[Clas12_verystrange] Omega-

[Michael Dugger]

Derek,

There is always the possibility that there is something wrong in my code. 
We will have to sort this out.

One thing you could do as a check, is see how the cascade-(1320) signal to 
background looks when you do a missing mass (MassX) from the reaction:
gamma p -> K+ K+ X

If we can get agreement on the cascade, we can then look for differences 
in the way our Omega- is dealt with.

It might also be useful to set the generator to real photons, generate 
g6 energies and compare to John Price's results. There will be detector 
efficiency differences, but perhaps the signal to background ratios we get 
simulating CLAS12 will not be too very different than what Price got.

I'm sure we will get this figured out. This is just a normal part of the 
development cycle.

Take care,
Michael

On Fri, 24 Feb 2012, Derek Glazier wrote:

> Hi Mike,
>  My analysis of the same final state gives quite different results. 
> Basically I just weight the number of generated events by the cross sections 
> of total hadronic events (130,000nb) to Omega- (0.5nb). i.e I use 260,000 
> times more generated events for the total hadronic background, than for 
> Omega-. I simulated 200M pythia events and get a signal to background ratio 
> of around 1:10. I attach the plot. I generate events tagged by the forward 
> tagger with e- energy range 0.5-6GeV. I do not use any PID scheme as such, 
> just assume the particles are identified correctly. I also cut on the K0 mass 
> and pi-pi+ coming from the same vertex, but I do not care if it is detached 
> from the K+ vertex or not.
>  I also attach a similar plot for also detecting the K- where the situation 
> is improved and in particular, if a vertex cut is used the background is 
> zero.
>  I prefer your results however, so will try and see if I can track down a 
> bug.
> Cheers
> Derek
>
>
> On 02/24/12 17:12, Michael Dugger wrote:
>> I have the cross section for the Omega- set to
>> (1/10)*crossSection(neutral cascade).
>> 
>> -Michael
>> 
>> On Fri, 24 Feb 2012, andrei afanasev wrote:
>> 
>>> Mike,
>>> The signal looks very good. What was the value you used for the production 
>>> cross section for Omega? Since it is unknown, it makes sense to vary it 
>>> within realistic estimates that we put in the Omega LOI before.
>>> -Andrei
>>> -----Original Message-----
>>> From: Michael Dugger<dugger at jlab.org>
>>> Sender: clas12_verystrange-bounces at jlab.org
>>> Date: Fri, 24 Feb 2012 11:32:26
>>> To:<clas12_verystrange at jlab.org>
>>> Reply-To: clas12_verystrange at jlab.org
>>> Subject: [Clas12_verystrange] Omega-
>>> 
>>> 
>>> Hi,
>>> 
>>> I have generated ~100 million background events and blended them with an
>>> Omega- signal, and want to see if the plot I get seems reasonable.
>>> 
>>> The plot OmegaMbranch.gif is attached and shows the relative amount of
>>> background to be expected when a K+ K+ and K0 is seen (the K0 is
>>> reconstructed from a pi+ pi- pair). I have put in a PID scheme, but do not
>>> approximate the Cerenkov counter response. The PID is only from beta and
>>> momentum information.
>>> 
>>> Thanks for your time.
>>> 
>>> Take care,
>>> Michael
>>> 
>>> _______________________________________________
>>> Clas12_verystrange mailing list
>>> Clas12_verystrange at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/clas12_verystrange
>>> 
>> _______________________________________________
>> Clas12_verystrange mailing list
>> Clas12_verystrange at jlab.org
>> https://mailman.jlab.org/mailman/listinfo/clas12_verystrange
>
>
> -- 
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>
>