STAR Flow, Chirality and Vorticity PWG

[jagbir <jagbir AT rcf.rhic.bnl.gov>]

Dear Fuqiang,

Thank you for your nice reply with analogy. Please see my reply below:

1. These plots are simply Delta gamma, right? Then they are expected to 
be non-zero. I don't understand the statement here "the correlated 
background is zero". What do you mean?

The correlated background is obtained by restoring the charges of 
shuffled and flipped charges in each event which in this case means one 
gets original default AMPT event in which delta gamma is zero. So, the 
correlated background is zero.

2. How did you obtain the points on slide 25? Is it red-black and 
blue-black of some sort from slide 24? How were the black points on s25 
obtained?

All points on slide 25 are for different samples (i.e., Fix-1(Red), 
Fix-2(Blue) and AMPT(Black)) obtained from slide 24 as discussed earlier 
i.e.,

(delta_gamma_data - delta_gamma_shuffle - delta_gamma_corr)/delta 
gamma_data

delta_gamma_shuffle is not shown in slide 24. This presentation is 
regarding the comments.
Black points are for default AMPT.

3(a). f_DbCs from events shuffled +/- particles <-> Nch from events 
shuffled charged/neutral particles

We consider f_DbCS from data itself in different centrality bins not 
just from Shuffled.

3(b). We take difference between real signal and shuffled signal.

We first take difference between gamma_OS and gamma_SS for data as well 
as for charge shuffled events. So we get two delta gamma, one for data 
(without shuffled) and other for charge shuffled events. Now the 
difference is taken between the delta gamma data and delta gamma charge 
shuffled to get f_CME.
How do you take difference between real signal and shuffled signal?

3(c). You're seeing positive Delta gamma in large f_DbCs events;

We see positive Delta gamma in large f_DbCs in data as well as in charge 
shuffled.

3(d). I'm seeing neutral/charged>1/2 in peripheral events and <1/2 in 
central events. I'll see this even when neutral/charged=1/3 is 
independent of centrality (not to say possibly centrality-dependent 
neutral/charged).This is called selection bias.

Did you get these number from running AMPT and how many events were 
used? Are you seeing this in shuffled events? How it can happen let me 
understand this.
I hope during shuffle you keep number of charged particles and neural 
particles same in each event. If it is so how this ratio of 
neutral/charged can change after shuffle. Centrality bin you define by 
the number of charged particle. So if number of charged particle in each 
event remain the same, as you keep Nch and neutral same during shuffle, 
so the centrality bin should remain the same. So this ratio of 
neutral/charged should remain the same in peripheral events as well as 
in central events you had before
shuffle. You have wrote about neutral/charged for charge shuffled 
events. You did not write any thing about real events whereas we 
discussed both real data and charge shuffled.

During shuffle I keep the number of positive and negative particle same 
in each event and also keep flow in. Alice collaboration used event 
shape engineering to probe CME signal (Phys. Lett. B777, 151 (2018)). 
Here, each centrality is divided into 10 bins depending on Q value. Is 
this selection bias?

