STAR Muon Telescope Detector development

["张炜" <wzhang AT m.scnu.edu.cn>]

Hi Rongrong，

Thank you for your very detailed advice，i will compare the data of 27GeV with the pt shape of Toymc,and use it as input to ToyMC.

Best

Wei

张炜

华南师范大学M邮箱/量子物质研究院

华南师范大学始建于1933年，是一所学科门类齐全的国家“211 工程”重点建设大学。
“艰苦奋斗、严谨治学、求实创新、为人师表 ”是华南师范大学校训。

 

 

 

------------------ Original ------------------

From:  "STAR Muon Telescope Detector dev"<star-mudet-l AT lists.bnl.gov>;

Date:  Thu, Dec 8, 2022 04:14 AM

To:  "STAR Muon Telescope Detector dev"<star-mudet-l AT lists.bnl.gov>;

Subject:  [Star-mudet-l] Procedure for momentum smearing

 

Hello Dandan, Gaohan, Wei, Kaifeng

Since you are doing or have done the momentum smearing procedure for extracting the Jpsi lineshape from embedding, I think it would be good to agree upon the procedure such that consistent results can be obtained. In the end, we should only use one common smearing factor for one dataset (Isobar or 27 GeV).

The main metrics to determine the smearing factor is to match either the Jpsi invariant mass distribution or Jpsi width vs. pt between embedding and data. Since the Jpsi width depends on pt, it is important to make sure that the Jpsi spectrum shapes in data and embedding are similar.

Here is the procedure I am suggesting:
1) Determine input Jpsi spectrum shape for toyMC
- For 27 GeV analysis for which we do not have corrected Jpsi spectra yet, I suggest to extract the raw Jpsi yield vs. pt from data, parameterize the distribution and use it as input to ToyMC. In order to have an accurate parameterization, we should try to have as many pt bins as possible in the distribution of raw Jpsi yield vs. pt. I know this is challenging, but let's do our best.
- For Isobar analysis, we have two approaches: i) parameterize the raw Jpsi yield vs. pt from data as done for 27 GeV (the more pt bins, the better); ii) use the preliminary Jpsi spectra as input and apply detector efficiency. Both approaches should give similar shapes

2) Run toyMC to obtain either the Jpsi invariant mass or Jpsi width vs. pt, depending on which method you want to use, by scanning the smearing factor. Actually it will be nice to try both methods, since currently we see very different results from the two methods, which is puzzling. We should try to understand this.

3) Calculate chi2 between data and toyMC, and determine the best smearing factor that matches toyMC to data

4) As a sanity check, we should make the following plot:
- Compare Jpsi yield vs. pt between data and toyMC with best smearing factor to make sure their shapes are similar
- Compare Jpsi width vs. pt between data and toyMC with best smearing factor
- Compare Jpsi invariant mass for both pt integrated and in different pt bins between data and toyMC with best smearing factor

Hopefully, we can arrive at consistent results from different analyzers and using different methods.

Please let me know if you have any comments. Thanks.

Best
Rongrong
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