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COSMOGENIC BACKGROUND TO NUCLEON
DECAYMatt RobinsonKarl Warburton
Vitaly KudryavtsevElena Korolkova
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
DATA• Target of 109 muons simulated now reached and
surpassed. Just over 2x109 now produced. Copies on LHC grid (LFN:/dune/user/m/matthew.robinson/mctruth/), at FNAL (/pnfs/dune/persistent/musun/mctruth) and at Sheffield.
• Small amount of grid enabled storage at Sheffield used to buffer data was sufficient as it was being continuously downloaded and deleted as jobs finished.
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
ANALYSIS• Analysis runs through sim::IDE objects (idealised “Hits” from
geant4) and separates out energy depositions resulting from charged Kaon interactions, secondaries, decay products and from interactions not associated with a charged Kaon.
• Only events where a single charged Kaon appears in the detector are considered background.
• Limits of a likely real detector not properly accounted for in this approach. Likely to represent an optimal limit in what can be done.
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
ANALYSIS• “Near” energy now being accounted for as in Karl’s analysis.
• Analysis module completely rewritten as it was getting rather too ugly.
• Same background event revealed with new analysis, plus one additional event from the second 109 events.
• Need to decide how to handle “near” energy in final analysis. Karl’s GENIE data will help with this.
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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Charged Kaon Spectrum, 2x109 filtered muons
x=energy from kaon and secondaries
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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“Near” Energy Spectrum, 2x109 filtered muons
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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Proton Decay Background Candidates
y=energy from kaon and secondariesx=all other event energy including “near” but not “decay”.
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
NEAR ENERGY AND BACKGROUND EVENTS• Background event at
• enear = 0 MeV• kaon+secondaries = 172 MeV• other (without near) = 2.5 MeV• kaon+secondaries+enear = 172 MeV
• Background event at • enear = 0.35 MeV• kaon+secondaries = 114 MeV• other (without near) = 17 MeV• kaon+secondaries+enear = 114 MeV
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• As “Near” energy is zero in first background event it does not appear in a log plot where enear is an axis.
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
"Near" energy [MeV]1−10 1 10 210 310 410
ene
rgy
depo
sitio
n (in
cludi
ng s
econ
darie
s) [M
eV]
+/-
K
1
10
210
310
410 All single kaons (4985)Passing Muon cut (2477)Passing Fiducial cut (10)Inside Energy ROI (2)
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Kaon Energy vs “Near” Energy, 2x109 filtered muons
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
Other energy excluding "Near" [MeV]1 10 210 310 410 510
ene
rgy
depo
sitio
n (in
clud
ing
seco
ndar
ies)
[MeV
]+/
-K
1
10
210
310
410 All single kaons (4985)Passing Muon cut (2477)Passing Fiducial cut (10)Inside Energy ROI (2)
10
Kaon Energy vs Other energy excluding “Near”, 2x109 filtered muons
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
Other energy excluding "Near" [MeV]1 10 210 310 410 510
+ "N
ear"
ener
gy d
epos
ition
[MeV
]+/
-K
1
10
210
310
410 All single kaons (4985)Passing Muon cut (2477)Passing Fiducial cut (10)Inside Energy ROI (2)
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Kaon + “Near” Energy vs Other Energy, 2x109 filtered muons
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
PRE-RECONSTRUCTION FILTER• Second filter to apply before hit reconstruction
has been finalised.Cuts events with Etotal > 3 GeV, Etotal < 10 MeV, and with energy within 10 cm of edges > 5 MeV.
• 106 muons reconstructed, 17402 passing original (muon track length) filter and of those 2310 (13% or 0.23% muons).
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
HIT RECONSTRUCTION
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• Hit reconstruction, after various problems arising from collapse of IC dirac system, change in dependencies between larsoft v5 and v6 (redhat-lsb-core) and various other issues, now progressing well.
• Will not have full data set, but should have some plots for FDTF. Expecting first 109 by the end of the week.
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
CONCLUSIONS• Initial production phase finally complete with 2x109 muons
simulated.
• Filter finalised and hit reconstruction tested.
• Hit reconstruction progressing (finally). First 109 by the end of the week (hopefully).
• “Near” energy now being considered.
• Need to look at GENIE data and other information to improve identification of likely background events.
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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• K0L produced outside detector
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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• K0L converts to K+ well inside active volume• No hits from K0 so looks like proton decay
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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• K+ decays as expected, pi+ produced
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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• pi+ eventually decays to very low energy mu+
Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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K0L in from side, 168 MeV
K+, 109 MeV
pi+, 110 MeV
p, 52 MeV
Various gammas
SECOND BACKGROUND CANDIDATE