Thank you,

With Best Regards,
Jagbir Singh
Panjab University
Chandigarh


On 2021-05-11 20:53, Wang, Fuqiang wrote:
> Jagbir,
>
> Please see my comments below.
>
> Best regards,
> Fuqiang
>
> > -----Original Message-----
> > From: jagbir <jagbir AT rcf.rhic.bnl.gov>
> > Sent: Tuesday, May 11, 2021 7:44 AM
> > To: esumi.shinichi.gn AT u.tsukuba.ac.jp; ptribedy AT rcf.rhic.bnl.gov;
> > jiangyong.jia AT stonybrook.edu; levanfinch AT gmail.com; aihong AT bnl.gov;
> > aggarwal AT pu.ac.in; Wang, Fuqiang <fqwang AT purdue.edu>
> > Cc: STAR Flow, Chirality and Vorticity PWG
> <star-fcv-l AT lists.bnl.gov>; star-cme-
> > focusgroup-l AT lists.bnl.gov
> > Subject: Re: [Star-fcv-l] FCV PWG meeting, 18/Nov/2020 (Wed) 9:30am
> (New
> > York time zone)
> >
> > Dear Fuqiang,
> >
> > Thanks for your nice comments. Please find below my reply to your
> comments.
> > 1. Effectively, your signal after subtraction of correlated
> background will
> > average to zero within a centrality bin.
> >
> > Not true, In case of Fix-1 and Fix-2 substracting the correlated
> background
> > which is obtained from default AMPT, signal is not zero within
> centrality bin as
> > the correlated background is zero (Slide 18 & 19).
> [Fuqiang Wang] These plots are simply Delta gamma, right? Then they
> are expected to be non-zero. I don't understand the statement here
> "the correlated background is zero". What do you mean?
>
> > 2. You divide this centrality bin into 10 bins according to your
> dumbbell variable,
> > in real event and in shuffled event. You take the difference of two,
> so you're
> > deemed to have some bins positive and other bins negative. You are
> always
> > going to have CME signal no matter what (except the rare case where
> all bins
> > are zero).
> >
> > Not true, In slide 24 (slide 25 for f_{CME}) we do not see any CME
> signal for
> > default AMPT.
> [Fuqiang Wang] How did you obtain the points on slide 25? Is it red -
> black and blue - black of some sort from slide 24? How were the black
> points on s25 obtained?
>
> > 3. I don't think you can take such a liberty to claim positive bins
> as CME signal
> > and ignore negative bins.
> >
> > We are categorising events depending on the back-to-back charge
> separation as
> > one divides events in to different collision centralities depending
> on the impact
> > parameter or event multiplicity. The positive bin corresponds to
> gamma positive
> > for opposite-sign charge pairs and gamma negative for same-sign
> charge pairs
> > which means same sign charge pairs are strongly correlated whereas
> opposite-
> > sign charge pairs are weekly correlated which is considered as the
> CME signal.
> > The negative bin corresponds to opposite-sign charge pairs strongly
> correlated
> > (negative gamma) and same-sign charge pairs weekly correlated
> (positive
> > gamma) those evens look
> > like normal events i.e, no CME signal.
> [Fuqiang Wang] Let me use your analogy of f_DbCs binning ßà
> centrality binning:
> Your selection is f_DbCs ßà my selection is Nch
> f_DbCs from events shuffled +/- particlesßà Nch from events shuffled
> charged/neutral particles
> Delta gamma ßà neutral/charged ratio
> We take difference between real signal and shuffled signal.
> You're seeing positive Delta gamma in large f_DbCs events; I'm seeing
> neutral/charged>1/2 in peripheral events and <1/2 in central events.
> I'll see this even when neutral/charged=1/3 is independent of
> centrality (not to say possibly centrality-dependent neutral/charged).
> This is called selection bias.
> I cannot claim those neutral/charged>1/2 events as some exotic
> physics, and ignore the neutral/charged<1/2 events (or vice versa).
>
> > Thanking you,
> >
> > With best regards,
> > Jagbir Singh
> > Panjab University
> > Chandigarh
> >
> > On 2021-05-06 13:23, jagbir wrote:
> > > Dear all,
> > >
> > > These are our email exchange from December last year. We have
> answered
