[Clas_cascades] {SpamScore: ssss}Re: eg3 data analysis

[Igor Strakovsky]

Dear Ralf,

On Mon, 20 Sep 2010 07:52:16 -0400, Ralf W Gothe <gothe at physics.sc.edu> wrote:

>>> As Zhiwen already pointed out to you, you may find it on our wiki page
>>> or in his slides e.g.
>>> http://www.jlab.org/Hall-B/secure/hadron/meetings/19mar10/hadron20100319_zwzhao_Lambda1520Theta+.pdf 
>>
>> I've looked through Zhiwen's slides, but I could not find a picture that
>> I asked Zhiwen to show me. If you mean a particular slide, please let
>> me know which one.
> I thought your "KS plot" is the one Zhiwen talked about, i.e. the invariant 
> mass of the K-short?!

Nope, I asked a plot for recoil Ks.  Can I see it?

>> BTW, the slide of p21 gives a very intriguing picture. It shows data and
>> simulation for the proton momentum distribution. They exactly coincide at
>> P<0.2 GeV/c(?), where direct detection of protons in CLAS is technically
>> impossible. However, in the whole region P>0.2 GeV/c, where the direct
>> detection is possible, the data and simulation are strongly different,
>> up to 10 times or even more.
>>
>> Could you please explain why the boundary between good and bad agreement
>> of data and simulation is just the lowest detected momentum?
>>
> If we trust the Deuteron model that goes into the simulation, then as you 
> know the difference is that neutron is not purely quasi-free.

First of all, you did not answer my question which is crystal, I hope
Then, I cannot understand your point.  Can you please be more specific?

>> OK, one question on just this slide 21 was formulated above. Here is one
>> more question. The slide shows the proton momentum distribution in the
>> log scale.
>>
>> Is it possible to see a linear scale for P<250 MeV/c or so?

> I don't have the source, but Zhiwen could produce it.

I would love to see it.

>> BTW, if you are going to use impulse approximation (spectator mechanism),
>> you have to keep your cut on the level P<50 MeV/c (average momentum of
>> the nucleon in the deuteron), not P<200 MeV/c.
>>
> No matter where you cut, you always have non-quasi-free contributions, which 
> can never be determined precisely.

What?  What are you talking about?

>> And an additional question. For me, the missing proton mass distributions
>> (p20} look too broad. It means for me that your proton momentum recovery
>> might be not sufficiently good.

And ???

Thanks, Igor