The NOvA Experiment

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New Oscilla+on Results from the NOvA Experiment

Alex Himmel, Fermilab for the NOvA Collabora6on

July 2 ^nd , 2020

u/Demux0 @ Reddit

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The NOvA Experiment

• Long-baseline neutrino oscillation experiment

• NuMI beam: ν

_μ

or ν̅

_μ

• 2 functionally identical, tracking calorimeter detectors

– Near: 300 T underground – Far: 14 kT on the surface – Placed off-axis to produce a

narrow-band spectrum

• 810 km baseline

– Longest baseline of current experiments.

Take a tour

in VR!

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Physics Goals

P. Vahle, Neutrino 2016 3

Results from 3 different oscillation analyses

¨ 

Disappearance of ν _µ CC events

¤ 

clear suppression as a function of energy

¤ 

2015 analysis results Phys.Rev.D93.051104

sin ² (2✓ ₂₃ )

m ² ₃₂

¨ 

Appearance of ν _e CC events

¤ 

810 km baseline

enhances matter effects

¤ 

±30% effect

¤ 

2015 analysis results in PRL.116.151806

✓ ₁₃ , ✓ ₂₃ , _CP ,

and Mass Hierarchy

¨ 

Deficit of NC events?

¤ 

suppression of NCs could be evidence of oscillations involving a sterile neutrino

¤ 

Fit to 3+1model

¤ 

new! m ² ₄₁ , ✓ ₃₄ , ✓ ₂₄

NOvA Physics

³

• Atmospheric sector oscillations:

– Δm

²₃₂

, sin

²

θ

₂₃

, δ

_CP

• Key open questions in oscillations:

– Is the neutrino mass hierarchy normal or inverted?

– Is CP violated in the neutrino sector?

– Is θ

₂₃

mixing maximal?

• ν

_μ

-ν

_τ

symmetry

• If not, what is the octant of θ

₂₃

?

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NOvA Physics

⁴

• Atmospheric sector oscillations:

– Δm

²₃₂

, sin

²

θ

₂₃

, δ

_CP

• Key open questions in oscillations:

– Is the neutrino mass hierarchy normal or inverted?

– Is CP violated in the neutrino sector?

– Is θ

₂₃

mixing maximal?

• ν

_μ

-ν

_τ

symmetry

• If not, what is the octant of θ

₂₃

?

• Disentangle by measuring…

– disappearance P(ν

_μ

→ν

_μ

) and appearance P(ν

_μ

→ν

_e

)

– in neutrinos and antineutrinos – over long baselines to separate

hierarchy and δ effects.

Physics Goals

P. Vahle, Neutrino 2016 3

Results from 3 different oscillation analyses

¨ 

Disappearance of ν _µ CC events

¤ 

clear suppression as a function of energy

¤ 

2015 analysis results Phys.Rev.D93.051104

sin ² (2✓ ₂₃ )

m ² ₃₂

¨ 

Appearance of ν _e CC events

¤ 

810 km baseline

enhances matter effects

¤ 

±30% effect

¤ 

2015 analysis results in PRL.116.151806

✓ ₁₃ , ✓ ₂₃ , _CP ,

and Mass Hierarchy

¨ 

Deficit of NC events?

¤ 

suppression of NCs could be evidence of oscillations involving a sterile neutrino

¤ 

Fit to 3+1model

¤ 

new! m ² ₄₁ , ✓ ₃₄ , ✓ ₂₄

NOvA: L=810 km, E=2.0 GeV

e

% ν

µ

→

P ν

0 2 4 6 8

%

e

ν →

µ

ν P

0 2 4 6

8

sin²2θ13^=0.085

eV2

10-3

×

|=2.44

2

m32

∆

|

=0.404,0.623 θ23

sin2

δ=0 δ=π/2

=π

δ δ=3π/2

0.404

0.623 0.404

0.623

NOvA: L=810 km, E=2.0 GeV

Inv er te d H ier arc hy

No rm al Hi era rch y Uppe

r O ctan t Lo wer

Oc tan t

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NOvA Physics Beyond 3-ﬂavor

⁵

Neutrino 2020 Talks

• Cross-section measurements with NOvA – Linda Cremonesi

Neutrino 2020 Posters

• 358. Astrophysics with NOvA, Matt Strait & Oleg Samoylov

• 550. Galactic Supernova Neutrinos,

Justin Vasel, Andrey Sheshukov, Alec Habig

• 555. Event Selection and Systematics, Adam Lister & Anne Norrick

• 442. Sterile Neutrino Search via NC Disappearance with Antineutrinos, Mike Wallbank

