STAR Flow, Chirality and Vorticity PWG

[ShinIchi Esumi <esumi.shinichi.gn AT u.tsukuba.ac.jp>]

Dear Petr, Alexander, Alexey, Grigory and Arkady
You have now excluded all high pT kaon results from the figures, my last 
concern 
is whether your new kaon data on p.12 left panel in the energy dependence 
plot 
is consistent to what you used in your introduction slide on p.4 right panel 
from 
our previous publication or not. I do not see the systematic errors on the 
previous 
data on p.4 (where the value is very close to zero compared to the symbol 
size), 
but your systematic error is small enough to be positive finite value on 
p.12. So 
it could be OK, if you have clear explanation why your new data look 
different 
from the previous data, because of the different centrality or pT selection 
etc, 
otherwise this is not consistent from the published one that you’ve even used 
in your introduction. I’m hoping pi and p are mostly consistent, where you 
can 
come back to the PWG to discuss about the detailed pT, centrality and beam 
energy dependences, we could end up to correct some of the previous data with 
your findings... 
Best regards, ShinIchi

PS : After you store all your preliminary plots in the special drupal area, 
we can 
approve your talk. 


> On Oct 5, 2020, at 2:31, arkadij71 <arkadij71 AT gmail.com> wrote:
> 
> Dear ShinIchi,
> 
> Thank you very much for your comments, questions and suggestions.
> Kaons are very interesting and by doing the comparison with published
> results we saw the same strong pt dependence of v2(K+)/v2(K-) ratio
> at low pT - but statistics of BES-I are too low to study this effect in
> detail. We think that the charged kaons should be analysed together
> with KShort - as in the STAR published results one sees very interesting
> differences, please see the link to the compilation.  We know that there
> are some 10-15% differences between v2 of charged kaons and Kshort at
> LHC - if we trust ALICE results. It looks like  the same difference one
> see in published STAR results - it is 5-6% at 39-62.4 GeV and it is
> smaller at lower energy.
> https://drupal.star.bnl.gov/STAR/system/files/kaons.pdf
> We will come back to PWG with new checks for kaons.
> 
> Our main goal for particle-antiparticle analysis was the v3 of protons
> and antiprotons and  we chose new run18 27GeV data - only because of
> the high statistics and energy - where we see a rather big difference in v2.
> The preliminary v3 results were controversial - in 2014 one STAR analysis
> saw the difference between v3 of protons and antiprotons, part of 2019
> - the difference was not visible in the other analysis and we happy, that
> Now we all see this difference in v3 and it looks in some way similar to
> v2 of protons and antiprotons.
> 
> Concerning your points for v2 of K+ and K- difference at high energies -
> we checked the STAR published results for 10-40% at 39 GeV and 62.4 GeV
> from Phys. Rev. C 93 (2016) 14907
> and we do not see that the integral v2 value can be slightly negative -
> it is really close to zero, but it has positive values at lower pT -
> please see link to kaons.pdf
> we also provide the same comparison for 10-40% from our analysis and as
> we cut at pT < 1.5 GeV - we are getting a slightly positive signal, see 
> page 7-8
> in kaons.pdf
> 
> 
> Following your request we removed all hight pT kaon points from all plots
> and we posted  a new version of the presentation.
> https://drupal.star.bnl.gov/STAR/system/files/ICPPA2020_Parfenov.pdf
> We hope for your help and
> suggestions very much as the conference in Moscow will start tomorrow.
> 
> 
> Thank you very much.
> With best regards
> 
> Petr, Alexander, Alexey, Grigory and Arkadiy
> 
> 
> 
> On Sun, Oct 4, 2020 at 3:37 AM ShinIchi Esumi via Star-fcv-l 
> <star-fcv-l AT lists.bnl.gov> wrote:
> Dear Petr, Alexander, Alexey, Grigory and Arkadiy
> We are not asking whether the data is consistent with the previous data, 
> as you have already shown the comparison in the PWG. The kaon+/- ratio 
> (difference) data are closer to proton/anti-proton at lower pT and are 
> closer 
> to the pi+/- at higher pT, which could be real based on some physics. We 
> are 
> just asking whether you are sure about the contamination or other 
> experimental 
> effects which could be affecting the ratio in pT dependent way in your own 
> analysis, let’s just do not trust the previous data too much. Looking at 
> the PRC88 
> Fig.11 panel(b) lower delta_v2 plots, I see the similar effect especially 
> around 
> the beam energy of 10-30GeV and the major/important effect (change) would 
> be more at lower pT getting closer to proton difference. 
> 
> You are showing only for 27GeV data, since this is new from run18? Have you 
> also looked at the similar pT dependent ratio or difference for other beam 
> energies? 
> nSigma cut from tpc dedx is defined in momentum dependent way (right?), 
> however 
> your m2 cut is not done in the same way (common for all momentum), so the 
> inclusion 
> of TOF does not help much in this sense, where m2 width would get wider 
> caused by 
> the momentum resolution at high pT. If you have any doubt in the kaon data 
> as you 
> have removed the higher pT points from the ratio, I would do the same for 
> all the 
> other figures, not just removing the ratio plots. 
> 
> I've also realized that your data delta_vn vs energy data show always 
> positive 
> finite delta_v2 for kaon up to 60GeV 0-60% centrality, while it went 
> slightly negative 
> or very close to zero around 40GeV or above in the energy dependence plot 
