Comparisons of data/mc using down-going muons Jon Dumm, Chad Finley, Teresa Montaruli UW-Madison April 26, 2007

Outline Low level Reconstruction level Time differences between NN DOMs, Occupancies, Nchan, Nstring Reconstruction level Zenith, Azimuth, residuals, Quality cuts (Ndir, Ldir, paraboloid sigma)

Data sets Down-going muons (~0.5M) with high quality reconstructions 34-fold muon-llh, gulliver, paraboloid Data for comparison (~ 1 hr livetime) IC9 minbias data from June 2006 Corsika Simulation V01-09-06, datasets 296, 394 Both single and coincident muons Cuts Trigger level (Cleaned) Hard Cuts Sigma<3 deg, Ndir>9 ~11% signal efficiency (E^-2), ~95% background rejection

Time difference between NN DOMs Sim LC window Exp LC window (ns) Known problem: wrong LC time window!

Zoomed in on time difference (ns) This plot tells us about hole ice properties – local scattering near DOMs.

Occupancy – trigger Ratio of Exp / Sim Frequency each DomID is hit Format for remainder of talk: -Data vs corsika+doublemu = total sim -No normalization. Real rates as given. Structure washed out in sim Ratio of Exp / Sim 0 ~ 1450m 60 ~ 2450m Not enough light near bottom of IC in sim

Nchan – trigger Number of DOMs hit in an event Cut at Nchan<46 for blindness Difference gets worse at higher Nchan

Nchan – hard cuts Hard cuts = Sigma<3, Ndir>9 Number of DOMs hit in an event Even with cuts, the difference at high Nchan does not quite go away

Nstring – trigger Number of strings hit in an event Similar to the difference at high Nchan but worse!

Nstring – hard cuts Hard cuts = Sigma<3, Ndir>9 Number of strings hit in an event

Zenith - trigger Reconstructed zenith given by paraboloid The rates of mis-reconstructed events are underestimated by simulation Ideally, we need to find a way to oversample these fakes to save CPU time

Zenith – hard cuts Hard cuts = Sigma<3, Ndir>9 Reconstructed zenith given by paraboloid In order to test background rejection, may need weighted corsika sample near horizon

Azimuth - trigger Reconstructed azimuth given by paraboloid Structure is from having only 9 strings

Azimuth – hard cuts Hard cuts = Sigma<3, Ndir>9 Reconstructed azimuth given by paraboloid

Time Residual Time Residual = (Observed time – expected time) given Cherenkov cone and track Remember, simulation LC window at 500 ns instead of 1000ns

Time Residual at two depths DomID 45 ~ 2300m DomID 5 ~1600m Keep in mind, there is an LC time window problem after 500 ns

Ndir - trigger Direct hit time window: -15 ns <residual time <+75 ns 1 hit per DOM (first hits) Difficult to hope for agreement without agreement in Nchan

Ndir – hard cuts Hard cuts = Sigma<3, Ndir>9 Direct hit time window: -15 ns <residual time <+75 ns 1 hit per DOM (first hits)

Ldir - trigger Length of direct hits along track μ Ldir Direct hit Good agreement, but not ideal for IC9 since the detector is asymmetric

Ldir – hard cuts Hard cuts = Sigma<3, Ndir>9 Length of direct hits along track μ Ldir

Paraboloid Sigma - trigger Paraboloid samples the likelihood space around the track and fits it to a paraboloid. Sigma is the circularized width of this paraboloid. L Sigma θ,φ There have since been further improvements in paraboloid for higher efficiency

Paraboloid Sigma – hard cuts Hard cuts = Sigma<3, Ndir>9 Paraboloid Sigma – hard cuts Paraboloid samples the likelihood space around the track and fits it to a paraboloid. Sigma is the circularized width of this paraboloid. L Sigma θ,φ

The End We have some confidence in our quality cuts for IC9 analysis Fix LC bug and reprocess We need to standardize these comparisons for all to see avoid making it too long and painful to be useful