[Primex] meeting

[Aron Bernstein]

Dear Liping and all,
         here are my comments to what Liping has written
regards,
Aron

On Jul 14, 2010, at 9:50 PM, Gan, Liping wrote:

> Hi, all,
>
> I would like to comment on Aron's suggestion:
>
> (1) In abstract, I suggest to mention that our result improved the  
> precision of PDG average more than two and half time. However, we  
> should not emphasize the comparison with the next-to-leading order  
> chiral prediction since our current error bar is too big to draw any  
> definite conclusion. We will have to wait for PrimEx II result.

If we cannot draw any conclusions from our data then we have no right  
to submit this
to the Phys Rev. Lett. In this case we should wait until PrimEx 2 is  
completed and send the present results to an archival journal!

>
> (2) As for Fig. 1, I would suggest to stick with our collaboration  
> meeting decision. We should discuss with Jose and other theorists.  
> If they have no problem with the Fig.1, we just keep as it is.

This is not my understanding of what  we agreed on. I assumed that the  
discussion with the local theorists was for the benefit of any of you  
who wanted to think  more about this issue. At that point I assume  
that we will have another discussion (by e mail or phone) about what  
the conclusion is and arrive at a consensus as we usually do for  
important matters.

   Again I have done the calculation and presented it to the PrimEx  
collaboration. The result is that the eta' mixing contributes ~1/3 of  
the total 4.8% addition in the pi0 width. If you don't believe this  
calculation then please repeat it or ask your favorite theorist to do  
so. The omission of this contribution is what makes the Ioffe  
calculation smaller then the others.  Rory has indicated his agreement  
with my suggestion not to show this contribution in Fig. 1.


>
> Best regards,
>
> Liping
>
>
>
>
> -----Original Message-----
> From: primex-bounces at jlab.org [mailto:primex-bounces at jlab.org] On  
> Behalf Of Aron Bernstein
> Sent: Tuesday, July 13, 2010 3:08 PM
> To: Ashot Gasparian
> Cc: primex at jlab.org; Aron Bernstein
> Subject: Re: [Primex] meeting
>
> Dear Ashot and all,
>
>     Following yesterday's discussion about the pi0 paper I agree  
> that a strong conclusion should be presented in the abstract. My  
> suggestion is to add a last sentence in the abstract:
>
> This is consistent with the theoretical prediction which is  
> dominated by the QCD axial anomaly plus a 4.8% chiral correction.
>
> I also want to reiterate my suggestion that that the only  
> theoretical lines that should be shown in Fig. 1 are the axial  
> anomaly and the chiral perturbation prediction. This experiment is  
> important because there is a QCD prediction that should be  
> accurately tested. The graph as it is now presented does not make  
> this point. It implies that there is a theoretical uncertainty that  
> in fact does not exist. As it now stands Fig. 1 diminishes the  
> impact of our experiment- this is why I have raised this point so  
> forcefully.
>
> Regards,
> Aron
>
> Aron M. Bernstein
> Professor of Physics
> MIT
> Cambridge, MA. 02139
> office: 26-419
> phone: 617-253-2386
>
>
>
>
>
>
>
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