>> predictions for the Czz data from the Oh-Lee model?
>> 
>> * When you write "The loop contributions to the dressed vertex" are you 
>> referring to a vertex form factor?
>> 
>> Thanks,
>> Michael
>> 
>> On Fri, 10 Jun 2011, Franz Klein wrote:
>> 
>>> 
>>> Patrick,
>>> your results look interesting. I agree with Mike that OBE (pion,eta) 
>>> cannot produce Beam-Target asymmetry, whether the 'pomeron' does, depends 
>>> on whether you use Landshoff (0+ with 1- component) or VMD model (0+).
>>> Even with OBE dominance near threshold, there is still the nucleon pole, 
>>> which makes a large contribution in BT asymmetries, esp. with circ.pol. 
>>> beam (actually in the Oh-Lee model it looks very similar to Patricks 
>>> results ... possibly there is also some off-shell F15 (and D13).
>>> When looking at omega production near threshold, the loop contribution in 
>>> the dressed vertex are rather strong: thus as Igor points out, look at 
>>> Mark's work (~EBAC).
>>> 
>>> My 2 cents Franz
>>> On Fri, 10 Jun 2011, Patrick Collins wrote:
>>> 
>>>> Hello all,
>>>> To demonstrate what I was talking about yesterday about t-channel in
>>>> omega I've added a couple of plots of beam asymmetry for omega from g8b
>>>> with similar W values at the bottom of my page. You can see that the
>>>> forward angles are close to zero asymmetry. I took a look at Williams PWA
>>>> and he does say that there are two strong resonances in omega production
>>>> near threshold the F15(1680) and D13(1700), so these could be producing
>>>> the large helicity asymmtries. I just don't understand why they would be
>>>> so strong here and so weak in beam asymmetry, especially in the forward
>>>> direction which normally where t-channel is very strong.
>>>> 
>>>> http://clasweb.jlab.org/rungroups/g9/wiki/index.php/Patrick%27s_analysis_page#Ex
>>>> amples_of_.CE.A3_from_g8b_for_similar_W
>>>> 
>>>> Cheers,
>>>> Patrick
>>>> 
>>>> 
>>> 
>>> ===============================================================
>>>                  Franz J. Klein, Associate Professor
>>>                  CUA, Department of Physics
>>>                  Washington, DC 20064
>>>  office: Hannan Hall 206          phone: 202-319-6190
>>>  or: Jefferson Lab,CC F-243       phone: 757-269-6672
>>> ---------------------------------------------------------------
>> 
>
> ===============================================================
>                  Franz J. Klein, Associate Professor
>                  CUA, Department of Physics
>                  Washington, DC 20064
>  office: Hannan Hall 206          phone: 202-319-6190
>  or: Jefferson Lab,CC F-243       phone: 757-269-6672
> ---------------------------------------------------------------
>