Global Picture Multiple sources Multiple detectors 18 July 2017 2 - - PowerPoint PPT Presentation

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Global Picture Multiple sources Multiple detectors 18 July 2017 2 - - PowerPoint PPT Presentation

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Oscillation Measurements with KM3NeT-ORCA Joo Coelho APC Laboratory 18 July 2017 18 July 2017 1 arXiv:1611.01514 [hep-ph] Global Picture Multiple sources Multiple detectors 18 July 2017 2 Missing Pieces Is q 23 = p /4? Underlying

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SLIDE 1

Oscillation Measurements with KM3NeT-ORCA

João Coelho

APC Laboratory

18 July 2017

18 July 2017 1

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SLIDE 2

Global Picture

18 July 2017 2

  • Multiple sources
  • Multiple detectors

arXiv:1611.01514 [hep-ph]

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SLIDE 3

Missing Pieces

  • Is q23 = p/4? Underlying symmetry?
  • Do neutrinos violate CP? (dCP)
  • What is the mass ordering? (Mass Hierarchy)

same? dCP ?

18 July 2017 3

Dm2

32 < 0 ?

Normal Hierarchy Inverted Hierarchy

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SLIDE 4

4

One weird trick to measure the Mass Hierarchy…

18 July 2017

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SLIDE 5

Matter Effects

18 July 2017 5

H0 V

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SLIDE 6

Resonances

18 July 2017 6

q12 q13 q23 Dm2

21 cos2q12

Dm2

31 cos2q13

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SLIDE 7

Resonances

18 July 2017 7

IH NH q12 q13 q23

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SLIDE 8

Resonances

18 July 2017 8

ORCA ARCA T2K NOvA DUNE q12 q13 q23 JUNO

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SLIDE 9

18 July 2017 9

Atmospheric Neutrinos

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SLIDE 10

Nue appearance at the surface

Atmospheric Neutrinos

18 July 2017 10

Oscillations are resonant at certain energies Eres ~ 7 GeV in Mantle Eres ~ 3 GeV in Core core mantle

Neutrino Source

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SLIDE 11

Atmospheric Neutrinos

18 July 2017 11

Oscillations are resonant at certain energies Eres ~ 7 GeV in Mantle Eres ~ 3 GeV in Core core mantle IH NH

1 5 10 Eν [GeV] 1 0.5

νμ νe

P(νμ → νx) for θ=130º

  • Resonance occurs for NH only for neutrinos

and vice versa for antineutrinos

  • Mantle crossing neutrinos provide

strongest signal for MH measurements

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SLIDE 12

The Challenge

18 July 2017 12

qZ

  • Measure neutrino direction and energy
  • Search for oscillation patterns from matter effects
  • Sensitive to difference in patterns between NH and IH
  • Requires large statistics and good energy and direction res.
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SLIDE 13

KM3NeT Collaboration

18 July 2017 13

11 Countries >200 scientists >40 Institutions www.km3net.org

ARCA Site

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SLIDE 14

Main Objectives

  • ORCA: Determine the

Mass Hierarchy (MH)

  • ARCA: Discover/Observe

high-energy neutrino sources in the universe

Talk by A. Kouchner Thursday

18 July 2017 14

Normal Hierarchy Dm2

32 > 0

Inverted Hierarchy Dm2

32 < 0

m2 m2

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SLIDE 15

~210 m 9 m

The ORCA Detector

  • ~6 Mton instrumented
  • 115 strings
  • 18 DOMs / str
  • 31 PMTs / DOM
  • Total: 64k 3’’PMTs

18 July 2017 15

43 cm

Optimized for MH sensitivity 2450m Depth

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SLIDE 16

Trigger

18 July 2017 16

40Ca

b-

40Ca

b-

40Ca

b-

  • Optical background mostly from 40K decays in the water
  • Measured: 8 kHz uncorr., 340 Hz level-two coinc. / PMT [Eur. Phys. J. C 74, 3056 (2014)]
  • Look for coincidences in time and PMT direction to reduce trigger rate.
  • Causality further restricts space and time correlations for extra power.
  • Final trigger rate ~59 Hz, with 70% of events containing a cosmic ray muon.

40K 40K 40K 40K

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SLIDE 17

Trigger

18 July 2017 17

  • Optical background mostly from 40K decays in the water
  • Measured: 8 kHz uncorr., 340 Hz level-two coinc. / PMT [Eur. Phys. J. C 74, 3056 (2014)]
  • Look for coincidences in time and PMT direction to reduce trigger rate.
  • Causality further restricts space and time correlations for extra power.
  • Final trigger rate ~59 Hz, with 70% of events containing a cosmic ray muon.

