Constraints on Hadron Production from the MINOS Near Detector

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Constraints on Hadron Production from the MINOS Near Detector. arko Pavlovi. FNAL, March 2009. Outline. NuMI beamline, calculating flux and systematic errors Fitting the ND data (Beam tuning) Few comments on NuMI offaxis flux Conclusion. Neutrino Beamline. 120 GeV protons - PowerPoint PPT Presentation

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Slide 1

Constraints on Hadron Production from the MINOS Near Detectorarko Pavlovi

FNAL, March 200912OutlineNuMI beamline, calculating flux and systematic errors

Fitting the ND data (Beam tuning)

Few comments on NuMI offaxis flux

Conclusion3Neutrino Beamline120 GeV protons 1m long graphite target 2 magnetic hornsVariable beam energyBeam composition (LE10/185kA): 92.9% 5.8% 1.3% e / e

TargetHornsDecay PipeAbsorberHadron MonitorMuon MonitorsRock++10 m30 m675 m5 m12 m18 m4Near and Far SpectraFlux at Near and Far detector not the sameNeutrino energy depends on angle w.r.t parent momentum

qfto FarDetectorDecay Pipep+p+(soft)(stiff)qntargetND

p4Far over near ratio20-30% correction on top of R-2 for ND at ~1km

Need to have detector at 7km to have corrections at 2% level5

6Hadron productionProton beam momentum

Target material

Thick target

7Thick-Target EffectsHadron production data largely from thin targets.

Particles are created from reinteractions in NuMI target.

Approx 30% of yield at NuMI p0=120 GeV/c

MiniBooNENuMICNGSJ-PARCFluka 20058Cascade modelsVariation in calculated flux depending on the cascade model

Indicates ~8% uncertainty in peak and ~15% in high energy tail

9Focusing uncertaintiesMisalignments & miscalibrations

Input from beamline instrumentation

Affects falling edge of the peak

Focusing peak10F/N focusing uncertaintiesSmall effect on Far/Near ratio (2% level)

11ND Data/MCMC/Data show some disagreement

Adjust the yields of and K

Fit data from all the beams simultaneously

LE010/185kALE100/200kALE250/200lAHadron ProductionSame pT-xF bin contributes differently to different beams

LE010/185kALE100/200kALE250/200kA

LE010/185kALE100/200kALE250/200kALE010/185kALE100/200kALE250/200kAHadron Production (contd)Different beams sample different pionsNot shown, but also using data from LE150/200kA

LE010/185kALE010/0kALE010/170kALE010/200kALE100/200kALE250/200kA14Hadron production parameterizationAdjust yields as a function of pT-pz

Parameterize fluka yields using 16 parameters

15Tuning MCFit ND data from all beam configurationsSimultaneously fit and spectraAllow that some discrepancy due to cross sections and detector reconstruction

LE010/185kA

LE010/185kALE100/200kALE250/200kA1516Tuning MCAdjust the yields of and K

Re-weight MC based on pT-xF

Weights applied vs pz & pT17+/- ratioBest fit to and changes the +/- ratioGood agreement with NA49 data and preliminary MIPP results

1718Far/Near RatioConstrained hadron production using ND data

Reduced errors on F/N ratio

Systematic error due to beam uncertainty small

NuMI offaxis beamMiniBooNE detector sees offaxis neutrinos from NuMI (110mrad)Good agreement between data and MC

MiniBooNEdiagram not to scale!

20Two views of the same decaysDecays of hadrons produce neutrinos that strike both MINOS and MiniBooNEParent hadrons sculpted by the two detectors acceptances.

Plotted are pT and p|| of hadrons which contribute neutrinos to MINOS (contours) or MiniBooNE (color scale)

MINOSMiniBooNEMINOSMiniBooNE2121

nenm

MiniBooNEdiagram not to scale!NuMI offaxis beamMINOS ND constrains only the target componentLarger error on parents produced in downstream shielding and especially absorberExcluded neutrinos from absorber in this analysis22ConclusionTune hadron production to simultaneously fit all ND data

Technique independent of particle production experiments Beam systematics well constrained