STAR Flow, Chirality and Vorticity PWG

[Xu Sun <xusun AT impcas.ac.cn>]

Dear CW,

No matter how much technical detail or distraction you introduce to 
complicate the discussion, it doesn't change the fundamental fact that the 
method is mathematically flawed. You can't argue your way around algebra.

You seem obsessed with defending your approach, so let's ask again: your 
correction depends on the sample provided (even if the daughter-kaon spectra 
are the same), as you've shown with rotated and mixed events. If we provided 
you with a different sample with the same kaon spectra, we suggest that the 
correction would be different. How can you demonstrate that our statement is 
incorrect?

One can argue that combinatorial background and signal are either the same or 
different, but one cannot claim both to be true at the same time.

We have heard arguments seemingly to be aimed at rescuing faulty algebra.  It 
is deeply concerning to us that obvious mathematical issues are being 
obscured with the excuse of "systematics" or other deflective reasonings.

Best,

Xu

> On Oct 10, 2024, at 03:46, Robertson, Charles William <rober558 AT purdue.edu> 
> wrote:
> 
> Hi Xu, All,
> 
> Please see my reply below in red.
> 
> Quote: The data-driven methods for theta* and phi* we have presented by 
> definition take care of detector effects. 
> 
> A: We don't believe a method can be deemed correct solely by definition. We 
> think validating any method through checks against simulation/embedding is 
> a crucial step.
> 
> We feel the definition takes precedence over checks against 
> simulation/embedding. A good question to ask is: What if embedding is 
> incorrect in handling two-particle effects? Of course, multiple ways to 
> look at things are always good, and we have no problem looking at 
> embedding. As we showed at the last focus meeting with Xin, we are looking 
> at embedding for the theta* and phi* corrections. Regarding 
> simulation/embedding, I have asked multiple times to see the effect of 
> corrections on the Nature raw data at each energy. Again, what is the 
> difference between your raw rho00 and the final rho00 for the Nature energy 
> dependence plot?
> 
> Quote: For the data-driven correction for theta*, the correction applies to 
> K+ and K- pairs that have the same single particle kinematics of phi-decay 
> pairs. Are you suggesting that the detector effects would be different 
> between a phi-decay pair and a combinatorial pair that are otherwise 
> identical?
> 
> A:  Combinatorial pairs and phi-decay pairs are not truly identical, even 
> if they seem to have similar spectra. Otherwise, there wouldn't be a 
> visible structure (like bump or dip) at the resonance invariant mass.  You 
> can't, in the same procedure, treat them as different to fit the invariant 
> mass and extract raw rho_00, then assume they're identical in the next step 
> to justify your correction method.
> 
> Detector effects should not depend on the physics signal. In our method, we 
> weight each kaon in data to have the same single particle kinematics as 
> those from phi decays in data. When it comes to kaon pairs, the phi decays 
> strongly (all particles are from the primary vertex), and any pair of 
> particles can affect each other.  Therefore, after weighting the single 
> particle spectra to match, there is no way to tell where a particular kaon 
> pair comes from in data. For our correction, we compare decay kaons in REAL 
> data and those FOLDED FROM PUBLISHED PHI RESULTS. The difference between 
> these two groups of kaons includes detector effects from single particle 
> efficiencies, pair effects, and anything else that may be contained in 
> data. That's the beauty of the data-driven methods.
> 
> Quote: I do not really know how to reply to your forth point, but I will 
> quote it and bold some of the worse you used for emphasis "Later on in the 
> correspondence the Purdue group has attempted to use systematic errors to 
> obscure the mathematical issues in their approach, and we believe this is 
> unacceptable."
> 
> I was referring to the tone of your comment. We studied various ways of 
> approaching the correction, and the differences could be attributed to 
> systematics. Your comment reminds me of the 200 GeV Run 11 and Run 14 
> difference quoted in the nature publication divided by sqrt(12), such that 
> the two runs were no longer consistent within total uncertainties. Was this 
