Neutrino decay sensitivity with ORCA Pablo Fern´ andez de Salas Oskar Klein Centre for Cosmoparticle Physics, Stockholm University 29-11-2018 Based on: PFdS, S. Pastor, C.A. Ternes, T. Thakore, M. T´ ortola, arXiv:1810.10916 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 1
Neutrino decay: motivation Despite current experimental precision, there are some unknown neutrino properties : neutrino mass ordering true θ 23 octant absolute neutrino mass · · · H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 2
Neutrino decay: motivation Despite current experimental precision, there are some unknown neutrino properties : neutrino mass ordering true θ 23 octant absolute neutrino mass · · · In the past , ν decay was one of the proposed solutions to the atmospheric and solar problems H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 2
Neutrino decay: motivation Despite current experimental precision, there are some unknown neutrino properties : neutrino mass ordering true θ 23 octant absolute neutrino mass · · · In the past , ν decay was one of the proposed solutions to the atmospheric and solar problems Some theories predict neutrino decay (e.g. Majoron models): ν i → ν j + J H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 2
Neutrino decay: motivation Despite current experimental precision, there are some unknown neutrino properties : neutrino mass ordering true θ 23 octant absolute neutrino mass · · · In the past , ν decay was one of the proposed solutions to the atmospheric and solar problems Some theories predict neutrino decay (e.g. Majoron models): ν i → ν j + J Testing ν decay through oscillations vs SN and cosmology H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 2
Neutrino decays Standard Model neutrino decay extremely suppressed: ν i → ν j + γ ν i → ν j + ν k + ν l τ � 10 37 yr J.M. Berryman et al., PRD 92 (2015) 073003 C. Broggini et al, Adv.High Energy Phys. 2012 (2012) 459526 In BSM scenarios, the decay product ν j involves: An active neutrino : visible decay Otherwise: invisible decay H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 3
Neutrino decays Standard Model neutrino decay extremely suppressed: ν i → ν j + γ ν i → ν j + ν k + ν l τ � 10 37 yr J.M. Berryman et al., PRD 92 (2015) 073003 C. Broggini et al, Adv.High Energy Phys. 2012 (2012) 459526 In BSM scenarios, the decay product ν j involves: An active neutrino : visible decay Otherwise: invisible decay H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 3
Our case: Invisible neutrino decay ν 3 → ν 4 + J Normal Ordering: m 1 < m 2 < m 3 and m 4 < m 3 No mixing among the sterile and active neutrinos � ν α � � U � � ν k � 0 = ν s 0 1 ν 4 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 4
Flavour oscillations and invisible decay Full neutrino Hamiltonian H = 1 2 E ( H 0 + H m + H D ) Vacuum and matter terms 0 0 0 0 0 N e √ U † , ∆ m 2 H 0 = U 0 0 H m = 2 E 2 G F 0 0 0 21 ∆ m 2 0 0 0 0 0 31 Neutrino decay term ∆ m 2 31 → ∆ m 2 31 − i α 3 0 0 0 U † 0 0 0 H D = U α 3 = m 3 /τ 3 0 0 − i α 3 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 5
Flavour oscillations and invisible decay decay standard decay standard ( ) P ( e ) 5 eV 2 P 5 eV 2 3 = 10 3 = 10 0.0 0.0 0.00 0.000 0.2 0.2 0.05 0.4 0.4 0.10 0.015 z z cos cos 0.6 0.6 0.15 0.030 0.20 0.8 0.8 0.045 0.25 1.0 1.0 5 10 15 20 5 10 15 20 E [GeV] E [GeV] P ( ) P ( ) 0.0 1.0 0.0 1.0 0.2 0.8 0.2 0.8 0.4 0.6 0.4 0.6 z z cos cos 0.6 0.4 0.6 0.4 0.8 0.2 0.8 0.2 1.0 0.0 1.0 0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 E [GeV] E [GeV] H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 6
