STAR Flow, Chirality and Vorticity PWG

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

Hi Diyu,

Are you saying that you choose a cut, claim that gives the max. range in 
result, and when questioned, you respond by
> That's based on experience and common sense,

?

PS. I don’t know where the dca<0.1 or 0.01 you wrote comes from. I certainly 
did not propose it. I said we might not even be able to confidently say we’ve 
gotten the max. range with the DCA cut as there’s certain limit we can push 
(e.g. it certainly doesn’t make sense to cut into the DCA resolution).

Best regards,
Fuqiang


> On Dec 7, 2023, at 11:52 PM, dshen <dshen AT rcf.rhic.bnl.gov> wrote:
>
> [You don't often get email from dshen AT rcf.rhic.bnl.gov. Learn why this is 
> important at 
> https://urldefense.com/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!P4SdNyxKAPE!CpyI9OY4dIthltZgJsQy_wVkYQ9KIc1i5f7_C9L36EGOSpNmUGD36TKI0Mt1ULjcGjdTnYsoGKrmBgwwJdsGDDqWYA$
>   ]
>
> ---- External Email: Use caution with attachments, links, or sharing data 
> ----
>
>
> Hi Fuqiang,
>
> That's based on experience and common sense, like the choice of DCA<0.1
> is against common sense.
> There is no way to prove it on fundamental level, I think.
>
> Best,
> Diyu
>
>> On 2023-12-08 11:32, Wang, Fuqiang wrote:
>> Hi Diyu,
>>
>> You say
>> “We don't have to scan the DCA to find the min and mix number, we just
>> need to find a reasonable range that we are confident to cover the
>> non-biased value.”
>>
>> But how?
>>
>> Best regards,
>> Fuqiang
>>
>>>> On Dec 7, 2023, at 9:51 PM, dshen <dshen AT rcf.rhic.bnl.gov> wrote:
>>>
>>> [You don't often get email from dshen AT rcf.rhic.bnl.gov. Learn why
>>> this is important at
>>> https://urldefense.com/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!P4SdNyxKAPE!Bsyx4QcescF8h1OLbfzezN5EP0REDR-juHp56CPfJ8UXg5E-HCoyteFVKBxkMvjvG3d-NTiUNA5H_qpUy-Yhvtw$
>>> ]
>>>
>>> ---- External Email: Use caution with attachments, links, or sharing
>>> data ----
>>>
>>>
>>> Hi Fuqiang,
>>>
>>> I disagree with this statement:
>>> "For example, just for the sake of illustration, it is possible that
>>> DCA<1.5 cm gives the min. result and DCA<0.8 cm gives the max result,
>>> however, one would have to scan the DCA space to know this."
>>> We don't have to scan the DCA to find the min and mix number, we just
>>> need to find a reasonable range that we are confident to cover the
>>> non-biased value. Certainly you will have a large variation if you use
>>> DCA<0.01 - there are only few tracks, but we don't use it based on
>>> common sense.
>>>
>>> Best,
>>> Diyu
>>>
>>>
>>>> On 2023-12-08 10:30, Wang, Fuqiang wrote:
>>>> Hi Diyu,
>>>>
>>>> Please see comments in color below.
>>>>
>>>> Best regards,
>>>> Fuqiang
>>>>
>>>> -------------------------
>>>>
>>>> From: dshen <dshen AT rcf.rhic.bnl.gov>
>>>> Sent: Thursday, December 7, 2023 7:07 PM
>>>> To: STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
>>>> Cc: Wang, Fuqiang <fqwang AT purdue.edu>
>>>> Subject: Re: [Star-fcv-l] Discussion of systematic uncertainty
>>>> calculation - FCV PWG meeting on 06/December/2023 Wed. 9:30 AM EDT
>>>>
>>>> [You don't often get email from dshen AT rcf.rhic.bnl.gov. Learn why
>>>> this
>>>> is important at
>>>> https://urldefense.com/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!P4SdNyxKAPE!Bsyx4QcescF8h1OLbfzezN5EP0REDR-juHp56CPfJ8UXg5E-HCoyteFVKBxkMvjvG3d-NTiUNA5H_qpUy-Yhvtw$
>>>> [1] ]
>>>>
>>>> ---- External Email: Use caution with attachments, links, or sharing
>>>> data ----
>>>>
>>>> Hi Fuqiang,
>>>>
>>>> It seems we have an agreement on the first point, i.e. the result to
>>>> lie
>>>> between def - diff and def + diff. It doesn't say the diff should be
>>>> the
>>>> maximum, say, it has to be default to DCA<0.01 or <100.
