Invisible and Visible Neutrino Decay and Constraints on them from - - PowerPoint PPT Presentation

▶
invisible and visible neutrino decay and constraints on
SMART_READER_LITE
LIVE PREVIEW

Invisible and Visible Neutrino Decay and Constraints on them from - - PowerPoint PPT Presentation

Jun 18, 2023 123 likes •408 views

Invisible and Visible Neutrino Decay and Constraints on them from Oscillation Experiments O. L. G. Peres 1 1 Instituto de Fsica Gleb Wataghin UNICAMP , Brazil NUFACT2017 25 October of 2017 unicampLogo 1 / 13 Neutrino Oscillations In the

slide-1
SLIDE 1

unicampLogo

Invisible and Visible Neutrino Decay and Constraints on them from Oscillation Experiments

  • O. L. G. Peres1

1Instituto de Física Gleb Wataghin

UNICAMP , Brazil

NUFACT2017 25 October of 2017

1 / 13

slide-2
SLIDE 2

unicampLogo

Neutrino Oscillations

In the latest years there are stronger evidences for neutrino

  • scillation

Daya Bay Experiment SNO experiment All evidences point to non-zero neutrino masses.

2 / 13

slide-3
SLIDE 3

unicampLogo

Why include neutrino decay in this picture?

If the neutrino have mass then it can decay. Can we test the neutrino stability using present neutrino detectors?YES. The suppression factor of the decay is φdecay φ = Pdecay = e

−

  • t

τLAB

  • = e

− m

τ

L

Eν T.Kajita et al., Nuclear Physics 908, 14 (2016) Exclude PURE decay at 4σ What happened when we have

  • scillation and decay AT same time?

3 / 13

slide-4
SLIDE 4

unicampLogo

Framework of Neutrino Decay

We will assume that the

Heavier neutrinos decay to lighter neutrinos (normal hierarchy)

4 / 13

slide-5
SLIDE 5

unicampLogo

Framework of Neutrino Decay

Possible scenarios:

Initial neutrino states − → final neutrino states final neutrino states

  • INVISIBLE

VISIBLE

INVISIBLE:     

  • Sterile

states

  • Below

the threshold

  • f experiment
  • Depletion of event rates: even for NC rates

VISIBLE:

  • Flavor

states

  • Increase/Depletion of event rates

4 / 13

slide-6
SLIDE 6

unicampLogo

Constrains on Invisible neutrino decay

Invisible neutrino decay scenario for solar neutrinos: Berezhiani et al. 1992, Choubey it et al. 2000, Beacom/Bell 2002,Choubey/Goswami 2003 Berryman, Gouvea/Hernandez 2015, Picoreti et al. 2016 P(νe → νe) = c4

13

  • P ⊙

e1 P ⊕ 1e + P ⊙ e2 exp

  • −

m2 τ2 L Eν

  • P ⊕

2e

  • + s4

13 ,

  • Picoreti et al. 2016 : energy distortion and seasonal dependence

Analysis Neutrino Decay mode Limit Solar data Picoreti et al. ν2 Invisible τ2/m2 > 7.2 × 10−4 s/eV Solar data Berryman et al. ν2 Invisible τ2/m2 > 7.1 × 10−4 s/eV

5 / 13

slide-7
SLIDE 7

unicampLogo

Constrains on Invisible neutrino decay

Invisible neutrino decay scenario for long-baseline experiments and atmospheric ν Barger et al. 1999, Fogli et al. 2004, Gonzalez-Garcia et al. 2008, Gomes et al. 2015, Choubey, Goswami and Pramani 2017 Analysis Neutrino Decay mode Limit Atmospheric and LBL data ν3 Invisible τ3/m3 > 2.9 × 10−10 s/eV MINOS and T2K data Gomes et al. ν3 Invisible τ3/m3 > 2.8 × 10−12 s/eV DUNE sensitivity (CHOUBEY et al.) ν3 Invisible τ3/m3 > 4.3 × 10−11 s/eV and medium baseline reactor experiments Abrahão et al. 2015 Analysis Neutrino Decay mode Limit JUNO expected sensitivity ν3 Invisible τ3/m3 > 7.5 × 10−11 s/eV

5 / 13

slide-8
SLIDE 8

unicampLogo

Visible neutrino decay

The visible neutrino scenario take into account the final states of neutrino decay: Lindner/Ohlsson/Winter 2001, Palomarez-Ruiz/ Pascoli/Schwetz 2005 Gago/Gomes2/Jones-Pérez/ Peres 2017, Coloma and Peres 2017 It is dependent of specific decay model of neutrino. We will assume a two-body neutrino decay ν′ → ν + φ, φ is a scalar/pseudo-scalar. Lint =

  • i=1,2

g3i 2 ¯ νiν3φ + g′

3i

2 ¯ νiiγ5ν3φ + h.c. ,

SCALAR PSEUDO-SCALAR

6 / 13

slide-9
SLIDE 9

unicampLogo

Visible neutrino decay

  • Helicity conserving decays : ν3 → ν1 + φ
  • Helicity non-conserving decays : ν3 → ¯

ν2 + φ

Given a original νµ flux, we have (νµ = Uµ1ν1 + Uµ2ν2 + Uµ3ν3). If ν3 decay to ν2 then the ν2 mass eigenstate (ν2 = U ∗

e2νe + U ∗ µ2νµ + U ∗ τ2ντ)

An original pure νµ can from the chain above to have νµ → νe and also νµ → ¯ νe . : mheavy, mlight and from neutrino-scalar couplings.

