[Rgc_analysis] [EXTERNAL] Question about HWP and TPol when cooking

[Gregory Matousek]

Hello,

I had a question about how helicity is stored in the HEL::online bank of the sidisdvcs trains ( or any hipo file for that matter ). There are several recent NH3 runs which I am analyzing, and I am getting some counterintuitive results for N+ and N- for each run. I am referring to the 8.5.0 HBT cooks.

For example, Run 17577 has HWP in, and NMR Pt > 0. I find from my DIS channel that 51% of events have helicity = +1 , and the remaining 49% have helicity = -1. I would have initially thought that there would be more helicity = -1 events? I was wondering if the cooking had been accounting for the fact that the HWP was in, and was correctly "flipping" the electron's helicity when storing it in the hipo bank.

Next, we look at Run 17589, with HWP out and NMR Pt>0. Here, I counter-intuitvely find 49% of events have helicity = +1 , and now 51% have helicity = -1. Again, I am just reading the entries in HEL::online. This is odd, because since our asymmetry is positive, this would calculate a negative target polarization in the end (N+ < N-)

For Run 17604, with HWP out and NMR Pt <0. We find 50.88% of events with helicity = +1 and 49.12% with helicity = -1. This is backwards from how I thought the asymmetries would work.

Does anybody familiar with the newest coatjava know how the HEL::online bank is formed? Does it read from the CCDB in anyway to adjust the helicity information based on the HWP or Tpol status? At the moment, the solution is for me to swap N+ <--> N- .


Here, then, are the DIS polarizations I am getting for the NH3 runs. It looks like we were near -80% polarization two days ago.

[cid:24e9a450-d431-4bd0-baf5-19aa17361cff][cid:f6616463-fded-4ce4-80da-780bf5fffa97]
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