[Clascomment] OPT-IN: Electromagnetic decay of the ??*0 to ???

[Dustin Keller]

Hi Kei,
In table 2 you can see all channels considered under each hypothesis. 
Only values from each channel pertaining to a specific hypothesis 
that where found to have a numeric impact on the ratio where 
used in Eq. 7.

dustin

On Mon, 14 Feb 2011, Kei Moriya wrote:

>
> Dear Dustin and Ken,
>
> Congratulations on finishing up a difficult analysis.
> I can see that a tremendous amount of work has gone into
> estimating the systematics for this analysis.
>
> I apologize for being late to make my comments,
> and hope my comments are not too late.
> I just had one questions about the analysis.
>
> The analysis focuses on the decay Sigma* -> Lambda gamma.
> One thing I thought when reading the paper was the possibility
> of Sigma* -> Sigma0 gamma -> 2 gamma + Lambda,
> where you end up with 2 missing photons in the final state.
> Is there a reason to omit this possibility? I wonder because
> your final result, while consistent with the previous measurement
> of Taylor, is higher than the theoretical predictions by factors
> ranging from 1.5-3. Could this be part of the reason, if you
> are including the above reaction in your result?
>
> Other than that, I am a bit worried about how the
> Sigma* cross section and resolution change over the
> energy and angle range of g11a, but you seem to have
> done a lot of work on the systematics to match up the
> data and Monte Carlo, so I assume things are OK.
>
> Best of luck for the next step.
> Once again my apologies for not being able to
> respond sooner.
>
> 	Kei Moriya
>
>
> (2/2/11 12:28 PM), Reinhard Schumacher wrote:
>> Hello Dustin,
>> 	With a fresher head, I reread the part of the paper that I said was
>> confusing.  This time I see what you were trying to say, and it seems
>> pretty reasonable.  For clarity I would recommend changing one sentence:
>> 
>> page 9, column 2, paragraph 6, last 3 lines:  "To maximize COUNTING
>> statistics WHILE minimizing THIS uncertainty, the optimal..."  This gets
>> rid of the offending word 'recovery' in quotes, which I thought may be
>> needlessly distracting.
>> 
>> > My other comments still apply, of course.
>> 
>> Best Regards,
>> 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
>> ___________________________________________________________________
>> 
>> 
>> Dustin Keller wrote:
>>> Hi Reinhard,
>>> 
>>> Thank you for your careful consideration and suggestions on our paper.
>>> The first suggestions you mentioned are mostly easy fixes.  In your last
>>> comment you mentioned that the discussion of the uncertainty when
>>> compensating for events lost in doing the two confidence level cuts was
>>> unclear.  The correction for events lost is inherent in the ratio
>>> calculation seen in Eq. 21 for the simplified two channel case.  In the
>>> original study of the confidence level cuts optimization Eq. 21 was used
>>> to calculate the resulting ratio from a Monte Carlo mixture of
>>> radiative and pi0 decays.  The recovery uncertainty was minimized while
>>> considering both the level of statistics seen in the data and the
>>> statistical uncertainty produced in the ratio.  After using these
>>> studies to find a range of optimized confidence level cuts for P^a and
>>> P^b a variation of these cut was chosen that would lie just outside the
>>> optimization range for each cut.  The cut and the effect of the
>>> variation is listed in Table 3.  For presentation clarity the numerical
>>> specifics are omitted and only a general statement is given however the
>>> CLAS-note 2010-015 goes into this type of study and is available for the
>>> general public.  We give the appendix to help guild a motivated reader
>>> through the calculation of the full ratio.  So with the acceptance terms
>>> in Table 2 and the resulting raw counts from the fits in each case one
>>> quickly knows the corrections for
>>> each channel.  What maybe confusing in the discussion you mentioned is
>>> the phrase "recovery" uncertainty.   This is the difference between the
>>> ratio input to the Monte Carlo and the value recovered using the
>>> described analysis framework with specific confidence level cuts.  We
>>> would be interested in clearing up any confusion with the hope of
>>> conservatively adding to this discussion as to not dilute the more
>>> critical points.
>>> 
>>> thanks again,
>>> Dustin
>>> 
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>