> > > all the comments earlier.
> > > Please check.
> > >
> > > Thank you,
> > > Jagbir Singh
> > > Panjab University
> > > Chandigarh
> > >
> > >
> > > On 2020-12-17 16:40, jagbir wrote:
> > >> Dear Fuqiang,
> > >>
> > >> Please find my replies here below:
> > >>
> > >> In the rightmost data points, the f_cme signals appear negative
> > >> beacuse of substracting the correlated background. But we
> interpret
> > >> CME-like signal if gamma_ss is negative and gamma_os is positive
> > >> which is the case for leftmost data points whereas for the
> rightmost
> > >> data points gamma_ss is positive and gamma_os is negative, so
> these
> > >> rightmost points do not correspond to CME-like.
> > >> So, for the rightmost data points, we can not interpret it as
> > >> negative f_cme signal.
> > >> The rightmost points correspond to normal behavior where opposite
>
> > >> sign charged particles are correlated and same sign charged
> particles
> > >> are uncorrelated.
> > >>
> > >> Thank you,
> > >>
> > >> With regards,
> > >> Jagbir Singh
> > >>
> > >> On 2020-12-16 03:40, Wang, Fuqiang wrote:
> > >>> Jagbir,
> > >>>
> > >>> Thanks for the plot. So you interpret the leftmost points as
> from
> > >>> CME and extract a CME fraction from it. What physics would you
> > >>> interpret the rightmost data points where the signals appear
> negative?
> > >>>
> > >>> Best regards,
> > >>> Fuqiang
> > >>>
> > >>>
> > >>>
> > >>>> -----Original Message-----
> > >>>> From: jagbir <jagbir AT rcf.rhic.bnl.gov>
> > >>>> Sent: Tuesday, December 15, 2020 8:55 AM
> > >>>> To: Wang, Fuqiang <fqwang AT purdue.edu>
> > >>>> Cc: STAR Flow, Chirality and Vorticity PWG
> > >>>> <star-fcv-l AT lists.bnl.gov>; star-cme-
> focusgroup-l AT lists.bnl.gov;
> > >>>> aggarwal AT pu.ac.in
> > >>>> Subject: Re: [Star-fcv-l] FCV PWG meeting, 18/Nov/2020 (Wed)
> 9:30am
> > >>>> (New York time zone)
> > >>>>
> > >>>> Dear Fuqiang,
> > >>>>
> > >>>> Please find my replies below:-
> > >>>>
> > >>>> ------------------------------
> > >>>>
> > >>>>       1. because your selection is predominated by statistical
> > >>>> fluctuations yet
> > >>>>       you're applying a cut on those statistical fluctuations.
> > >>>>
> > >>>>       Our selection is not by statistical fluctuations but
> based on
> > >>>> fractional
> > >>>>       Dumbbell charge separation in the data. However, similar
> type
> > >>>> of charge
> > >>>>       separation can be due to statistical fluctuations, to
> account
> > >>>> for that
> > >>>>       we are using charge reshuffle. Now we are having about
> 160M
> > >>>> events.
> > >>>> It is
> > >>>>       seen that observed delta gamma in the data is large
> beyond
> > >>>> statistical
> > >>>>       fluctuations than those of charge reshuffle for  the top
> > >>>> 0-20%
> > >>>> Db+-max
> > >>>>       bins. The plot you asked is attached here with email.
> > >>>>
> > >>>> ------------------------------
> > >>>>
> > >>>>       2. I mean the max Dbmax_shuffle bin is a random
> collection of
> > >>>> events from
> > >>>>       this centrality bin.
> > >>>>
> > >>>>       The max Dbmax_shuffle bin is not a random collection of
> > >>>> events from
> > >>>>       this centrality bin. As explained earlier we generated
> charge
> > >>>> reshuffle
> > >>>>       events by reshuffling charges of partices in the real
> data in
> > >>>> a given
> > >>>>       collision centrality. So, charge reshuffle events are
> > >>>> completely independent
> > >>>>       sample from real data sample in  given centrality though
> > >>>> number of
> > >>>>       positive/negative charged partciles are kept same in each
>
> > >>>> reshuffle event
> > >>>>       corresponding to real data event. Again  Dbmax_shuffle
> bins
> > >>>> are made
> > >>>>       according to the fractional Dumbbell charge separation in
> the
> > >>>> charged
> > >>>>       reshuffle event sample for a given collision centrality.
> > >>>>
> > >>>> ------------------------------
