[Frost] meeting tomorrow

[Michael Dugger]

Eugene,

Brian and I have started working on a new version.

-Michael

On Fri, 23 Jul 2010, Eugene Pasyuk wrote:

> It might be also effect of different phase space for protons from these
> two reactions.
> Anyhow, it looks like pi0 mass is consistently high in all analyses.
> We need to take another look at eloss. May be we still missing something
> there.
>
> -Eugene
>
> Michael Dugger wrote, On 07/23/10 15:29:
>>
>> Sungkyun,
>>
>> You might be seeing a "pre-selection" effect. When you define the reaction
>> as being "gamma p ->  p pi+ pi-" you have to make some sort of cut. This
>> means that only those events that you pre-select as candidates are further
>> processed in determining the "missing" mass values for pi+ and pi-.
>>
>> -Michael
>>
>> On Fri, 23 Jul 2010, Sungkyun Park wrote:
>>
>>> Hi Eugene,
>>>
>>>    I have found the missing mass of pi0 in topology gamma p ->  p X and butanol target.
>>>    The pi0 mass 162 MeV
>>>
>>>     Michael Dugger ->  pi0 (no momentum restriction) = 163 MeV
>>>                                 pi0 ( momentum>  600 MeV) = 157 MeV
>>>     Hideko Iwamoto ->  pi0 ~ 168 MeV
>>>     Jo McAndew     ->  pi0 ~ 176 MeV
>>>
>>> I also tried to find out the missing mass of pi+ and pi- in topology  gamma p ->  p pi+ pi-
>>> The pi+ mass I found is 144 MeV and the pi- mass is 142 MeV.
>>> It is very strange why pi0 mass has a big difference with real particle and pi+ and pi- has a very similar value in the same code.
>>>
>>> Best Wishes
>>>
>>> Sungkyun Park
>>> Florida State University
>>>
>>>
>>>
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