[Olympus] PRL paper
Inti Lehmann
inti.lehmann at glasgow.ac.uk
Wed Nov 9 10:16:14 EST 2016
Dear Douglas,
Thank you. I seem to have difficulties to open the attachment. Could you please re-post it?
I also asked for the picture with the result in full order calc long time ago. Could you please also forward it to me for my information only?
I’m afraid, I had to rush out of the last meeting before it really started, because of an urgency here - my apologies! Is there some kind of conclusion, which was drawn on that meeting?
Cheers,
Inti
> On 09 Nov 2016, at 15:42, Douglas K Hasell <hasell at mit.edu> wrote:
>
> Dear Stan,
>
> Explaining the MIE including the higher order corrections would be very difficult in a short PRL paper. Leaving it as a simple ratio of rates is accurate to first order and while the thesis and future MIE paper are not readily available now we will be happy to provide these to any reviewer. The MIT theses will take a month or so to be made available online. Note at that point the OLYMPUS results will be public knowledge. So we are under some pressure to get our publication out before the results shown in the theses are public.
>
> We have corrected the table of systematics to address your concerns. Geometry included detector and beam alignment and this is not stated in the table. Details of the individual effects are well reported in Brian’s thesis.
>
> Finally, I want to point out that while the MWPCs worked very well during the experiment the analysis of the MWPC data was not. The analysis code from Alexander Kisselev had several problems and was extremely hard to understand. Alexanders tracking produced stripes in the data. Brian Henderson spent about a year figuring out how Alexander’s code worked and in the end rewrote the tracking for the MWPC. This is why the 12 degree result is so good.
>
> I do not want to disrespect the contribution from any group but everyone should realise the tremendous effort made by the graduate students.
>
> Cheers,
> Douglas
>
> 26-415 M.I.T. Tel: +1 (617) 258-7199
> 77 Massachusetts Avenue Fax: +1 (617) 258-5440
> Cambridge, MA 02139, USA E-mail: hasell at mit.edu
>
>
>
>
>
>
>
>
>> On Nov 7, 2016, at 07:59, Belostotski, Stanislav <stanislav.belostotski at desy.de> wrote:
>>
>> Dear Michael,
>> Many thanks for explanations.
>> Yet, the MIE method, probably correct, will make a reader puzzled.
>> The thesis is good but hard to find for reading.
>> So a few lines of explanations are still needed.
>> Also my other comments (e.g. beam position/slope uncertainties) are not answered.
>> What is really missing is a written "data release report" with all details of the data analysis. This is a standard request in a collaboration before the results go for publication. The internal criticism is much too much better then external one.
>> I am terribly sorry but can anybody explain why we are so much in a hurry to publish our FIRST results.
>> With best regards Stan
>>
>> On 07.11.2016 15:12, Michael Kohl wrote:
>>> Dear Stan,
>>>
>>> let me try to chip in a few remarks which are hopefully helpful.
>>>
>>>
>>> On 1./ regarding pion production:
>>> Background rates are asymmetric w.r.t. pi+/pi-, however each pion is
>>> almost symmetric w.r.t. e+/e- (ignoring TPE).
>>> Pion backgrounds would have to be either of type where a pion (pi0) is
>>> produced in addition to ep but not detected (highly but not totally
>>> suppressed by missing mass analysis), or by misidentification of pi+ as
>>> e+, or pi- as e-. These are suppressed even more because there would be
>>> no proton in coincidence.
>>> If at all, we are dominated by the former which is mostly e+/e-
>>> charge-symmetric. In reality the nature of observed residual backgrounds
>>> is more random-like, from the particle flux from upstream to downstream.
>>> Residual background was identified and subtracted, but not modeled in MC.
>>> The size of residual background is now mentioned.
>>>
>>> On 2.:
>>> The MIE method is described in detail in Axel's thesis, and as far as I
>>> can tell, it correctly takes the intensity dependence of the coinc ee&ep
>>> (prop L^2) over single ee (prop. L) into account.
