sPHENIX is a new detector at RHIC.

[Xu-Dong Yu <yuxd AT stu.pku.edu.cn>]

Dear all,

Sorry for late reply to the questions raised from last PCM, since i am busy with offline data analysis and calibration.

The slides have been updated in indico: https://indico.bnl.gov/event/24442/contributions/94982/attachments/56437/96949/20240809_yuxd_PCM_PhotonConv.pdf

The note has been updated in invenio: https://sphenix-invenio.sdcc.bnl.gov/communities/sphenixcommunity/requests/7c15ed3f-80c2-43e7-b05f-0a9baf3be0ed

Please see answers to questions below.

Best regards,

Xudong

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Some Homework items:

-> check the E and p values for the tracks and EMCal towers/clusters - do we have a reasonable E/p matching?

Answer: I have checked the E and p values for tracks and EMCal clusters, please see P3 of the slides. The E/p is closed to 1.

-> check the z-vertex position

Answer: I have checked z-vertex position distribution, please see P17 in the slides.

-> can we see some examples of other candidate events?

Answer: Sure. I have already put three more events in the slides P18-20.

-> is the separation between the e+ and e- consistent with them having about 2 GeV each? 

Answer: Yes, i use SV from KFP, moemtum after Kalman filter given by KFP, considering charged track bending under magnatic field to draw the tracking curve. Please see P16 in the slides. You can see that tracking curve is closed to real TPC clusters, and matched with EMCal clusters. Therefore, the separation is reasonable.

Plotsmanship: can we make the red tracks in the right plot more visible?

Answer: I have already enlarged the size of TPC clusters to make it more conspicuous.

Link from Joe on code to do track->calo projection: https://github.com/sPHENIX-Collaboration/macros/blob/master/TrackingProduction/Fun4All_FieldOnAllTrackersCalos.C 

Q: Could this be a pi0 Dalitz decay? Seems unlikely since the tracks are consistent with an external conversion on the face of the TPC, but analyzers can check

Answer: Probably not, because the secondary vertex radius deviates from origin, in the inner face of the TPC. Pi0 is short-life-time particle, it will decay quickly after generation.

On Aug 5, 2024, at 17:12, Xu-Dong Yu <yuxd AT stu.pku.edu.cn> wrote:

Dear all,

Here is a note outlining the details of conversion dielectron analysis using Run 24 pp data, and two event display plots which are applied to get approval. Please let us know if you have any comments or questions. Thanks!

Invenio link for the note: https://sphenix-invenio.sdcc.bnl.gov/communities/sphenixcommunity/requests/7c15ed3f-80c2-43e7-b05f-0a9baf3be0ed

Best regards,

Xudong for the authors.