-------- Forwarded Message --------

Subject:	RK* EB reading notes
Date:	Wed, 26 Apr 2017 13:35:51 +0200
From:	Vladimir Gligorov <Vladimir.Gligorov@cern.ch>
To:	LHCb-PAPER-2017-013-reviewers (LHCb-PAPER-2017-013-reviewers) <LHCb-PAPER-2017-013-reviewers@cern.ch>, lhcb-review-RD-RKstar (lhcb-review-RD-RKstar) <lhcb-review-RD-RKstar@cern.ch>

Dear All,

here are my notes from today’s meeting — many thanks to everyone for a very efficient meeting! I am afraid that I didn’t quite catch all the line by line comments… don’t type fast enough.

I am copying the review list for the analysis so that the people who have been following the ongoing physics discussions mentioned at the start of my notes can see what we discussed and decided.

Thanks,

Vava

== Discussion about the combination == 

We began the meeting by discussing whether or not to quote a combination of the two q2 bins, and if we did, whether to compute a significance from the SM or the improvement in the fit quality when comparing the SM to NP scenarios (what was done for the K*mumu paper and as suggested by Warwick). The second option was quickly rejected because it is not well defined, given the wide range of NP scenarios on the market, and because the comparison to the SM is extremely well defined and unambiguous, in contrast to the K*mumu case where the SM prediction is still debated because of hadronic uncertaintes (a point actually noted in the K*mumu paper). The first option (demanded in one way or another by CERN, NIKHEF, and Warwick) was discussed at more length since as it is at least well-defined and technically feasible. The meeting was nevertheless unanimous that for both physics reasons (the two bins probe different Wilson coefficients) and for political reasons we should not report such a combination, and should persist in this refusal in the face of potential journal requests to the contrary.

On the contrary we agreed to add something along the lines of a suggestion made by Guy

"Model-independent fits to the ensemble of FCNC data that allow for non-SM contributions [ref to somebody] lead to predictions for RK* in the central-q2 region that are similar to the value observed; smaller deviations are expected at low q2.   The larger data set currently being accumulated by LHCb will allow for more precise tests of these predictions.”

to the conclusions, partly addressing Zurich’s CDS comment.

== Discussion about quoting a BF of K*ee == 

The EB meeting unanimously agreed not to do it. The dedicated measurement of K*mumu uses a different q2 binning so cannot be trivially used to produce a K*ee BF, and extracting the BF from the RK* analysis alone would require a dedicated treatment of the systematics which would delay the paper, in contrast with strong requests from the collaboration (notably Warwick) to proceed as quickly as posisble to publication.

== Line by line == 

— Abstract —

typo on line 2

request to rephrase the second sentence

put sentence explaining what we mean by K* (recoed in KPi in a mass window) back into the abstract and conclusion

change “dielectron to dimuon” to “di-muon to di-electron”

— Introduction — 

line 3 change end of sentence to “and the model is referred to as exibiting LU”

line 7 “The absence of a dominant SM tree-level contribution means that such transitions are rare, and they are therefore sensitive…”

line 9 break sentence btw “particles” and “that”

line 10 “or as a change” => “or can change”

line 12 “where H represents a hadron containing an s quark”

Replace scripted R_H with non-scripted R_H, rephrase “equal to unity” with “close to unity”

line 20 add decimal places to definition of q2 range

line 21 performed by the LHCb collaboration. The measurement is made with a relative precision of… and is found to be …

Use curly “l” for lepton in line 23

line 25 drop FCNC

line 25 put commas around “neutral” drop “involving”

line 28 drop FCNC

line 30 don’t start sentence with LU

Line 35 This analysis -> The analysis

Add a sentence about how big the S-wave fraction is expected to be in line with the Warwick comment

Figure 1 : make caption coherent with diagram (tree level Z’)

Use a different symbol other than Delta for the leptoquark (coherent between plot and text)

line 51 “is measured to be lepton universal”

line 52 “a blind analysis was performed”

line 54 “the effect of … is not included …”

Table 1 and the later figures with theory predictions should be made coherent once the new numbers from Gino are available

Table 1 caption “Recent SM predictions for RK*"

line 56 comma before “as well”

— Detector and dataset — 

lines 84/85 give separate ET ranges for electrons and hadrons in trigger description

a couple of subsequent comments which I missed but I saw the proponents noted

— Electron reconstruction — 

line 95/96 then the electron and the photons typically deposit their energy in different calorimeter cells

Define “neutral cluster” before using it

line 124 clusters

line 128 resolution

line 130 and previously, drop Firstly/Secondly/Finally

line 131 require higher thresholds are imposed

line 136 not associated with a signal candidate

line 137 is worse in the electron case compared to the muons… 

then remove “in decays with electrons” from the end of that sentence

— Corrections to the Simulation — 

line 150 unbiased control samples selected from the data. 