• 431. Poisson Likelihood Covariance Technique for 3+1 Sterile Searches, Jeremy Hewes

• 541. Neutrino Tridents, Erica Smith & Kelli Michaels

• 398. Inclusive CC ν_μ, Connor Johnson

• 505. Inclusive CC ν_e,Matt Judah

• 228. CC ν_μπ^±, Cathal Sweeney

Papers since NEUTRINO 2018

• Observation of seasonal variation of atmospheric multiple-muon events in the NOvA Near Detector, Phys.Rev.D 99 (2019) 12, 122004

• Search for Multi-Messenger Signals in NOvA Coincident with LIGO/Virgo Detections, Phys.Rev.D 101 (2020) 112006

• Supernova neutrino detection in NOvA, arXiv:

2005.07155 [physics.ins-det]

• Measurement of Neutrino-Induced Neutral-Current Coherent π⁰Production in the NOvA Near Detector, Accepted to PRD, arXiv: 1902.00558 [hep-ex]

• Adjusting Neutrino Interaction Models and Evaluating Uncertainties using NOvA Near Detector Data, arXiv:

2006.08727 [hep-ex]

Astrophysics Cross Sec/ons Sterile and BSM

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• Typically ~670 kW

• Peaks >750 kW

• 50% more neutrino beam data in this analysis

• Working towards 900+ kW

– Upgrading the NuMI beamline components – Allows gradual increase in

power up to 850 kW with faster cycle times

– Early PIP-II upgrades allow 900+ KW

MW-capable target MW-capable horn

The NuMI Beam

2019 Dataset

2020 Dataset

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• Segmented liquid scintillator detectors provide 3D tracking and calorimetry

• Optimized for electron showers: ~6 samples per X

₀

and ~60% active

• Good time resolution (few ns) and spatial resolution (few cm) – Allows clear separation of individual interactions

The NOvA Detectors

⁷

NOvA - FNAL E929 Run: 13507 / 23 Event: 1510 / -- UTC Tue Jan 14, 2020

17:19:2.684361216 218 220 222 224 226 228

µsec) t ( 1

10 102

hits

10 10² 10³

q (ADC) 1

0 200 400 600 800 1000 1200 1400 1600

-200 -100 0 100 200

x (cm)

0 200 400 600 800 1000 1200 1400 1600

z (cm)

-200 -100 0 100 200

y (cm)

Pile-up during a 10 µs ND beam spill Zoom of a ν

_e

candidate in the FD

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Observe flavor change as a function of energy over a long distance while mitigating uncertainties on

neutrino flux, cross sections, and detector response.

How to Measure Oscillations

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Observe ;lavor change as a function of energy over a long distance while mitigating uncertainties on

neutrino ;lux, cross sections, and detector response.

How to Measure Oscillations

⁹

Neutrino ID

Extrapola1on

Models

Reconstruction

(10)

Observe ;lavor change as a function of energy over a long distance while mitigating uncertainties on

neutrino ;lux, cross sections, and detector response.

How to Measure OscillaCons

Neutrino ID

Extrapola1on

Models

Updated for 2020

Reconstruction

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Neutrino Interaction Model

• Constantly evolving understanding of ν interactions.

• Upgrade to GENIE 3.0.6 → freedom to choose models

• Chose the most “theory-driven” set of models plus GENIE’s re-tune of some parameters*.

• Some custom tuning is still required.

–

Substantially less than was needed with GENIE 2.12.2, which required tweaks to most models.