First ARCA lines show trigger clearly muon dominated.

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SLIDE 18

Measuring Neutrinos

18 July 2017 18

Track-like Shower-like

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SLIDE 19

Reconstruction

18 July 2017 19

1) Start with a track or shower hypothesis 2) Use causality to perform a robust hit selection 3) Find vertex and direction that best match hit pattern 4) Estimate track range for computing track energy (0.24 GeV / m) 5) Estimate Shower energy and direction from hit distribution after initial fit to the vertex position and time qC

Track Hypothesis Shower Hypothesis

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SLIDE 20

Reco Performance

18 July 2017 20

  • Energy resolution: ~25% (Close to limit arXiv:1612.05621)
  • Angular resolution: Better than 10 degrees at relevant energies

nm-CC ne-CC ne-CC q Res. E Res. q Res. E Res. nm-CC

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SLIDE 21

18 July 2017 21

Event Selection

  • Events are classified through a

Random Decision Forest (RDF)

  • At 10 GeV:
  • 90% of ne-CC are shower-like
  • 70% of nm-CC are track-like
  • Most atmospheric muons are

removed by containment cuts

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SLIDE 22

Full Statistical Analysis

Profile over 4 oscillation & 5 systematic parameters

18 July 2017 22

  • Generate pseudo-experiments and

compute

  • For each MH assumption, LLR distribution

will peak at different values

  • Median sensitivity: probability of
  • bserving median LLR of wrong hierarchy

for PEs generated with fixed true hierarchy

IH NH

mIH mNH sIH

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SLIDE 23

Sensitivity Results

18 July 2017 23

  • ~3s MH sensitivity in 3 years
  • The combination of NH and upper
  • ctant of q23 would significantly

improve sensitivity (5s in 3 years)

  • The value of dcp has small but non-

negligible impact on sensitivity

  • In the IH, sensitivity is mostly

independent of octant of q23

  • Best case scenario could achieve

>5s by 2022 (1.5 years)

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SLIDE 24

Other Parameters

18 July 2017 24

  • High statistics and excellent resolution → Measure Dm2

32 and sin2q23

  • Competitive with NOvA and T2K projected sensitivity in 2020
  • Achieve 2-3% prec. in Dm2

32 and 4-10% in sin2q23

Normal Hierarchy

T2K 2015 NOvA 2020 T2K 2020 MINOS KM3NeT

68% C.L.

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SLIDE 25

Extended Models

Non-Standard Interactions (NSI) Sterile Neutrinos (3+N Flavours)

18 July 2017 25

Arbitrary Perturbation

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SLIDE 26

Enhanced Matter Effects

18 July 2017 26

NSI (eet = 0.2) Steriles (“Curr.” Limits)

Visit https://goo.gl/CJyFoK for more

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SLIDE 27

Non-Standard Interactions

18 July 2017 27 [1] JHEP 0908:090 (2009) [2] JHEP 1309:152 (2013) [3] KM3NeT-ORCA Preliminary

  • ORCA sensitive to NSI effects
  • f order 10% of the Fermi int.
  • Direct bounds are more than

10x larger in some cases

  • ORCA improves over current

atmospheric scale bounds

  • Limits competitive with global

limits from oscillation

*Phys. Rev. D 84, 113008 (2011) *

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SLIDE 28

Sterile Neutrinos

18 July 2017 28

  • Promising sensitivity in Ut4 mixing
  • Factor of two better sensitivity than

current limits from SK and IC

  • After only 1 year of data taking

[1] PRD 85, 077301 (2012); PRL 117, 151801 (2016) [2] J. J. Evans, Neutrino 2016; PRL 117, 151803 (2016) [3] Phys. Rev. D 91, 052019 (2015) [4] PRL 117, 071801 (2016); arXiv:1702.05160 (2017) [5] KM3NeT-ORCA Preliminary [6] Phys. Rev. D 64, 112007 (2001)

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SLIDE 29

Earth tomography

  • ORCA is sensitive to the electron density Ne

while geophysics measure rm

  • 1s uncertainty after 10 years assuming NH:
  • 5% in the whole mantle (c)
  • 6% in the whole outer core (b)
  • PREM model basis for rm
  • uniform Z/A rescaling in layer
  • Monte Carlo response & PID

10 year sensitivity including systematics

Outer core Mantle

NO

IO

18 July 2017 29

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SLIDE 30

Tau neutrino appearance

  • nt app. tests unitarity and new physics
  • ~ 3k nt CC events/year with full ORCA
  • Rate constrained within ~10% in 1 year
  • Sensitivity with few strings is under study

No app. Unitarity

  • Monte Carlo response and PID
  • same PID as MH (not optimised for nt)

New phys.