>>>>
>>>> Just to make sure we're on the same page: If we say the results lie
>>>> between def - diff and def + diff, we mean these are min and max. We
>>>> do have to make reasonably sure these are the min-max range. They of
>>>> course do not have to come from the min-max range of the cut, as the
>>>> result may not linearly depend on the cut. For example, just for the
>>>> sake of illustration, it is possible that DCA<1.5 cm gives the min.
>>>> result and DCA<0.8 cm gives the max result, however, one would have
>>>> to
>>>> scan the DCA space to know this.
>>>>
>>>> Regarding 1 sigma should be diff/sqrt(12) or 2*diff/sqrt(12), let me
>>>> explain it in terms of probability.
>>>> Let's take an example, say, the measured quantity is 0, and the
>>>> variation is 1. Then we assume the non-biased value is in between -1
>>>> to
>>>> 1 with a uniform distribution. So I present the result as 0 +-
>>>> 1/sqrt(12), it means the non-biased value falls within +- 1/sqrt(12)
>>>> with a probability of 2*1/sqrt(12) which is exactly the standard
>>>> deviation of 2*varition=2. If you define 1 sigma as
>>>> 2*variation/sqrt(12), then we should present as +- half sigma to have
>>>> the same probability as before.
>>>>
>>>> For a flat distribution of width 2, the equivalent Gaussian sigma is
>>>> 2/sqrt(12). So the error is +/- 2/sqrt(12). It is +/- 1/sqrt(3) or
>>>> approximately +/- 0.6, or 1.2 out of 2, i.e. 60%.
>>>>
>>>> Thanks,
>>>> Diyu
>>>>
>>>>> On 2023-12-08 02:17, Wang, Fuqiang via Star-fcv-l wrote:
>>>>> Hi Diyu,
>>>>>
>>>>> So the central issue is whether you get the maximum variation. If
>>>> one
>>>>> varies towards only one side, and quote +/- assuming the variation
>>>> is
>>>>> symmetric, then you’re really assuming the result to lie between
>>>> min
>>>>> def-diff and max diff+diff, so you should quote def +/-
>>>> diff/sqrt(3).
>>>>>
>>>>> Best regards,
>>>>> Fuqiang
>>>>>
>>>>>> On Dec 7, 2023, at 1:08 PM, Wang, Fuqiang <fqwang AT purdue.edu>
>>>> wrote:
>>>>>>
>>>>>> ---- External Email: Use caution with attachments, links, or
>>>> sharing
>>>>>> data ----
>>>>>>
>>>>>>
>>>>>> Hi Diyu,
>>>>>>
>>>>>> I realize that there may be a misunderstanding on the term “max.
>>>>>> variation”. It means variations in cuts that result in maximum
>>>>>> variation in result.
>>>>>>
>>>>>> Regarding sqrt(12) vs sqrt(3):
>>>>>> If one believes def. is min and sys. is max, then it’s probably
>>>> better
>>>>>> to quote the average of def. and sys. as the central value and +/-
>>>>>> diff/sqrt(12) as the error.
>>>>>> If there’s strong reason to quote the value to be the min. (or
>>>> max.
>>>>>> for that matter) and the negative side error is really zero, then
>>>> we
>>>>>> should quote the value as def.+diff/sqrt(3) not sqrt(12) because
>>>> the
>>>>>> common understanding of error is that it covers 68% probability.
>>>>>>
>>>>>> Best regards,
>>>>>> Fuqiang
>>>>>>
>>>>>>> On Dec 7, 2023, at 10:50 AM, dshen <dshen AT rcf.rhic.bnl.gov>
>>>> wrote:
>>>>>>>
>>>>>>> [You don't often get email from dshen AT rcf.rhic.bnl.gov. Learn
>>>> why
>>>>>>> this is important at
>>>>>>>
>>>> https://urldefense.com/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!P4SdNyxKAPE!HrVa2wHd3fzH5a6Dr0kh6WgIrrU2y5XXz4t2XzuC3J9-Pwp1Dh9szY1HZyJ18mNbUqk5PWsV8mJ1HGVk7kTAs3ZK0w$
>>>> [2]
>>>>>>> ]
>>>>>>>
>>>>>>> ---- External Email: Use caution with attachments, links, or
>>>> sharing
>>>>>>> data ----
>>>>>>>
>>>>>>>
>>>>>>> Hi Fuqiang,
>>>>>>>
>>>>>>> One sigma is |def.-sys.|/sqrt(12), and it shows as +- 1 sigma for
>>>> the
>>>>>>> case of (def. - |def.-sys.|,  def. + |def.-sys.|).
