Dear friends,
Here is a proposal for the general comment I would like to submit to the Bs->mumu paper along the lines as we discussed in the meeting last friday. I have understood in the mean time that the authors are working on a condensed version of the paper, so some of our comment might already be solved. However, I do think we should inform the authors of our opinion of the first draft.
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Dear authors,
This comments below result after a Nikhef group discussion of the Bs->mumu paper draft (noting that our local Bs->mumu experts were not involved). From your answers to other comments we have understood that you are currently preparing a shorter version of the paper, so we here give only our main, general, feedback. This is an excellent (and complex) analysis leading to an important result that will receive a lot of attention. However, it was generally commented in our group that the paper is very dense with information and difficult to read. Many intricacies of the analysis, although mentioned, are difficult to understand for an outsider. In several cases we had to turn to the analysis note to understand what was being done (the analysis note is of excellent quality!). We get the impression that the paper in its current state tries to include the wealth of information of the analysis note into a letter, and therefor becomes very difficult to read for an outsider.
In particular it was commented in our group that the "Analysis Strategy" section in the *analysis note* was much more helpful to understand the measurement than the corresponding section in the paper. (e.g. alpha = normalization factor or *single event sensitivity*).
Here are some examples that triggered our comments:
Section 5.1 It is hard to understand the exact role of MC. Although we understand that the measurement uses data as much as possible for normalization, the efficiency calculations are done by MC. However, the tracking uncertainty of 4%/track is taken from another paper, where it is calibrated with data from other channels. (By the way: is the value of 4% relevant for B->mumu?).
Section 5.2 This section is very dense with information and very difficult for a non-LHCb collaborator to understand. If TIS-TOS-ing is new to the reader, it is very difficult to understand the text on the bottom of page 7.
Section 6 Here several details of the analysis could be skipped in a letter. E.g the exact use of Crystal Ball functions and value of alpha (confusing notation with "normalization factor" alpha). The text of the determination of the GL with B->hh , and the solution to the trigger TIS complication using emulation is difficult to follow.
best regards, - Marcel for the Nikhef/VU groups