[G12] similar study of eloss in g11

[mpaolone at jlab.org]

I thought that gsim removes energy from the tracks depending on what
materials they pass through, then you must run eloss in your analysis to
recover what gsim removed.  I also think that gsim removes energy from the
tracks by default, and you have to turn off a switch somewhere to get rid
of that functionality if you want to.  I am not a gsim expert, and if
anyone else has a different understanding, please correct me.

-Michael


> I don't recall a conclusive answer as to whether or not GSIM data
> requires eloss to be applied (see attached).
>
>
> On 09/13/2011 02:41 PM, Lei Guo wrote:
>> HI, Craig,
>>
>> Nathan Baltzell did a very comprehensive study of eloss for g11. What
>> I recall is that he uncovered quite a few mistakes here and there,
>> mostly on the gsim side,  by comparing the delta_P (momentum change)
>> as a function of various variables (vertex positions, theta, momentum,
>> etc) using both real data and simulation. I think you already have the
>> all the info now. It might be worthwhile now to make sure that we did
>> eloss correctly, by checking the delta_p's as a function of z, theta,
>> p, and it should be similar to what gsim has, if we are doing eloss
>> correctly.
>>
>> Personally, I still think the low mass might come from the shifted
>> electron beam energy.
>>
>> Lei
>>
>>
>>
>> On Sep 14, 2011, at 6:45 AM, Craig Bookwalter wrote:
>>
>>> Hi folks,
>>>     I've posted a few more things to the wiki in relation to our
>>> discussion Friday about the issues I'm having with energy loss and the
>>> mass of the neutron being too low:
>>>
>>> http://clasweb.jlab.org/rungroups/g12/wiki/index.php/Charged_3pi_event_selection#Neutron_Mass
>>>
>>>
>>> Specifically, Mike Paolone and I each did our own eloss corrections to
>>> a
>>> common set of events and I find our corrections to be identical. In
>>> addition, I've examined a sample of p pi+ pi- events and when I
>>> reconstruct the proton via missing mass off the pi+pi-, I see a similar
>>> underestimation of the mass of the proton.
>>>
>>> Feel free to ponder this til Friday, or respond now via the list if you
>>> so desire. Any ideas are welcome.
>>>
>>> --cb
>>>
>>>
>>> --
>>> -------------------------------------------------------------------------
>>>
>>>  Craig Bookwalter            FSU Office:  (850) 644 3808
>>>  Department of Physics            JLab Office: (757) 269 5465
>>>  Florida State University        craigb at hadron.physics.fsu.edu
>>>  Tallahasse, FL 32306            craigb at jlab.org
>>>
>>> "Tower, this is Ghostrider requesting a flyby."
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>>
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>
>
> --
> -------------------------------------------------------------------------
>   Craig Bookwalter			FSU Office:  (850) 644 3808
>   Department of Physics			JLab Office: (757) 269 5465
>   Florida State University		craigb at hadron.physics.fsu.edu
>   Tallahasse, FL 32306			craigb at jlab.org
>
> "Tower, this is Ghostrider requesting a flyby."
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>
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