[Nuclear] XLASNPA conference contribution

[William Brooks]

Hi Ken, 

 Thanks for your comments. I do have time to revise it.

 Just a word to explain these two points: 

1. The equation for the calculation of Feynman x includes the hadron energy as well as other variables. We shift the hadron energy used in the computation of Feynman x by the value of energy loss. Therefore, for each guess of the energy loss, we have a slightly different value of the Feynman x cut for the heavy target. We optimize using a Komolgorov test to compare the D and shifted Pb spectra. In all cases the spectra have integral = 1 so that the shapes can be compared.

2. The concepts behind the Figure 5 caption are not simple, so the confusion is understandable. Probably I can find better wording. The majority of the attention paid to this subject emphasizes the quadratic dependence of total energy loss on length. This is more clearly seen in a plot (which I show in my talks). For system lengths below a critical length, the behavior is quadratic, then above the critical length it is linear in system length; and all of that is for 'high' energies. The plot I'm showing here is more relevant to nuclei. It is for *fixed* system length and asks the question as to what the energy dependence is. In the caption I was trying to connect the L^2 concept, which is more familiar, to the energy dependence, which is less familiar but more relevant to measurements on nuclei. I'll try to express this more clearly.

Thanks for the feedback!

- Will



On Apr 7, 2014, at 12:31 PM, "Hicks, Kenneth" <hicks at ohio.edu> wrote:

> Hi Will,
> 
> I read through your proceedings contribution, and I found the discussion about Fig. 4 to be confusing.  At first, I thought the Pb spectrum was simply shifted and normalized to "unity" (i.e., to have the same integral?).  But when I read further, it says that there is a cut on Feynman x and "taking the putative energy loss into account for the heavy nucleus".  This latter statement is too vague, and it would be helpful if you explain (or give an equation for) what you mean here.  The whole point here is that there is an "optimum shift" but I have no idea how this shift was optimized.
> 
> Also, I find the caption to Fig. 5 to be a bit confusing.  From the figure, it appears that Delta E_quark saturates above E_critical, whereas the caption says that the energy loss is quadratic in system length and energy-independent, which means something else to me.  Although I think I know what you want to say here, the wording of the figure caption could be improved (significantly).
> 
> I hope these comments are helpful.  Do you still have time to revise the manuscript?
> 
> Best regards,
> Ken
> 
> -----Original Message-----
> From: nuclear-bounces at jlab.org [mailto:nuclear-bounces at jlab.org] On Behalf Of William Brooks
> Sent: Friday, April 04, 2014 10:19 AM
> To: nuclear at jlab.org
> Subject: [Nuclear] XLASNPA conference contribution
> 
> Dear all, 
> 
> I wrote a conference proceedings contribution for the XLASNPA conference in Montevideo, Uruguay. After receiving your comments and suggestions, I would like to post it in revised form on the preprint server. Although my talk was more general and included data from HERMES, CMS, and ATLAS in addition to CLAS, I chose to only highlight CLAS preliminary data in the writeup. Any comments you may have will be appreciated. There is room for more references, for instance.
> 
> Best regards, 
> 
> - Will
> 
>