>>>>>>> The critical point is that it doesn't require a maximum variation,
>>>> it
>>>>>>> just requires that the variation could cover the true value. The
>>>>>>> confidence level is based on experience and common sense, there is
>>>> no
>>>>>>> mathematical way to quantify it - it is not statistics.
>>>>>>>
>>>>>>> Best,
>>>>>>> Diyu
>>>>>>>
>>>>>>>
>>>>>>>>> On 2023-12-07 23:28, Wang, Fuqiang wrote:
>>>>>>>> Hi Diyu,
>>>>>>>>
>>>>>>>> What you wrote is just another way to say that the physics
>>>> quantity
>>>>>>>> in
>>>>>>>> question is within the min and max of (def. - |def.-sys.|,  def.
>>>> +
>>>>>>>> |def.-sys.|), respectively. In such a case, one would quote a
>>>> sigma
>>>>>>>> of
>>>>>>>> 2*|def.-sys.|/sqrt(12) = |def.-sys.|/sqrt(3). The essential point
>>>> is
>>>>>>>> to demonstrate to reasonable confidence that this is indeed the
>>>>>>>> maximum syst. variation in the result.
>>>>>>>>
>>>>>>>> Best regards,
>>>>>>>> Fuqiang
>>>>>>>>
>>>>>>>>> On Dec 7, 2023, at 6:32 AM, dshen via Star-fcv-l
>>>>>>>>> <star-fcv-l AT lists.bnl.gov> wrote:
>>>>>>>>>
>>>>>>>>> ---- External Email: Use caution with attachments, links, or
>>>>>>>>> sharing
>>>>>>>>> data ----
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Hi Fuqiang, Zhiwan and all,
>>>>>>>>>
>>>>>>>>> It was a inspiring discussion on the systematic uncertainty
>>>>>>>>> calculations
>>>>>>>>> yesterday, it pushes me to think.
>>>>>>>>> I tend to agree with Zhiwan and what the blind-analysis did,
>>>> i.e.
>>>>>>>>> use
>>>>>>>>> denominator of 1/sqrt(12).
>>>>>>>>> The argument was that one shouldn't divide the variation by
>>>>>>>>> 1/sqrt(12)
>>>>>>>>> because the variation isn't proved to be the maximum - minimum,
>>>> I
>>>>>>>>> think
>>>>>>>>> there is a misunderstanding of the reason behind it.
>>>>>>>>> It isn't based on the assumption that the variation is maximum -
>>>>>>>>> minimum, the underlying assumption is that the true value falls
>>>>>>>>> within
>>>>>>>>> "default cut" +- "variation".
>>>>>>>>> Let's take an example, say, the default cut is DCA<2, and the
>>>>>>>>> systematic
>>>>>>>>> cut is DCA<1.
>>>>>>>>> The assumption is that the non-biased value is in the interval
>>>> of
>>>>>>>>> (def.
>>>>>>>>> - |def.-sys.|,  def. + |def.-sys.|), and it can be any value in
>>>>>>>>> that
>>>>>>>>> interval with equal probability (uniform distribution) assuming
>>>> we
>>>>>>>>> don't
>>>>>>>>> have any pre-knowledge to the best position. That's the reason
>>>> of
>>>>>>>>> why
>>>>>>>>> people assign |def.-sys.|/sqrt(12) as 1 sigma and use two-side
>>>>>>>>> band.
>>>>>>>>> It hasn't to be the maximum - minimum, although it isn't
>>>> incorrect
>>>>>>>>> technically to use larger uncertainty, say, use Dca<0.1 to
>>>> Dca<100.
>>>>>>>>> But
>>>>>>>>> I think the principal is to provide the best estimate instead of
>>>>>>>>> the
>>>>>>>>> most conservative value.
>>>>>>>>> What variation can be considered as reasonable? I think it is
>>>> based
>>>>>>>>> on
>>>>>>>>> experience and common sense to a specific physics topic. For CME
>>>>>>>>> study,
>>>>>>>>> like what Zhiwan did, it is reasonable to assume the non-biased
>>>>>>>>> value
>>>>>>>>> falls with in DCA<2 +- |DCA<2 - DCA<1|, for example.
>>>>>>>>>
>>>>>>>>> That's my two cents.
