PPFX Implementation in DUNE

Amit Bashyal (Oregon State University) On behalf of Deep Underground Neutrino Experiment (DUNE) Collaboration

1 Deep Underground Neutrino Experiment (DUNE) • DUNE is a future long baseline neutrino experiment

• Neutrino oscillation studies to test CP violations in lepton sector and mass ordering

• Near Detector will be at 574 m from the start of first focusing horn • Far Detector at 1300 km in Sanford, South Dakota

2 DUNE Beamline (Reference)

Simulation starts from proton beam hitting the target to neutrino production

Magnetic horns to focus pions and kaons • Proton Beam hits the target

• Charged pions and kaons are Horn 2 produced which in turn are focused Horn 1 by magnetic horns Proton 200 meters long Beam Decay Pipe • 200 meters long decay pipe to let focused pions and kaons decay to Target produce neutrinos

3 DUNE Beamline (Reference & Optimized)

Horn C Horn B Horn A

Horn 1 Horn 2

Beam/Parameters Reference Optimized Target 1 meter graphite 2 meter graphite

Nominal Horns 2 horn (Numi Style) 3 Horn (Ideal, no Optimized Eng. Constraints)

Current 230 kA 298 kA

Proton Energy 120 GeV 120 GeV 4 DUNE Beam Simulation

• LBNF beam line (g4lbnf) written with GEANT4 package • Detailed simulation of particle production, transportation and decay leading to the neutrino flux production • Produced neutrinos are projected at the Far and Near Detector locations for physics studies.

5 Numu Flux at Near Detector

×10−3 0.35 Reference Beam/Parameters Reference Optimized Optimized 0.3 Target 1 meter graphite 2 meter graphite

0.25 Horns 2 horn (Numi Style) 3 Horn (Ideal, no / POT 2 Eng. Constraints) 0.2 Current 230 kA 298 kA s / GeV m

0.15µ ν Proton Energy 120 GeV 120 GeV 0.1 Unosc

0.05

0 0 2 4 6 8 10 12 14 16 18 20 νµ Energy (GeV)

6 Neutrino Flux Prediction Business

Neutrino Flux Prediction Business

Near/Far Flux And Their Systematics in Correlation the neutrino Flux

Ratio Method Matrix Method Focusing Hadron Production

It’s a BOTTOM TOP BUSINESS…

7 Neutrino Flux Prediction Business

Neutrino Flux Prediction Business

Near/Far Flux And Their Systematics in Correlation the neutrino Flux

Ratio Method Matrix Method Focusing Hadron Production

• Correlated because neutrino flux comes from • Uncertainties in beamline parametersàHorn same hadron hose. position, current, target position, number of • Complex correlation because of detector protons hitting the target etc. locations and beamline geometry

8 Uncertainties from Hadron Production

Accurate neutrino flux prediction relies on detailed modeling and understanding of processes starting from primary proton on carbon interaction leading to neutrino production

Y Primary X

Proton Primary proton hits the Secondary proton re-interacts A pion is target and produces X to produces Y produced

Pion is focused by Pion decays to Magnetic horn • Simulated neutrino flux relies on hadronicmodels used in simulation neutrino (QGSP_BERT,FTFP_BERT) • Significant disagreement with real data • Constrain the hadron production models by external data

9 PPFX……Finally

• An experiment independent neutrino flux determination package for the NuMI beam*

• Correction for hadron production uncertainties using existing thin target data sets**

• Developed by Leo Aliaga for the MINERvA collaboration • Currently used by NoVA as well

*L. Aliaga Soplin, Neutrino Flux Prediction for the NuMI Beam, Phys. Rev. D 94, 092005 (2016) ** Data set names are listed in the backup slide 10 How PPFX Works?

Coverage of interaction by Existing Data sets Simulation Full Neutrino For Ancestry Each interaction in an ancestry • Direct Coverage • Coverage By Extension

• No Coverage at all *Coverage by Extension of Data Sets Extend the coverage for interactions that are not covered directly wherever possible

*No Coverage at All Apply uncertainties based on best estimation from Full ancestry of a neutrino event (from primary proton current physics models if an interaction is not covered hitting target to neutrino production) directly or indirectly

11 Neutrino Ancestry and Hadronic Interaction in DUNE Flux

Interactions coverage by Reweighters Total νµ flux at near detector • To apply the constraints from Hadron production ×10−12 nu_flux_ancestry_7

2.5 ν νµ flux at near detector for ancestry 3 Entries 9427776 Thin Taget Data sets: ν flux at near detector for ancestry 4 µ Mean 3.053 Total Absorption 4 ν flux at nearStd detector Dev for ancestry 1.59 5 − • Need to understand the ancestry of the µ 10 Target Absorption 2 νµ flux at near detector for ancestry 6 pC-->π X

pC-->KX

neutrino Events per ND nC-->π X • Ancestry 3: pàXà� pC-->nucleonX 1.5 −5 Weighted Neutrino Flux 10 meson inc. • Ancestry 4: pàXàYà � nucleon-A

• And so on 1

10−6

• Need to categorize interactions based on 0.5 coverage by hadron production data set

0 10−7 0 1 2 3 4 5 6 7 8 9 10 −100 −50 0 50 100 150 200 250 ν Energy(GeV) Z cm

DUNE neutrino flux at ND for 80 Hadron production location and GeV proton beam reference design coverage by ppfx reweighters as a function of ancestry length (not a stacked plot)

12 How Uncertainties are Categorized

1 1. Total Hadron Production Interactions 2 2. Interactions (excluding 8. interactions) not covered by any of the below categories.