Then break the sentence

line 156/157 remove description of tag-and-probe

Proponents to rethink explanation around 159-162 (is it clear that this is then applied to electrons?) and we come back to it for 2nd reading

line 165 “are used as a control sample in place of…”

line 166 statistics -> sample size

then break sentence then “The two … are compared and give … "

line 167 any B0 -> signal B0 candidate

do not hyphenate words where the first half ends in “ly”

line 174/177 in order to take into account

line 185 with all the previous corrections

line 186 drop “in the first and last steps”

think about explanation of interpolation on 190

line 191 remove “on all key observables”

— Selection of Signal Candidates — 

line 201 in order to form

line 203 chosen -> selected

reorder sentence on 201-202

line 204 is required to be small

line 206 break sentence, the “The direction is inferred from…”

line 211 priority ordered => which in order of precedence are

line 215 associated

line 218 decays -> candidates

line 221 drop “as explained in Sec 3”

line 222 drop “chosen to be”

line 226 and subsequently do not slant NN 

line 226 put reference after symbol definition

line 228 move “represent the signal” to before first comma

line 232 and subsequent use the already defined IPChi2 symbol

line 245 add information about what is actually done with the information from the kinematic fit

line 250 start sentence with “In the approximation that brems photons do not strongly modify… "

line 254 large resolution -> poor resolution

line 254 drop quality

check signficance/chi2 definitions

line 267/268 K->kaon, pi->pion

— Exclusive Backgrounds — 

line 268 move comma from after cases to after candidate

line 273 remove full stop after Refs

line 274 and can therefore…

line 280 interval around the known

line 282 has a branching fraction four orders of magnitude

line 296 mass hypothesis

line 297 These requirements result in…

— Fits to the KPill invariant mass distribution — 

line 309 add comma after reference 50

line 310/311 the mean and the width are allowed to vary in the fit

line 318 to the data in reference 52

line 322-326 proponents to think about whether this is unnecessary repetition

line 330 one or more clusters are recovered

line 330  comma after CB

line 334 being -> having been

line 336 change allowed to shift (scale) to "allowed to vary”

line 341 explain what “X” means, and swap “B0” for “B"

— Efficiencies — 

add q2 ranges to the plots

swap B0 for B in plots

put pull plots back into Figures 3/4

line 347 while the normalization is constrained

line 361 do not capitalize Bremsstrahlunhg

line 361 rephrase to make it clear that we go back to pre-FSR

line 363 in the low and central q2 regions, respectively

line 365 that->which

— Cross-checks — 

line 369 are performed… and are discussed

line 379 make “decay kinematics” more detailed and explicit

line 388 and is observed to be in agreement

line 391 The ratio of the efficiencies changes

line 394 Between data and simulation using both… and … candidates to test possible q2 dependence of the modelling

line 397 change the sPlot label to the standard LHCb one

line 405 break sentence before “while”

line 406 add comma after “similar"

— Systematic Uncertainties — 

line 413 and are described below

line 430 break sentence after considered

line 439 predicted to contaminate the central q2 region

line 440 remove word conservative

line 449 clarify “are applied” to what?

line 460 branching fraction

— Results —

line 484 drop “of proper width"

Figure 5 make legends bigger, space btw “ln” and “L” on y-axis

line 494 depending on the precise theory prediction used

add a qualitative statement about the correlation in the systematics

— Conclusions — 

Figure 6 make the caption more tediously verbose to explain what the B-factories actually did with their vetoes

line 496 This paper reports… 

add sentence proposed by Guy

add a statement about how the likelihoods will be placed on HEPData

— Appendices — 

Make primary vertex blob same size as secondary vertex blob in Fig A1

A1 caption “the brems photons that are not recovered… are assumed to follow… “

drop table B1

B1 caption “assign a cluster to a track unambiguously”

Fig B1/C1-4 make legend text bigger

mention BW colours in Fig captions

make inset in Fig C3 its own plot

slant “l” in theta_ll throughout

add the author list