[G14_run] [Clas_hadron] Draft slides for my talk on NSTAR2013

[A.M. Sandorfi]

Igor,
Regarding Fermi motion, while the peak in deuterium is 50 MeV/c, deuterium
has a known large high-energy tail that becomes small only above about 200
MeV/c. (See Hamada and Johnston, Nucl Phys 34 (62)382.) That's the
motivation for the location of the cut in Tsuneo's slide 13.

Tsuneo is working on adding to slide 13 a histogram of the missing momentum
before the co-planarity cut - the difference is quite dramatic. The two
different cuts make similar physics selections.

Reinhard,
The side peaks in the co-planarity plot, or rather the dips, are created by
holes in the CLAS azimuthal acceptance. I suspect it's premature to double
the width of the cut to include multiple sectors until we get farther along
with the DC calibrations.

Andy



On 5/21/13 10:26 AM, "Igor Strakovsky" <igor at va.gwu.edu> wrote:

> Thank you, Eugene, for your clarification.  Now it works (more or less) for
> me
> 
> Cheers, Igor
> 
> On Tue, 21 May 2013 10:16:02 -0400 (EDT), Eugene Pasyuk <pasyuk at jlab.org>
> wrote:
> 
>> Igor,
>> 
>> Coplanarity cut and missing proton (spectator) momentum cut are used for
>> "quasi-free" reaction selection. pi- threshold is to large extent irrelevant
>> for selection of "quasi-free" events. It only affects accessible kinematic
>> range. Nobody argues that these cuts do not remove all FSI.
>> 
>> -Eugene
>> 
>> ----- Original Message -----
>>> From: "Igor Strakovsky" <igor at va.gwu.edu>
>>> To: "Eugene Pasyuk" <pasyuk at jlab.org>
>>> Cc: "g14 run" <g14_run at jlab.org>, "CLAS Hadron Spectroscopy"
>>> <clas_hadron at jlab.org>
>>> Sent: Tuesday, May 21, 2013 9:45:54 AM
>>> Subject: Re: [Clas_hadron] [G14_run] Draft slides for my talk on NSTAR2013
>>> 
>>> Eugene,
>>> 
>>> If g14 analysis is using pi- to get gn-->pi-p from gd-->pi-pp then it
>>> is difficult task but that is doable for specific kinematics.
>>>  Meanwhile
>>> there is a cut-of for charged pions as well, say 100 MeV/c - please
>>> correct if I am wrong
>>> 
>>> igor
>>> 
>>> 
>>> On Tue, 21 May 2013 09:30:41 -0400 (EDT), Eugene Pasyuk
>>> <pasyuk at jlab.org>
>>> wrote:
>>> 
>>>> Igor,
>>>> 
>>>> Your statement about threshold for proton would be correct if we
>>>> would
>>>> attempt to detect spectator proton.
>>>> We don't do that, spectator is reconstructed as a missing particle.
>>>> For
>>>> missing particle there is no threshold problem. If you look at the
>>>> spectrum
>>>> you will see it starts at 0.
>>>> 
>>>> -Eugene
>>>> 
>>>> ----- Original Message -----
>>>>> From: "Igor Strakovsky" <igor at va.gwu.edu>
>>>>> To: "Reinhard Schumacher" <schumacher at cmu.edu>, "Tsuneo Kageya"
>>>>> <kageya at jlab.org>
>>>>> Cc: "g14 run" <g14_run at jlab.org>, "CLAS Hadron Spectroscopy"
>>>>> <clas_hadron at jlab.org>
>>>>> Sent: Tuesday, May 21, 2013 9:25:23 AM
>>>>> Subject: Re: [G14_run] Draft slides for my talk on NSTAR2013
>>>>> 
>>>>> Dear Reinhard,
>>>>> 
>>>>> I am afraid to try to correct you but the "select quasi-free
>>>>> neutrons"
>>>>> condition is not possible for CLAS.  CLAS cannot make a deal with
>>>>> proton
>>>>> with p < 200 MeV/c - there is a cut-off.  The 'quasi-free neutron'
>>>>> term
>>>>> is applying to the protons for p = 50 MeV/c or less.
>>>>> 
>>>>> Best, Igor
>>>>> 
>>>>> On Tue, 21 May 2013 09:18:49 -0400, Reinhard Schumacher
>>>>> <schumacher at cmu.edu>
>>>>> wrote:
>>>>> 
>>>>>> Hello Tsuneo,
>>>>>> I took a look at your slides for NSTAR2013 and have a few
>>>>>> suggestions
>>>>>> about them.  Overall, they look to be in good shape.
>>>>>> 
>>>>>> Slide 11:  the position of the coplanarity cuts seems quite
>>>>>> arbitrary.
>>>>>> I would ask:  how does the result change if you double the width
>>>>>> of
>>>>>> the cut?
>>>>>> 
>>>>>> Slide 13: For this slide you state the energy range as 1.1 to
>>>>>> 1.3,
>>>>>> whereas the previous two slides had 0.7 to 1.3.  For
>>>>>> consistency,
>>>>>> maybe
>>>>>> keep the energy range the same?  Also, on this slide you have
>>>>>> the
>>>>>> phrase
>>>>>> "excludes bound neutrons".  This is needlessly obscure and not
>>>>>> strictly
>>>>>> correct.  Maybe you want to say "select quasi-free neutrons"
>>>>>> 
>>>>>> Have a great trip.
>>>>>> 
>>>>>> Reinhard.
>>>>>> 
>>>>>> ___________________________________________________________________
>>>>>> Reinhard Schumacher         Department of Physics, 5000 Forbes
>>>>>> Ave.
>>>>>> Carnegie Mellon University, Pittsburgh, PA 15213, U.S.A.
>>>>>> phone: 412-268-5177         web: www-meg.phys.cmu.edu/~schumach
>>>>>> ___________________________________________________________________
>>>>>> 
>>>>>> On 05/20/2013 11:12 PM, Tsuneo Kageya wrote:
>>>>>>> Hi,
>>>>>>> 
>>>>>>>   I would like to get some comments and suggestions for my
>>>>>>>   slides
>>>>>>>   on
>>>>>>> NSTAR2013.
>>>>>>> My talk is related to the preliminary double spin asymmetries
>>>>>>> on
>>>>>>> g14
>>>>>>> experiments.
>>>>>>> I have 20 minutes including the discussion.
>>>>>>> I got comments from Volker and others when I showed slides and
>>>>>>> tried talking
>>>>>>> about this this Monday.
>>>>>>> I modified based on their comments, but I have still homework
>>>>>>> to
>>>>>>> do; page
>>>>>>> 10, need to show the graph
>>>>>>> with colors.   Most of others have been changed.
>>>>>>> 
>>>>>>>   Some of you may have different aspects; please let me know,
>>>>>>>   if
>>>>>>>   you have
>>>>>>> comments.
>>>>>>> A pdf file is attached.
>>>>>>> 
>>>>>>>         Regards, Tsuneo Kageya.
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