> > >>>>
> > >>>> Thank you,
> > >>>> Jagbir Singh
> > >>>>
> > >>>>
> > >>>> On 2020-12-14 22:46, Wang, Fuqiang wrote:
> > >>>> > Jagbir,
> > >>>> >
> > >>>> > Please see my replies below.
> > >>>> >
> > >>>> > Best regards,
> > >>>> > Fuqiang
> > >>>> >
> > >>>> >
> > >>>> >
> > >>>> >> -----Original Message-----
> > >>>> >> From: jagbir <jagbir AT rcf.rhic.bnl.gov>
> > >>>> >> Sent: Monday, December 14, 2020 11:18 AM
> > >>>> >> To: Wang, Fuqiang <fqwang AT purdue.edu>
> > >>>> >> Cc: STAR Flow, Chirality and Vorticity PWG
> > >>>> >> <star-fcv-l AT lists.bnl.gov>;
> > >>>> >> star-cme-
> > >>>> >> focusgroup-l AT lists.bnl.gov; aggarwal AT pu.ac.in
> > >>>> >> Subject: Re: [Star-fcv-l] FCV PWG meeting, 18/Nov/2020 (Wed)
>
> > >>>> >> 9:30am (New York time zone)
> > >>>> >>
> > >>>> >> Dear Fuqiang,
> > >>>> >>
> > >>>> >>     Please find my replies below:-
> > >>>> >>
> > >>>> >> 1.   I understand your motivation doing that but I don't
> agree this is
> > >>>> >> the right approach
> > >>>> >>     (I think it causes biases).
> > >>>> >>
> > >>>> >>     Please let me know why this is not the right approach
> and
> > >>>> >> what kind of biases you meant.
> > >>>> > [Fuqiang Wang] because your selection is predominated by
> > >>>> > statistical fluctuations yet you're applying a cut on those
> > >>>> > statistical fluctuations.
> > >>>> >
> > >>>> > Can you plot (data-chrgR. Bkg) and (Correlated bkg) vs (Dbmax
>
> > >>>> > bin) on slide 25 so we can see the details better?
> > >>>> >
> > >>>> >>
> > >>>> >>
> > >>>> >> 2.   you have only one point left. Your f_cme is basically
> the
> > >>>> >>       (Delta gamma of those events in that Dbmax bin)
> > >>>> >>       - (Delta gamma of a random collection of events in the
>
> > >>>> >> same centrality bin which happen
> > >>>> >>       to have the same Dbmax_shuffle bin)
> > >>>> >>       - (Delta gamma of those same random events calculated
> > >>>> >> after the charges are shuffled)
> > >>>> >>       Do I understand it correctly?
> > >>>> >>
> > >>>> >>     If only one point is left as you wrote, please see the
> > >>>> >> explanation
> > >>>> >> below:
> > >>>> >>
> > >>>> >>     Here, there is nothing like random collection of events
> in
> > >>>> >> the same centrality bin.
> > >>>> > [Fuqiang Wang] I mean the max Dbmax_shuffle bin is a random
> > >>>> > collection of events from this centrality bin.
> > >>>> >
> > >>>> >>     We select events depending on Db+-max i.e., depending on
> the
> > >>>> >> back-to-back charge
> > >>>> >>     separation fDbCS = Db+-max-1. As you wrote only one
> point,
> > >>>> >> in that case it is the
> > >>>> >>     top 10% Db+-max events corresponding to maximum
> back-to-back
> > >>>> >> charge separation events.
> > >>>> >>     It is similar to selecting events in particular
> collision
> > >>>> >> centrality depending on
> > >>>> >>     the impact parameter or event multiplicity. As we have
> > >>>> >> selected in the data top 10%
> > >>>> >>     Db+-max corresponding to maximum back-to-back charge
> > >>>> >> separation events, in  same way
> > >>>> >>     we select events from charge reshuffle in the same
> collision
> > >>>> >> centrality for top 10%
> > >>>> >>     Db+-max(here Db+-max of charge reshuffle) corresponding
> to
> > >>>> >> maximum
> > >>>> >> back-
> > >>>> >> to-back
> > >>>> >>     separation. Now we get delta_gamma_data of real data
> events
> > >>>> >> corresponding to top
> > >>>> >>     10% Db+-max of data and delta_gamma_sta of charge
> reshuffle
> > >>>> >> events corresponding to top
> > >>>> >>     10% Db+-max of charge reshuffle for a given collision
> > >>>> >> centrality which gives
> > >>>> >>     us delta_gamma due to statistical fluctuations. Now for
> > >>>> >> correlated background we
> > >>>> >>     look for real events in the data corresponding to the
> top
> > >>>> >> 10%
> > >>>> >> Db+-max
> > >>>> >>   of charge
