[Clas12_verystrange] Omega-

[Igor Strakovsky]

Folks,

As we discussed before, please use 0.3 nb as total cross section for the
exclusive Omega- photoproduction

Thanks, Igor

On Fri, 24 Feb 2012 13:18:02 -0500 (EST), Michael Dugger <dugger at jlab.org> 
wrote:

> 
> 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.
>>
>>
> _______________________________________________
> Clas12_verystrange mailing list
> Clas12_verystrange at jlab.org
> https://mailman.jlab.org/mailman/listinfo/clas12_verystrange

Igor Strakovsky, SAID CNS The George Washington University
Tel: 703-726-8344(NV),202-994-4742(FB),Skype: igors1945_2
Fax: 202-994-3001(FB),Emails: igor at va.gwu.edu, igor at jlab.org