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What beamline group will supply for the (day-1) oscillation analysis

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##### What beamline group will supply for the (day-1) oscillation analysis

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**What beamline group will supply for the (day-1) oscillation**analysis A.K.Ichikawa For T2K beamline group**Note**This is just a starting-point material for day-1 analysis. More discussion among the beamilne group is necessary. This note will be modified when more studies arises, real data come, or statistic increases after day-1.**What beamline group will supply for the oscillation analysis**• Expected neutrino flux at the near detectors and far detector. • Correlation between flux at the near detectors and that at the far detector, i.e. far-to-near ratio. • Systematic errors for above quantities. For the real data processing, refer Nakadaira-san’s presentation file at the last collaboration (pre) meeting.**Systematic errors to be taken into account for oscillation**analysis • Beam/horn miss-alignment • Horn magnetic field • Absolute field strength • Distortion of the distribution • Primary beam profile • Primary hadron production • Secondary hadron interaction • Something which is not yet forseen.**How to propagate beam systematic errors for ND/SK spectrum**fitting • Correction function/vector for spectrum itself for each systematic errors. Example: DF(Ei)=Dy*ci : Dy is proton beam mis-hit position • Correlation matrix for systematic errors. • Neutrino spectra itself will be re-weighted and fitted by near/far detector observations within the constraints of the systematic error matrix.**Q: Method for evaluating impact of parameter variation**• Use beam MC**Q: Corresponding available data or measurements, internal**T2K or external, available to constrain these parameter variations • Beam/horn miss-alignment • Survey during the installation • Data from primary beam monitor, MUMON and INGRID • Horn magnetic field • Absolute field strength • Field measurement • Current Transformer at stripilne • Distortion of the distribution • Field measurement • Indirectly, MUMON and INGRID • Primary beam profile • Data from primary beam monitor • Primary hadron production • Model comparison and reasonable assumption on the model discrepancy • NA61 result • ND280 off-axis measurement • Secondary hadron interaction • Same as the primary hadron production**Q: is reweighting possible?**• Yes, we will provide neutrino-energy- histogram based weighting for systematic errors**Q: effect of parameter on numu analysis, on nue analysis**(this may be extracted from the global analysis) precision achievable on parameter from the data • If beamline components including MUMON and INGRID work as expected, effect on the oscillation analysis from the beam related systematic errors will be sufficiently small compared to day-1 statistics and quite controllable except for the hadron production part. • For the hadron production part, NA61 results will help a lot. Further MC study is necessary to evaluate the effect on the oscillation analysis from hadron production uncertainty either before NA61 and after NA61. And off course, ND280 off-axis detector is expected to put constraint on the numu and nue flux.**Followings are specific questions to beamline group and**answers to them**How will we feedback the data from the muon monitors, NGRID**and even ND280 into the beam monte carlo (Jnubeam) to either adjust it, evaluate systematic errors, reweight or include it in a global fit of ND280 (which depends both on flux and cross-sections)? • As written in previous pages, the information from MUMON and INGRID (and primay beam monitor) will be used to constrain the uncertainty of the beam/horn misalignment and probably asymmetric distortion of the horn fields. The correction function of the neutrino energy spectrum will be made from jnubeam. The actual correction is a product of a systematic error amplitude and corresponding correction function. The systematic error amplitude can be constraint by the information from MUMON and INGRID etc. • On the other hand, the data from the ND280 off-axis detector will be used to put a constraint on the { flux (neutrino energy spectra) x cross section}. The far detector {flux x cross section} can be obtained by extrapolating the ND measurements.**1. how to establish the misalignments experimentally? Just**as an example: one could think of taking initial runs with the beam monitors and the NGRID and operating e.g. no horn, then one horn at a time, etc.. to assess whether one can constrain the alignment of each of the horns individually (I believe this does not require high intensity) • MUMON and INGRID !! (with Horn operation.) • If horn-off running helps or not is not trivial. I’m afraid that profile is too broad with horn-off running to obtain useful information. But yes, we can and should do study with beam MC.**how will the feedback from the near detector (ND280) be**done? (or what observations are more sensitive to flux and what are more sensitive to cross-section model?) I think this will involve some sort of global fit... • Off-axis method gives numu flux which is rather independent on the hadron production. So it is expected that the ND280 off-axis measurement would be sensitive on the neutrino cross section. NA61 will further strength this direction. • More beam MC study is necessary to evaluate how precisely we can predict the nue flux without NA61 nor ND280 off-axis measurement. Since the main contributor to nue at around the peak energy is muon decay, the uncertainty may be sufficiently small for the quantity nue/numu. But it is absolutely helpful if either NA61 Kaon or ND280 measurement (numu high energy tail or nue itself) is on time for day-1 analysis. (Note that high precision results are not necessary.)**as a related question to the previous one: how will the nue**flux to SK be determined two methods are possible -- direct from nue events in ND280 -- indirect from numu events in ND280 constraining the nue prediction from JNUBEAM • Yes, both methods seems possible. See the next slides. It is expected that the nue from muon has less uncertainty if nue/numu is used. While the Kaon uncertainty may be rather large, but this part may be constraint by numu high-energy tail measurement.**Red : Kaon contribution**Red : Kaon contribution