[Clas_cascades] pentaquark search with pK0Km skim

[Zhiwen Zhao]

Hi,Igor

Yes, Limiting the missing momentum will not cut all FSI away, but by comparing 
to simulation, the cut should eliminate a major portion of it.
For Lambda1520 study, my goal is cross section, so I think the cut may be good 
enough.
However for theta+ search, the cut may not even be needed because FSI may 
enhance the theta+ production. my impression is that LEPS didn't correct FSI 
either as they couldn't do that with two missing particle (PHYSICAL REVIEW C 79, 
025210 (2009))

Please let me know once you have a Lambda1520 talk or note available.

Thank you very much.

Zhiwen

On 2/18/2010 1:30 PM, Igor Strakovsky wrote:
> Hi Zhiwen,
>
> Unfortunately, your analysis will not allow to accomplish FSI study. It
> requires theor calculations. They may be small but nobody knows how large
> they are.
>
> Two more small questions for your slides - I did not see your colleniarity
> cuts. Your #10 shown a selection for M(pi+pi-) only. Then your #24 said
> about \phi and L(1520) interference but no details
>
> Hall A data have been published recently Y. Qiang et al. (JLab Hall A
> Collaboration), Phys. Rev. C 75, 055208 (2007); arXiv:hep-ex/0609025 and
> we made analysis addressed to the determination of the L(1520) parameters
>
> Igor
>
>
> On Thu, 18 Feb 2010 12:07:19 -0500, Zhiwen Zhao <zwzhao at jlab.org> wrote:
>
>> hi, Igor
>>
>> The statistics won't allow me to study FSI, so I plan to cut on quasi
>> free reaction by limiting missing momentum later on.
>> I didn't know you are doing Lambda1502 in HallA. That's GREAT news.
>> Can you show me some notes or talks you already have?
>>
>> Thank you
>>
>> Zhiwen
>>
>> On 2/17/2010 9:04 PM, Igor Strakovsky wrote:
>>> Hi Zhiwen,
>>>
>>> On Wed, 17 Feb 2010 16:56:21 -0500, Zhiwen Zhao <zwzhao at jlab.org> wrote:
>>>
>>>> Hi,Igor
>>>>
>>>> On 2/14/2010 12:45 PM, Igor Strakovsky wrote:
>>>>> Hi Zhiwen,
>>>>>
>>>>> Thank you for your prompt reaction. I would afraid to make a claim
>>>>> until
>>>>> to get strong arguments. It sounds that you do not have them yet
>>>> Exactly, I am not making any claim
>>>>>
>>>>> A little bit more below
>>>>>
>>>>> On Sat, 13 Feb 2010 22:28:40 -0500, Zhiwen Zhao <zwzhao at jlab.org>
>>>>> wrote:
>>>>>
>>>>>> Hi, Igor
>>>>>>
>>>>>> No, I am not sure at this point as the result is just a first look
>>>>>> into the data, not even qualified as preliminary.
>>>>>> However these cuts I showed are supposed either to enhance the theta+
>>>>>> signal or to match LEPS condition.
>>>>>
>>>>> As your slides shown that you did not do exact LEPS condition
>>>> For angle, LEPS has horizontal 20 degree and vertical 10 degree
>>>> coverage. So far I require theta < 20 degree and it's only for Km, not
>>>> for all charged particles like LEPS. I will test more cuts.
>>>> For photon energy, my cut matches their condition 2-2.4GeV
>>>
>>> Well, as I said your condition does not fit LEPS configuration well;)
>>>
>>>>>> I have looked their Anti-cuts also, no sign of theta+ either.
>>>>>> Some cuts I didn't show such as photon selection,PID, fiducial,
>>>>>> vertex, sc dad counter etc, are mostly standard and similar to what
>>>>>> Hovanes used in his
>>>>>
>>>>> As far as you probably know, CLAS has so many standards. It is good to
>>>>> clarify them
>>>> Some cuts you can see from Hovanes's analysis note
>>>> http://clasweb.jlab.org/rungroups/eg3/wiki/index.php/Analysis_review_by_Hadron_Spectroscopy_Working_Group
>>>>
>>>>
>>>> I am in the process of writing Lambda1520 note also.
>>>>>
>>>>>> eg3 pentaquark Phi-- upper limit analysis which is currently under
>>>>>> review.
>>>>>> The same PK0Km channel is used for Lambda1520 study which is my
>>>>>> thesis
>>>>>> topic, I have preliminary cross section now.
>>>>>
>>>>> Sorry, I know nothing about your theses and would love to see your
>>>>> Lambda(1520). Unfortunately, the size of your figures do not allow
>>>>> to see details
>>>> Here's a talk I gave for Lambda1520
>>>> http://clasweb.jlab.org/rungroups/eg3/wiki/images
>>>> /5/52/ApsApril2010_zwzhao_Lambda1520.pdf
>>>> I apologize for the figures, I will update them with better ones.
>>>
>>> Thank you for your figures, I missed them. It seems to me that our
>>> coming
>>> paper addressed to the analysis of the Hall A Lambda(1520)
>>> electroproduction
>>> data at small Q2 may be interesting for you. I hope we will submit it in
>>> 2-3 weeks.
>>>
>>> To be honest, your analysis of the neutron data is a big problem for me
>>> because you did not take into account FSI
>>>
>>>>>> I have MC for the Lambda1520 production, but not PK0Km yet.
>>>>>
>>>>> Can you show them, please? What did you use as the generator
>>>> will do.
>>>> I use fsgen which is a phase space generator with t-slope=2 as input
>>>> for my Lambda1520 channel.
>>>
>>> OK, thanks. Igor
>>>
>>>>>> I will add more stuff on the wiki when the analysis proceeds.
>>>>>> Any comment from you is greatly appreciated.
>>>>>
>>>>> Thanks, I look forward to learn more details from you
>>>>> Igor
>>>>>
>>>>>> Zhiwen
>>>>>>
>>>>>>
>>>>>> On 2/12/2010 1:14 AM, Igor Strakovsky wrote:
>>>>>>> Hi Zhiwen,
>>>>>>>
>>>>>>> How are so sure? You made so many cuts... Can you explain all of
>>>>>>> them?
>>>>>>> Can you show any well known resonances? Do you have MC?
>>>>>>>
>>>>>>> Igor
>>>>>>>
>>>>>>> On Fri, 12 Feb 2010 01:04:37 -0500, Zhiwen Zhao <zwzhao at jlab.org>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> hi, Eg3er
>>>>>>>>
>>>>>>>> Here is some updates of the pentaquark search with pK0Km skim
>>>>>>>> http://clasweb.jlab.org/rungroups/eg3/wiki/index.php/PrtK0Km_theta1530
>>>>>>>>
>>>>>>>>
>>>>>>>> So far, there's no sign of pentaquark.
>>>>>>>> Any commend is appreciated.
>>>>>>>>
>>>>>>>> Zhiwen