Neutrino Nucleon Elastic Scattering in MiniBooNE

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Neutrino Nucleon Elastic Scattering in MiniBooNE
? p ? ? p
David Christopher Cox (Indiana University)
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?s in Neutrino Nucleon Scattering
Nucleon Weak Current
(assumes time and isospin invariance,
pseudoscalar f.f. 0)
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?s in ? N Cross Sections
G1 dominant at low Q2(? proton KE) to first order
0.0 0.1
0.2 0.3
flux weighted cross section (10-38cm-1)
Ratios reduce sensitivities to systematics,
nuclear effects, etc. in study MiniBooNE
FINeSSE
0.1 0.3 0.5 0.7
0.9 1.1
Q2 (GeV2)
Rex Tayloe BE007
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Basic ? N Scattering Events in MiniBooNE
250 kgal baby oil sphere constantly monitored by
PMTs (main veto)
Chris Green CG002
Charged Current Quasi-Elastic CCQE
Neutral Current Elastic (NCE)
????????
scintillating
some scint
71 ???????? Scintillation
Take advantage of different event structures
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Monte Carlo Look at NCE Event Separation
No decaying leptons (none in neutral current) Low
light level in veto (eliminates punch through
leptons) Low light level in main tank (eliminates
high Evis events)
Preliminary
greatly reduces CCQEs
Number of hit PMTs in main tank
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NCE events in the data
Additional cut data in beam window
Preliminary
sensitive to details
200MeV p 15MeV e- equiv
Relatively normalized
good shape agreement
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Identify NCE distinguish protons/electrons/muons
Protons below threshold (Q20.7GeV2) ?
scintillate Muons, electrons above threshold ?
(mainly) ????????
Predict different hit time distributions (include
gauß recon. smearing)
Scintillation
????????
exponent (20ns decay)
d-function (prompt)
predicted time distribution (analytic)
time (ns)
time (ns)
Hypothesize 100 pure ????????, 100 pure
Scintillation particles Use log likelihood
analysis to match real particles to
hypotheses Predicted time distributions ? pdfs
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Testing the model
Generate single particle proton, electron events
in MC Use combined power of log(L_scint) and
log(L_???) with ratio
some separation between protons, electrons. encou
raging continue studies
Preliminary
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Summary Future Work
Goal measure ?s in MiniBooNE Use NCE vs CCQE
different event structures Separate p/µ/e using
timedistinguish NCE events Encouraging
results Pursue furtherinclude topology
Scintillation
????????
isotropic (no shape)
ring shaped