[clas12_rgk] 2 pion cuts

[Francois-Xavier Girod]

Dear all

>From what I had understood the goal of the double pion analysis,
ultimately, is to measure a cross section. Are we sure that a blanket veto
on “no other hadron” is safe for cross sections?

Best regards
FX

On Wed, Jun 17, 2020 at 7:41 PM burkert <burkert at jlab.org> wrote:

> Evgeny,
> Maybe I don't understand the nomenclature. But it appears that
>
> - In first cut you ask for presence of (2pi+ and no other hadrons), and
> in the MM2 (e, pi+, pi-), where do you get the pi- from?
>
> - in second cut you ask for presence of (p, 2pi+ and no other hadrons)
> and in MM2 you ask for presence of p,pi+,pi-). Again, where is the pi-
> from?
>
> Volker
>
>
>
> On 6/17/20 1:30 PM, golovach at jlab.org wrote:
> > Dear Volker,
> >
> > I do no see the typos
> > the first arrow ---> pi+, pi+ are present
> > the second arrow ----> p, pi+, pi+ are present
> > That is correct.
> >    Evgeny
> >
> >
> >> Evgeny,
> >>
> >> Is seems to me there are two typos in your selection (marked by arrow
> >> --->:)
> >>
> >>
> >> On 6/17/20 12:19 PM, golovach at jlab.org wrote:
> >>> Hi Nick,
> >>>
> >>> MM2 cuts for the 2 pion events are:
> >>> The presence of extra electrons and neutrals are not taken into
> account.
> >>> if p, pi+   are present and there are no other hadrons,
> >>>     then  MM2(e_prot_pip)>-0.35 && MM2_e_prot_pip<0.35
> >>> if p, pi-   are present and there are no other hadrons,
> >>>     then  MM2(e_prot_pim)>-0.35 && MM2_e_prot_pim<0.35
> >>> ---> if pi+, pi+ are present and there are no other hadrons,
> >>>     then  MM2(e_pip_pim)> 0.62 && MM2_e_pip_pim<1.18
> >> should that be: if pi+, pi- are present ......
> >>
> >>> ----> if p, pi+, pi+ are present and there are no other hadrons,
> >>>     then  MM2(e_prot_pip_pim)> -0.018 && MM2_e_prot_pip_pim<0.018
> >> should that be: if  p, pi+, pi- are present,,
> >>
> >>
> >> Volker
> >>
> >>
> >>> Could you, produce train15 (say for the run 5898) for the test?
> >>>
> >>>
> >>> I do not understand one thing.
> >>> Annalisa has shown that the train eTwoChargedH takes 17% of the total
> >>> size.
> >>>
> >>> I have analyzed a subset of the dst files in
> >>>
> /lustre19/expphy/volatile/clas12/rg-k/production/pass0/v1_1.1.12/dst/recon/005898/
> >>> and I see much larger reduction of the number of the 2 pion events.
> >>> If I select 2 pion events I have only ~2% of the total number of
> events.
> >>> If I select 2 pion events and apply MM2 cuts I have ~0.88% of the total
> >>> number of events.
> >>> May be the MM2 cuts are not necessary?
> >>>
> >>> My selection of the 2 pion events as I mentioned is:
> >>>     The presence of extra electrons and neutrals are not taken into
> >>> account.
> >>>     p, pi+   are present and there are no other hadrons
> >>>     p, pi-   are present and there are no other hadrons
> >>>     pi+, pi+ are present and there are no other hadrons
> >>>     p, pi+, pi+ are present and there are no other hadrons
> >>>
> >>>     Evgeny
> >>>
> >>>
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> >>
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