>>>>>>>>>
>>>>>>>>> Best,
>>>>>>>>> Diyu
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> On 2023-12-06 05:10, Zhiwan Xu via Star-fcv-l wrote:
>>>>>>>>>> Dear Conveners,
>>>>>>>>>> I would like to update the paper proposal on the CME search in
>>>>>>>>>> STAR
>>>>>>>>>> BES-II.
>>>>>>>>>> Please kindly add me to the schedule.
>>>>>>>>>>
>>>>>>>>>> The paper proposal webpage:
>>>>>>>>>>
>>>>>>>>>>
>>>> https://drupal.star.bnl.gov/STAR/blog/zhiwanxu/Paper-Proposal-Search-Chiral-Magnetic-Effect-RHIC-Beam-Energy-Scan-II
>>>> [3]
>>>>>>>>>> The slides:
>>>>>>>>>>
>>>>>>>>>>
>>>> https://drupal.star.bnl.gov/STAR/system/files/paper_proposal_CME_BESII_v2.pdf
>>>> [4]
>>>>>>>>>>
>>>>>>>>>> Best,
>>>>>>>>>> Zhiwan
>>>>>>>>>>
>>>>>>>>>> ------------------------------------
>>>>>>>>>> Zhiwan Xu,
>>>>>>>>>> Department of Physics and Astronomy, UCLA
>>>>>>>>>> zhiwanxu AT physics.ucla.edu
>>>>>>>>>>
>>>>>>>>>> ----- Original Message -----
>>>>>>>>>> From: "subhash via Star-fcv-l" <star-fcv-l AT lists.bnl.gov>
>>>>>>>>>> To: "STAR Flow, Chirality and Vorticity PWG"
>>>>>>>>>> <star-fcv-l AT lists.bnl.gov>
>>>>>>>>>> Cc: "subhash" <subhash AT rcf.rhic.bnl.gov>
>>>>>>>>>> Sent: Sunday, December 3, 2023 11:21:34 PM
>>>>>>>>>> Subject: [Star-fcv-l] FCV PWG meeting on 06/December/2023 Wed.
>>>>>>>>>> 9:30
>>>>>>>>>> AM
>>>>>>>>>> EDT
>>>>>>>>>>
>>>>>>>>>> Dear All,
>>>>>>>>>>
>>>>>>>>>> We shall have our weekly FCV PWG meeting this Wednesday
>>>>>>>>>> (06/Dec/2023)
>>>>>>>>>> at
>>>>>>>>>> 9:30 AM EDT. If you would like to present please let us know.
>>>>>>>>>> Please
>>>>>>>>>> try
>>>>>>>>>> posting your slides by Tuesday. The agenda will be collected
>>>> at:
>>>>>>>>>>
>>>> https://drupal.star.bnl.gov/STAR/blog/jjiastar/bulkcorr
>>>> [5]
>>>>>>>>>>
>>>>>>>>>> Zoom details are copied below.
>>>>>>>>>>
>>>>>>>>>> Thanks and regards,
>>>>>>>>>> Prithwish, Zhenyu and Subhash
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> ZOOM LINK FOR FCV MEETING:
>>>>>>>>>> Join ZoomGov Meeting
>>>>>>>>>>
>>>> https://urldefense.com/v3/__https://bnl.zoomgov.com/j/1612377416?pwd=V3kvcnN5ZTRLVEc4U01QWUUycDQ1UT09__;!!P4SdNyxKAPE!Av9BM9pZUBzjZ_00gC1v6T-rpsdGpwGXddNo2NvBobwjtpFEHdX8vla8TPZfmG4ld-LS-FpqRe7vqLmI9mb3UG7nFqyunx-QfA$
>>>> [6]
>>>>>>>>>>
>>>>>>>>>> Meeting ID: 161 237 7416
>>>>>>>>>> Passcode: 106847
>>>>>>>>>>
>>>>>>>>>> One tap mobile
>>>>>>>>>> +16692545252,,1612377416#,,,,*106847# US (San Jose)
>>>>>>>>>> +16468287666,,1612377416#,,,,*106847# US (New York)
>>>>>>>>>>
>>>>>>>>>> Dial by your location
>>>>>>>>>>     +1 669 254 5252 US (San Jose)
>>>>>>>>>>     +1 646 828 7666 US (New York)
>>>>>>>>>>     +1 551 285 1373 US
>>>>>>>>>>     +1 669 216 1590 US (San Jose)
>>>>>>>>>> Meeting ID: 161 237 7416