3 3. Pion production in proton Carbon Interaction

4 4. Kaon production in proton Carbon Interaction

5 5. Pion production in neutron Carbon Interaction

6 6. Nucleon production in proton Carbon Interaction

7 7. Meson incident Interactions

8 8. Nucleon Incident interactions not covered by any data 2 contains the interactions 3,4,5,6,7,9 and 10 9 9. Absorption outside the target category interactions that are not covered by 10 10. Absorption inside the target thin target data.

13 How Uncertainties are Categorized

1 2 Hadron Production 3

4 Based on pC Thin Target Data 5 6 Quasi elastic interactions, interactions covered by material 7 extensions and interactions outside the range of thin target data sets 8

9 Meson Incidents have large 10 uncertainties

14 How Uncertainties are Categorized

1 2 Attenuation 3 • When a particle traverses through the volume, correction is: � �(� � ) � ���� �� 4 • � � = � � [1] 5 • When an interaction happens inside a volume: �� �(����� ���) 6 ����� • � � = � � [1] ��� 7 • Here: 8 • C(r ) is the central value correction 9 • � is the number of atoms with atomic number A seen by the particle when it traverses the volume 10

15 Interactions Per Near Detector Neutrino

Beam/Parameters Reference Optimized total total h_aveint_vs_enu_tot h_aveint_vs_enu_tot 2.5 2.5 Total HP Entries 7976 Total HP Entries 9565 pC-->π X pC-->π X Mean 18.52 Mean 18.14 pC-->KX pC-->KX Std Dev 11.61 Std Dev 11.35Target 1 meter graphite 2 meter graphite nC-->π X nC-->π X 2 2 pC-->nucleonX pC-->nucleonX meson inc. meson inc. nucloen-A Horns 2 horn (Numi Style) 3 Horn (Ideal, no nucloen-A others Eng. Constraints) others

1.5 number of interactions 1.5 number of interactions Current 230 kA 298 kA 1 1 Proton Energy 120 GeV 120 GeV

0.5 0.5 Number of interactions per near detector neutrino covered by various ppfx reweighters 0 0 0 5 10 15 20 25 30 35 40 0 5 10 15 20 25 30 35 40 neutrino energy (GeV) neutrino energy (GeV) for 2 different beamline design

Reference: 120 GeV Optimized: 120 GeV

16 Fractional Uncertainties

DUNE Reference Beam Fractional Uncertainty DUNE Optimized Beam Fractional Uncertainty

0.2 0.2 Total HP Total HP

others others 0.18 0.18 pC-->π X pC-->π X

pC-->KX pC-->KX 0.16 0.16 Optimized nC-->π X nC-->π X pC-->nucleonX pC-->nucleonX 120 GeV 0.14 Reference 0.14 meson inc. meson inc.

nucleon-A nucleon-A 0.12Fractional Uncertainty 120 GeV 0.12Fractional Uncertainty other abs. other abs. Target Absorption Target Absorption 0.1 0.1

0.08 0.08

0.06 0.06

0.04 0.04

0.02 0.02

0 0 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 νµ Energy (GeV) νµ Energy (GeV)

17 Fractional Uncertainties

others Total HP meson inc. 0.022 Reference Reference 0.07 0.02 Optimized Optimized Reference 0.018 0.06 0.12 0.016 0.05 0.014

Optimized 0.012 0.04 0.1 0.01 0.03 0.008

0.006 0.02 0.004 0.08 0.01 0.002

0 0 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 Target Absorption 0.06 nucloen-A

0.07 Reference 0.07 Reference

0.06 Optimized 0.04 0.06 Optimized

0.05 0.05

0.04 0.04 0.02 0.03 0.03

0.02 0.02 0 0 2 4 6 8 10 12 14 16 18 20 0.01 0.01

0 0 0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20

18 Summary

• PPFX was successfully adapted for the DUNE • Overall uncertainty for both reference and optimized design is below 12% in the region of interest. • Deliverables • Evaluated apriori flux uncertainties • Flux error matrix based on simulated DUNE flux (Laura Fields) delivered to the Near Detector Task Force • Infrastructure is present in the current DUNE beam simulation software for future apriori flux evaluation for optimized designs

19 Back Up Slides

20 Thin Target Data Sets

21