IPP15 @ IPM, Tehran

Non-standard Neutrino Interactions and the

Reactor Neutrino Experiments

Amir Khan

COMSATS IIT and IIU, Islamabad

In Collaboration with:

Douglas McKay & John Ralston

(University of Kansas)

F. Tahir (COMSATS IIT)

September 26, 2015

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Contents

An Introduction to Neutrinos

Electroweak (EW) Model and the Elementary Transitions

Status of the Neutrinos Mass in the EW model

Introducing Nonstandard Interactions

(NSIs)- our model for NSIs.

Applying our model to reactor neutrinos Short Baseline

Experiments

Analyzing Daya Bay and TEXONO experiments for NSIs.

Predictions for the future upgrades of the Daya Bay

and TEXONO experiments.

Recap & Conclusions

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Introduction to Neutrinos

Tiniest and most abundant after photons

Produced in Sun, atmosphere in cosmic ray showers,

Supernovae, Big bang, Accelerators and Reactors…

Energy ranges (μeV - PeV)

Based on their characteristic energy range, detected

by the different techniques like,

The Radiochemical Techniques,

Water Cerenkov Technique,

Scintillation Technique,

Tracking and Hybrid Technique.

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H0γ

W±, Z0

W±, Z0

γ

Electroweak Model & Interactions

f 'f

e

L L L L LL

u s t

d c b e

, , , , , , ,R R R R R R R R Ru d s c t b e

EW Interaction Vertex:

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Weak Interactions of Quarks and Leptons

CC

NC

W c:g cosθ (V- A)

III III

e

e

W c:g sinθ (V- A)

Quark Mixings

0Z

l l

l

0Z

l- -μ l l 5

z V A:g γ (c -c γ )

W

usd u

0Z 0Z

l lν νμ 5

z V A:g γ (c -c γ )

W

l

lW:g (V- A)

W

l

W

Lepton Mixings: NO

Lepton Universality

l

l l l l

,

II

u dq ,

I

u dq,u dq ,u dq

I II III

u c t

d s b

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Weak Interactions of Quarks and Leptons

CC

NC

W c:g cosθ (V- A) W c:g sinθ (V- A)

Quark Mixings

0Z

l l

l

0Z

l- -μ l l 5

z V A:g γ (c -c γ )

W

usd u

0Z 0Z

l lν νμ 5

z V A:g γ (c -c γ )

W

l

lW:g (V- A)

W

l

W

Lepton Mixings: NO

Lepton Universality

l

l l l l

2

,u dq 1

,u dq,u dq ,u dq

III III

e

e

I II III

u c t

d s b

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Weak Interactions of Quarks and Leptons

CC

NC

W c:g cosθ (V- A) W c:g sinθ (V- A)

Quark Mixings

0Z

l l

l

0Z

l- -μ l l 5

z V A:g γ (c -c γ )

W

usd u

0Z 0Z

l lν νμ 5

z V A:g γ (c -c γ )

W

l

lW:g (V- A)

W

l

W

Lepton Mixings: NO

Lepton Universality

l

l l l l

2

,u dq 1

,u dq,u dq ,u dq

III III

e

e

I II III

u c t

d s b

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Lu Ru

X

2

u

u

gm

ug

Ll Rl

X

2

l

l

gm

lg

Ld Rd

X

2

d

d

gm

dg

l L

X

2

l

l

gm

lg

l R

Yukawa Interactions:

Leptons:

Quarks:

Status of Neutrino Masses in the SM

Lf

Rf

0X2

2

f

f

gm

fg

gf ≡ Arbitrary dimensionless constant

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Lu Ru

X

2

u

u

gm

ug

Ll Rl

X

2

l

l

gm

lg

Ld Rd

X

2

d

d

gm

dg

l L

X

2

l

l

gm

lg

l R

Yukawa Interactions:

Leptons

:

Quarks:

Status of Neutrino Masses in the SM

Lf

Rf

0X2

2

f

f

gm

fg

gf ≡ Arbitrary dimensionless constant

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Lf

Rf

0X2

2

f

f

gm

fg

Lu Ru

X

2

u

u

gm

ug

Ll Rl

X

2

l

l

gm

lg

Ld Rd

X

2

d

d

gm

dg

l L

X

2

l

l

gm

lg

l R

Yukawa Interactions:

Leptons:

Quarks:

Status of Neutrino Masses in the SM

gf ≡ Arbitrary dimensionless constant

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The SM Observations & Neutrinos Experiments

In the SM

There is Mixing only in the “Quark Sector” but no

mixing in the “Lepton Sector”

“Lepton Flavor Conservation”

There is “Lepton Universality”

Might have connection with “masslessness” of neutrinos!