18 July 2017 30

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SLIDE 31

Simulation Update

  • J. Phys. G 43 (2016) 084001

Performances based on temporary detector layout New set of simulations started Trigger + reconstruction + PID + background rejections Some new results here Accounts for technical constraints

18 July 2017 31

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SLIDE 32

New Geometry Design

New Footprint From 6 Mton (LoI) to 8 Mton (accounts for technical constraints)

18 July 2017 32

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SLIDE 33

Improvements at trigger level

  • Addition of a new trigger

now: ONE local coincidence (L1) plus causally-connected hits in vicinity (do not have to be coincidences) before: cluster of causally-connected L1 hits (2 L0 hits on sam DOM) Keep bandwidth requirements: trigger rate from pure-noise smaller than irreducible trigger rate from to atmospheric muons. Increase of effective volume at low energies despite sparser detector ne CC

18 July 2017 33

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SLIDE 34

Improvements in reconstructions

  • Reconstruction strategies adjusted for new trigger: allows for fainter events

Tracks:

  • prefit based on a single local coincidence plus casually connected hits in the

vicinity (for an assumed track direction)

  • Scan in all directions, with a step size of 5 degrees
  • Full fit procedure applied to 96 “best” reconstructed tracks

Much higher efficiency w.r.t. the trigger (low E) - angular resolution unchanged

18 July 2017 34

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SLIDE 35

Improvements in reconstructions

  • Reconstruction strategies adjusted for new trigger: allows for fainter events

Showers: main changes in the hit selection (loosened) Now 20% faster turn-on and 40% larger plateau compared to LoI-9m with similar reconstruction resolutions Expect an increase in MH sensitivity and oscillation parameters, but a robust estimate requires a full chain processing (on going).

18 July 2017 35

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SLIDE 36

18 July 2017 36

Summary

  • ORCA is being built in the Mediterranean sea to measure
  • scillations with atmospheric neutrinos
  • Main goal is to determine the Neutrino Mass Hierarchy
  • ORCA will also improve measurements of other
  • scillation parameters such as Dm2

32 and q23

  • Lots of potential for other searches: sterile neutrinos,

NSI, earth tomography, tau neutrinos, etc.

  • MH could be determined by 2023
  • Stay tuned for updated sensitivities
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SLIDE 37

18 July 2017 37

Thank you!

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SLIDE 38

18 July 2017 38

Backup Slides

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SLIDE 39

Construction Status

18 July 2017 39

Phase 1: 7 string array

  • demonstrate technology/detection
  • funded

Phase 2: deploy 1 building block (115 strings)

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SLIDE 40

Deployment

  • String fitted to Launcher Vehicle
  • Delivered at a depth of 2450m
  • Dynamic Positioning: 1m precision
  • Acoustic triangulation: 10cm prec.
  • ROV connects cable to junction box
  • Boat triggers unfurling of the string
  • Watch ARCA string deployment at:

18 July 2017 40

LV ROV Unfurling

https://www.youtube.com/watch?v=tR8jwgG6uzk

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SLIDE 41

Funding and Schedule

18 July 2017 41

  • Construction is ongoing
  • 2 strings in operation (ARCA)
  • First ORCA strings ready for

deployment

  • Total ORCA cost: ~45 M€
  • Selected for 2016 ESFRI Roadmap

2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 ORCA Construction MH Determination

115 Strings Full Detector

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SLIDE 42

Atmospheric Neutrinos

18 July 2017 42

  • Factor of ~2.5 between ne and nm
  • Factor of ~2 between n and anti-n
  • nm + anti-nm = (nm + anti-nm + ne + anti-ne) -> (nm + anti-nm)
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SLIDE 43

Resonance Formulas

18 July 2017 43

Depends on sign of Dm2

31 (MH)

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SLIDE 44

Trigger Performance

18 July 2017 44

  • Input a conservative noise rate of 10 kHz uncorr. (500Hz level-two coinc.)
  • Achieve a total triggered rate of 59 Hz
  • About 70% of events contain a muon (41 Hz)
  • High efficiency for nm and ne above 4 GeV
  • Slightly more efficient for up-going neutrinos (Larger PMT coverage)

ne-CC

Neutrino Rate: ~ 1 n / 10 min

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SLIDE 45

Optimizing DOM Spacing

  • Simulated small (6m) vertical spacing detector
  • Mask off 1/3, 1/2 or 2/3 of DOMs to emulate larger spacing
  • Smaller spacing enables measurement at lower energies
  • Larger spacing improves statistics due to larger volume

