STAR task force for evaluating tracking efficiency uncertainty

["Ma, Rongrong" <marr AT bnl.gov>]

Hello Gene

Thanks for following up on this, and providing the additional information. 

My momentum resolution is the relative resolution, and therefore the "a" 
value is equivalent to p1. 

I am a bit surprised to see that the momentum resolution from MC with HFT has 
a p1 value of 0.008. Are those primary tracks with HFT hits? In single 
particle embeddings, we have constantly seen p1 values of ~ 0.0035 over the 
years, which we know is way too good compared to data. 

Do we have a back-of-envelope estimate of what the TPC momentum resolution at 
1 GeV/c should be? 

I think we can start with Run11 and Run14 cosmic ray data, and decide later 
on whether we need to produce Run19 cosmic ray. 

Best
Rongrong

> On Oct 20, 2022, at 1:14 PM, Van Buren, Gene <gene AT bnl.gov> wrote:
> 
> Hi, all
> 
>> On Oct 20, 2022, at 8:38 AM, Ma, Rongrong via Star-tf-trkeff-l 
>> <star-tf-trkeff-l AT lists.bnl.gov> wrote:
>> 
>> Hello Robert
>> 
>> Thanks a lot. The new fit looks very nice, and the p1 value is very close 
>> to what we have seen based on Jpsi width from Run18 Isobar data.
> 
> So the fit is actually p0 + p1 *pT, and the finding is that p1 is 0.0075.
> 
> If we focus on the high pT region, then I think we can all agree that the 
> relative resolution of pT (the absolute resolution of pT, divided by pT) is 
> equal to the relative resolution of (1/pT), and that these rise linearly in 
> pT. This relation can be derived from the understanding that the TPC 
> measures points in physical space with a generally pT-independent spatial 
> resolution, such that the absolution resolution of (1/pT) is generally 
> constant at high pT. That constant is p1:
> 
> dpT / pT = d(1/pT) / (1/pT)
> =>
> relative resolution = p1 / (1/pT) = p1 * pT
> 
> Rongrong's study has me a little confused. Is his momentum resolution the 
> relative resolution, or the absolute resolution? If it is relative 
> resolution, then his "a" parameter is the same as p1, determining the high 
> pT behavior of the resolution.
> 
> Past studies have shown (see the links I sent)  that p1 for tracks without 
> a primary vertex in their fit get values near 0.01.  The cosmic ray study I 
> did got something like 0.014. I managed to find one of the Monte Carlo QA 
> plots from 2016 when the S&C team was trying to get HFT tracking working:
> https://www.star.bnl.gov/~jwebb/2016/BaseQA_April_13/evals1/pidPtiRGl_zy_1.png
> In that plot we can see a rise of ~0.008 between pT = 2 GeV/c to 3 GeV/c, 
> so perhaps as good as 0.008 with the HFT.
> 
> Robert's result of 0.0075 manages to get close to that even without the 
> HFT. And Rongrong's past results of 0.0054 are much better, and his 0.0035 
> number from embedding blows that away. I don't see how we could have ever 
> had it that good.
> 
> So, I'm confused about these numbers and findings. If someone understands 
> something I've missed, please let me know.
> 
>> So we have a good consistency here. I really appreciate if you can help 
>> analyze other datasets (Run11, 14, 19) as well. Hopefully, this won't take 
>> too much of your time. 
>> 
>> Gene: is it possible that you can restore cosmic ray data from Run11, 
>> Run14 and Run19? I think a quarter of the Run18 statistics used here for 
>> each dataset is probably sufficient. 
> 
> Run 11, I see P11id FullField and ReverseFullField MuDsts that I will 
> restore.
> 
> Run 14, I see P14ih Half, Fulll, and ReverseFullField MuDsts that I will 
> restore.
> 
> Run 19, I do not think we did an official production, but I believe Yuri 
> handled a private production for use in TPC calibration work. We can do an 
> official production if it is desired.
> 
> Thanks,
> -Gene
> 
>> 
>> 
>> Best
>> Rongrong
>> 
>>> On Oct 20, 2022, at 8:21 AM, Robert Líčeník <licenik AT ujf.cas.cz> wrote:
>>> 
>>> Hello Rongrong,
>>> 
>>> since the y axis is log-scale (but the values are not), a simple linear 
>>> function will not work, so I think you meant something like p0 + p1*10^x 