> discrepancy known to the GPC of the nature paper? 
> 
> A: Below, I've pasted an email exchange between you and Aihong on the FCV 
> list. I'll leave it to others to draw their own conclusions.
> 
> From: Xu Sun <xusun AT impcas.ac.cn>
> Sent: Wednesday, October 9, 2024 1:56 AM
> To: STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
> Cc: Xu Sun <xusun AT impcas.ac.cn>; Robertson, Charles William 
> <rober558 AT purdue.edu>; Wang, Fuqiang <fqwang AT purdue.edu>
> Subject: Re: [[Star-fcv-l] ] QM abstracts (please send to the list by Oct 1)
>  ---- External Email: Use caution with attachments, links, or sharing data 
> ----
> Hi CW, All,
> 
> Please find our reply below:
> 
> ============
> 
> Quote: The data-driven methods for theta* and phi* we have presented by 
> definition take care of detector effects. 
> 
> A: We don't believe a method can be deemed correct solely by definition. We 
> think validating any method through checks against simulation/embedding is 
> a crucial step.
> 
> Quote: For the data-driven correction for theta*, the correction applies to 
> K+ and K- pairs that have the same single particle kinematics of phi-decay 
> pairs. Are you suggesting that the detector effects would be different 
> between a phi-decay pair and a combinatorial pair that are otherwise 
> identical?
> 
> A:  Combinatorial pairs and phi-decay pairs are not truly identical, even 
> if they seem to have similar spectra. Otherwise, there wouldn't be a 
> visible structure (like bump or dip) at the resonance invariant mass.  You 
> can't, in the same procedure, treat them as different to fit the invariant 
> mass and extract raw rho_00, then assume they're identical in the next step 
> to justify your correction method.
> 
> Quote: I do not really know how to reply to your forth point, but I will 
> quote it and bold some of the worse you used for emphasis "Later on in the 
> correspondence the Purdue group has attempted to use systematic errors to 
> obscure the mathematical issues in their approach, and we believe this is 
> unacceptable."
> 
> A: Below, I've pasted an email exchange between you and Aihong on the FCV 
> list. I'll leave it to others to draw their own conclusions.
> 
> ------------
> 
> May 17, 2024
> 
> Hi CW,
> 
> You said, "Detector correction is meant to correction for detector effects, 
> not physics." 
> Let's not talk about physics for now. Let me try again, and I hope I have 
> made this crystal clear. Your correction depends on the sample provided 
> (even their daughter-kaon spectra are the same), as you've demonstrated. I 
> just gave you a different sample with the same kaon spectra. I suggest that 
> the correction for this sample would be different. How can you demonstrate 
> that my statement is incorrect ?
> 
> Thanks,
> 
> Aihong
> 
> You answer to that question is (in red bold) :
> 
> On May 17, 2024, at 9:02 PM, Robertson, Charles William 
> <rober558 AT purdue.edu> wrote:
> Hi Aihong,
> 
> That is what the systematic uncertainty is for.
> 
> Can you explain why the nature paper corrections are so irregular, positive 
> for some beam energies and negative for others, and very non-monotonic in 
> beam energy? 
> 
> Thanks,
> -CW
> 
> 
> 
>> On Oct 9, 2024, at 04:56, Robertson, Charles William <rober558 AT purdue.edu> 
>> wrote:
>> 
>> Hello Xu, All,
>> 
>> 
>> I will reply to your points below.
>> • My understanding from Xin's special task force is that the 27 GeV data 
>> has been completely checked with nearly identical analysis procedure among 
>> the groups. The 200 GeV data were also understood to be checked out where 
>> slight numerical differences can arise from systematics as the procedures 
>> are not literally identical. If my understanding is incorrect, then we 
>> need to hear from Xin.
>> 
>> • The data-driven methods for theta* and phi* we have presented by 
>> definition take care of detector effects. 
>> 
>> • For the data-driven correction for theta*, the correction applies to K+ 
>> and K- pairs that have the same single particle kinematics of phi-decay 
>> pairs. Are you suggesting that the detector effects would be different 
>> between a phi-decay pair and a combinatorial pair that are otherwise 
>> identical?
>> 
>> • I do not really know how to reply to your forth point, but I will quote 
>> it and bold some of the worse you used for emphasis "Later on in the 