11

Process Model Reference

Quasielastic Valencia 1p1h J. Nieves, J. E. Amaro, M. Valverde, Phys. Rev. C 70 (2004) 055503 Form Factor Z-expansion A. Meyer, M. Betancourt, R. Gran, R. Hill, Phys. Rev. D 93 (2016) Multi-nucleon Valencia 2p2h R. Gran, J. Nieves, F. Sanchez, M. Vicente Vacas, Phys. Rev. D 88 (2013) Resonance Berger-Sehgal Ch. Berger, L. M. Sehgal, Phys. Rev. D 76 (2007)

DIS Bodek-Yang A. Bodek and U. K. Yang, NUINT02, Irvine, CA (2003) Final State Int. hN semi-classical cascade S. Dytman, Acta Physica Polonica B 40 (2009)

* We call our tune N1810j_0211a, and it is built by starting with G1810b_0211a and substituting the Z-expansion form factor for the dipole one. This combination was not available in the 3.0.6 release, but it may be available in future versions.

Fig: Teppei Katori, “Meson Exchange Current (MEC) Models in Neutrino Interaction Generators” AIP Conf.Proc. 1663 (2015) 030001

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0 0.2 0.4 0.6 0.8 1

(GeV) Visible E

had

0 5 10 15 20 25

Events

4

10

ND Data MEC QE RES DIS Other

Default GENIE NOvA 2020 Tune

Neutrino Beam

CC Selection nµ

µ + n

NOvA Preliminary

Neutrino Interaction Model

• 2p2h or Meson Exchange Current or Multi-nucleon Interactions:

– Disagreement of models with multiple experiments well-known – Tuned to NOvA ND data with two

2D gaussians in q

₀

-| ⃗ q| space.

– Generous systematics covering normalization and kinematic shape

• Final State Interactions

– Used external π-scattering data primarily to set uncertainties – Required adjusting central value,

change in overall xsec was small.

67. Cross section adjustments for 2p2h

–

Maria Martinez Casales

352. Central value tuning and uncertainties for the hN FSI model in GENIE 3

–

Michael Dolce, Jeremy Wolcott, Hugh Gallagher

Po st er s

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182. Improvements and New Applications of Machine Learning – Ashley Back & Micah Groh

120. Data-Driven cross checks for ν_eselection efjiciency in NOvA – Anna Hall & Liudmila Kolupaeva

258. Data-Driven Wrong-Sign Background Estimates – Abhilash Yallappa Dombara

Po st er s

SelecCng and IdenCfying Neutrinos

¹³

• Identify neutrino Flavor using a convolutional neural network.

– A deep-learning technique from computer vision – New, faster network for 2020.

• Before main PID:

– Events are contained in the detector – CC ν_μrequire a well-reconstructed μtrack – Reject cosmic rays with BDTs

• Performance relative to preselection:

– ν_μ: ~90% efjicient, 99% bkg. rejection – ν_e: ~80% efjicient, 80% bkg. rejection

• Validate performance against data-driven control samples in both detectors.

q (ADC)

10 10² 10³

q (ADC)

10 10₂ 10₃

q (ADC)

10 ¹⁰ 10² ¹⁰² 10³ ¹⁰³ q (ADC)

νμ

νe e

ν p

μ

p

p π

γ

1m

π0

CC ν

_μ

CC ν

_e

NC

First CNN in HEP result: A. Aurisano, et al. JINST 11 (2016) 09, P09001

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Energy Reconstruction

268. Neutrino Energy Estimation in the NOvA Experiment

– Nitish Nayak

Po st er s

ν

_μ

Events

ν

_e

Events E

_µ

from length, ~4% resolution

E

_had

from calorimetry,

~30% resolution

E

_EM

from calorimetry,

~10% resolution

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0.5 1 1.5

2 2.5

POT20 10×Events / 116 10

Data

Total Simulation Total Background Wrong Sign

NOvA Preliminary

0 1 2 3 4 5

Energy [GeV]

Reconstructed µ 0.2

0.4 0.6 0.8 1 1.2 1.4

POT20 10×Events / 11.86 10

Near Detector ν _μ Spectra

• Band around the MC shows the large impact of flux and cross-section uncertainties in only a single detector.

• We use this sample to predict both ν

_µ

and ν

_e

signal spectra at the Far Detector.