>>>
>>> On 3.:
>>> Many crosschecks were done with the MC, including e.g. generating and
>>> propagating an e+p sample but analyzing it as e-p and vice versa, and by
>>> switching the toroid back and forth for the MC samples.
>>> The generator was extensively tested and validated against ESEPP.
>>>
>>> Best regards
>>> Michael
>>>
>>>
>>>
>>> On Mon, 7 Nov 2016, Belostotski, Stanislav wrote:
>>>
>>>> Dear Douglas and all,
>>>> I am surprised not to find ANY reaction to my comments sent 04.11.2016,
>>>> neither in the paper text nor at least by a mail. To remind, the
>>>> comments are attached below. Regards StanB
>>>> P.S. Sorry, I will not participate the meeting today
>>>> ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
>>>> 1.Table 1.
>>>> A couple of items :
>>>> -uncertainty due to beam positions and slopes is missing ;
>>>> -"geometry". What does geometry mean? Is that alignment imperfection?
>>>> "Elastic (event) selection and bgr subtraction".
>>>> There is no discussion in text about background which at large angles
>>>> is mostly related to pion production. Remember, the latter is charge
>>>> asymmetrical. I can assume that the pion contribution is small but at
>>>> least a few lines on pion production is needed.
>>>> 2.Page 3, left, paragraph "The integrated luminosity...."
>>>> These MIE , as stated in this paragraph, are coincidences of small angle
>>>> ep scattering and Moller or BhaBha coincidence events.So they are random
>>>> coincidences(?). Then they must be corrected for the beam intensity
>>>> variations(?). Or this is my ignorance (?).Ref.29 does not help ( "to be
>>>> published"). Why just small angle ep scattering is not usable for
>>>> normalization?
>>>> I presume similar questions will be put by a referee.
>>>> 3. It is well known that kinematic constrains used for event selection
>>>> effect strongly on RC contribution. Extraction of net TPE effect from
>>>> the ratio is only possible if these constrains are strictly identical
>>>> for e+ and e-. On the other hand the e+/e- acceptances are different.In
>>>> a bin in Q**2 this is of course solved applying eq.1. The question is
>>>> still how much false asymmetry can be resulted from imperfections of MC
>>>> simulation. Was the MC model tuned somehow and cross-checked?
>>>> I think we need a few lines on that point.
>>>> 4.page4 with Fig.2.correct misprint at line 4. left (simulation)
>>>> 5. My opinion on ranking in the author list is in details in my previous
>>>> mails.
>>>> ..............................................................
>>>>
>>>>
>>>>
>>>> On 07.11.2016 2:09, Douglas K Hasell wrote:
>>>>> Dear Colleagues,
>>>>>
>>>>> Attached is what is I hope the final version of the PRL paper.
>>>>>
>>>>> Just a reminder: the collaboration meeting is tomorrow, Monday,
>>>>> November 7, at 10:00 EST (16:00 CET).
>>>>>
>>>>> Cheers,
>>>>> Douglas
>>>>>
>>>>> 26-415 M.I.T. Tel: +1 (617) 258-7199
>>>>> 77 Massachusetts Avenue Fax: +1 (617) 258-5440
>>>>> Cambridge, MA 02139, USA E-mail: hasell at mit.edu
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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>>>
>>> +---------------------------------------------------------------------
>>> | Dr. Michael Kohl, Associate Professor and Staff Research Scientist
>>> | Physics Department, Hampton University, Hampton, VA 23668
>>> | Jefferson Lab, C117, 12000 Jefferson Avenue, Newport News, VA 23606
>>> | Phone: +1-757-727-5153 (HU), +1-757-269-7343 (Jlab)
>>> | Fax: +1-757-728-6910 (HU), +1-757-269-7363 (Jlab)
>>> | Email: kohlm at jlab.org, Cell: +1-757-256-5122 (USA)
>>> +---------------------------------------------------------------------
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