On the other hand

There are several experiments for neutrinos of any

type (Solar, Atmospheric, Accelerator, Reactor) which

give evidence that neutrinos are massive!

“Neutrino Oscillations Experiments” (NOEs).

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W

ν aν

W

a aν =U ν

Source Detector

e p e n

e e

How does a NOE Work?

e

l

n pe

l

l l

-

βl

ν

l

U Mass Mixing Matrix

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-

-

-

n pe ν (NSIcase)

n

n pe ν ( case)

pe ν (NSIcase)

e

SM

Search For NSIs in Neutrino Interactions

At Source

ν p e (NSIcase)

ν p e (NSIcase)

ν ν e (

ν p e ( case)

, case)

ν ν e ( , NSIcase)

e

e

e

n

SM

S

n

n

M

At Detector

s λ †αF αβ αβ λ L βa a LL =-2 2G (δ +K )( γ P U ν )(dγ P u) +h.c.l

Model For NSIs in SL

NSIs

GF =

Fermi

Constant

K = Flavor Mixing

Matrix, violating CC,

LFC and LU in SL.

U = Standard Mixing

Matrix PL =Left-hand

helicity Projector

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NU FC

μαF μ R L L ααR αL

α

eP λαF αβ λ L β

α,β

L =L +L

L =-2 2G (eγ (g P +(g +1)P e)(ν γ P ν )

-2 2G ε (eγ Pe)(ν γ P ν )

l l l

l

2 eR 2 eL

W αα W αααR αL

1where, g =sin θ +ε and g =sin θ +ε

2

GF =

Fermi

constant

ε = Flavor Mixing

Matrix violating LFC

and LU in Lepton Sec.

P=PL ,PR

α,β=e, μ, τ

Search For NP in Neutrino Interactions

Model For NSIs in Pure Leptonic Processes

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I: Daya Bay Case

Experiment:

2 2

31θ Δmee 2

13L P 1- sin sin (1.267 )

E

2

13sin (2 ) 0.089 0.01(stat.) 0.005(syst.)

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A Little Digression:

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2 2ee 31 21 31 21 31

2 4 3 3 2

21 13 13 12 12 23 - 13 13 12 23 +

2 2 2

21 12

2

ij 2 2 2

ij ij i

31

3 13 1

32 3221

21

j

3

1

2

Δm Lx = and Δm =m -m

1P =1-[( +cos(2x ) )sin x +( + )sin x sin(2x )sin(2 x )]

2

=sin

P

(2θ )c +4c sin(2θ )cos(2θ )c K -4c s sin (2θ )c K

=sin

P

P (2θ )c -

P

P

P

4s

E

P

4

c 2

3 12 23 - 12 13 13 23 +

2 2 2 2

13 12 13 13 12 23 - 12 13 13 23 +

23 + eμ eμ 23 eτ eτ 23

23 eμ eμ 23 eτ eτ 23

32

sin(2θ )c K +4c cos(2θ )sin(2θ )c K

=sin (2θ )s +4s c sin(2θ )c K +4s cos(2θ )sin(2θ )c K

c K K cos(δ+ )s + K cos(δ+ )c

c K

P

K cos c - K cos s

eμ eμeτ a eτi -ii -2ix -i* * *

ee ea eμ μa eτ τa ea eμ μa eτ τaA =(U + K e U + K e U )e (U + K e U + K e U )

Oscillation Amplitude:

Oscillation Probability:

I. NSIs in Oscillation Experiments:

A handle on MH

A. N. Khan et al, Phys. Rev. D 88, 113006 (2013)

Only Two NSI Parameters!

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I:Constraining sin2(2θ13) and NSI in SBLEs

2

3 3 12 311 ( )sinee PP xP

1-2 km SBLEs (Daya Bay, RENO, D-Chooz)

determine the coefficient of sin2 x31

e.g. Daya Bay sin2(2θ13)=0.089±0.011

2

13 13 13 231 32 3( ) sin (2 ) 4cos(2 )sin(2 )

0.089 0.011

P cP K

In our Model

In SM

2

1

2

33 1sin (21 sin)eeP x

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I: The Event Rate

max

th

Epeeν + - IBD ν E2 E

ν

12 2

2

E

N T ddN(E )= dE P (L, E, K , K )σ (E)G(E-E , σ (a,b)),

dE 4πL dE

awhere σ (a,b)=E +b Detector Energy Resolution

E

Gaussian SmearingInverse β-decay X-SectionReactor Neutrino Flux

Systematic UncertaintyStatistical Uncertainty

L. Zhan et al, Phys. Rev. D79 (2009) 073007

Shao-Feng Ge et al, JHEP 1305 (2013) 131

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The Spectrum Study: NSIs Vs. SMM parameters