18 July 2017 45

nm + nm CC ne + ne CC

  • Simulated small (6m) vertical spacing detector
  • Mask off 1/3, 1/2 or 2/3 of DOMs to emulate larger spacing
  • Smaller spacing enables measurement at lower energies
  • Larger spacing improves statistics due to larger volume
  • Tune spacing to obtain maximum sensitivity to Mass Hierarchy
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SLIDE 46

Optimizing DOM Spacing

  • Simulated small (6m) vertical spacing detector
  • Mask off 1/3, 1/2 or 2/3 of DOMs to emulate larger spacing
  • Smaller spacing enables measurement at lower energies
  • Larger spacing improves statistics due to larger volume
  • Tune spacing to obtain maximum sensitivity to Mass Hierarchy

18 July 2017 46

Derived from data in the KM3NeT 2.0 LoI: https://arxiv.org/abs/1601.07459

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SLIDE 47

Simple c2 Analysis

  • 9m spacing achieves best sensitivity

18 July 2017 47

Mass Hierarchy Sensitivity

9m 6m 12m True NH True IH

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SLIDE 48

NSI Motivation

Non-Standard Interactions (NSI)

18 July 2017 48

Arbitrary Perturbation Dimension-6 + Naturalness TeV Scale ~ 10-2

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SLIDE 49

Resonances w/ NSI

18 July 2017 49

q12 q13 q23 q12 q13 q23

eee = 1 eet = 0.5, ett = 0.25

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SLIDE 50

NSI Phase Space

18 July 2017 50

  • Very different from MH for nue
  • Sensitivity in both channels, but numu is correlated with MH

eet = 0.2, ett = 0.04

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SLIDE 51

NSI Phase Space

18 July 2017 51

eet = 0.2, ett = 0.04

  • Very different from MH for nue
  • Sensitivity in both channels, but numu is correlated with MH
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SLIDE 52

Sterile Neutrino Motivation

18 July 2017 52

|Ue4|2 |Um4|2 |Ut4|2 LSND: nm →ne at L/E ~ 1 km/GeV Dm2

43 ~ 100x Dm2 32

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SLIDE 53

Resonances w/ Steriles

18 July 2017 53

m2

2

m1

2

m3

2

m4

2

Ve Vn q12 q13 q23 q14 q24 q34 q23 Suppression Dm2

41 = 0.3 eV2

  • New resonant peak due to Dm2

41

  • Some intermediate behaviour between q13 and q14 resonances
  • q23 suppression seems to be fairly independent of Dm2

41

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SLIDE 54

Resonances w/ Steriles

18 July 2017 54

m2

2

m1

2

m3

2

m4

2

Ve Vn q12 q13 q23 q14 q24 q34 q23 Suppression Dm2

41 = 10 eV2

  • New resonant peak due to Dm2

41

  • Some intermediate behaviour between q13 and q14 resonances
  • q23 suppression seems to be fairly independent of Dm2

41

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SLIDE 55

ORCA Studies

18 July 2017 55

  • Strong sensitivity with nm channel
  • Very different from 3n resonance
  • Suppression of disappearance for

vertically up-going nm at ~20 GeV

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SLIDE 56

MINOS MINOS+ IceCube Super-K

Sterile Neutrinos (3+1)

18 July 2017 56

|Ue4|2 |Um4|2 |Ut4|2

Super-K: Phys. Rev. D 91, 052019 (2015) IceCube: Phys. Rev. Lett. 117, 071801 (2016) MINOS+: Justin Evans, Neutrino 2016 Solar+React.: Mod. Phys. Lett. A 28, 1330004 (2013)

Solar+Reactors IceCube Super-K MINOS+

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SLIDE 57

Tau Coupling

18 July 2017 57

  • ORCA/PINGU can probe the Ut4 coupling at low energies
  • At high energies, effect is related to Um4
  • New constraints on Um4 impact sensitivity at low energy too

|Ut4|2 = 0.18 d24 = {0, p/2, p, 3p/2} |Um4|2 at IC limit Ut4 = 0 cosqz < -0.9

IceCube Analysis Region

Super-K and DeepCore probed low-E with similar sensitivity

  • A. Terliuk, P2.024 Neutrino 2016

DeepCore ORCA/PINGU Probability Difference