>> correspondence the Purdue group hasattempted to use systematic errors to 
>> obscure the mathematical issues in their approach, and we believe this is 
>> unacceptable."
>> 
>> • I agree all analyses should be carefully checked, including ours.
>> Thanks,
>> -CW
>> 
>> From: star-fcv-l-request AT lists.bnl.gov <star-fcv-l-request AT lists.bnl.gov> 
>> on behalf of Xu Sun <xusun AT impcas.ac.cn>
>> Sent: Tuesday, October 8, 2024 2:05 AM
>> To: STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
>> Cc: Xu Sun <xusun AT impcas.ac.cn>
>> Subject: Re: [[Star-fcv-l] ] QM abstracts (please send to the list by Oct 
>> 1)
>>  ---- External Email: Use caution with attachments, links, or sharing data 
>> ----
>> 
>> 
>> Hi all,
>> 
>> There are many things packed in this abstract. We would like to point out 
>> a few key facts for clarification:
>> 
>> 1. There has been cross-checks between three groups for the raw results at 
>> 200 GeV and 27 GeV, with standard theta*-bin-fitting method (not the 
>> invariant-mass method). A difference has been observed between the 
>> published 2014 results at 200 GeV and the current checks. However, from 
>> the same excise, it is also found that the Purdue group’s results do not 
>> align with other people's independent checks at 200 GeV and 27 GeV. The 
>> reason is not completely understood yet. We believe it's essential to 
>> ensure agreement on the conventional raw results before talking about 
>> alternative methods.
>> 
>> 2. The analysis approach adopted by the Purdue group has not been 
>> demonstrated to properly account for finite detector acceptance/efficiency 
>> effects. There has been no cross-check using embedding to verify their 
>> method.
>> 
>> 3. The data-driven correction method is mathematically flawed. When 
>> decomposed algebraically, it fails to provide the intended correction. 
>> (See: 
>> https://urldefense.com/v3/__https://nam04.safelinks.protection.outlook.com/?url=https*3A*2F*2Fdrupal.star.bnl.gov*2FSTAR*2Fsystem*2Ffiles*2FDecomposePurdueSpinAlignmentProcedure_May2024_v2.pdf&data=05*7C02*7Crober558*40purdue.edu*7Cda4b9e3b9cfe46956caf08dce75f5b5b*7C4130bd397c53419cb1e58758d6d63f21*7C0*7C0*7C638639643974279834*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C0*7C*7C*7C&sdata=Wfj9Y9i5JdMeTpVtR6mjzkvKHIS7V6d7pPf6RCVoNpA*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSU!!P4SdNyxKAPE!GjNFNebtf-1T_Bu8nlmbuAc9jduMd69OiOaecjwOo6Tg-PfJtM2Xy19clUl7rWNbK43iUUi6fQnthJ4-HyShOzvHdg$
>>  ) This correction only works for combinatorial backgrounds. When asked if 
>> the correction could be applied to a different sample other than 
>> combinatorial backgrounds, the Purdue group did not deny that they did not 
>> know the answer.
>> 
>> 4. Later on in the correspondence the Purdue group has attempted to use 
>> systematic errors to obscure the mathematical issues in their approach, 
>> and we believe this is unacceptable.
>> 
>> 5. Spin alignment relative to the beam axis is a highly challenging 
>> analysis, strongly influenced by the cylinder acceptance of our detector. 
>> The signal is a second-order effect on top of the artificial ρ_00 induced 
>> by the cylindrical shape of our detector. It has to be carefully checked 
>> with embedding. It also needs to be cross-checked with the published ρ_00 
>> measurements in the x and y directions for normalization consistency.
>> 
>> Best,
>> 
>> Xu
>> 
>> > On Oct 8, 2024, at 01:04, Robertson, Charles William 
>> > <rober558 AT purdue.edu> wrote:
>> >
>> > Hello FCV convenors,
>> >
>> > I would like to submit a talk for QM2025.
>> >
>> > The title is: New Analysis of ϕ Meson Global Spin Alignment in Heavy Ion 
>> > Collisions by STAR
>> >
>> > The abstract and 2-slide presentation can be found through the drupal 
>> > link below:
>> > https://urldefense.com/v3/__https://nam04.safelinks.protection.outlook.com/?url=https*3A*2F*2Fdrupal.star.bnl.gov*2FSTAR*2Fblog*2Fcwrobertson*2FQM-20205&data=05*7C02*7Crober558*40purdue.edu*7Cda4b9e3b9cfe46956caf08dce75f5b5b*7C4130bd397c53419cb1e58758d6d63f21*7C0*7C0*7C638639643974296990*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C0*7C*7C*7C&sdata=PphWT1odKnNMeKu544Dt4CBZkLK17G5*2BUXCCumjZXs0*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUl!!P4SdNyxKAPE!GjNFNebtf-1T_Bu8nlmbuAc9jduMd69OiOaecjwOo6Tg-PfJtM2Xy19clUl7rWNbK43iUUi6fQnthJ4-HyRy_xm1zw$
>> >  
>> >
>> > Thanks,
>> > -CWFrom: star-fcv-l-request AT lists.bnl.gov 