> > >>>> >>     reshuffle in a given centrality and get delta_gamma_cor
> from
> > >>>> >> those real
> > >>>> >>     data events.
> > >>>> >>
> > >>>> >>     Now the f_CME is obtained as
> > >>>> >>
> > >>>> >>     f_CME = N1*(delta_gamma_data - delta_gamma_sta -
> > >>>> >> delta_gamma_cor)/(delta_gamma_data * N)
> > >>>> >>
> > >>>> >>     Where N1 is number of events in top 10% Db+-max and
> > >>>> >>     N is total number of events in a given collision
> centrality.
> > >>>> >>
> > >>>> >> Thank you,
> > >>>> >> With regards,
> > >>>> >> Jagbir Singh
> > >>>> >>
> > >>>> >> On 2020-12-14 10:32, Wang, Fuqiang wrote:
> > >>>> >> > Jagbir,
> > >>>> >> >
> > >>>> >> > Thanks for your answers.
> > >>>> >> >
> > >>>> >> > To your questions:
> > >>>> >> >> Please clarify the following
> > >>>> >> >>       Of course you've also removed the large
> charge-shuffle
> > >>>> >> >> background which is basically
> > >>>> >> >>       an autocorrelation effect (sort to speak) due to
> the
> > >>>> >> >> Dbmax (and
> > >>>> >> >> Dbmax_shuffle)
> > >>>> >> >>       selection bias.
> > >>>> >> > I was just saying it in passing, referring to the fact
> that
> > >>>> >> > you're largely selecting on statistical fluctuations and
> > >>>> >> > trying to remove the auto-correlation effect by shuffling.
> It wasn't a
> > question.
> > >>>> >> >
> > >>>> >> >>       Please explain the following:
> > >>>> >> >>       So is your finite signal really due to the
> difference
> > >>>> >> >> between the average of ratios
> > >>>> >> >>       and the ratio of averages (or perhaps also due to
> > >>>> >> >> residual effect from shuffling)?
> > >>>> >> > I was referring to the fact that if you had a single Dbmax
> bin (i.e.
> > >>>> >> > taking average first and then ratio) then you'd get zero
> > >>>> >> > signal by definition. You now have 10 bins and take ratios
>
> > >>>> >> > first in each bin and then take average of the ratios, and
> get a positive
> > signal.
> > >>>> >> > During the focus meeting discussion, it was made clear
> that
> > >>>> >> > your analysis required multiple Dbmax bins, not taking
> average
> > >>>> >> > of all bins, but only those with Delta gamma > 0. So now I
>
> > >>>> >> > think I understand technically how you did it. I
> understand
> > >>>> >> > your motivation doing that but I don't agree this is the
> right
> > >>>> >> > approach (I think it causes
> > >>>> biases).
> > >>>> >> > So let me try to understand better:
> > >>>> >> > On slide 9 of your focus meeting presentation
> > >>>> >> >
> https://drupal.star.bnl.gov/STAR/system/files/CME_FOCUS.pdf,
> > >>>> >> > you
> > >>>> >> > state:
> > >>>> >> > (1) If Delta gamma_bkg. is negative then it is taken as
> zero.
> > >>>> >> > (2) If gamma_SS is not negative and gamma_OS is not
> positive
> > >>>> >> > then delta gamma = 0.
> > >>>> >> > Now to slide 25, let's take one centrality say 40-50%, you
>
> > >>>> >> > have the blue points (signal) and red+green points (bkg).
> The
> > >>>> >> > 8 points to the right of this centrality: all of them have
>
> > >>>> >> > negative bkg and negative Delta gamma, so they are not
> counted
> > >>>> >> > in your calculation of CME fraction. Now you're left with
> the
> > >>>> >> > two leftmost points. Do both points satisfy (2) above? I
> know
> > >>>> >> > both points seem to have
> > >>>> >> > bkg>0 & Delta
> > >>>> >> > gamma>0 but it's unclear if they satisfy SS<0 & OS>0.
> Assume
> > >>>> >> > gamma>they do,
> > >>>> >> > then you're taking average of these two data points. For
> the
> > >>>> >> > sake of simplicity, let me say you have only one point
> left.
> > >>>> >> > Your f_cme is basically the (Delta gamma of those events
> in
> > >>>> >> > that Dbmax bin)
> > >>>> >> > - (Delta gamma of a random collection of events in the
> same
> > >>>> >> > centrality bin which happen to have the same Dbmax_shuffle
>
> > >>>> >> > bin)
> > >>>> >> > - (Delta gamma of those same random events calculated
