Comments from Y. Hayato, with replies from Rik. Gran. I.Introduction "There are many experimental neutrino programs" YH>> I'm not a native speaker but "neutrino experiments" and YH>> "experimental neutrino programs" sound differently. Don't they? RIK>> Yes. I would interpret "neutrino experiments" simply and narrowly, RIK>> such as neutrino oscillation experiments. But a program is larger, RIK>> and I am implying that K2K and others are making many measurements. "in the calculation of cross-sections, backgrounds, and nuclear corrections" YH>> Here, you suddenly use the word "backgroudns" but I'm afraid YH>> the reader is not able to figure out what kind of "backgrounds" YH>> you are talking about. RIK>> Improved now. "In this study..." YH>> You are explaining Q2 at first but it seems to better to explain YH>> about what you want to discuss about. Start with the description YH>> of MA (meaning of MA in the neutrino interactions). RIK>> Improved now. YH>> Also, please use consistent definition of K2K experiment. II.Cross-section and form factor expressions B. Other cross-sections "with modifications following Marteau" YH>> The latest analysis does not include Marteau's correction. RIK>> Removed from text. RIK>> The NC coherent pion background does not affect this analysis. C. Nuclear effects "The primary effect on this nucleon momentum distribution" YH>> This beginning is somewhat misleading. As you stated at the end YH>> of this sentence, the suppression is caused by Pauli-blocking YH>> effect. RIK>> Fixed. The primary effect (Pauli Blocking) leads the sentence. RIK>> Secondary effects then follow. "secondary pions and recoil protons" YH>> In the simulation, not only protons but neutrons are tracked. RIK>> Fixed. III.Experiment A. The beam and detectors "The wide band neutrino beam at KEK is produced when 12GeV protons hit an aluminum target." YH>> The word "when" is not incorrect but not accurate, I think. RIK>> As the start of this paragraph, it is fine. RIK>> By itself, without further description I agree it is not accurate. "The mu+ are absorbed by approx. 100 meters of earth" YH>> Quite a lot of muons are aborted by beam dump. RIK>> Improved. "There are small number of muons which need to be vetoed" YH>> This sentence appears suddenly. Therefore, reader might get YH>> confused. These muons are generated by neutrinos from the target YH>> and thus, they are background for "this measurement" but not YH>> the external ones. YH>> I think it is better to clarify (separate) external (accidental) YH>> backgrounds and neutrino beam correlated ones. RIK>> Improved "The near detector hall of" YH>> It is better to explain detector little bit earlier. Then, YH>> it will be easy to understand the explanations of the backgrounds. RIK>> Improved "The energy spectrum analysis is .." YH>> Please use consistent words for our analysis. YH>> Our neutrino oscillation analysis and the flux measurement in the YH>> near detector is coupled but they are separated physics analysis. YH>> At least, it is better to clarify these two differences. RIK>> Improved. B. The SciFi detector "Starting in 2002, there are additional .." YH>> I think they have not been used so far, it is not necessary to YH>> mention here. RIK>> I removed it. "When two tracks reach the MRD, .." YH>> These sentences can be located in the data sample part. RIK>> Improved "The Muon Range Detector is made of..." YH>> You have already use MRD in your descriptions. Therefore, it is YH>> necessary to explain MRD earlier. RIK>> The essential part of the MRD and its role is explained in III-A. RIK>> I think including the steel plate structure would detract from RIK>> the overview presented in III-A, so it is here instead. RIK>> This follows a consistent quantification of typial energy loss RIK>> for SciFi, SciBar, LG, and MRD in the previous paragraph. C. Data samples "The MC simulation includes..." YH>> Again, not only proton but neutron are simulated. RIK>> Fixed D. Muon momentum and angle distributions "if not all of this deficit is because there is too much coherent pion .." YH>> there is too much CC coherent pion... RIK>> Fixed IV ANALYSIS A. Calculating q2 and E_\nu "The resulting value of E_\nu resolution ..." YH>> There are discussions about sigma but how well the mean values YH>> agree with the predictions? RIK>> There is no simple discussion. The