– Appearing ν

_e

’s are still ν

_μ

’s at the ND

15

ν̅

_μ

ν

_μ

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1 2 3 4

POT20 10×Events / 113 10

ND data Total MC

e CC NC

µCC

NOvA Preliminary

0 1 2 3 4 5

Energy [GeV]

Reconstructed e 0.5

1 1.5 POT20 10×Events / 11.83 10

Near Detector ν _e -like Spectra

• The ND ν

_e

-like spectrum contains the background to the appearing ν

e

’s at the FD.

• Largest background is the irreducible ν

_e

/ν̅

_e

blux component.

– 50% in neutrino-mode – 71% in antineutrino mode

• We use this sample to predict the background to ν

_e

appearance.

ν

_e

ν̅

_e

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0 5 10 15 20 25

POT-equiv20 10´Events / 13.60

Low PID High PID

Core Peripheral

Reconstructed neutrino energy (GeV)

1 2 3 4 1 2 3 4

e CC n Signal

e WS n

e CC n Beam NC

µ CC n

t CC n Cosmic

NOvA Preliminary

-beam n

QuarFle 1 σ

_E

= 6%

Enhancing SensiCvity to OscillaCons

ν _μ sample

• Sensitivity depends primarily on the shape of the energy spectrum.

• Bin by energy resolution →

bin by hadronic energy fraction

17

ν _e sample

• Sensitivity depends primarily on separating signal from background.

• Bin by purity → bins of low & high PID

• Peripheral sample:

– Captures high-PID events which might not be contained close to detector edges.

– No energy binning.

Quartile 2 σ

_E

= 8%

QuarFle 3

σ

_E

= 10% Quartile 4

σ

_E

= 12%

Mostly real νe’s

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ExtrapolaCng from Near to Far Detector

• Observe data-MC differences at the ND, use them to modify the FD MC.

– Extrapolation performed in the analysis binning of energy + (resolution or PID).

• Significantly reduces the impact of uncertainties correlated between detectors – Especially effective at rate effects like the flux (7% → 0.3%).

0 1 2 3 4 5

Energy [GeV]

nµ

Reconstructed

0.5 1 1.5 2 2.5

POT20 10´ Events / 116 10

Data

Total Simulation Total Background Wrong Sign Data

Total Simulation Total Background Wrong Sign

NOvA Preliminary

Neutrino Mode

0 1 2 3 4 5

0 50 100

150 No oscillation

Oscillated syst. range 1-

Background

Events / 0.1GeV

NOvA Preliminary

-beam

Near

Detector Far

Detector

Extrapola7on

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354. Near-to-Far Extrapolation in Transverse Momentum at NOvA

– Aaron Mislivec

Po st er s

ExtrapolaCng KinemaCcs

¹⁹

Near Det.

Far Det.

• Containment limits the range of lepton angles more in the Near Detector than in the Far.

– The ND is 1/5 the size of the FD.

• Mitigate by extrapolating in bins of lepton transverse momentum, p

_t

– Transverse to the ν-beam direction

≈ the central axis of the detectors

• Split the ND sample into 3 bins of p

_t

, extrapolate each separately to the FD.

– Effectively “rebalances” the kinematics to better match between the detectors.

– Re-sum the p

_t

bins before fitting.

(20)

SystemaCc UncertainCes with p _t ExtrapolaCon

• Increased robustness also leads to a 30% reduction in cross section uncertainties.

–

Reduces the size of the systematics most likely to contain “unknown unknowns”

–

Slightly increase the sensitivity to well-understood systematics on lepton reconstruction.

• Overall systematic reduction is 5-10%,

–

The largest systematics come from the detector energy scale.

-0.06 0.00 0.06

2

)

-3

eV

´ 10

32

( m

2

D Uncertainty in

NOvA Preliminary

-0.04 0.00 0.04

q

23

Uncertainty in sin

2 Statistical Uncertainty

Total Syst. Unc.

Beam Flux Lepton Reconstruction Detector Response Near-Far Uncor.

Neutrino Cross Sections Neutron Uncertainty Detector Calibration

NOvA Preliminary

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OscillaCon Fit

• Simultaneous fit of all samples, reactor-constrained sin

²

2θ

₁₃

= 0.085±0.003.

