Proposal for joint neutrino oscillation analysis using data from the T2K and reactor experiments

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Proposal for joint neutrino oscillation analysis using data from the T2K and

reactor experiments

Maria Antonova, Anselmo Cervera, Alexander Izmaylov, Pau Novella

IFIC, (CSIC and Universitat de Valencia) Valencia

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Proposal for joint neutrino oscillation analysis using data from the T2K and reactor experiments

Super‐Kamiokande Near Detectors J‐PARC

Neutrino Beam 295 km

Mt. Noguchi‐Goro 2,924 m Mt. Ikeno‐Yama

1,360 m

1,700 m below sea level

T2K experiment

!2

μ−like

e−like

50kt water Cherenkov detector

Excellent separation between event types

ND280 INGRID

• Off-axis detector

• Constraints on flux and cross-section models

• On-axis detector

• Beam stability and rate

~40% of expected data

Tokai-to-Kamioka long-baseline neutrino experiment

High purity muon neutrino (antineutrino) beam

peak at 0.6 GeV, tuned for 1^stosc. maximum at 295 km

• Data accumulated since 2010:

• 1.51x10²¹POT in ν mode

• 1.65x10²¹ POT in ν mode

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Current oscillation analysis

!3

not enough precision on θ

13

to probe CP violation

ν

^e

appearance probability (T2K)

Sensitive to (θ

13,

δ

cp

)

( )

⎟⎟⎠

⎞

⎜⎜⎝

⎛ Δ

⎟⎟⎠

⎞

⎜⎜⎝

− ⎛ Δ

⎟⎟⎠

⎞

⎜⎜⎝

⎛ −

+ Δ

⎟⎟⎠

⎞

⎜⎜⎝

≈ ⎛ Δ

→

ν ν

ν µ

δ θ

θ θ

θ

θ θ

θ ν

ν

E L m E

L m m

a E

L P e m

sin 4 sin 4

sin cos

2 sin 2

sin 2

sin

sin 2 2 1

4 1 sin 2

sin sin

) (

2 21 2

2 32 13

13 23

12

13 2 2

31 2

2 32 13 2 23 2

Present reactor constraint implementation

Constraint on θ

13

from the PDG reactor data average

ν -

^e

disappearance (reactor experiments)

Sensitive to θ

13

independently of δ

cp

• Exclusion of CP

conservation at 2σ level

Pros

•

Gaussian approximation

•

No prior correlation with Δm

223

Cons

T2K only

T2K with

reactor constraint

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Proposed analysis

T2K + (θ

13

, Δm

223

) reactor likelihood

•

Combine θ

13

-Δm

223

likelihood surfaces from T2K and reactor experiments

•

Take advantage of reactor

experiments being sensitive to Δm

223

•

Take into account asymmetry of the likelihood surface

•

Include θ

13

-Δm

223

correlations

!4

T2K and Daya Bay have

comparable sensitivity to Δm

223

Best sensitivity to θ

13

An Fet al(Daya Bay Collaboration) 2018, Phys. Rev. Lett. 121, 241805

Planned likelihood surface input:

Daya Bay

T2K

NH IH

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Expected improvement

• Improvement on Δm 223

• At ~√2 level

• Slightly improve δ cp and θ 23 accuracy

• Put prior simultaneously on two parameters (θ 13 , Δm 223 ) instead of one (θ 13 )

• Set stronger constraint on θ 13

• Daya Bay prior error band is smaller than the one currently used

!5

No public results yet but coming

• Implementation within VALOR analysis framework (https://valor.pp.rl.ac.uk/)

• Framework is used for analysis in T2K, DUNE, SBND

• New multi-experiment software under

development

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Thank you!

This work has been supported by funds from "la Caixa” Foundation (ID 100010434, fellowship code LCF/BQ/

IN17/11620050), the European Union’s Horizon 2020 Research and Innovation programme under the Marie Sklodowska-Curie grant agreement no. 713673