Km3 v4r5 OPA update

C.W.James, AWG meeting 17th Dec 2012

Notes from last telecon (30th Nov)

• Complete one-particle approximation testing

• Test effects of:- Increasing absorption length by 5%- Changing the low-cos-theta angular acceptance

• Still to-do:• Implement read-out of hit tables for SIRENE

• + New modifications requested

C.W.James, AWG telecon, 17th Dec 2012 2

OPA testing

• This has gone slowly!- Results for showers less well known- Finding bugs takes longer

• Simulation chain:- Take 100 runs (need more stats for showers)- Simulate shower events

• nue, anue, numu, anumu• 2 CC (nue & anue ) +4 NC (all)• ‘a’ (100-1e5 GeV) and ‘b’ (5e4-1e8 GeV)

- Evaluate these 12x100 files using• Km3v4r5+geasim• Km3v4r5 w OPA (no geasim)

- Process w standard reco + dusj shower recoC.W.James, AWG telecon, 17th Dec 2012 3

Other particles in OPA

• Example file:

~1 PeV electron-neutrinoPions, photons – and an anti-neutron!

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Treating non-standard particles

• New OPA 1st run:- Charged pions: w(E) according to M. Dentler (was 0.2)- Neutral pions, gammas, electrons, K0 (short and

long): w=1- Others: w=0

• Physical problems:- K0 expect to interact before decaying (t_0 c = ~3cm

for K0 short, >100m for K0 long) - K0: decay branching ratio to EM-only products ~30%- Other mesons/bosons also interact to produce

‘hadronic’ – and hence electromagnetic – products

• Trial solution: treat all GEANT IDs >= 8 as charged pionsC.W.James, AWG telecon, 17th Dec 2012 5

Results… still being run!

• If everything goes well, in one day I will have proper comparison plots

• Current philosophic question:- OPA uses particle kinetic energy to estimate

Cherenkov yield- Charged pion fit -> minimum at 0.2 GeV (approx rest

mass).- At low energies, other particles will behave similarly

relative to their own rest masses.- How to estimate this?

• Does NOT matter for ANTARES/km3net• WILL matter for ORCAC.W.James, AWG telecon, 17th Dec 2012 6

Results on angular efficiency

• Use different low a_effs:

• Run 4x106 runs with OPA facing away from the Cherenkov angle.

C.W.James, AWG telecon, 17th Dec 2012 7

Results on angular efficiency

• Results: photon arrival-time histograms

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Results on angular efficiency

• Results: histograms near the peak

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Results on angular efficiency

• Results: total number of photons

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