[Rgc_analysis] [EXTERNAL] Progress On Probing Helicity Asymmetry

[Raffaella De Vita]

Hi Derek,

I wanted to thank you for doing this work: it is really useful to have independent confirmation about the statistics needed to get reliable monitoring of the asymmetry.

As mentioned in our last email exchange, one thing that would really help for ND3 monitoring is to see the effect of a momentum cut on the electron selection or even better of a calorimeter energy cut. This seems critical for the ND3 because the asymmetry is smaller and the contribution of events where the electron has low momentum (below 2-3 GeV) is close to 0 or maybe even opposite to the asymmetry for higher momenta.

In the trigger, it’s easier to apply a selection on the forward calorimeter energy rather than electron momentum. Therefore what could be done is to check how the asymmetry accuracy varies as a function of a threshold on the total ECAL energy, spanning from 300 MeV, which is the cut applied in the main electron trigger now, to let’s say 800 MeV. This could be done using a fixed number of events based on your current optimized value.

To access the calorimeter energy, you would need to read the REC::Calorimeter bank and sum up the value of the variable “energy” for the rows where the variable “pindex" is equal to 0, i.e. the row refers to the electron in the 0 row of REC::Particle.

Let me know if you have any questions or need more information.

Best regards,
	Raffaella


> On 14 Sep 2022, at 04:12, Keith Griffioen <griff at physics.wm.edu> wrote:
> 
> Derek, Carlos.  This  is very nice progress.  In principle you want to have such plots for all the data that have been taken.  This is one of the best monitoring  tools for the polarization and luminosity.
> 
> -Keith
> 
>> On Sep 13, 2022, at 9:21 PM, Holmberg, Derek <deholmberg at wm.edu> wrote:
>> 
>> Hey everyone,
>> 
>> Here are some slides for what Carlos and I have been working on. In short, we’ve been talking with Rafaella about trying to figure out the minimum number of electrons that are needed to well-constrain the target polarization calculated from scattered particle kinematics. To give us some insight, we tried to determine how many electrons are needed to constrain the calculated helicity asymmetry. Included in the attached pdf are slides which detail my program and the results for the runs I analyzed.
>> 
>> If anyone has any suggestions for improvement or would like to discuss this further, please let us know! (I hope I used the right HIPO banks…)
>> 
>> Sincerely,
>> Derek Holmberg
>> <Helicity_Progress.pdf>
> 
>