> after
> > >>>> >> > the charges are shuffled) Do I understand it correctly?
> > >>>> >> >
> > >>>> >> > Best regards,
> > >>>> >> > Fuqiang
> > >>>> >> >
> > >>>> >> >
> > >>>> >> >
> > >>>> >> >> -----Original Message-----
> > >>>> >> >> From: jagbir <jagbir AT rcf.rhic.bnl.gov>
> > >>>> >> >> Sent: Sunday, December 13, 2020 10:12 AM
> > >>>> >> >> To: Wang, Fuqiang <fqwang AT purdue.edu>
> > >>>> >> >> Cc: STAR Flow, Chirality and Vorticity PWG
> > >>>> >> >> <star-fcv-l AT lists.bnl.gov>;
> > >>>> >> >> star-cme-
> > >>>> >> >> focusgroup-l AT lists.bnl.gov; aggarwal AT pu.ac.in
> > >>>> >> >> Subject: Re: [Star-fcv-l] FCV PWG meeting, 18/Nov/2020
> (Wed)
> > >>>> >> >> 9:30am (New York time zone)
> > >>>> >> >>
> > >>>> >> >> Dear Fuqiang, all,
> > >>>> >> >>
> > >>>> >> >>    Sorry for not answering your email. Infact, I did not
> look this
> > >>>> >> >>    email. Please go through my replies below:
> > >>>> >> >> ------------------------
> > >>>> >> >>
> > >>>> >> >>   1. A few events do not satisfy this cut so not
> including in
> > >>>> >> >> it
> > >>>> >> >> Db+-max
> > >>>> >> >>      but in overall calculations all events are included.
>
> > >>>> >> >>
> > >>>> >> >>   2. Yes
> > >>>> >> >>
> > >>>> >> >>   3. We reshuffle charges in each event. We donot
> randomize
> > charges
> > >>>> >> >>      according to the positive/negative charge ratio of
> the
> > >>>> >> >> given event.
> > >>>> >> >>      In fact, we pick up one event and reshuffle
> > >>>> >> >> positive/negative charges
> > >>>> >> >>      keeping theta,  phi, number of postive charges and
> > >>>> >> >> number of negative
> > >>>> >> >>      charges as such. After this we calculate gamma
> correlator.
> > >>>> >> >> This procedure
> > >>>> >> >>      is repeated for each event. The Db+-max of reshuffle
>  is
> > >>>> >> >> a bit bit wider
> > >>>> >> >>      than the  real distribution which may be due to some
>
> > >>>> >> >> correlations in the
> > >>>> >> >>      real data whereas reshuffle is purely randomize.
> Db+-max
> > >>>> >> >> binning is
> > >>>> >> >>      done on the basis of same fractions.
> > >>>> >> >>
> > >>>> >> >>   4. Let me explain this point
> > >>>> >> >>
> > >>>> >> >>      We pick up a real data event and calculate following
>
> > >>>> >> >>      i)  Dbmax+- of real data event
> > >>>> >> >>      ii) reshuffle charges in an event
> > >>>> >> >>
> > >>>> >> >>      iii) again calculate Dbmax+- and termed it Db+-max
> of
> > >>>> >> >> charge reshuffle
> > >>>> >> >>      iv)  calculate gamma of real data event
> > >>>> >> >>      v)   calculate gamma of reshuffle event
> > >>>> >> >>
> > >>>> >> >>      Now for a given centrality
> > >>>> >> >>      Steps i) to v) repeated for each event. Db+-max
> (data)
> > >>>> >> >> and
> > >>>> >> >> Db+-max(reshuffle)
> > >>>> >> >>      sliced into ten percentile bins.
> > >>>> >> >>      Now average gamma is found in every sliced Db+-max
> > >>>> >> >> (data) and
> > >>>> >> >> Db+-max(reshuffle)
> > >>>> >> >>      from the respective event samples. It should be
> noted
> > >>>> >> >> that events in the top
> > >>>> >> >>      say 10% Db+-max(data) are not the same as in the top
> 10%
> > >>>> >> >> Db+-max(reshuffle) i.e,
> > >>>> >> >>      real events in the top 10% Db+-max(data) are
> different
> > >>>> >> >> from those top 10%
> > >>>> >> >>      Db+-max(reshuffle). Now the correlated background is
>
> > >>>> >> >> caculated from the real events
> > >>>> >> >>      corresponding to the top 10% Db+-max(reshuffle)
> events.
> > >>>> >> >>
> > >>>> >> >>       Please clarify the following
> > >>>> >> >>
> > >>>> >> >>       Of course you've also removed the large
> charge-shuffle
> > >>>> >> >> background which is basically
> > >>>> >> >>       an autocorrelation effect (sort to speak) due to
> the
> > >>>> >> >> Dbmax (and
> > >>>> >> >> Dbmax_shuffle)
> > >>>> >> >>       selection bias.
> > >>>> >> >>
