Decoherence in Neutrino Propagation through matter and bounds from - PowerPoint PPT Presentation

Decoherence in Neutrino Propagation through matter and bounds from IceCube/DeepCore Hiroshi Nunokawa Department of Physics Pontifícia Universidade Católica do Rio de Janeiro Based on Collaboration with Pilar Coloma, Jacobo Lopez-Pavan, Ivan Martinez-Soler, arXiv: 1803.04438 [hep-ph] PANE2018, ICTP, May 31, 2018

Outline Introduction Neutrino oscillation in matter with decoherence effect Analysis Procedure Analysis Results Conclusions

Introduction • So far, no convincing evidence/confirmation of physics beyond the standard three neutrino flavor framework • It is interesting to probe/constrain some new physics beyond the standard framework • As one of the examples of such new physics, in this talk, we consider (non-standard) quantum decoherence in neutrino oscillation • It is important to test the paradigm of the standard three flavor framework

Introduction • Neutrino oscillations occur due to quantum interference • “Coherence” is needed to that happen • Oscillation is suppressed due to “decoherence” effect, for example, by separation of the wave packets matter density fluctuation finite energy and/or spatial resolution (uncertainty) • we consider non-standard decoherence effect which may come from some new physics (which may be related to quantum gravity) assuming a phenomenological model

Introduction Incomplete list of previous works on decoherence: Benatti, Floreanini, JHEP 02, 032 (2000) Lisi, Marrone, Montanitno, PRL 85, 1166 (2000) Gago et al., PRD63, 073001 (2001) Morgan et al., Astropart. Phys.25, 311 (2006) Fogli et. al., PRD 76, 0330066 (2007) Farzan, Schwetz, Smirnov, JHEP 07, 067 (2008) Bakhti, Farzan, Schwetz, JHEP 05, 007 (2015) Oliveira, Eur. Phys. J. C76, 417 (2016) Guzzo, Holanda, Oliveira, NPB908, 408 (2016) Coelho, Mann, Bashar, PRL118, 221801 (2017) Carpio, Massoni, Gago, arXiv:1711.03690 [hep-ph] Gomes et al., arXiv:1805.09818 [hep-ph]

Quantum Decoherence: density matrix formalism H: Hamiltonian describes decoherence assuming positivity (Lindbald form) Hermicity (to avoid unitarity violation) Energy Conservation (or small enough to be neglected)

Neutrino propagation in uniform matter where : mixing matrix in matter

For constant matter density In a more familiar way, : effective mass squared difference in matter : decoherence parameters (see next slide)

Assumptions on the Decoherence Parameters Following the previous works, we assume power-law energy dependence to have sizable effect of decoherence, we can roughly estimate that (but not enough condition)

For 1 layer of constant matter density For multi layers of constant matter densities for 2 layers for 3 layers

3 layer approximation of the Earth matter density profile (mantle - core - mantle)

We consider the following 3 distinct cases (A) Atmospheric limit: ϒ 21 = 0 ( ϒ 32 = ϒ 31 ) (B) Solar limit I: ϒ 32 = 0 ( ϒ 21 = ϒ 31 ) (C) Solar limit II: ϒ 31 = 0 ( ϒ 21 = ϒ 32 )

Some examples of oscillation probabilities 1 0.8 P( ν µ →ν µ ) 0.6 Normal ordering 0.4 (A) γ 31 = γ 32 (B) γ 21 = γ 31 (C) γ 21 = γ 32 0.2 Standard Osc. 0 10 100 E (GeV)

Some examples of oscillation probabilities 1 0.8 P( ν µ →ν µ ) 0.6 Inverted ordering 0.4 (A) γ 31 = γ 32 (B) γ 21 = γ 31 (C) γ 21 = γ 32 0.2 Standard Osc. 0 10 100 E (GeV)

Some examples of oscillation probabilities 1 1 0.8 0.8 P( ν µ →ν µ ) P( ν µ →ν µ ) 0.6 0.6 Normal ordering Inverted ordering 0.4 0.4 (A) γ 31 = γ 32 (A) γ 31 = γ 32 (B) γ 21 = γ 31 (B) γ 21 = γ 31 0.2 (C) γ 21 = γ 32 (C) γ 21 = γ 32 0.2 Standard Osc. Standard Osc. 0 0 10 100 10 100 E (GeV) E (GeV) 1 1 0.8 0.8 P( ν µ →ν µ ) P( ν µ →ν µ ) 0.6 0.6 Normal ordering Inverted ordering 0.4 0.4 (A) γ 31 = γ 32 (A) γ 31 = γ 32 (B) γ 21 = γ 31 (B) γ 21 = γ 31 (C) γ 21 = γ 32 (C) γ 21 = γ 32 0.2 0.2 Standard Osc. Standard Osc. 0 0 10 100 10 100 E (GeV) E (GeV)

We consider the following 3 distinct cases (A) Atmospheric limit: ϒ 21 = 0 ( ϒ 32 = ϒ 31 ) (B) Solar limit I: ϒ 32 = 0 ( ϒ 21 = ϒ 31 ) (C) Solar limit II: ϒ 31 = 0 ( ϒ 21 = ϒ 32 ) there are following approximated correspondences NO of (A) IO of (C) NO of (B) IO of (A) NO of (C) IO of (B) NO (IO): Normal (Inverted) mass Ordering

