[Clas_cascades] pentaquark search with pK0Km skim

Thu Feb 18 19:52:42 EST 2010

Hi Zhiwen,

There are several readings for the Delta region.  But let me ask you to
be patient again. We have to accomplish analysis of the g10 data for
gn-->pi-p (Wei Chen's thesis) and you will have a lot of readings.  Sure, 
process is different but you will get a picture

Igor

On Thu, 18 Feb 2010 18:14:35 -0500, Zhiwen Zhao <zwzhao at jlab.org> wrote:

> Hi, Igor
> 
> It's good to know more about the FSI effect
> Can you point me to some further reading?
> Thanks a lot
> 
> Zhiwen
> 
> On 2/18/2010 5:46 PM, Igor Strakovsky wrote:
>> Hi Zhiwen,
>>
>> On Thu, 18 Feb 2010 14:28:03 -0500, Zhiwen Zhao <zwzhao at jlab.org> wrote:
>>
>>> 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.
>>
>> No way, there is a component which you cannot measure, you have to
>> calculate
>> There is a chance that this component is small but nobody knows that in
>> advance
>>
>>> For Lambda1520 study, my goal is cross section, so I think the cut may
>>> be good enough.
>>
>> Sorry, I am not sure (see above). This FSI factor has energy and angular
>> dependence
>>
>>> 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))
>>
>> Yes, LEPS calculated nothing and they made some evaluation of the Fermi
>> which is a fraction of FSI
>>
>>> Please let me know once you have a Lambda1520 talk or note available.
>>
>> Please be patient. I will let you know when it will come
>>
>> Igor
>>
>>> 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