STAR Flow, Chirality and Vorticity PWG

["Wang, Fuqiang" <fqwang AT purdue.edu>]

Hi Aihong,

Thanks for the information!

If I understand it correctly, you have 5 syst. sources. Let’s call them s1,s2,s3,s4,s5. If you do the syst assessment in the way people normally do, you get s1=s2=s3=s4=0, and s5 nonzero, under Barlow prescription. So you decided to do variations s1+s5, s2+s5, s3+s5, s4+s5, and get syst uncertainties of s5, s5, s5, s5 for all four of them (maybe I’ve oversimplified a bit here), and the final total syst uncertainty is sqrt(s5^2 + s5^2 + s5^2 + s5^2) = 2*s5, so it’s larger by a factor of 2 than the s5 syst uncertainty that you would normally get. This is bizarre! You’ve quadruple counted syst uncertainties. I believe it’s wrong. This is not written anywhere, not in the paper, not in the analysis note (actually the analysis note wrote otherwise). If it were, it would certainly be caught and corrected. 

So up to this point, assuming everything else is correct including the division by sqrt(12), the current syst uncertainty is artificially blown up by a factor of 2 or so. 

By “fitting procedure” I think you meant integration range etc. as written in the analysis note, not background function modeling. Was background function modeling NOT included in the syst. uncertainty assessment? 

Best regards,

Fuqiang

On Aug 31, 2023, at 1:04 AM, Tang, Aihong <aihong AT bnl.gov> wrote:



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Hi, Fuqiang :

We possess four systematic sources considered independent. If we move the systematic error from fitting procedure out from each of the four sources, we introduced one additional independent systematic contribution. However, at the same time, this action diminished the existing contribution from the four systematic sources. The net outcome is that the new systematic error is smaller than the current one.  

Thanks,

Aihong

On Aug 30, 2023, at 12:54 PM, Wang, Fuqiang via Star-fcv-l <star-fcv-l AT lists.bnl.gov> wrote:

Baoshan,

As I said during your rehearsal, you have 6 syst. variations. Normally people would vary each one and get 6 syst. uncertainties, and then add them in quadrature at end. You vary some of them simultaneously and it looks like you get 3 numbers for syst. uncertainties, and add only those 3 in quadrature. I don't understand how come you would get a more conservative syst. uncertainty this way. I would think 6 sources of syst. uncertainties would give you a larger syst. uncertainty value.

Your approach is only valid when there're indeed only 3 independent syst. sources and the others are coupled to those 3 sources. However, it looks to me all those 6 systematics are viable sources.

Actually the phi nature paper analysis note (see the snapshot below) seems to indicate all the variations were varied independently. Is it a misdescription in the analysis note? Is there an independent variation in the functional form in modeling the background? We know this gives a large systematic effect.

Best regards,
Fuqiang

<image.png>

---

From: xibaoshan AT fudan.edu.cn <xibaoshan AT fudan.edu.cn>
Sent: Wednesday, August 30, 2023 6:06 AM
To: STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
Cc: Wang, Fuqiang <fqwang AT purdue.edu>
Subject: Re: Re: [Star-fcv-l] STAR presentation by Baoshan Xi for Quark Matter 2023 submitted for review

 

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Hi Fuqiang,

Regarding your question on systematic error in phi analysis, we believe that the errors related to the fitting procedure and other systematic sources aren't entirely independent of each other. For instance, the dca cut has the potential to alter the background shape, thereby impacting the fitting procedure and overall selection criteria. To comprehensively account for the full range of potential values, we conducted a scan of each systematic error category employing various fitting procedures. It's worth noting that if one were to decouple the errors related to fitting from other sources, the total systematic error would be smaller. Our approach is a conservative measure.

Regarding your point about spin alignment and its relationship to the participant plane, we are not sure. The spin alignment t induced by vorticity should theoretically be more sensitive to spectator nucleons due to the initial torque generated by their rotation. Similarly, the magnetic field-induced global spin alignment also has ties to spectator nucleons.

In response to your comment about our current CME fraction at 200 GeV, the reasoning is straightforward. A rho_00 value is less than 1/3 contributes negatively to delta gamma. If we were to devise a method to eliminate this non-CME contribution, the resulting delta-gamma, post removal, would exceed the apparent value.

Best,

Baoshan

-----原始邮件-----
发件人: "Wang, Fuqiang via Star-fcv-l" <star-fcv-l AT lists.bnl.gov>
发送时间: 2023-08-30 01:11:30 (星期三)
收件人: "STAR Flow, Chirality and Vorticity PWG" <star-fcv-l AT lists.bnl.gov>
抄送: "Wang, Fuqiang" <fqwang AT purdue.edu>
主题: Re: [Star-fcv-l] STAR presentation by Baoshan Xi for Quark Matter 2023 submitted for review

Hi Baoshan, 

On your backup slide 28, the procedure of syst. uncertainty estimation is described.  But it's not clear to me whether the min-max ranges are faithfully assessed. 

From an earlier communication with Gavin, https://lists.bnl.gov/pipermail/star-fcv-l/Week-of-Mon-20230821/004005.html, it turns out that multiple cuts were being varied simultaneously to obtain the min-max ranges, following the procedure in the Nature publication. 

This is rather a peculiar way to estimate syst. uncertainties, and I'm not sure what it entails. 

To the very least, this should be fully discussed with details, e.g., with values of syst. variations in the results, to assess whether the min-max ranges are faithfully assessed for each syst. source variation. 

