STAR Flow, Chirality and Vorticity PWG

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

Dear Fuqiang,

Thanks for your reply. Please see my reply below:

1. I'm confused. Why does default AMPT give Delta gamma = 0?

Because there is no CME in default AMPT.

2. Does the default AMPT have Delta gamma = 0 as you said above?

Yes

3. you brought up the analogy of f_DbCs to centrality, so I was using 
neutral/charged to tell you that your enhanced f_DbCs events are mostly, 
if not all, selection bias. The neutral/charged in my example serves 
different purpose from the +/- in your analysis. Please think about it.

I brought up the analogy with centrality to make my point, as selecting 
events with impact parameter is not a selection bias, like that 
selecting events with f_DbCS is not a selection bias. f_DbCS is a event 
characteristic as impact parameter. Small impact parameter leads to high 
multiplicity events whereas large impact parameter give rise to small 
multiplicity events. As I wrote ALICE collaboration divided the each 
collision centrality further in to ten bins according to the Q value 
(Phys. Lett. B777, 151 (2018)). It selects larger flow events with large 
Q value. Elliptic flow increases with increasing Q.
You did not tell me wether or not it is a selection bias.

4. I did not understand your statement "enhanced f_DbCS events are 
mostly, if not all, selection bias".

5. Regarding The neutral/charged

I'm seeing neutral/charged>1/2 in peripheral events and <1/2 in central 
events.

You did not write how you got these numbers. Is it from simulation?
It can not happen in shuffling as I wrote earlier.

Thank you,

with Best Regards,
Jagbir Singh
Panjab University
Chandigarh

On 2021-05-16 06:22, Wang, Fuqiang wrote:
> Jagbir,
>
> See comments below.
>
> Best regards,
> Fuqiang
>
> > -----Original Message-----
> > From: jagbir <jagbir AT rcf.rhic.bnl.gov>
> > Sent: Friday, May 14, 2021 3:01 PM
> > To: Wang, Fuqiang <fqwang AT purdue.edu>
> > Cc: 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; 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,
> >
> > 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.
> >
> _[Fuqiang Wang] I'm confused. Why does default AMPT give Delta gamma =
> 0?_
>
> > 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.
> _[Fuqiang Wang] __Does__ the default AMPT __have Delta gamma = 0 as
> you said above?_
> > 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?
> _[Fuqiang Wang] __Because you brought up the analogy of _f_DbCs _to
> centrality, so I was us__ing__ neutral/charged __to tell you that your
> enhanced _f_DbCs _events are mostly, if not all, selection bias.__ The
> neutral/charged in my example serves diff__erent purpose from the +/-
> in your analysis.__ Please think about it._
>
> > 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