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Km3 v4r5 update

Km3 v4r5 update. C.W.James , AWG telecon 10 th Jan 2013. Updates this telecon. Completed one-particle approximation testing Results of ‘ dusj ’ using v4r5 w/ wo OPA Test effects of: Increasing absorption and scattering lengths by 10% Also check increasing absolute OM efficiency by 5%

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Km3 v4r5 update

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  1. Km3 v4r5 update C.W.James, AWG telecon 10th Jan 2013

  2. Updates this telecon • Completed one-particle approximation testing • Results of ‘dusj’ using v4r5 w/wo OPA • Test effects of: • Increasing absorption and scattering lengths by 10% • Also check increasing absolute OM efficiency by 5% • Still to-do: • Implement read-out of hit tables for SIRENE • + New modifications requested C.W.James, ANTARES MC telecon, 10th Jan 2013

  3. One Particle Approximation – a reminder • Replace all non-muonic products with a single electron of ‘equivalent’ energy • Why? • Allow km3mc to handle shower events • Allow treatment of scattered photons for showers • Speed up simulations! • Finally, I’ve ironed out all the bugs (touch wood!) C.W.James, ANTARES MC telecon, 10th Jan 2013

  4. OPA results – it works! • Testing: • Used new km3 v4r5 (in development) • Compared run-by-run reconstruction chain using A: geasim, and B: km3 with the OPA, to simulate cascade events. • Used: 100 runs x [a]nuc_[CC/NC]_[a/b] and [a]_numu_NC_[a/b] files (12) per run: 1200 in total. • Used identical vertex inputs. • Processed with ‘dusj’ (F. Folger) shower reconstruction method to compared results. • Full sets of plots (>30) are found in the material on the web-site: • “v4r5_geasim.pdf” and “v4r5_OPA.pdf • BIG thanks to Florian Folger here! C.W.James, ANTARES MC telecon, 10th Jan 2013

  5. Summary of changes • Vertex position and direction reconstruction behave very similarly (plots #1-6). • Energy reconstruction for the OPA has a larger systematic offset but a small variance (plot #7). • Tends to reconstruct late vertex times (because some late, scattered photons are seen!) • OPA less efficienct above 100 TeV – why? • Coincidentally (or not!), this is where GEASIM’s one-particle-approximation kicks in – which is known to underestimate the number of photons by a factor of 5. • Overall loss of OPA efficiency: 10%. • But to what degree was the current dusj version tuned on incorrect MC data w/o scattered photons? C.W.James, ANTARES MC telecon, 10th Jan 2013

  6. Summary of changes • Dusj(GEASIM) vsdusj(OPA) – different dependencies on shower energy observed (plots #19-22). • More discussion with Florian in order to understand these points, and plots #23+. • Conclusion on accuracy: • “similar” (sometimes better, sometimes worse) • Might be improvable by adapting a new dusj version to the next run of rbr data. • Expectation: more accurate! • What about run-time? • Will save ~6 hr per run! C.W.James, ANTARES MC telecon, 10th Jan 2013

  7. Conclusion on OPA • OPA status: • Uses M. Dentler’sparameterisation for pions • Applied to all non-muonic events • We now have scattered photons for shower events, hurray! • Test results: • no great difference in shower reco accuracy • Some subtleties still need understanding • Expectation: • differences are because km3mc gets it right! • need e.g. clsim to decide definitively. • Release v4r5 with OPA on by default. • No need for GEASIM in Antares simulations! • OPA might not OK forORCA • will be perfect of km3net • Last question: which particle ID for OPA showers? C.W.James, ANTARES MC telecon, 10th Jan 2013

  8. Fiddling around with parameters • Question: What is the effect of changing X on Y? • X = scattering length, absorption length, optical module absolute efficiency • Y = downgoingmuon rate, upgoing neutrino rate • Assess using… • 10 runs for downgoingmuons • 40 runs for upcoming neutrinos ([a]numu_CC) • Full run-by-run MC treatment; look at Aafit results • Motivation: understand the magnitude of the effects • NOT physically motivated – this is NOT intended to make recommendations about the physical truth! C.W.James, ANTARES MC telecon, 10th Jan 2013

  9. Increasing scattering length • Changing the scat length • Lscat’(λ) = Lscat(λ) x 1.1 • This is not physical – it is Monte Carlo! • Eta (fraction of scattering off seawater) is an unchanged function of wavelength • Absorption length left unchanged • Param set: C.W.James, ANTARES MC telecon, 10th Jan 2013

  10. Increasing scattering length • Changing the scat length • Labs’(λ) = Labs(λ) x 1.1 • This is not physical – it is Monte Carlo! • Scattering length left unchanged • Param set: C.W.James, ANTARES MC telecon, 10th Jan 2013

  11. Increased OM area • Increasing OM collecting area • Actually 5% more photons produced per track • Equivalent to 5% larger PMT area • Difficult to compare quantitatively to changing absorption/scattering lengths (not distance dependent) • No wavelength-dependence: • no plots here • use meaningless sub-points to take up otherwise ugly white space • put this point in italics to make it look more meaningful C.W.James, ANTARES MC telecon, 10th Jan 2013

  12. Results – atmospheric muons (up and down) Notes: • Cumulative distribution left-to-right • Errors bars are correlated between colours and over-estimates C.W.James, ANTARES MC telecon, 10th Jan 2013

  13. Results – muon CC neutrino events Notes: • Cumulative distribution left-to-right • Errors bars are correlated between colours and over-estimates C.W.James, ANTARES MC telecon, 10th Jan 2013

  14. Partial derivatives at lambda=-5.4 • Atmospheric muons • [a]numu_CC (ignoring error bars – I will get round to fixing this problem soon*!) *cosmologically speaking C.W.James, ANTARES MC telecon, 10th Jan 2013

  15. Conclusions on km3 v4r5 w OPA to be released soon. Hurray! Effects of changing water parameters measured. New set of water properties still undecided - I think we should have a dedicated face-to-face meeting on this. Oujda? Somewhere/when else? C.W.James, ANTARES MC telecon, 10th Jan 2013

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