[esa-t474] [Fwd: esa-t474 post from drw1@hep.phy.cam.ac.uk requiresapproval]

[Woods, Michael B.]

Hi, a concise explanation of how the energy spectrometer data is used together Bhabha acolinearity to extract the lumi spectrum should be given, consistent with the comments below.  Some additional references to add to Ref. 1 are needed.  There seems to be a misconception by the editor of connections between energy spectrometer goals and physics analyses using PFAs and jet energy measurements; this should be addressed as well in comments to him.  Some comment on physics analyses to complement energy spectrometer measurements would be useful in the paper as well; ex. to comment on use of radiative return events and give a reference.

Would be good to have people suggest references for Mark to review and then synthesize that information into a concise description in the text and a response to the reviewer.  One such reference is IPBI TechNote IPBI-TN-2003-1, http://www.slac.stanford.edu/xorg/lcd/ipbi/notes/white.pdf which addresses energy spectrometer requirements, luminosity spectrum and physics analyses; it also contains a number of good references regarding energy precision required and relevant physics analyses.

Mike

-----Original Message-----
From: Bino Maiheu [mailto:bino at hep.ucl.ac.uk] 
Sent: Friday, December 14, 2007 3:40 AM
To: ESA T474 Mailing list
Subject: [esa-t474] [Fwd: esa-t474 post from drw1 at hep.phy.cam.ac.uk requiresapproval]

Hi All,

I'm forwarding a bounced mail from David to the T474 list.

This beam strahlung issue is indeed important, maybe we could mention something in the introduction, but for sure a detailed is *far* beyond the scope of this paper, and leans more closely to a future spectrometry paper.

Cheers,
     bino


-------- Forwarded Message --------
From: David Ward <drw1 at hep.phy.cam.ac.uk>
To: Mark Slater <slater at hep.phy.cam.ac.uk>
Cc: esa-t474 at hep.ucl.ac.uk
Subject: Re: [esa-t474] Your submission (fwd)
Date: Fri, 14 Dec 2007 11:45:11 -0000 (GMT)

Hi Mark,

     Probably Stew understands this more deeply than I do.  Beamstrahlung (and ISR) shifts the collision energy downwards, but there's still a sharp peak at the full energy.  And for things like threshold scans, it is crucial to know the maximum energy, because this matters most in determining how the cross-section turns on.  Measuring the luminosity spectrum (i.e. the shape of the beamstrahlung/isr curve) is a separate issue, addressed by (for example) Bhabha acollinearity - see the old paper by Frary and Miller.

Cheers,

     David.

> Dear All,
>
> Here are the first comments from the reviewer. Does anyone have a good 
> answer to this?
>
> Thanks,
>
> Mark
>
> ---------- Forwarded message ----------
> Date: Thu, 13 Dec 2007 21:08:00 -0000
> From: nim at lbl.gov
> To: slater at hep.phy.cam.ac.uk
> Subject: Your submission
>
> Nuclear Inst. and Methods in Physics Research, A
> Title: Cavity BPM System Tests for the ILC Energy Spectrometer
>
> Dear Dr. Slater,
>
> Thank you for your recent submission to Nuclear Inst. and Methods in 
> Physics Research, A.
>
> Before proceeding further with the review process, I would like you to 
> address in detail the following issue.  Beamstahlung will spread the 
> energy of the electrons and positrons at the collision point by an 
> amount far greater than the precision of the instrument that you 
> propose. Indeed, for the purposes of data analysis new approaches, 
> such as particle flow analysis, must be developed because one cannot 
> balance momentum in the beam direction. Your treatment of this issue 
> should speak to how the information from the proposed instrument would 
> be used as an input to the new physics analysis approaches.
>
> Sincerely,
>
> William A. Barletta
> Editor
> Nuclear Inst. and Methods in Physics Research, A
>
>
> _______________________________________________
> esa-t474 mailing list
> esa-t474 at hep.ucl.ac.uk
> https://mail.hep.ucl.ac.uk/mailman/listinfo/esa-t474
>


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