Γ

++

Γ

++

Γ

+-

Γ

+-

  • ×-

×- ×- ×-

() Γ ⨯ () Coloma and Peres 2017

6 / 13

slide-10
SLIDE 10

unicampLogo

Analysis of Visible decay for MINOS and T2K

Work in collaboration with Gago/Gomes2/Jones-Pérez/ Peres 2017, ν3 → ν1 + φ /one non-zero coupling νe: invisible decay black dashed , visible decay: solid black (both with δCP = π/2) and standard oscillation is in δCP = π/2(δCP = −π/2) for red dotted( dashed) curve

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1 2 3 4 5 6 Eν(GeV)

μ

7 / 13

slide-11
SLIDE 11

unicampLogo

Analysis of Visible decay for MINOS and T2K

Energy (GeV)

5 10

POT

20

10 × Events/GeV/10.71

100 200 300 400

µ

ν Scalar

Standard Oscillation 90% C.L. α Invisible Decay with 90% C.L. α Full Decay with MINOS Data

νµ neutrino events from MINOS

7 / 13

slide-12
SLIDE 12

unicampLogo

Analysis of Visible decay for MINOS and T2K

Allowed regions for MINOS and T2K: solid regions are standard oscillations and hollow regions are with decay

x + +

0.00 0.01 0.02 0.03 0.04 0.05

  • 3
  • 2
  • 1

1 2 3 s13

2

δCP

7 / 13

slide-13
SLIDE 13

unicampLogo

Analysis of Visible decay for MINOS and T2K

∆χ2 for T2K and MINOS showing the constrains on the decay parameter: left : scalar, right :pseudo-scalar

T2K MINOS T2K+MINOS 10-5 10-4 1 2 3 4 5 6 α(eV2) Δχ2 T2K MINOS T2K+MINOS 10-5 10-4 1 2 3 4 5 6 α(eV2) Δχ2 7 / 13

slide-14
SLIDE 14

unicampLogo

Visible neutrino decay for DUNE

Made in collaboration with Pilar Coloma Assume ν3 → ν1/ν2 + φ with democratic couplings H = U    

∆m2

21

2E ∆m2

31

2E

− iΓ3 2     U † + A   1   , Matter effects are important for DUNE m3 =

  • m2

1 + ∆m2 31 −

→ ˜ m3 =

  • m2

1 + ∆ ˜

m2

31 ,

Affecting the total width as Γ3 − → ˜ Γ3 ≡ ˜ m3/(τ3E) .

8 / 13

slide-15
SLIDE 15

unicampLogo

Visible neutrino decay for DUNE

ν =

  • ν ()

/

ν =

  • ν ()

/ ν =

  • ν ()

/

ν =

  • ν ()

/ 8 / 13

slide-16
SLIDE 16

unicampLogo

Visible neutrino decay for DUNE

Sensitivity for DUNE experiment

() () + () + ()

  • ()
  • 8 / 13
slide-17
SLIDE 17

unicampLogo

Conclusions

  • Neutrino decay can change the solar neutrino phenomenology? .
  • Solar ν data + KamLand/ Daya Bay: strongest bounds on ν2 decay

LBL experiments can give a bound on the ν3 lifetime Invisible and visible ν decay have different behaviours: depletion and excess of events. We got from T2K+MINOS present data α(s)

T2K < 6.3 × 10−5 eV2 , α(p) T2K < 5.6 × 10−5 eV2

α(s)

TK2+MINOS < 7.8 × 10−5 eV2 ,

α(p)

TK2+MINOS < 6.9 × 10−5 eV2 . 9 / 13

slide-18
SLIDE 18

unicampLogo

Conclusions

Analysis Neutrino Decay mode Limit Solar data ν2 Invisible τ2/m2 > 7.2 × 10−4 s/eV Solar data ν2 Invisible τ2/m2 > 7.1 × 10−4 s/eV Atmospheric and LBL data ν3 Invisible τ3/m3 > 2.9 × 10−10 s/eV MINOS and T2K data ν3 Invisible τ3/m3 > 2.8 × 10−12 s/eV MINOS and T2K data ν3 Visible τ3/m3 > 1.5 × 10−11 s/eV JUNO expected sensitivity ν3 Invisible τ3/m3 > 7.5 × 10−11 s/eV DUNE expected sensitivity ν3 Visible τ3/m3 > 1.95 − 2.6 × 10−10s/eV

9 / 13

slide-19
SLIDE 19

unicampLogo

Results for neutrino decay

Stable neutrino ↑ Previous limit

  • Our limit: τ2

m2 > 7.7 × 10−4 s/eV 1

1Similar bound from J.M.Berryman, A. Gouvea and D. Hernandez,Phys.