• We perform a frequentist analysis and use the Feldman-Cousins method to ensure proper coverage in all contours and intervals.

21

ν

_μ

ν̅

_μ

ν̅

_e

ν

_e

Δm

²₃₂

, sin

²

θ

₂₃

, δ

_CP

Octant, Hierarchy,

CP-violation

262. Accelerating Calculation of Conjidence Intervals for NOvA's Neutrino Oscillation Parameter Estimation with Supercomputers

– Steven Calvez, Tarak Thakore

Po st er s

(22)

Events / 0.1 GeV

FD data 2020 Best-fit

syst. range s

1-

Background

NOvA Preliminary

-beam n

Ratio to no osc.

Reconstructed neutrino energy (GeV)

0 5 10 15 20

0 1 2 3 4 5

0 0.2 0.4 0.6 0.8 1

Events / 0.1 GeV

FD data 2020 Best-fit

syst. range s

1-

Background

NOvA Preliminary

-beam n

Ratio to no osc.

Reconstructed neutrino energy (GeV)

2 4 6 8 10

0 1 2 3 4 5

0 0.2 0.4 0.6 0.8 1

ν _μ and ν̅ _μ Data at the Far Detector

ν̅

_μ

ν

_μ

211 events, 8.2 background 105 events, 2.1 background

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23

0 10 20 30

POT-equiv20 10´Events / 13.60

1 2 3 4 1 2 3 4

FD data 2020 best-fit

syst range 1-s

Wrong sign bkg Total beam bkg Cosmic bkg

NOvA Preliminary

-beam n

0 5 10 15 20

POT20 10´Events / 12.50

1 2 3 4 1 2 3 4

FD data 2020 best-fit

syst range s

1-

Wrong sign bkg Total beam bkg Cosmic bkg

NOvA Preliminary

-beam n

ν _e and ν̅ _e Data at the Far Detector

ν̅

_e

ν

_e

Total Observed 82 Range Total Prediction 85.8 52-110

Wrong-sign 1.0 0.6-1.7

Beam Bkgd. 22.7 Cosmic Bkgd. 3.1

Total Bkgd. 26.8 26-28

Total Observed 33 Range Total Prediction 33.2 25-45

Wrong-sign 2.3 1.0-3.2

Beam Bkgd. 10.2 Cosmic Bkgd. 1.6

Total Bkgd. 14.0 13-15

>4σ evidence of ν̅

_e

appearance

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0.4 0.5 0.6

q 23

sin 2

2.0 2.5 3.0

) 2 eV -3 (10 32 2 m D

NOvA best fit

NOvA Preliminary

Normal Hierarchy 90% CL

NOvA 2020 MINOS+ 2018 T2K 2020 IceCube 2018 SK 2018

0.4 0.5 0.6

q 23

sin 2

2.0 2.5 3.0

) 2 eV -3 (10 32 2 m D

NOvA best fit

Normal Hierarchy 90% CL

NOvA 2020 MINOS+ 2018 T2K 2020 IceCube 2018 SK 2018

0.4 0.5 0.6

q 23

sin 2

2.0 2.5 3.0

) 2 eV -3 (10 32 2 m D

NOvA best fit

NOvA Preliminary

Normal Hierarchy 90% CL

NOvA 2020 MINOS+ 2018 T2K 2020 IceCube 2018 SK 2018

T2K Nature 580

Precision measurements of Δm

²₃₂

(3%) and sin

²

θ

₂₃

(6%)

_.

Best Fit

Normal hierarchy

Δm

²32

= (2.41±0.07)×10

^-3

eV

²

sin

²

θ

23

= 0.57

^+0.04-0.03

Prefer non-maximal mixing by 1.1σ.