>>>>>>>>>> Passcode: 106847
>>>>>>>>>> Find your local number:
>>>>>>>>>>
>>>> https://urldefense.com/v3/__https://bnl.zoomgov.com/u/abVqdu5fbU__;!!P4SdNyxKAPE!Av9BM9pZUBzjZ_00gC1v6T-rpsdGpwGXddNo2NvBobwjtpFEHdX8vla8TPZfmG4ld-LS-FpqRe7vqLmI9mb3UG7nFqxQ4jG3og$
>>>> [7]
>>>>>>>>>>
>>>>>>>>>> Join by SIP
>>>>>>>>>> 1612377416 AT sip.zoomgov.com
>>>>>>>>>>
>>>>>>>>>> Join by H.323
>>>>>>>>>> 161.199.138.10 (US West)
>>>>>>>>>> 161.199.136.10 (US East)
>>>>>>>>>> Meeting ID: 161 237 7416
>>>>>>>>>> Passcode: 106847
>>>>>>>>>> _______________________________________________
>>>>>>>>>> Star-fcv-l mailing list
>>>>>>>>>> Star-fcv-l AT lists.bnl.gov
>>>>>>>>>>
>>>> https://lists.bnl.gov/mailman/listinfo/star-fcv-l
>>>> [8]
>>>>>>>>>> _______________________________________________
>>>>>>>>>> Star-fcv-l mailing list
>>>>>>>>>> Star-fcv-l AT lists.bnl.gov
>>>>>>>>>>
>>>> https://lists.bnl.gov/mailman/listinfo/star-fcv-l
>>>> [8]
>>>>>>>>> _______________________________________________
>>>>>>>>> Star-fcv-l mailing list
>>>>>>>>> Star-fcv-l AT lists.bnl.gov
>>>>>>>>>
>>>> https://lists.bnl.gov/mailman/listinfo/star-fcv-l
>>>> [8]
>>>>>> _______________________________________________
>>>>>> Star-fcv-l mailing list
>>>>>> Star-fcv-l AT lists.bnl.gov
>>>>>>
>>>> https://lists.bnl.gov/mailman/listinfo/star-fcv-l
>>>> [8]
>>>>> _______________________________________________
>>>>> Star-fcv-l mailing list
>>>>> Star-fcv-l AT lists.bnl.gov
>>>>>
>>>> https://lists.bnl.gov/mailman/listinfo/star-fcv-l
>>>> [8]
>>>>
>>>> Links:
>>>> ------
>>>> [1]
>>>> https://urldefense.com/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!P4SdNyxKAPE!EjpBbeU0hZJonbaEgO1BIObB5ChakAucmBia_AjoDrMf0hNjZDd4P5OIhSJhG7y7GBJB_Ydydq8Rx5YipZVhK98$
>>>> [2]
>>>> https://urldefense.com/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!P4SdNyxKAPE!HrVa2wHd3fzH5a6Dr0kh6WgIrrU2y5XXz4t2XzuC3J9-Pwp1Dh9szY1HZyJ18mNbUqk5PWsV8mJ1HGVk7kTAs3ZK0w$
>>>> [3]
>>>> https://drupal.star.bnl.gov/STAR/blog/zhiwanxu/Paper-Proposal-Search-Chiral-Magnetic-Effect-RHIC-Beam-Energy-Scan-II
>>>> [4]
>>>> https://drupal.star.bnl.gov/STAR/system/files/paper_proposal_CME_BESII_v2.pdf
>>>> [5] https://drupal.star.bnl.gov/STAR/blog/jjiastar/bulkcorr
>>>> [6]
>>>> https://urldefense.com/v3/__https://bnl.zoomgov.com/j/1612377416?pwd=V3kvcnN5ZTRLVEc4U01QWUUycDQ1UT09__;!!P4SdNyxKAPE!Av9BM9pZUBzjZ_00gC1v6T-rpsdGpwGXddNo2NvBobwjtpFEHdX8vla8TPZfmG4ld-LS-FpqRe7vqLmI9mb3UG7nFqyunx-QfA$
>>>> [7]
>>>> https://urldefense.com/v3/__https://bnl.zoomgov.com/u/abVqdu5fbU__;!!P4SdNyxKAPE!Av9BM9pZUBzjZ_00gC1v6T-rpsdGpwGXddNo2NvBobwjtpFEHdX8vla8TPZfmG4ld-LS-FpqRe7vqLmI9mb3UG7nFqxQ4jG3og$
>>>> [8] https://lists.bnl.gov/mailman/listinfo/star-fcv-l