

Section 2.3 - Just to repeat the comment in my email from earlier. It seems to me that Eq (8) and some of the DGLAP stuff around Eq (15) is overlapping with what would go in the previous section, as Jun as pointed out.

 

So I think we might want to consider reorganising this somehow. For example (not the only choice), a small section on hadroproduction factorization, one on DIS factorization, and one on DGLAP evolution. To keep the DIS section of a similar length to the hadroproduction we could move some of the quark parton model info (Eqs 9-14 etc) to the DIS part of section 3, where PDF sensitivity might be discussed.


Fig. 2 - Might it be better to be less NNPDF specific and remake these plots with a PDF4LHC set? This would seem more appropriate for a review.


Section 3.2 - My understanding was that in these sections we planned to describe what PDF sensitivity a given measurement had, in which case some of Section 2.3 might go here (see above). This is clearly to be discussed though.


Table 1 - As I said in my email, the x regions need to be agreed on. This is perhaps better done/checked in real time when we talk. I personally find the '+X' a bit distracting, and the 'pp->' a bit repetitive, so would prefer to just have one heading saying e.g. 'LHC' and then the final state, with a comment in the caption that these are all inclusive unless otherwise stated. This doesn't work so well for the fixed target/DIS though. Another thing is whether to have a separate LHC table.


Section 3.2.2 - The first part is great I think, but I do wonder if all of the details of FONLL are needed for a review. Somehow the physics seems to me to be contained in Eqs. (31) and (32) (+ some words of explanation)- I am not sure if the additional equations/definitions help in this context. It might also be better to say at least a little about the other schemes. Again, just my immediate reaction and certainly not something I feel so strongly about - I do also see the benefit of giving specifics.


Section 3.2.3 - The bullet points look good I think, so perhaps we need to agree on using these when e.g. listing experimental data, to achieve overall consistency.


Section 3.3 - I am not sure about Fig.5 (right), which looks a bit messy to me.


Section 3.4 - My sections are broken up into quite regimented 'PDF sensitivity, Data, Tools and theory status' (probably to be hidden in the TOC). My personal opinion is that this helps achieve greater clarity. On the other hand this sectioning is less sensible for e.g. the DIS section arguably, and more generally it might seem artificial. Anyway this is something we need to agree on using (or not).


Section 3.4.1 - Possibly a bit too long. Might summarise the Tevatron and fixed target stuff to be shorter. A plot showing the impact on PDFs of a given measurement is needed (todo), and also a replacement of Fig. 8.


Section 3.4.1 - Eqs (33)-(35) possibly not needed now we have table 1 (could just refer to that). See also Eqs (50) and (51).


Section 3.6 - Impact on PDF plot should be added.


Section 3.7 - I guess the final part about single top production is to be expanded on?


Section 4.1.3 - On reflection I think it would be good to add a discussion of intrinsic charm here. Also mentioning top quarks, the photon (with reference to the EW section), leptons, and other electroweak partons would make sense.


Section 4.5 - Maybe this could benefit from some subsectioning/bullet points for the various combination methods?


Section 5 - General comment. Looking at this I think we need to find a middle ground here. My MMHT and ABM sections are certainly too short, but I also think that the CT and NNPDF sections are too long. I think ~2 max rather than ~3 pages would be optimal here, which to me seems too long for a review. I don't think this will require any huge changes, just a bit of streamlining, and moving some parts to earlier sections (see below).


Section 5.1 - Some of the parameterisation stuff (e.g. Eq (84)) overlaps with section 4.1.1, so this could be shortened, with a suitable reference to that section.


Section 5.1 - Discussion of d/u is perhaps a bit too detailed, and possibly in places overlapping with section 3.4.1.


Section 5.1 - Discussion about the Hessian method/uncertainties could be streamlined a bit, with suitable reference to section 4.2.1. In fact maybe even some of this could be moved to that section?


Section 5.2 - Too short, needs more details + some plots.


Section 5.3 - I think pages 48-49, which concentrate on the NNPDF history, should be streamlined. Of course the earlier fits are of interest to see how things have progressed, but I think too much detail is given. For example discussing how the strangeness was treated in NNPDF1.2 seems too detailed to me. I also have in mind achieving some uniformity with the other PDF sections, where generally this level of historical detail is not given.


Section 5.3 - The Bayesian reweighting part is hidden away here. I think it would useful to include a separate subsection on this in section 4, and move this there, with some added discussion.


Section 5.3 - Perhaps better to move some of the intrinsic charm to section 4.1.3, where this can be discussed along with the CT work? Of course it could still be mentioned here, I just have in mind the details/motivation.


Section 5.4 - Too short, needs a plot or two, more details about how higher twists are treated, and perhaps even a little more discussion of flavour schemes/alpha_s.