reconstruction is tuned to MC, RIK>> so the agreement is exact. Data/MC disagreement is affected by RIK>> the muon momentum scale uncertainty and is discussed separately. V Results and discussion B. Fit Results "The migration is expressed such that 0.90 means 10% of .." YH>> Someone may ask you like: YH>> Is the uncertainty of 1trk-2trk migration you quoted (5%) YH>> reasonable? or Are there any problem in the Monte-Carlo or YH>> fitting method? RIK>> True. The migration error we quote is based on detector effects only, RIK>> Other effects (interaction model? spectrum uncertainties?) are not RIK>> included in the quoted error, but are revealed by the pull. RIK>> I think, but could not confirm that these parameters are trying RIK>> to produce a better fit in the 2-track nonQE bin at 0.2 GeV2. RIK>> This could be related to your other comment below. YH>> In the paper, you mention about "proton re-scattering is YH>> 1.43 if we fix the migration parameter." But again, one YH>> may feel that 1.43 is fairly large. YH>> It is better to have another explanation to this. YH>> (Did you try to set migration=0.95 and obtain parameters?) RIK>> I had not thought of this. RIK>> Setting the migration to 0.95 (the 1-sigma boundary) yields RIK>> a similar chisquare to the best fit, and the following parameters RIK>> MA = 1.20, Proton rescattering 1.20, NQEQE = 1.26, NORM = .975 RIK>> and Chisquare = 261. RIK>> I agree this is a better example to use in the paper. RIK>> Changed. "MA=1.20" YH>> Did you try to obtain MA by using Monte-Carlo as input(data) YH>> instead of using real data and check the consistency? YH>> (Here, you have to use dipole vector coupling to get MA=1.1. YH>> Also, it will be interesting if you use "different" vector YH>> coupling and see the difference. This will give a qualitative YH>> explanation of the result shown in section E. RIK>> Yes, and it is consistent. I actually did a large number of RIK>> tests using MC as input-data, especially to study the systematics. "Fig. 8" YH>> If I take look at the right most figures, the K2K-I and K2K-II YH>> data show some discrepancy. This seems to affect MA value from YH>> K2K-I and K2K-II. Am I correct? (Though they are non-QE..) RIK>> Yes. My interpretation is that the MA for 1-pi events would RIK>> account for some, or most of this disagreement. However, I RIK>> do not have a suitable reweighting function for MA-1pi that RIK>> would allow me to add an extra parameter for this fit. RIK>> I use the central value of 1.1 and a separate analysis of the error, RIK>> and the effect on the QE MA is included in the total error. "Fig. 9" YH>> If I take look at this figure, the q2 cut you choose was YH>> "bottom". Do you have any explanation? (especially for the YH>> higher q2 cut values. I don't care about the lower cut value.) RIK>> No. The shape of the right hand side is affected significantly RIK>> by the systematic errors. This plot really only demonstrates that RIK>> the fits do not become unphysical -- 1.80 or something. "Fig. 10" YH>> The lowest energy bin (0.5 to 1.0), how large the fraction of YH>> 2-track QE sample is? RIK>> You mean the relative size of the QE sample, or the relative purity? RIK>> The purity is about the same, the relative size is smaller. RIK>> I don't have exact numbers, but I think the QE fraction there is RIK>> similar (~60%). That particular energy range has about 80% of its RIK>> data removed with the Q2 > 0.2 cut. So they don't have much effect RIK>> on the fit, nor yield information about the energy dependence of MA. D. Systematic uncertainties 1. Muon momentum scale YH>> Could you explain why +1% of momentum scale will change the YH>> MA by -0.05GeV qualitatively? RIK>> There is such a description ("the Q2 distribution becomes RIK>> more or less compressed") I think the effect is that simple. RIK>> I do not have a good qualitative reason for the *size* of the effect. 2. Flux for each energy region and normalization "We get a consistent result MA=1.13 ..." YH>> Which energy bin was most sensitive to the change of MA? RIK>> The bin from 1.0 to 1.5 GeV remains fixed, and the largest RIK>> shift is in the next bin up (1.5 to 2.0 GeV). RIK>> Because these bins have most of the data for SciFi, RIK>> The implication is that the fit wants to pull these two bins RIK>> further apart from each other by roughly another 10%.