For higher energy (> 15 GeV) neutrinos, for normal mass ordering for inverted mass ordering

To see the effect more globally 𝝃 oscillogram is useful

Analysis Procedure IceCube: Poissonian log-likelihood analysis DeepCore: Gaussian Maximum likelihood analysis For each analysis, simultaneous fit on the parameters of was performed

Analysis Procedure For IceCube, we consider the data presented in PhD thesis by B.J.P. Jones, available at http:/ /hdl.handle.net/1721.1/101327 from 400 GeV to 20 TeV , from cos θ z = -1.02 to 0.24 systematic errors for IceCube data Source of uncertainty Value Flux - normalization Free Flux - π /K ratio 10% Flux - energy dependence as ( E/E 0 ) η ∆ η = 0 . 05 Flux - ¯ ν / ν 2.5% DOM e ffi ciency 5% Photon scattering 10% Photon absorption 10% Table 1 : The most relevant systematic errors used in our analysis of IceCube data,

Analysis Procedure Expected event distribution for IceCube with and w/o decoherence 800 E rec =[ 0.4, 0.6 ] TeV E rec =[ 0.6, 0.9 ] TeV 600 400 200 0 E rec =[ 1.3, 1.9 ] TeV 800 E rec =[ 0.9, 1.3 ] TeV 600 400 200 0 800 E rec =[ 1.9, 6.2 ] TeV E rec =[ 6.2, 20 ] TeV 600 400 200 0 - 1.0 - 0.8 - 0.6 - 0.4 - 0.2 - 1.0 - 0.8 - 0.6 - 0.4 - 0.2 0.0 0.0 rec ) rec ) cos ( � z cos ( � z IceCube Data: B.J.P .Jones, PhD thesis http://hdl.handle.net/1721.1/101327

Analysis Procedure For DeepCore we consider the data presented in Aartsen et al., PRL117, 071801 (2016) from ～ 10 GeV to ～ 1 TeV , 8 bins below cos θ z = 0 systematic errors for DeepCore data Source of uncertainty Value Flux - normalization Free Flux - energy dependence as ( E/E 0 ) η ∆ η = 0 . 05 Flux - ( ν e + ¯ ν e ) / ( ν µ + ¯ ν µ ) ratio 20% Background - normalization Free DOM e ffi ciency 10% Optical properties of the ice 1% Table 2 : Systematic errors used in our analysis of DeepCore data, taken from refs. [44, 48].

Analysis Procedure Expected event distribution for DeepCore with and w/o decoherence 200 E rec =[ 6, 8 ] GeV E rec =[ 8, 10 ] GeV 150 100 50 0 200 E rec =[ 10, 14 ] GeV E rec =[ 14, 18 ] GeV 150 100 50 0 200 E rec =[ 24, 32 ] GeV E rec =[ 24, 32 ] GeV 150 100 50 0 200 E rec =[ 32, 42 ] GeV E rec =[ 42, 56 ] GeV 150 100 50 0 - 1.0 - 0.8 - 0.6 - 0.4 - 0.2 - 1.0 - 0.8 - 0.6 - 0.4 - 0.2 0.0 0.0 rec ) rec ) cos ( � z cos ( � z DeepCore Data: IceCube Collab. PRL117, 071701 (2016)

Bounds from IceCube and DeepCore 30 � ij = � 0 SK ( 90 % CL ) 25 n = 0 20 ----- � 32 = � 21 ��� 2 solid curves: IC 15 ----- � 31 = � 21 KamLAND ( � 21 ,95 % CL ) 10 ----- � 31 = � 32 95 % CL dashed curves: DC 5 0 10 - 25 10 - 23 10 - 21 � 0 ( GeV ) 30 � ij = � 0 ( E / GeV ) 25 n = 1 20 ----- � 32 = � 21 ��� 2 15 ----- � 31 = � 21 10 ----- � 31 = � 32 95 % CL 5 0 10 - 29 10 - 27 10 - 25 10 - 23 � 0 ( GeV ) 30 � ij = � 0 ( E / GeV ) 2 SK ( 90 % CL ) 25 n = 2 20 ----- � 32 = � 21 ��� 2 15 � 31 = � 21 10 � 31 = � 32 95 % CL 5 0 10 - 34 10 - 32 10 - 30 10 - 28 10 - 26 10 - 24 � 0 ( GeV ) p

� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 10 - 17 � = � 0 ( E / GeV ) n 10 - 20 10 - 23 � 0 ( GeV ) �� � 31 = � 32 10 - 26 �� � 21 = � 31 �� � 21 = � 32 10 - 29 10 - 32 - 2 - 1 0 1 2 n IceCube DeepCore

� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � roughly, 10 - 17 � = � 0 ( E / GeV ) n 10 - 20 10 - 23 � 0 ( GeV ) �� � 31 = � 32 10 - 26 �� � 21 = � 31 �� � 21 = � 32 10 - 29 10 - 32 - 2 - 1 0 1 2 n IceCube DeepCore