> (PRC88 Fig.21 and PRL110 Fig.2 for 0-80%, PRC93 Fig.7 for 10-40%), can you 
> say for sure this difference is caused by your different centrality choice 
> or somewhat 
> different mean pT coming from the different ways of PID, where your 
> systematic 
> error is quite small? 
> Best regards, ShinIchi
> 
>> On Oct 4, 2020, at 4:55, arkadij71 <arkadij71 AT gmail.com> wrote:
>> 
>> Dear   ShinIchi   and  Jiangyong ,
>> Thank you very much for the comments. Our pid v2 results are fully 
>> consistent
>> with published STAR v2 pid results from
>> Phys. Rev. C 93 (2016) 14907
>> Phys. Rev. C 88 (2013) 14902
>> Phys. Rev. Lett. 110 (2013) 142301
>> for 0-10%, 10-40% , 40-80% and 0-80% for
>> all points in collision energy as it was demonstrated. It means that STAR 
>> published
>> results also show such pt dependence for the difference between v2 of K+
>> and K- for all bins in centrality and collision energy.
>> We think that the STAR published results are correct as they were obtained
>> with more probably robust procedure for kaon/pion separation using m2 
>> rotation method.
>> We are using the stringent cut on mass2 for particle separation. However, 
>> we
>> are getting consistent results for v2 with published ones.
>> We understand your concern and worry about the particle purity and our 
>> students
>> Alexey Povarov and Alexander Demanov are started to do the homework - 
>> however, 
>> we are not able to finish it before the
>> conference and therefore we proposed to limit pt range for kaons in the 
>> figure on
>> slide 11 to pt range - where pions and kaons are very well separated. We 
>> will come
>> back with the results of the homework soon. If you request to remove slide 
>> 11 from the conference
>> presentation we agree to do it.
>> Concerning the systematics, the biggest source is coming from the results 
>> for different
>> eta gaps. The influence of different PID cuts was found to be small as it 
>> was shown.
>> We plan to check the rotation mass2 method as an additional cross-check.
>> 
>> With best regards
>> Petr,  Alexander , Alexey, Grigory, Arkadiy,  
>> 
>> On Fri, Oct 2, 2020 at 4:51 PM ShinIchi Esumi via Star-fcv-l 
>> <star-fcv-l AT lists.bnl.gov> wrote:
>> Dear Petr
>> One more point that if you think the ratio (or difference) does have 
>> issues, 
>> Then we should also be worrying about individual vn for k+ and k- as well. 
>> 
>> After you store all your preliminary plots in the 
>> special drupal area for the preliminary location with necessary 
>> information at : 
>> https://drupal.star.bnl.gov/STAR/pwg/bulk-correlations/bulkcorr-preliminary-summary
>> then I would approve your talk. 
>> Best regards, ShinIchi
>> 
>> > On Oct 2, 2020, at 22:14, ShinIchi Esumi via Star-fcv-l 
>> > <star-fcv-l AT lists.bnl.gov> wrote:
>> > 
>> > Dear Petr
>> > Concerning on the same point on page 11 as Jiangyong mentioned, we’ve 
>> > asked you 
>> > to make sure the sign change of kaon vn ratio (and difference) at higher 
>> > pT is real or 
>> > it’s coming from pion contamination etc, which we did not hear you back 
>> > on this particular 
>> > issue, but it seems that you have now excluded the higher pT point from 
>> > the plot, although 
>> > you’ve shown us in the collaboration meeting up to higher pT and it was 
>> > consistent with 
>> > our previous publication, which might have the same issue as well, then 
>> > we would need to 
>> > correct the previous data, if this is really the case. Does that mean 
>> > you do now think they 
>> > are indeed affected by some PID problem at high pT? Since you’ve changed 
>> > the plot in 
>> > the last minutes after the last PWG, I would think we should be 
>> > excluding these ratios (and 
>> > differences) plots at least for kaon as a function of pT, until you 
>> > explain us with more details 
>> > especially in terms of the sign change trend with systematic error 
>> > including PID purity etc. 
>> > What do you think? 
>> > Best regards, ShinIchi
>> > 
>> >> On Oct 2, 2020, at 20:59, Jiangyong Jia via Star-fcv-l 
>> >> <star-fcv-l AT lists.bnl.gov> wrote:
>> >> 
>> >> Hi, Grigory and Petr,
>> >> 
>> >> The slides are nicely written, I don't have major comments on the 
>> >> structure of the talk.
>> >> 
>> >> I have one question that I asked during Petr's presentation a couple 
>> >> weeks ago.
>> >> 
>> >> Slide 11 when you show the difference and ratios between particle and 
>> >> antiparticles, the errors are extremely small. 
>> >> Do you assume the systematic uncertainty mostly cancel?  What about the 
>> >> purity and efficiency of PID cut, I assume
>> >> they will not cancel (yield of particles are anti-particles are 
>> >> different at low energy)
>> >> 
>> >> thanks,
>> >> 
>> >> Jiangyong
>> >> 
>> >> n 10/2/20 6:47 AM, Grigory Nigmatkulov via Star-fcv-l wrote:
>> >>> Dear Conveners,
>> >>> 
>> >>> Please take a look at the Petr Parfenov's slides and sign off you have 
>> >>> no questions.
>> >>> The conference starts on Monday.
>> >>> 
>> >>> Best regards,
>> >>> Grigory, Arkadiy and Petr
>> >>> 
>> >>> On Wed, 23 Sep 2020 at 20:53, webmaster--- via Star-fcv-l 
>> >>> <star-fcv-l AT lists.bnl.gov> wrote:
>> >>> Dear star-fcv-l AT lists.bnl.gov members,
>> >>> 
>> >>> Grigory Nigmatkulov (nigmatkulov AT gmail.com) has submitted a material 
>> >>> for a  
>> >>> review, please have a look:
>> >>> https://drupal.star.bnl.gov/STAR/node/52191
>> >>> 
>> >>> ---
>> >>> If you have any problems with the review process, please contact  
>> >>> webmaster AT www.star.bnl.gov
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