On your conclusion slide, you state "complicates CME analyses that rely on ratios (Ru/Zr, PP/SP)." As far as I understand, any possible rho spin alignment is related to the participant plane because it arises from spin-orbital interactions within the participant zone, and therefore it is part of the flow-induced background and already taken care of in Ru/Zr and PP/SP analyses. So it is unclear what your conclusion means. Can you elaborate more on this point in the talk so you can make such a conclusion?

You also have a summary statement "This means that our current CME fraction at 200 GeV is under stated." If my understanding above is correct, then I don't think your talk supports such a statement. Again it would be helpful if more discussions are given in the talk in this regard. 

Best regards, 

Fuqiang 

---

From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> on behalf of Baoshan Xi via Star-fcv-l <star-fcv-l AT lists.bnl.gov>
Sent: Monday, August 28, 2023 5:04 AM
To: subhash <subhash AT rcf.rhic.bnl.gov>
Cc: xibaoshan AT fudan.edu.cn <xibaoshan AT fudan.edu.cn>; STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Baoshan Xi for Quark Matter 2023 submitted for review

  

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Dear Subhash and all,

Sorry for the mistake.
I have updated the files for both websites.

Best,
Baoshan


> -----原始邮件-----
> 发件人: subhash <subhash AT rcf.rhic.bnl.gov>
> 发送时间:2023-08-28 16:05:36 (星期一)
> 收件人: "STAR Flow, Chirality and Vorticity PWG" <star-fcv-l AT lists.bnl.gov>
> 抄送: xibaoshan AT fudan.edu.cn
> 主题: Re: [Star-fcv-l] STAR presentation by Baoshan Xi for Quark Matter 2023 submitted for review
>
> Dear Baoshan,
>
> Could you please upload your latest/correct talk at this link?
> https://nam04.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fnode%2F64789&data=05%7C01%7Cfqwang%40purdue.edu%7C89c66b4657894580352208dba7a5ecf1%7C4130bd397c53419cb1e58758d6d63f21%7C0%7C0%7C638288103403826311%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=JQvtU0WbXbQ2k7XUMCUbwBqtcdoLvkTLogCoSQg6xTw%3D&reserved=0
> Currently, it has 58 slides, I don't think it is the intended slide
> version.
>
>
> The following link correspond to QM abstract that was submitted.
> https://nam04.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fpresentations%2FQuark-Matter-2023%2FNew-Insights-Global-Spin-Alignment-Heavy-Ion-Collisions-Measurements&data=05%7C01%7Cfqwang%40purdue.edu%7C89c66b4657894580352208dba7a5ecf1%7C4130bd397c53419cb1e58758d6d63f21%7C0%7C0%7C638288103403826311%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3mg0THXXF5L6gd1epZSn8ty6EnfhjT8Fxw5EcIi8xQY%3D&reserved=0
> It should contain QM abstract that is submitted.
>
> Thanks and regards,,
> Subhash
>
>
> On 2023-08-23 09:23 PM, Baoshan Xi via Star-fcv-l wrote:
> > Dear conveners and all,
> >
> > I have made some updates to the slides.
> >
> > Please kindly find the updated report by the link:
> >
> > https://nam04.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fpresentations%2FQuark-Matter-2023%2FNew-Insights-Global-Spin-Alignment-Heavy-Ion-Collisions-Measurements&data=05%7C01%7Cfqwang%40purdue.edu%7C89c66b4657894580352208dba7a5ecf1%7C4130bd397c53419cb1e58758d6d63f21%7C0%7C0%7C638288103403826311%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3mg0THXXF5L6gd1epZSn8ty6EnfhjT8Fxw5EcIi8xQY%3D&reserved=0
> >
> > Best,
> > Baoshan
> >
> >
> >
> >
> >> -----原始邮件-----
> >> 发件人: "webmaster--- via Star-fcv-l" <star-fcv-l AT lists.bnl.gov>
> >> 发送时间:2023-08-21 20:55:52 (星期一)
> >> 收件人: star-fcv-l AT lists.bnl.gov
> >> 抄送: webmaster AT star.bnl.gov
> >> 主题: [Star-fcv-l] STAR presentation by Baoshan Xi for Quark Matter 2023
> >> submitted for review
> >>
> >> Dear star-fcv-l AT lists.bnl.gov members,
> >>
> >> Baoshan Xi (xibaoshan AT fudan.edu.cn) has submitted a material for a
> >> review,
> >> please have a look:
> >> https://nam04.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fnode%2F64789&data=05%7C01%7Cfqwang%40purdue.edu%7C89c66b4657894580352208dba7a5ecf1%7C4130bd397c53419cb1e58758d6d63f21%7C0%7C0%7C638288103403826311%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=JQvtU0WbXbQ2k7XUMCUbwBqtcdoLvkTLogCoSQg6xTw%3D&reserved=0
> >>
> >> Deadline: 2023-09-03
> >> ---
> >> If you have any problems with the review process, please contact
> >> webmaster@https://nam04.safelinks.protection.outlook.com/?url="http%3A%2F%2Fwww.star.bnl.gov%2F&data=05%7C01%7Cfqwang%40purdue.edu%7C89c66b4657894580352208dba7a5ecf1%7C4130bd397c53419cb1e58758d6d63f21%7C0%7C0%7C638288103403826311%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=tyH2NlEWZnzy%2FV0IBSgXCqOd76GDfvik2PLSwGaOw3I%3D&reserved=0
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