  • Rev. D 92, 073003 (2015)

10 / 13

slide-20
SLIDE 20

unicampLogo

Seasonal variation

Solar neutrino fluxes have geometrical dependence on distance φ⊕

ν =

φ⊙

ν

4π(L(t))2 , φ⊕

ν (Lmin)

φ⊕

ν (Lmax) = (1 + ǫ0)2

(1 − ǫ0)2 → seasonal variation of solar neutrino flux ǫ0 is the Earth eccentricity With decay we have geometrial factor+decay factor P(νe → νe) = c4

13

  • P ⊙

e1 P ⊕ 1e + P ⊙ e2 exp

  • −

m2 τ2 L Eν

  • P ⊕

2e

  • + s4

13 ,

(P(νe → νe)) (Lmin) > (P(νe → νe)) (Lmax) φ⊕

ν (Lmin)

φ⊕

ν (Lmax)

  • decay

= φ⊕

ν (Lmin)

φ⊕

ν (Lmax)

  • no decay

P(νe → νe)(Lmin) P(νe → νe)(Lmax)

  • >

φ⊕

ν (Lmin)

φ⊕

ν (Lmax)

  • no decay

Bigger seasonal effect with ν decay

11 / 13

slide-21
SLIDE 21

unicampLogo

Seasonal variation

  • Our limit solar+KL+DB+seasonal: τ2

m2 > 7.2 × 10−4 s/eV SK I (2003) SNO (2005) Borexino (2013) ǫ: eccentricity with decay ǫ0: eccentricity with no decay

11 / 13

slide-22
SLIDE 22

unicampLogo

Backup

We assume ν2 is unstable.

νe ν1 ν2 ν3

ր → ց

  • MSW effect

Decay ν1 ν2 ν3

  • νe

νµ ντ P(νe → νe) = c4

13

  • P ⊙

e1 P ⊕ 1e + P ⊙ e2 exp

  • −

m2 τ2 L Eν

  • P ⊕

2e

  • + s4

13 , 12 / 13

slide-23
SLIDE 23

unicampLogo

Backup

P(νe → νe) = c4

13

  • P ⊙

e1 P ⊕ 1e + P ⊙ e2

  • P decay

2

  • P ⊕

2e

  • + s4

13 ,

P decay

2

= exp

  • −

α2 Eν

  • L
  • α2 = m2

τ2

0.2 0.5 1.0 2.0 5.0 10.0 20.0 0.0 0.2 0.4 0.6 0.8 1.0

EΝ MeV Pee Night

m 21

2 8.00 105 eV2

sin2 Θ12 3.06 101 Α2 0 Α2 1013 eV2 Α2 1012 eV2 Α2 1011 eV2

νe ∼ ν2 νe ∼ ν1

12 / 13

slide-24
SLIDE 24

unicampLogo

Backup

Solar neutrino data Super-Kamiokande

10

  • 2

10

  • 1

1 10 6 8 10 12 14 16 18 20 Energy (MeV) Events/day/21.5kt/0.5MeV

Solar neutrino MC Observed solar neutrino events (efficiency corrected)

SNO +Homestake total rate, GALLEX and GNO combined total rate , SAGE total rate and Borexino 192-day low-energy data

12 / 13

slide-25
SLIDE 25

unicampLogo

Backup

P(νe → νe) = c4

13

  • P ⊙

e1 P ⊕ 1e + P ⊙ e2 exp

  • −

m2 τ2 L Eν

  • P ⊕

2e

  • + s4

13 ,

Parameters of problem: θ12, ∆m2

21, θ13

α2 = m2 τ2 External constrains: KamLand and Daya Bay KamLand : θ12, ∆m2

21, θ13 →

  • χ23ν

KL =

  • χ2no decay

KL

Daya Bay : θ13, ∆m2

ee →

  • χ23ν

DB =

  • χ2no decay

DB

KamLand: http://www.awa.tohoku.ac.jp/KamLAND/4th_result_data_release/ From previous decay limits 2: τ2 m2 > 8.7 × 10−5 s/eV ν2 is stable for these experiments.

  • χ2decay

KL

=

  • χ2no decay

KL

  • χ2decay

DB

=

  • χ2no decay

DB

Experimental Analysis from KamLand and Daya Bay can help to constrain the decay scenario

  • 2A. Bandyopadhyay, S. Choubey, S. Goswami, P

. Letters B555, 33 (2003).

12 / 13

slide-26
SLIDE 26

unicampLogo

Backup

Super-Kamiokande I seasonal dependence

13 / 13

slide-27
SLIDE 27

unicampLogo

Backup

Experiment ǫexp ± σexp (ǫexp ± σexp) /ǫ0 Borexino (2013) 0.0398 ± 0.0102 2.38 ± 0.61 SK-I (2003) 0.0252 ± 0.0072 1.51 ± 0.43 SNO Phase I (2005) 0.0143 ± 0.0086 0.86 ± 0.51

13 / 13