Newt Ganugapati & Paolo Desiati Progress Talk Newt Ganugapati & Paolo Desiati

NHITS PLOT AFTER QUALITY CUTS(recap) Singles Multiples The Multiple muon background still goes with the same slope as signal and we need to get rid of them as it is a major background Signal NHITS

NHITS PLOT(recap) This plot shows the signal and the back ground distribution(singles and multiple) after making a cut on early hits. Singles Multiples Signal NHITS

Data Agreement(recap) B.G. MC B.G MC S.G M.C S.G NHITS COS(ZENITH)

Time Delay Distributions(recap) zoom Data B.G. MC Signal Time delay(ns) Time delay(ns)

Vertical Muons The time delay distribution for vertical muons(<30degrees) fits well in the region on which early hits is defined but for horizontal muons we saw is not so good? clue Angular Resolution and Misreconstructed muon Data B.G M.C Region of intrest Time delay(ns)

Time delay Distributions Data Data B.G B.G Signal Signal Time delay(ns) Time delay(ns) Strings 1-10(inner) Strings 11-20(outer)

Time delay Distributions Data The inner most strings tend to describe the time delay best and the distributions tend to deviate as we move away to outer strings. Could be a geometrical effect(will be described in detail in what follows) B.G Signal Time delay(ns) Strings 1-4(inner most)

NHITS DISTRIBUTION Singles This plot is generated after cutting on early hits (allow no early hits) on strings1-10(inner strings).Note that this region id described well and so good agreement between data and M.C is to be expected. Multiples Signal NHITS

Data Agreement(Nhits) Note the good agreement between data and M.C obtained. This is to be expected as the cut was made on distributions that agree well B.G M.C Signal NHITS

Data Agreement(Zenith) B.G MC Signal Note that the disagreement near the horizon is because of misreconstructed muons(probably up going) Cos(zenith)

Agreement(Smoothness) Note the agreement in smoothness Data B.G M.C Signal Smootallphit(2)

Agreement(ldirb) Note agreement in the direct length after the cut Data B.G MC Signal Ldirb(2)

M.C. and track fitting The montecarlo generates the time residuals from the fit by propagating the muons in the same region of ice in which the hit takes place where as data is data and hence the effect of dust layers is not taken into account when the time residual from reconstructed track is arrived. What is the implication? Angular resolution gets effected.Those early hits in clear ice might have been lost in the data where as M.C overestimates the number of early hits from those direct hits and we get misreconstructed muons with goofy time pattern.

Ice Properties The clearest ice is the one with a low scattering coefficient and hits from Photons in this region need not originate in the same layer(clear) but are propagated in this region in the M.C. and hence the early hits are likely to be over-estimated.

Geometrical Effect Dust Clear Ice Data Real Track M.C

Fraction Fraction of OM’S with greater than 1 hit in strings 1-10 is plotted here.A projection of NHITS>200 is made just to look at High energy muons.The signal which are single muons tend to have lesser values.The plot is shown Multiples Signal Keep these Fraction

NHITS DISTRIBUTION There seems to be a fair bit of separation power in this cut as well. Singles Multiples Signal NHITS

True Energy spectra Singles The intersection of signal and multiple muon occurs roughly at 30TeV Multiples Signal Log10(energy)GeV