> > >>>> >> >>   5.  Db+-max distribution is sliced in to ten percentile
>
> > >>>> >> >> bins which represent
> > >>>> >> >>       different amount of charge separation in each
> sliced
> > >>>> >> >> db+-max bin.
> > >>>> >> >> Let us
> > >>>> >> >>       say we have Db+-max = 2, in this case fractional
> > >>>> >> >> dumbbell charge separation
> > >>>> >> >>       f_DbCS = Db+-max-1=1 i.e., 100% back-to-back charge
>
> > >>>> >> >> separation i.e.,
> > >>>> >> >>       positive charged particles on one side of the
> dumbbell
> > >>>> >> >> and negative charge
> > >>>> >> >>       particles on other side of the dumbbell. So,
> computing
> > >>>> >> >> gamma in different
> > >>>> >> >>       Db+-max and calculating things is different from
> just
> > >>>> >> >> making a single wide
> > >>>> >> >>       bin as you mentioned. This method is designed to
> get
> > >>>> >> >> CME-like enriched sample
> > >>>> >> >>       in given collision centrality as one divides all
> events
> > >>>> >> >> into different collision
> > >>>> >> >>       centralities depending on either the impact
> parameter
> > >>>> >> >> or event multiplicity but
> > >>>> >> >>       one does not study all events taken together
> without
> > >>>> >> >> making different
> > >>>> >> >>       collision centrality classes. However, for a single
>
> > >>>> >> >> wide
> > >>>> >> >> Db+-max bin as you
> > >>>> >> >>       wrote we will get zero signal.
> > >>>> >> >>
> > >>>> >> >>       Please explain the following:
> > >>>> >> >>
> > >>>> >> >>       So is your finite signal really due to the
> difference
> > >>>> >> >> between the average of ratios
> > >>>> >> >>       and the ratio of averages (or perhaps also due to
> > >>>> >> >> residual effect from shuffling)?
> > >>>> >> >>
> > >>>> >> >>
> > >>>> >> >> Thank you,
> > >>>> >> >>
> > >>>> >> >> with regards,
> > >>>> >> >> Jagbir Singh
> > >>>> >> >>
> > >>>> >> >>
> > >>>> >> >>
> > >>>> >> >> On 2020-11-18 23:18, Wang, Fuqiang wrote:
> > >>>> >> >> > Hi Jagbir,
> > >>>> >> >> >
> > >>>> >> >> > Your results are quite interesting. I have a few
> further
> > >>>> >> >> > questions about the details of your analysis:
> > >>>> >> >> > 1. For each event you have Dbmax with the condition of
> > |Dbasy|<0.25.
> > >>>> >> >> > You bin events of each centrality in Dbmax. You use all
>
> > >>>> >> >> > events in your analysis (i.e. you're not throwing away
> > >>>> >> >> > events based on Dbmax or Dbasy), right?
> > >>>> >> >> > 2. In your calculation of gamma=<...>/v2c for a
> particular
> > >>>> >> >> > Dbmax bin of a given centrality, the v2c is calculated
> > >>>> >> >> > using those events only, right?
> > >>>> >> >> > 3. For the charge reshuffle, you reshuffle the charges
> of
> > >>>> >> >> > all events, and repeat your analysis from step 1 (i.e.
> you
> > >>>> >> >> > treat this as a completely separate "new" data sample),
>
> > >>>> >> >> > right? Did you "randomize" the charges according to the
>
> > >>>> >> >> > positive/negative charge ratio of the given event? On
> s11,
> > >>>> >> >> > the Dbmax_shuffle distribution is a bit wider than the
> real
> > >>>> >> >> > distribution, do you understand why? How do you bin the
>
> > >>>> >> >> > Dbmax and Dbmax_shuffle into
> > >>>> >> >> > 10 bins, respectively (same bin edges or same
> fractions)?
> > >>>> >> >> > 4. Your correlated background gamma is calculated for
> the
> > >>>> >> >> > Dbmax bin where Dbmax is from the charge-shuffled
> events,
> > >>>> >> >> > but using restored charges, right? If so, then you're
> > >>>> >> >> > effectively taking gamma difference between Dbmax_i
> events
> > >>>> >> >> > and Dbmax_shuffle_i events (which are different
> events),
> > >>>> >> >> > right? Of course you've also removed the large
> > >>>> >> >> > charge-shuffle background which is basically an
> > >>>> >> >> > autocorrelation effect (sort to
> > >>>> >> >> > speak) due to the Dbmax (and Dbmax_shuffle) selection
> bias.
