LHCb-Paper-2014-048:
Precision measurement of the mass and lifetime of the Ksi_b^- baryon

A few Nikhef comments on this short paper:

Line 12:
Replace "which are in good agreement" by 
"and their values are in good agreement".
Otherwise we write that the measured "precisions" 
are in agreement with the predictions.

Line 16:
It is not made clear here why we refer to the lifetime ratio of 
Ksi_b^0 and Lambda_b^0.

Line 19:
Replace "our understanding" by "the understanding".
as it sounds rather pedantic in combination with "general interest" 
and general "benefit" (sic).
In fact the whole sentence "It is also of general ..." should be removed 
as there is no following prove or evaluation of this statement.

Line 21:
Replace "lifetime, measured using ..., yielded values of" by
"lifetime measurements, using ..., yielded values of".
Lifetime cannot be a "subject" that yields values.

Line 25:
Replace "precise mass measurements" by "precise mass values".

Lines 28-30:
We find this difficult to read, while the bracket notation for the
mass splitting is confusing; it looks like a multiplication.

We propose to replace "6.24 ... (6.4 ...) when extrapolating from 
the measured isospin splitting M(Ksi- ... (M(Ksi_c ...) [22]" by
"6.24 ... and 6.4 ... by extrapolating the measured isospin mass 
splitting of Ksi and Ksi_c, respectively [22]".
And thus we avoid the confusing expression M()-M() (M()_M()).

Line 31: 
Replace "than that that of the" by "than the mass of the".
Two times "that" that refer to "the mass".

Line 32:
- Replace "would" by "will" or "may", as we refer to the future.
- Remove ", or their mass splitting"d, or
replace "or" by "and".

Line 36:
Replace "normalized to the ... decay" by 
"compared to that of the Lambda_b^0 baryon in the ... decay".
"Normalized" is the wrong description,
certainly for the mass measurements.

Line 91: 
What is the systematic effect on the mean lifetime related to multiple 
candidates? 
In an extreme case one could keep the longest or shortest lifetime
candidates only and see by how much the mean lifetime is affected.

Line 150:
Replace "exponential parameter" by "exponential coefficient"
or remove "the exponential parameter".

Line 153-156: 
Since the TIS / TOS samples are large I wonder by how
much the observables (lifetimes/masses) are affected 
when splitting the sample in TIS and TOS parts. 
(This is probably more conservative than the systematic error 
described in lines 181-183).

Line 160:
Are we sure that we consider only the "systematic" uncertainties?

Line 203:
We miss a predicted mass difference value here, as announced 
in the abstract
(These measurements are ... consistent with theoretical expectations).