K+= K- =-0.04

K+= K-=0

K+=-0.04

K-=+ 0.04

NH

IH

a=0.06, b=0

NH

IH

a=0.06, b=0

K+= K-=0

Sin22θ12 - 1σ

Sin22θ12

Sin22θ12 + 1σ

Central values of all input parameters

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Spectrum Study: Effects of Sin22θ12 Uncertainty

NH

IH

a=0.06, b =0

K+ = K- = +0.04

Sin22θ12 - 1σ

Sin22θ12 +1σ

NH

IH

K+= K- = 0

K+= -0.04

K-= + 0.04

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Statistical Analysis

2

2 ( ) "

NSI SMM

iSMM

i

i

dN dN

dE dEE

dN

dE

pull"

Define a χ2- measure of sensitivity to NSIs

where

Energy range: 1.8 MeV< E < 6 MeV &

Bin width=0.01MeV

Rate labeled “SMM”=“data”

Rate labeled “NSIs”=“model”

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I. Δχ2 -Distributions

K+ = 0, sin22θ12 = 0.881sin22θ12 = 0.857 K+ = K- = 0

a=0.06, b=0 a=0.06, b=0

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I. Dependence on K+ ?

There is no dependence on K+

3Dim. Δχ2 surface above K+- K- plane

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I. Mass Hierarchy in event rates:

Difference between the NH and IH

K+= -0.04, K-= -0.04, P32 is Minimal

K+=0, K-=0

a=0.06, b=0 a=0, b=0

K+= -0.04, K-=+ 0.04, P32 is Maximal

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2

1( )

NH IH

N

MH ii IH

i

dN dN

dE dEE

dN

dE

Model=NH with Ks

Data= IH without Ks

Landscape of the Ratio: χ2NSI / χ2

SMM

I. Statistical Discrimination of MH

a=0.06, b=0Sensitivity to

MH is greater

(P32 maximal)

Sensitivity to

MH is smaller

(P32 minimal)

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II: Scattering SBLEs: The TEXONO Case

The sources are Accelerators & Reactors

Baselines are of the ranges- few meters

(e.g. TEXONO)

The baselines are short enough that the neutrino

oscillation effects can be safely neglected and flux of

each flavor is controlled by the NSI parameters

Designed for the scattering cross section.

Material used CsI(Tl) of total mass 187 kg for

detection.

Average neutrino flux KSNR= 6.4 × 1012 cm-2 s-1 .

Actual neutrino energy range is (0- 8)MeV, but the

range of interest is (3- 8) MeV.

e e

K

e

A.N. Khan et al, Phys. Rev. D 90, 053008 (2014)

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222e F e

SM+NSI

222 2

2

2G mdσ(ν e)[g

dT π

((g 1) ) 1

(g (g 1) [( ) ]]

eR

eeR

e

eL

eeL

e

eR eL ee eeR eL

e

T

E

m T

E

,[( ) ] cos( ),eR eL eR eL eL eR eL R

e e e e e e e where are the NSI phases

II: The Three Differential Cross Sections

222μ F e

SM+NSI

2

22

2

2G mdσ(ν e)= [g

dT π

((g ) 1

(g g [( ) ]]

eR

R

eL

L

eR eL eR L

T

E

m T

E

For scattering replacing μ by τ.e

1

2

3

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22 2e μ τ

ee SM+NSI eμ SM+NSI eτ SM+NSI

dσ(ν e) dσ(ν e) dσ(ν e)F= 1+K [ ] + K [ ] + K [ ]

dT dT dT

II: Total Differential Rate

maxνE

νXe ν ν

νT

d (E )dR=ρ F(E ) dE

dT dE

T(i+1)i XX

T(i)

dRR = Expectedevent rate

dT

Our2 Model

2

2i i

E X

ii stat

R R

where,

i

ER Experimental event rate

Total Differential Cross Section:

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6ν n

nn=0ν ν

d (E ) a=

dE (E )

Kue- Sheng Reactor neutrino spectrum

Fit Parameters Values

a0 -1.2 10^12

a1 3.7 10^13

a2 -4.4 10^14

a3 2.5 10^15

a4 -7.4 10^15

a5 1.1 10^16

a6 -6.7 10^15

II: The Neutrino Spectrum

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II: The Leptonic Case @ 90% C.L.