>> > <star-fcv-l-request AT lists.bnl.gov> on behalf of XIATONG WU 
>> > <maxwoo AT physics.ucla.edu>
>> > Sent: Friday, October 4, 2024 12:35 AM
>> > To: star-fcv-l AT lists.bnl.gov <star-fcv-l AT lists.bnl.gov>
>> > Subject: Re: [[Star-fcv-l] ] QM abstracts (please send to the list by 
>> > Oct 1)
>> >  You don't often get email from maxwoo AT physics.ucla.edu. Learn why this 
>> > is important
>> > ---- External Email: Use caution with attachments, links, or sharing 
>> > data ----
>> > Dear Conveners,
>> >
>> > I would like to submit a talk abstract for QM25. The title is 
>> > "Understanding the Quark Coalescence Dynamics with Directed and Elliptic 
>> > Flow of Identified Particles from the STAR BES-II Data".
>> > You may find the abstract and the short two-page slides here at 
>> > https://urldefense.com/v3/__https://nam04.safelinks.protection.outlook.com/?url=https*3A*2F*2Fdrupal.star.bnl.gov*2FSTAR*2Fblog*2Fmaxwoo*2FQM-2025-Abstract-and-Presentation&data=05*7C02*7Crober558*40purdue.edu*7Cda4b9e3b9cfe46956caf08dce75f5b5b*7C4130bd397c53419cb1e58758d6d63f21*7C0*7C0*7C638639643974305552*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C0*7C*7C*7C&sdata=Ar*2Bsz7f8192BzcNyMWk3kno*2Fy85Lq0UJYZJLtMrh*2Fv4*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUlJSU!!P4SdNyxKAPE!GjNFNebtf-1T_Bu8nlmbuAc9jduMd69OiOaecjwOo6Tg-PfJtM2Xy19clUl7rWNbK43iUUi6fQnthJ4-HySoVM5Yjw$
>> >  .
>> >
>> > Best,
>> > Xiatong
>> >
>> > On Wed, Oct 2, 2024 at 7:43 AM gpwang <star-fcv-l AT lists.bnl.gov> wrote:
>> > Hi conveners,
>> >
>> > My plan for QM25 is a poster, but I found my title in the talk list. 
>> > There might be a mistake somewhere.
>> > Please move my title to the poster list.
>> >
>> > Best regards
>> > Guoping
>> >
>> > gpwang
>> > gpwang AT mails.ccnu.edu.cn
>> >
>> > ---- Replied Message ---- From gpwang<gpwang AT mails.ccnu.edu.cn>
>> > Date 09/30/2024 12:53 To 
>> > star-fcv-l AT lists.bnl.gov<star-fcv-l AT lists.bnl.gov>
>> > Subject Re:[[Star-fcv-l] ] QM abstracts (please send to the list by Oct 
>> > 1) Dear Conveners and all,
>> >
>> > I would like to submit a poster for QM2025.
>> > The title is “The elliptic flow of identified particles in Au + Au 
>> > collisions at 3.0-4.5 GeV from STAR”
>> > Please find my abstract and the 2-pages presentation in the link:
>> > https://urldefense.com/v3/__https://nam04.safelinks.protection.outlook.com/?url=https*3A*2F*2Fdrupal.star.bnl.gov*2FSTAR*2Fblog*2Fgwang1*2FQM2025guoping&data=05*7C02*7Crober558*40purdue.edu*7Cda4b9e3b9cfe46956caf08dce75f5b5b*7C4130bd397c53419cb1e58758d6d63f21*7C0*7C0*7C638639643974313629*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C0*7C*7C*7C&sdata=Io7*2F447ourU5*2BJVWFkgTe*2F00FsKdnivTBt0wBL8u*2BIM*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUl!!P4SdNyxKAPE!GjNFNebtf-1T_Bu8nlmbuAc9jduMd69OiOaecjwOo6Tg-PfJtM2Xy19clUl7rWNbK43iUUi6fQnthJ4-HySf8ojalg$
>> >  
>> >
>> > Thank you!
>> > Best regards,
>> > Guoping
>> >
>> > gpwang
>> > gpwang AT mails.ccnu.edu.cn
>> >
>> > ---- Replied Message ---- From Richard Seto (via star-fcv-l Mailing 
>> > List)<star-fcv-l AT lists.bnl.gov>
>> > Date 09/28/2024 23:07 To STAR Flow, Chirality and Vorticity 
>> > PWG<star-fcv-l AT lists.bnl.gov>
>> > Subject [[Star-fcv-l] ] QM abstracts (please send to the list by Oct 1) 
>> > Hi Everyone
>> > Quark Matter 2025 is coming up (April 6-12, 2025). The date for STAR to 
>> > have all abstracts submitted is October 31. Sooraj has set an internal 
>> > date for abstracts to STAR of Oct 10.
>> > Hence for FCV, we are setting an internal FCV deadline for the evening 
>> > of ****Oct 1***** (three days from now). Please send to the list, an 
>> > abstract and a 2 page presentation via email and indicate whether it is 
>> > for a talk or poster. Short, 5 min presentations can be made at the next 
>> > FCV meeting on Wed Oct 2. We can then comment, have revisions and 
>> > perhaps combine some abstracts, review them at the FCV meeting on Wed 
>> > Oct 9, and final proposals can be submitted from the FCV working group 
>> > on Oct 10.
>> >
>> > So, please be putting together abstracts and short presentations  and 
>> > send them to the list by ***Oct 1***. It is OK that they are rough. We 
>> > will have a week to refine them.
>> >
>> > Thanks
>> > Rich - for Rich, Prithwish and Subash
>> >
>> >
>> > Richard Seto
>> > richard.seto AT ucr.edu
>> > Department of Physics and Astronomy
>> > University of California, Riverside
>> > Riverside, CA 92521