(25)

25

Best Fit

Normal hierarchy

Δm

²₃₂

= (2.41±0.07)×10

^-3

eV

²

sin

²

θ

₂₃

= 0.57

^+0.04_-0.03

δ = 0.82π

d

CP

0.3 0.4 0.5 0.6 0.7

23

q

2

sin

0 2

p p

2 3 p 2 p

1 s

£ £ 2 s £ 3 s Best Fit

NOvA Preliminary

NH

d

CP

0.3 0.4 0.5 0.6 0.7

23

q

2

sin

0 2

p p

2 3 p 2 p

1 s

£ £ 2 s £ 3 s Best Fit

NOvA Preliminary

IH

83. Long-baseline neutrino oscillation results from NOvA

– Liudmila Kolupaeva & Karl Warburton

262. Accelerating Calculation of Con@idence Intervals for NOvA's Neutrino Oscillation Parameter Estimation with Supercomputers

– Steven Calvez, Tarak Thakore

Po st er s

(26)

Inverted Hierarchy

Normal Hierarchy Upper O

ctant Lower O

ctant

CP 0

1 2 3 4 5

) ⇥ Significance (

0 2 ⇤ ⇤

2 ⇤

3 2 ⇤

NOvA FD 13.6◊10 POT equiv ⌅+ 12.5◊10 POT ⌅

NOvA Preliminary

NH Lower octant NH Upper octant IH Lower octant IH Upper octant

• We see no strong asymmetry in the rates of appearance of ν

_e

and ν̅

_e

• Disfavor hierarchy-δ combinations which would produce that asymmetry

• Consistent with hierarchy-octant-δ combinations which include some “cancellation.”

–

Since such options exist for both octants and hierarchies, results show no strong preferences.

(27)

27

Inverted Hierarchy

ctant Lower

Octant

CP 0

1 2 3 4 5

) ⇥ Significance (

0 2 ⇤ ⇤

2 ⇤

3 2 ⇤

NOvA FD 13.6◊10²⁰ POT equiv ⌅+ 12.5◊10²⁰ POT ⌅

NOvA Preliminary

• We see no strong asymmetry in the rates of appearance of ν

_e

and ν̅

_e

• Disfavor hierarchy-δ combinations which would produce that asymmetry

• Consistent with hierarchy-octant-δ combinations which include some “cancellation.”

–

Since such options exist for both octants and hierarchies, results show no strong preferences.

Exclude ΙΗ δ = π/2 at >3σ

Disfavor NH δ = 3π/2 at ~2σ

(28)

Inverted Hierarchy

ctant Lower

Octant

• We see no strong asymmetry in the rates of appearance of ν

_e

and ν̅

_e

• Disfavor hierarchy-δ combinations which would produce that asymmetry

• Consistent with hierarchy-octant-δ combinations which include some “cancellation.”

–

Since such options exist for both octants and hierarchies, results show no strong preferences.

CP 0

1 2 3 4 5

) ⇥ Significance (

0 2 ⇤ ⇤

2 ⇤

3 2 ⇤

NOvA FD 13.6◊10 POT equiv ⌅+ 12.5◊10 POT ⌅

NOvA Preliminary

Exclude ΙΗ δ = π/2 at >3σ Disfavor NH δ = 3π/2 at ~2σ

Prefer…

Normal Hierarchy at 1.0σ

Upper Octant at 1.2σ

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Comparison to T2K

• Clear tension with T2K’s preferred region.

• Quantifying consistency requires a joint iit of the data from the two experiments, which is already in the works.

–

Semi-annual workshops, regular joint group meetings, and a signed joint agreement.

29

d CP

0.3 0.4 0.5 0.6 0.7

23 q 2 sin

0 2

p p

2 3 p 2 p

Normal Hierarchy

NOvA Preliminary

T2K, Nature 580: BF £ 90% CL £ 68% CL

NOvA: BF £ 90% CL £ 68% CL

(30)

Comparison to T2K

d CP

0.3 0.4 0.5 0.6 0.7

23 q 2 sin

0 2

p p

2 3 p 2 p

Normal Hierarchy

NOvA Preliminary

T2K, Nature 580: BF £ 90% CL £ 68% CL NOvA: BF £ 90% CL £ 68% CL

NOvA-T2K Workshop, Fermilab, February 2019

(31)

Conclusions

• We present an updated neutrino oscillation analysis with:

– 50% more neutrino beam data,

– updated simulation and reconstruction, including a new GENIE 3 cross-section model, – updated extrapolation which mitigates differing detector acceptances.