> > >>>> >> >> > 5. You divide Dbmax (and Dbmax_shuffle) into 10 bins
> and do
> > >>>> >> >> > your analysis in each bin separately, and then take the
>
> > >>>> >> >> > weighted average for your f_cme result. You could just
> use
> > >>>> >> >> > a single wide Dbmax (and
> > >>>> >> >> > Dbmax_shuffle) bin, then in principle you should get
> zero
> > >>>> >> >> > signal because the correlated "background" is your real
>
> > >>>> >> >> > signal since they are now identical event sample. So is
>
> > >>>> >> >> > your finite signal really due to the difference between
> the
> > >>>> >> >> > average of ratios and the ratio of averages (or perhaps
>
> > >>>> >> >> > also due to residual effect from
> > >>>> shuffling)?
> > >>>> >> >> >
> > >>>> >> >> > This is a complicated analysis. It would be really good
> to
> > >>>> >> >> > have more discussions so the details can flesh out
> better.
> > >>>> >> >> >
> > >>>> >> >> > Thanks,
> > >>>> >> >> > Fuqiang
> > >>>> >> >> >
> > >>>> >> >> >
> > >>>> >> >> >
> > >>>> >> >> >> -----Original Message-----
> > >>>> >> >> >> From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> On
>
> > >>>> >> >> >> Behalf Of jagbir via Star- fcv-l
> > >>>> >> >> >> Sent: Tuesday, November 17, 2020 10:49 AM
> > >>>> >> >> >> To: ShinIchi Esumi
> <esumi.shinichi.gn AT u.tsukuba.ac.jp>;
> > >>>> >> >> >> STAR Flow, Chirality and Vorticity PWG
> > >>>> >> >> >> <star-fcv-l AT lists.bnl.gov>
> > >>>> >> >> >> Subject: Re: [Star-fcv-l] FCV PWG meeting, 18/Nov/2020
>
> > >>>> >> >> >> (Wed) 9:30am (New York time zone)
> > >>>> >> >> >>
> > >>>> >> >> >> Dear ShinIchi, Prithwish and Jiangyong,
> > >>>> >> >> >>
> > >>>> >> >> >> I would like to give "Update on event by event charge
> > >>>> >> >> >> separation in
> > >>>> >> >> >> Au+Au collisions at 200GeV with STAR detector"
> > >>>> >> >> >>
> > >>>> >> >> >> Please add me to agenda.
> > >>>> >> >> >> I will post my slides later.
> > >>>> >> >> >>
> > >>>> >> >> >> Thankyou,
> > >>>> >> >> >> Jagbir Singh
> > >>>> >> >> >>
> > >>>> >> >> >> On 2020-11-16 15:57, ShinIchi Esumi via Star-fcv-l
> wrote:
> > >>>> >> >> >> > Dear FCV PWG colleagues
> > >>>> >> >> >> > We will have our weekly FCV PWG meeting on coming
> > >>>> >> >> >> > Wednesday
> > >>>> >> >> >> > 18/Nov/2020
> > >>>> >> >> >> > 9:30AM (in BNL) at our usual time and place. So if
> you
> > >>>> >> >> >> > have anything to present, please let us know and
> please
> > >>>> >> >> >> > post your slide by
> > >>>> >> >> Tuesday.
> > >>>> >> >> >> > We'll talk about the "HLT express productions" in
> the
> > >>>> >> >> >> > beginning of the meeting as you see in the agenda
> page.
> > >>>> >> >> >> > Jiangyong, please send a link to your slide from
> last week.
> > >>>> >> >> >> >
> > >>>> >> >> >> > The zoom room link, ID and password are in our usual
>
> > >>>> >> >> >> > drupal agenda page below.
> > >>>> >> >> >> > Please also keep in mind that all the preliminary
> plots
> > >>>> >> >> >> > should have already been there in the summary area
> below.
> > >>>> >> >> >> > Best regards, Jiangyong, Prithwish and ShinIchi
> > >>>> >> >> >> >
> > >>>> >> >> >> > Meeting agenda page with zoom link :
> > >>>> >> >> >> >
> https://drupal.star.bnl.gov/STAR/blog/jjiastar/bulkcorr
> > >>>> >> >> >> >
> > >>>> >> >> >> > Preliminary page :
> > >>>> >> >> >> >
> https://drupal.star.bnl.gov/STAR/pwg/bulk-correlations/b
> > >>>> >> >> >> > ulkco
> > >>>> >> >> >> > rr-
> > >>>> >> >> >> > pre
> > >>>> >> >> >> > lim inary-summary
> > >>>> >> >> _______________________________________________
> > >>>> >> >> >> > Star-fcv-l mailing list
> > >>>> >> >> >> > Star-fcv-l AT lists.bnl.gov
> > >>>> >> >> >> > https://lists.bnl.gov/mailman/listinfo/star-fcv-l
> > >>>> >> >> >> _______________________________________________
> > >>>> >> >> >> Star-fcv-l mailing list
> > >>>> >> >> >> Star-fcv-l AT lists.bnl.gov
> > >>>> >> >> >> https://lists.bnl.gov/mailman/listinfo/star-fcv-l