Dear Elena, Roberta and Torsten,
thank you very much for the draft - you have really performed a most
admirable task, it is a wonderful summary.
I have looked at the sections you assigned me, and I find that they
are fine as they are. Just a small latex-nical point: if you write
fractions like dN/dx that way and not as dN\over dx or dN\frac dx,
then they don't become so minute.
OK
I'm afraid I do have a criticism concerning the introduction, again
on my favorite subject, calibrating quarkonium production. The
sentence
...is expected to be significantly suppressed with respect to the
proton-proton yield, scaled by the number of binary nucleon-nucleon
collisions."
is simply not correct. If, for whatever reason, the overall open
charm/bottom production is different in AA re scaled pp, then this
has to reflect on J/Psi production, whether there is suppession or
not. The scaled binary nucleon-nucleon collisions are only a reference
for quarkonia if total charm (or bottom) production in AA is binary
scaled pp production.
The last sentence on page 1 is incorrect for the same reason.
How about "In a hot and deconfined medium, in fact, quarkonium production is expected to be significantly suppressed with respect to the proton-proton yield, scaled by the number of binary nucleon-nucleon collisions, *as long as the total charm cross section remains unmodified.*"
For the last sentence on page 1, I propose: "The \raa is expected to be equal to unity if nucleus-nucleus collisions behave as a superposition of nucleon-nucleon interactions. This is, \eg, the case for electroweak probes (direct $\gamma$, W, and Z) that do not interact strongly~\cite{Afanasiev:2012dg,Chatrchyan:2012vq,Chatrchyan:2012nt,Aad:2012ew,Chatrchyan:2014csa}. Such a scaling is also assumed for the total charm cross section, although an experimental verification has large uncertainties at RHIC ($\approx25\%$)~\cite{Adare:2010de,Adamczyk:2014uip} and is lacking at the LHC (see discussion in Section~\ref{sec:hf_ref}). In this case,..."
You discuss all kinds of effects (cold nuclear matter, CGC, etc.)
on quarkonium formation, but implicitly assume always that open heavy
flavor production is not modified in AA, re binary scaled pp. Perhaps
a way out would be to simply state that and note that if this is not
true, it will lead to consequences discussed in 2.4.1.
In this context: it seems that section is the only one addressing open
heavy flavor. Would the title perhaps not better be just
Quarkonium Production in the LHC Era?
All the best for now - see you soon in Trento, I hope.
Helmut