-0.15<εeRee <0.08

-1.79<εeLee <0.41

-0.18<εeRαe <0.18

-0.76< εeLαe <0.76

-0.19<εeRαe <0.19

-0.84< εeLαe <0.84

-0.14<εeRee <0.08

-1.53<εeLee <0.38

sin2θW =0.251±0.031

sin2θW =0.251±0.031

TEXONO Result

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II: Interplay: SL & Leptonic

NSIs

@ 90% C.L.

-1.35<ImKee<1.35

-0.17<εeRee <0.07

-0.72<ImKee<0.72

-0.18< εeRαe <0.18

-0.72<ImKee<0.72

-0.76<εeLαe <0.76

-0.72<ImKe α <0.72 -0.72<ImKe α <0.72 -0.72<ImKe α <0.72 -0.72<ImKe α <0.72

εeRμ μ , εeR

ττ εeLμ μ εeL

ττ,εeR

αμ,εeRβτ, εeL

αμ,εeLβτ are unbounded

-0.90<ImKee<0.90

-1.4<εeLee <0.34

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II: Future Prospects: Leptonic Case

-0.0023<εeRee <0.0023

-0.04<εeLee <0.04

-0.03<εeRαe <0.03

-0.19< εeLαe <0.19

(α=μ,τ)

@ 90% C.L.

If the statistical uncertainty is improved to “±0.0013”

as reported by the TEXONO Collaboration

(M. Deniz et al, J. Phys. Conf. Ser. 375, 042044 (2012))

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II: Future Prospects: Leptontic Case

If the statistical uncertainty is improved to “±0.0013”

as reported by the TEXONO Collaboration

(M. Deniz et al, J. Phys. Conf. Ser. 375, 042044 (2012))

-0.0023<εeRee <0.0023

-0.04<εeLee <0.04

-0.03<εeRαe <0.03

-0.19< εeLαe <0.19

(α=μ,τ)-0.15<εeR

ee <0.08

-1.79<εeLee <0.41

-0.18<εeRαe <0.18

-0.76< εeLαe <0.76

@ 90% C.L.

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II: Interplay : NU SL & Leptonic NSIs @ 90% C.L.

-0.33<ImKee<0.33

-0.013<εeRee <0.002

-0.14<ImKee<0.14

-0.05<εeLee <0.04

-0.13<ImKee<0.13

-0.03< εeRαe <0.03

-0.13<ImKee<0.13

-0.18<εeLαe <0.18

-0.06<ReKee<0.05

-0.01<εeRee <0.02

-0.01<ReKee<0.01

-0.04<εeLee <0.04

-0.06<ReKee<0.01

-0.09< εeRαe <0.09

-0.02<ReKee<0.01

-0.25< εeLαe <0.25

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II: Interplay : NU SL & Leptonic NSIs @ 90% C.L.

-0.33<ImKee<0.33

-0.013<εeRee <0.002

-0.14<ImKee<0.14

-0.05<εeLee <0.04

-0.13<ImKee<0.13

-0.03< εeRαe <0.03

-0.13<ImKee<0.13

-0.18<εeLαe <0.18

-0.06<ReKee<0.05

-0.01<εeRee <0.02

-0.01<ReKee<0.01

-0.04<εeLee <0.04

-0.06<ReKee<0.01

-0.09< εeRαe <0.09

-0.02<ReKee<0.01

-0.25< εeLαe <0.25

-1.35<ImKee<1.35

-0.17<εeRee <0.07

-0.72<ImKee<0.72

-0.18< εeRαe <0.18

-0.72<ImKee<0.72

-0.76<εeLαe <0.76

-0.90<ImKee<0.90

-1.4<εeLee <0.34

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II: Future Prospects: FC Case

-0.1<K eα <0.1 -0.1<K eα <0.1 -0.1<K eα <0.1 -0.1<K eα <0.1

εeRμ μ , εeR

ττ εeLμ μ εeL

ττ,εeR

αμ,εeRβτ, εeL

αμ,εeLβτ are unbounded

(α=e,τ, β= e, μ)

Ks are real or imaginary

@ 90% C.L.

-0.72<ImKe α <0.72 -0.72<ImKe α <0.72 -0.72<ImKe α <0.72 -0.72<ImKe α <0.72

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Planned high precision reactor, solar neutrino oscillation

experiments and high precision accelerator experiments

can improve the NSI parameter space upto factor 5.

High precision medium baseline reactor experiments may

hint on the phases of NSIs also.

These can also give information on the MH and NP

which confuses each other’s effects.

High precision reactor scattering experiments can

probe deeper into the parameter space for some of NSI

parameters upto several order of magnitude and upto a

factor 5 to 10 and can hint on the phases of NSIs.

Recap & Conclusion

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Thank You All!