• New 3-Jlavor oscillation results:

– Δm

²32

= (2.41±0.07)×10

^-3

eV

²

– sin

²

θ

₂₃

= 0.57

^+0.04_-0.03

– exclude IH, δ = π/2 at > 3σ, – disfavor NH, δ = 3π/2 at ~2σ.

• Looking ahead:

– We can reach 3σ hierarchy sensitivity for 30-50% of δ values, with the full dataset and an upgraded beam.

– Plan to reduce our largest systematics, those related to detector energy scale, with the results of our test beam experiment.

31

314. Design and Operation of a Charged Particle Beamline

– David Duenas Tonguino, Mike Wallbank, Alex Sousa, Andrew Sutton, Teresa Lackey

Po st er s

(32)

Questions?

(33)

Backups

(34)

0 1 2 3 4 0

2 4 6 8

10

_{Quartile 3}

0 1 2 3 4 5

worst resolution Quartile 4

0 2 4 6 8

10

best resolution

Quartile 1

FD data Background

Quartile 2

2020 Best-fit syst. range 1-s

NOvA Preliminary

-beam n

Reconstructed neutrino energy (GeV)

Events / 0.1 GeV

ν

_μ

(35)

0 1 2 3 4 0

2 4

Quartile 3

0 1 2 3 4 5

worst resolution Quartile 4

0 2 4 6

best resolution Quartile 1

FD data Background

Quartile 2

2020 Best-fit syst. range 1-s

NOvA Preliminary

-beam n

Reconstructed neutrino energy (GeV)

Events / 0.1 GeV

35

ν̅

_μ

(36)

Pulls in the Fit

• Largest pulls also correspond to some of our known most important systematics:

–

Detector light model and energy scale (calibration)

–

Multi-nucleon cross section

• We see examples where a pull comes primarily from the neutrino or antineutrino beam,

but generally do not see contradictory pulls.

(37)

Spectra with NOvA and T2K Best Fits

• Both best \its also include minimization of our systematic uncertainties.

37

ν

_μ

ν̅

_μ

ν̅

_e

ν

_e

(38)

• The QE central value is quite similar, but the expanded uncertainty due to the Z-expansion is apparent.

• In resonance, the uncertainty remains similar, the but the central value has changed.

• New model, Berger-Seghal, plus the global retune to scattering data.

0 0.5 1 1.5 2

2) (GeV True Q2

5 10 15

Events5 10

2019 GENIE 2 NOvA tune 2020 GENIE 3 NOvA tune

Neutrino Beam Simulated true RES

NOvA Simulation

0 0.5 1 1.5 2

2) (GeV True Q2

2 4 6 8

Events5 10

2019 GENIE 2 NOvA tune 2020 GENIE 3 NOvA tune

Neutrino Beam Simulated true QE

2020 vs. 2017 Cross SecCon Model

(39)

hN2018 FSI tuning

• New FSI model in GENIE 3.0.6:

semi-classical cascade, “hN”

– Propagates hadrons through nucleus in binite steps

– Simulates interactions according to probabilities derived from Oset et al.

quantum model*

– Tuned using external pion scattering data, which is related to intranuclear probabilities using amplitudes from Oset model

• Old model (“hA”) simply assumes hadron scattering data applies directly to FSI

* L. L. Salcedo et al. Nucl. Phys. A484: 557 (1988).

†E.S. Pinzon Guerra et al. Phys Rev. D99: 052007 (2019).

... but hN2018 agrees poorly with pion scattering data on carbon.

Pion

absorption Total reactive

cross section

We retune hN2018 and develop systematics based in part on similar

work by T2K

^†

Pion

absorption Total reactive cross section

(40)

SelecCon: ValidaCng Performance

• Examine PID efJiciency relative to pre-selection.

– Speciiically target the behavior of the PID.

• ND: mixed data-MC sample

– Mix simulated electrons and real hadronic showers

• FD: decay-in-Jlight electrons

– Real electron showers from cosmic muons which decay

120. Data-Driven cross checks for ν

_e

selection efficiency in NOvA

– Anna Hall

258. Data-Driven Wrong-Sign Background Estimates

– Abhilash Yallappa Dombara

Po st er s

0 1 2 3 4

Energy (GeV) ne

0 0.2 0.4 0.6 0.8 1 1.2

Selection efficiency

NOvA Preliminary

-beam n

MRE Data MRE Simulation

syst. error s

1

(41)

41

• Create 3 energy spectra, one for each p

t

bin.

