cosmogenic background to nucleon decay
TRANSCRIPT
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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
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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“Near” Energy Spectrum, 2x109 filtered muons
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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”.
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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.
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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
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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
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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
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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.
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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
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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
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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• K+ decays as expected, pi+ produced
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Matt Robinson, Vitaly Kudryavtsev, Karl Warburton, Elena Korolkova
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• pi+ eventually decays to very low energy mu+
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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