deborah harris kevin mcfarland 12 may 2016 · deborah harris kevin mcfarland 12 may 2016 . 0.e+00...
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Deborah Harris Kevin McFarland
12 May 2016
0.E+00
1.E+20
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Sep-13
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4Au
g-14
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5Au
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6Au
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Proton
son
Target(PO
T)
DayintheMediumEnergyRun
POTDelivered
MINERvAPOT
MINERvA*MINOSPOT
MINERvA’s Run Plan • In the LE beam:
– 3.5E20POT in neutrino mode
– 1.7E20POT in antineutrino mode
• In the ME beam: 9.4E20POT accumulated so far in ν mode – 5E20 with full He target data – 4.4E20 with empty He target data – Want another 0.6E20 empty target data, expect to get that by
summer shutdown • We want 12E20 in antineutrino mode to complete our
medium energy physics program • For 14 days of RHC run, 1.2E18/day: 1.7E19 POT
would be “lost” out of the remaining 6E19 POT 12 May 2016 DAH and KSM, MINERvA @ EMG 2
Water Target Exposure • Water Target:
– Filled target on Monday Feb. 22
– Measured for creep every day the first week, now only measured once/week
– Target is stable – Have integrated
1.22E20POT – Could get to
1.8E20POT – 2 weeks less would
mean 1.65E20 POT 12 May 2016 DAH and KSM, MINERvA @ EMG 3
He Target Exposure
• Started ME run with full He target
• Emptied He target in January 2014
• Integrated 5.0E20 with target full
• Integrated 4.4E20 with target empty so far
• 0.17 of the next 0.6E20POT won’t change background subtraction precision
• Will start 2017 run with He target full again
12 May 2016 DAH and KSM, MINERvA @ EMG 4
Comparison of on-axis fluxes
12 May 2016 DAH and KSM, MINERvA @ EMG 5
Similar shapes, but antineutrino flux is peaked at 80% of neutrino flux Antineutrino Event rate per POT is therefore 0.4*Neutrino event rate
Expected Event Rates in RHC • Rates in Scintillator in FHC: (for events with muons
tracked into MINOS)
12 May 2016 DAH and KSM, MINERvA @ EMG 6
• Assume in RHC, with 0.17E20POT we would get factor of .075 times as many events than what is in this
• plot for a 2 weeks run: 5k per GeV, 20k in total
• Flux sample (“Standard Candle”): 2k per GeV, 8k total
Standard Candle Flux Events • Low nu analysis: see Jeff Nelson’s
JETP talk on January 8, 2016 • As hadron energy (“ν”) approaches 0,
σ(Ε) approaches a constant
• Total energy distribution of “0 hadron energy” events provide shape of flux distribution
• Normalize to external total cross section at higher energy
• “Low-nu technique” • Fraction of events that are • “low-nu” is small, but analysis
keeps it at about 40% 12 May 2016 DAH and KSM, MINERvA @ EMG 7
Summary
• For a switch to antineutrinos for 2 weeks before the shutdown: – MINERvA would lose:
• 10% of the statistics we would collect on the H2O Target • 3% of the statistics we would collect on the empty He target • 1.7% of the statistics we would collect on the rest of MINERvA
– MINERvA would gain: • 2k “standard candle” flux events/GeV in the peak of the neutrino
energy distribution • 8k flux events over all energies • 20k Charged Current Inclusive antineutrino events
• Benefits outweigh the losses, assuming 1.2E18 POT/day
12 May 2016 DAH and KSM, MINERvA @ EMG 8
Event Rate Comparison FHC/RHC
• Comparing quasi-elastic event rates in RHC and FHC:
12 May 2016 DAH and KSM, MINERvA @ EMG 9
For same mass, get half as many events/POT at QE peak