• Each spectra gets its own extrapolation.

• Predictions are summed before bitting.

0123450 2 4 6 8

0 20 40 60 80

012345 1 2 3 4

011200201

ND Events/1 GeV 105 True Energy (GeV)

True Energy (GeV)

ND Reco Energy (GeV)FD Reco Energy (GeV)

FD Events/1 GeV

ND Events510FD Events F/N Ratio-3 10)µν→µνP( ND dataBase SimulationData-Driven Prediction 0123450 2 4 6 8

0 20 40 60 80

012345 1 2 3 4

011200201

True Energy (GeV)

FD Events/1 GeV ND Events510FD Events F/N Ratio-3 10)µν→µνP( ND dataBase SimulationData-Driven Prediction

0123450 2 4 6 8

0 20 40 60 80

012345 1 2 3 4

011200201

True Energy (GeV)

FD Events/1 GeV ND Events510FD Events F/N Ratio-3 10)µν→µνP( ND dataBase SimulationData-Driven Prediction

The NOvA Experiment

New Oscilla+on Results from the NOvA Experiment

Alex Himmel, Fermilab for the NOvA Collabora6on

July 2 nd , 2020

The NOvA Experiment

• Long-baseline neutrino oscillation experiment

• NuMI beam: ν

or ν̅

• 2 functionally identical, tracking calorimeter detectors

– Near: 300 T underground – Far: 14 kT on the surface – Placed off-axis to produce a

narrow-band spectrum

• 810 km baseline

– Longest baseline of current experiments.

Take a tour

in VR!

Physics Goals

Results from 3 different oscillation analyses

Disappearance of ν µ CC events

clear suppression as a function of energy

2015 analysis results Phys.Rev.D93.051104

sin 2 (2✓ 23 )

m 2 32

Appearance of ν e CC events

810 km baseline

enhances matter effects

±30% effect

2015 analysis results in PRL.116.151806

✓ 13 , ✓ 23 , CP ,

and Mass Hierarchy

Deficit of NC events?

suppression of NCs could be evidence of oscillations involving a sterile neutrino

Fit to 3+1model

new! m 2 41 , ✓ 34 , ✓ 24

NOvA Physics

• Atmospheric sector oscillations:

– Δm

, sin

θ

, δ

• Key open questions in oscillations:

– Is the neutrino mass hierarchy normal or inverted?

– Is CP violated in the neutrino sector?

– Is θ

mixing maximal?

• ν

-ν

symmetry

• If not, what is the octant of θ

?

NOvA Physics

• Atmospheric sector oscillations:

– Δm

, sin

θ

, δ

• Key open questions in oscillations:

– Is the neutrino mass hierarchy normal or inverted?

– Is CP violated in the neutrino sector?

– Is θ

mixing maximal?

• ν

-ν

symmetry

• If not, what is the octant of θ

?

• Disentangle by measuring…

– disappearance P(ν

→ν

) and appearance P(ν

→ν

)

– in neutrinos and antineutrinos – over long baselines to separate

hierarchy and δ effects.

Physics Goals

Results from 3 different oscillation analyses

Disappearance of ν µ CC events

clear suppression as a function of energy

2015 analysis results Phys.Rev.D93.051104

sin 2 (2✓ 23 )

m 2 32

July 2 ^nd , 2020

Disappearance of ν _µ CC events

sin ² (2✓ ₂₃ )

m ² ₃₂

Appearance of ν _e CC events

✓ ₁₃ , ✓ ₂₃ , _CP ,

new! m ² ₄₁ , ✓ ₃₄ , ✓ ₂₄

Disappearance of ν _µ CC events

sin ² (2✓ ₂₃ )

m ² ₃₂

Appearance of ν _e CC events

✓ ₁₃ , ✓ ₂₃ , _CP ,

new! m ² ₄₁ , ✓ ₃₄ , ✓ ₂₄