Probing the second oscillation maximum at DUNE

Mehedi Masud

IBS IBS-CTPU, Daejeon, Korea &

IOP, Bhubaneswar, India

Probing the second oscillation maximum at DUNE

(work done with Sanjib Kumar Agarwalla)

Plan of the talk

• Outstanding issues in neutrino oscillation sector

• What is oscillation maximum & its importance

• Probing second oscillation maximum at probability & event level

• Can we establish second oscillation maximum in data?

• Summary

Outstanding issues in oscillation ν

Value of

Leptonic CP violation?

δ

₁₃

? Ordering of

neutrino masses?

Normal or Inverted?

Octant of θ

₂₃

?

θ₂₃ > π/4 ^or θ₂₃ < π/4?

Requirement of wide energy band

Precision measurement of osc. parameters

Necessary to exploit wide energy band (e.g., DUNE)

Extract information from more than one oscillation cycles

Huber, Kopp (1010.3706):

Ghosh, Goswami, Raut (1412.1744):

De Romeri, Fernandez-Martinez, Sorel (1607.00293):

Choubey, Ghosh, Kempe, Ohlsson (2010.16334):

Chakraborty, Dutta, Goswami, Pramanik (2012.04958):

Rout, Shafaq, Bishai, Mehta (2012.08269):

Oscillation maxima

P

_μe

= sin

²

2θ

₁₃

sin

²

θ

₂₃

sin

²

Δ

+ αΔ sin 2θ

₁₃

sin 2θ

₁₂

sin 2θ

₂₃

sin Δ cos(δ + Δ) Δ = Δm

312

L

4E = 1.27 Δm

₃₁²

[ eV

²

]L[ km ] E[ GeV ]

α = Δm

₂₁²

Δm

₃₁²

∼ 10

⁻²

Maximum when

where n=1,2,…

sin

²

Δ ≈ 1

 or 

Δ = (2n − 1)π /2

Oscillation maxima

P

_μe

= sin

²

2θ

₁₃

sin

²

θ

₂₃

sin

²

Δ

+ αΔ sin 2θ

₁₃

sin 2θ

₁₂

sin 2θ

₂₃

sin Δ cos(δ + Δ) Δ = Δm

312

L

4E = 1.27 Δm

₃₁²

[ eV

²

]L[ km ] E[ GeV ]

α = Δm

₂₁²

Δm

₃₁²

∼ 10

⁻²

n=1 n=2

n=1 ⟹ E 1 max ≈ 2.5  GeV

n=2 ⟹ E 2 max = E 1 max /3 ≈ 0.8  GeV

Maximum when

where n=1,2,…

sin

²

Δ ≈ 1

 or 

Δ = (2n − 1)π /2

Oscillation maxima

P

_μe

= sin

²

2θ

₁₃

sin

²

θ

₂₃

sin

²

Δ

+ αΔ sin 2θ

₁₃

sin 2θ

₁₂

sin 2θ

₂₃

sin Δ cos(δ + Δ) Δ = Δm

312

L

4E = 1.27 Δm

₃₁²

[ eV

²

]L[ km ] E[ GeV ]

α = Δm

₂₁²

Δm

₃₁²

∼ 10

⁻²

n=1 n=2

n=1 ⟹ E 1 max ≈ 2.5  GeV

n=2 ⟹ E max = E max /3 ≈ 0.8  GeV

In matter,

Δ → (1 − A)Δ

 ^where 

A = 2 2 G

_F

N

_e

E Δm

₃₁²

Maximum when

where n=1,2,…

sin

²

Δ ≈ 1

 or 

Δ = (2n − 1)π /2

Importance of Second oscillation maximum (SOM)

ΔP

_μe

= P

_μe

− P ¯

_μe

≈ − 2αΔ sin 2θ

₁₃

sin 2θ

₂₃

sin 2θ

₁₂

sin

²

Δ sin δ

Magnitude increases 3 times at SOM

1.

2.

Less distortion of CPV effects by matter at SOM

Our aim

To estimate the capability of DUNE to

probe the Second Oscillation Maximum

Dependence of second oscillation maximum (SOM) on parameters

• Parameters varied: θ

₂₃

, Δm

₃₁²

, δ

₁₃

Second oscillation

maximum zone First oscillation maximum zone

• Shift of oscillation maxima zones

• We analyse the narrowest SOM zone

Ecutoff min ≈ 0.99  GeV E ¯ cutoff

min ≈ 1.21  GeV

Second oscillation maximum (SOM) &

Event spectra

Spectra generated for two fluxes:

1. Covering entire energy range upto 20 GeV 2. Only covering the first osc. max. zone

Can DUNE probe SOM by distinguishing

two such spectra?

for probing Second oscillation maximum (SOM)

Δχ 2

• GLoBES cannot calculate between spectra from two different fluxes

• We implement a manual analysis within GLoBES

• We use the signals,backgrounds, energy resolution, systematics etc. from DUNE configuration file provided by collaboration

Δχ 2

Δχ 2

for probing Second oscillation maximum (SOM)

Δχ 2

Generated by flux covering entire

energy range Generated by flux

covering only first oscillation zone

• GLoBES cannot calculate between spectra from two different fluxes

• We implement a manual analysis within GLoBES

• We use the signals,backgrounds, energy resolution, systematics etc. from DUNE configuration file provided by collaboration

Δχ 2

Δχ 2

for probing Second oscillation maximum (SOM)

Δχ 2

• -mode & -mode give complementary results

• Combining both modes gives > sensitivity to probe SOM at DUNE

ν ν ¯

5σ

Summary

• Second oscillation maximum (SOM) potentially allows us to be more sensitive to CPV effects with less interference from matter

• Low energy distortion of event spectra

• Novel method to probe SOM: New implementation to calculate the sensitivity to SOM

• DUNE can probe SOM at irrespective of the value of Δχ 2

≳ 5σ δ 13

Backup

Tension () between allowed regions in plane by NOvA and T2K

(for NO)

δ 13 − sin 2 θ 23

Esteban, Gonzalez-Garcia, Maltoni, Schwetz, Zhou : 2007.14792

DUNE Collaboration, 1512.06148 [physics.ins-det]

DUNE Collaboration,

1601.05471 [physics.ins-det]

Backup

Backup

Backup

Backup

Flavor & Mass related by mixing

Solve Scrodinger’s eqn.

Recent work on Second osc. maximum

Huber, Kopp (1010.3706):

Ghosh, Goswami, Raut (1412.1744):

De Romeri, Fernandez-Martinez, Sorel (1607.00293):

Choubey, Ghosh, Kempe, Ohlsson (2010.16334):

➡ Maximize the data extracted from second max.

and probe BSM

➡ Two osc. maxima complement each other

➡ How it helps in resolving mass ordering degeneracy

➡ How energy resolution can be

improved in order to reconstruct the two osc. maxima

➡ Impact of osc. maxima on invisible decay Impact of osc. maxima on invisible decay

ν ν