>>> . It seems to do much better.
>>> Here are the updated slides:
>>> https://drupal.star.bnl.gov/STAR/event/2022/10/18/Tracking-Efficiency-Uncertainty-meeting/Cosmics-2018-update
>>> Would it be helpful if I shared the file with the produced TTree with 
>>> you? That way you can have a quick look by yourself and you don't have to 
>>> wait for me in a different time zone every time.
>>> However, I understand that you are very busy and I am of course more than 
>>> happy to help.
>>> 
>>> Cheers,
>>> Robert
>>> 
>>> On Wed, Oct 19, 2022 at 8:06 PM Ma, Rongrong <marr AT bnl.gov> wrote:
>>> Hello Robert
>>> 
>>> Could you try a linear function y = p0 + p1*x to do the fit? Thanks. 
>>> 
>>> Best
>>> Rongrong
>>> 
>>>> On Oct 19, 2022, at 11:55 AM, Robert Líčeník <licenik AT ujf.cas.cz> wrote:
>>>> 
>>>> Hi Rongrong,
>>>> 
>>>> you are correct. The fit function is written on the first slide with 
>>>> momentum resolution and the range is the full histogram for the red fit 
>>>> and (-0.4 - 2) for the blue fit.
>>>> 
>>>> Cheers,
>>>> Robert
>>>> 
>>>> On Wed 19. 10. 2022 at 17:40 Ma, Rongrong <marr AT bnl.gov> wrote:
>>>> Hi Robert
>>>> 
>>>> Thanks for the update. However, the fit does not seem to work well. What 
>>>> function and fit range are you using? Thanks. 
>>>> 
>>>> Best
>>>> Rongrong
>>>> 
>>>>> On Oct 19, 2022, at 9:05 AM, Robert Líčeník <licenik AT ujf.cas.cz> wrote:
>>>>> 
>>>>> Hi Rongrong,
>>>>> 
>>>>> no problem, here are the updated slides:
>>>>> https://drupal.star.bnl.gov/STAR/event/2022/10/18/Tracking-Efficiency-Uncertainty-meeting/Cosmics-2018-update
>>>>> 
>>>>> Cheers,
>>>>> Robert
>>>>> 
>>>>> On Tue, Oct 18, 2022 at 11:00 PM Ma, Rongrong <marr AT bnl.gov> wrote:
>>>>> Hello Robert
>>>>> 
>>>>> Thanks. If possible, could you redo the fit starting from the lowest 
>>>>> point, i.e. log(pt) ~ -0.4, and add the slope of the fit to the 
>>>>> figures? 
>>>>> 
>>>>> Best
>>>>> Rongrong
>>>>> 
>>>>>> On Oct 18, 2022, at 2:38 PM, Robert Líčeník via Star-tf-trkeff-l 
>>>>>> <star-tf-trkeff-l AT lists.bnl.gov> wrote:
>>>>>> 
>>>>>> Hi everyone,
>>>>>> I uploaded my slides from today's meeting:
>>>>>> https://drupal.star.bnl.gov/STAR/event/2022/10/18/Tracking-Efficiency-Uncertainty-meeting/Cosmics-2018-update
>>>>>> The only difference is that I replotted the momentum resolution 
>>>>>> figures in log-log scale, as requested. 
>>>>>> Cheers,
>>>>>> Robert
>>>>>> 
>>>>>> On Mon, Oct 17, 2022 at 12:07 PM Petr Chaloupka via Star-tf-trkeff-l 
>>>>>> <star-tf-trkeff-l AT lists.bnl.gov> wrote:
>>>>>> Dear All,
>>>>>> 
>>>>>> Please join our meeting tomorrow at 10:00 New York time.
>>>>>> 
>>>>>> Please upload any material for discussion to the drupal page:
>>>>>> https://drupal.star.bnl.gov/STAR/event/2022/10/18/Tracking-Efficiency-Uncertainty-meeting
>>>>>> 
>>>>>> With best regards,
>>>>>> Petr
>>>>>> 
>>>>>> To join the meeting:
>>>>>> 
>>>>>> https://bnl.zoomgov.com/j/1607035037?pwd=WDVqaEdwa0RtTEM5a1VvZ24yU2gwdz09
>>>>>> Meeting ID: 160 703 5037
>>>>>> Passcode: 099371
>>>>>> 
>>>>>> One tap mobile
>>>>>> +16692545252,,1607035037#,,,,,,0#,,099371# US (San Jose)
>>>>>> +16468287666,,1607035037#,,,,,,0#,,099371# US (New York)
>>>>>> 
>>>>>> Dial by your location
>>>>>>         +1 669 254 5252 US (San Jose)
>>>>>>         +1 646 828 7666 US (New York)
>>>>>> Meeting ID: 160 703 5037
>>>>>> Passcode: 099371
>>>>>> Find your local number: https://bnl.zoomgov.com/u/aoARs6rfR
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
>>>>>> Star-tf-trkeff-l mailing list
>>>>>> Star-tf-trkeff-l AT lists.bnl.gov
>>>>>> https://lists.bnl.gov/mailman/listinfo/star-tf-trkeff-l
>>>>>> _______________________________________________
>>>>>> Star-tf-trkeff-l mailing list
>>>>>> Star-tf-trkeff-l AT lists.bnl.gov
>>>>>> https://lists.bnl.gov/mailman/listinfo/star-tf-trkeff-l
>>>>> 
>>>> 
>>> 
>> 
>> _______________________________________________
>> Star-tf-trkeff-l mailing list
>> Star-tf-trkeff-l AT lists.bnl.gov
>> https://lists.bnl.gov/mailman/listinfo/star-tf-trkeff-l
>