Flavour oscillations and invisible decay decay standard decay standard ( e ) P ( ) P 5 eV 2 5 eV 2 3 = 10 3 = 10 0.0 0.0 0.00 0.000 0.2 0.2 0.05 0.4 0.4 0.015 0.10 z z cos cos 0.6 0.6 0.15 0.030 0.8 0.20 0.8 0.045 1.0 0.25 1.0 5 10 15 20 5 10 15 20 E [GeV] E [GeV] 1 P ( ) α 3 = 0 P µµ -5 eV 2 0.0 1.0 α 3 = 10 -4 eV 2 0.8 α 3 = 10 0.2 0.8 P µ e Probability 0.6 0.4 0.6 z cos 0.4 0.6 0.4 0.8 0.2 0.2 1.0 0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 0 E [GeV] 3 4 5 6 7 8 9 10 15 20 E [GeV] H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 6
Oscillation Research with Cosmics in the Abyss (ORCA) 115 lines, 20 m spaced 18 DOMs/line, 9 m spaced Angular resolution of just a few degrees for showers S. Adri´ an-Mart´ ınez, et al., Letter of intent for KM3NeT 2.0, J. Phys. G 43 (2016) 084001 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 7
Event topology Tracks : ν µ CC Showers : ν e ,τ CC and ν α NC S. Adri´ an-Mart´ ınez, et al., Letter of intent for KM3NeT 2.0, J. Phys. G 43 (2016) 084001 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 8
❝ Simulation Frequentist approach for the two topologies T : showers and tracks H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 9
Simulation Frequentist approach for the two topologies T : showers and tracks Simulation Mock data Systematics 2 N ij (sin 2 θ 23 , ∆ m 2 ǫ ) − N dat 31 , α 3 ; � � 2 � ǫ k − µ k ij χ 2 = min � � + � σ k ǫ � N dat i , j k ij Each topology receives contribution from each neutrino flavour α and interaction channel ❝ : N T � � T c α pid N c α ij = ij α c α = { e , µ, τ } , c = { CC , NC } , pid: particle identification performance H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 9
Simulation The simulated number of events depends on detector quantities and theoretical quantities � θ i +1 � E j +1 � π � + ∞ z , rec rec N c α = 2 π T d θ z , rec d E rec d θ z , true d E true ij E j θ i 0 0 rec z , rec × M c α eff ( E true ) Detector effective mass m p × R c α ( θ z , rec , E rec , θ z , true , E true ) Detector resolution d 2 φ 0 � × σ c α d cos θ z d E true P ν β → ν α β P ν β → ν α P ν β → ν α Neutrino cross section and flux β = { e ,µ } Simulation P ν β → ν α (cos θ z , E ν , α 3 ) H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 10
Sensitivity of ORCA to α 3 Mock data generated with α 3 = 0 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 11
Sensitivity of ORCA to α 3 Mock data generated with α 3 = 0 Minimize χ 2 for fixed (∆ m 2 31 , θ 23 ) and different α 3 values H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 11
Sensitivity of ORCA to α 3 Mock data generated with α 3 = 0 Minimize χ 2 for fixed (∆ m 2 31 , θ 23 ) and different α 3 values Minimize χ 2 varying also atmospheric oscillation parameters χ 2 (sin 2 θ 23 , ∆ m 2 χ 2 � � decay ( α 3 ) = min 31 , α 3 ) sin 2 θ 23 , ∆ m 2 31 Other neutrino oscillation parameters fixed to best fit from: PFdS, D.V. Forero, C.A. Ternes, M. T´ ortola, J.W.F. Valle, PLB 782 (2018) 633 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 11
Sensitivity of ORCA to α 3 25 10 years 3 years 20 15 fixed osc. parameters 2 ∆χ free osc. parameters 10 5 90% C.L. 90% C.L. 0 0 5 10 15 20 0 5 10 15 20 -6 eV 2 ] -6 eV 2 ] α 3 [10 α 3 [10 α 3 [eV 2 ] time τ 3 / m 3 [s/eV] < 4 . 6 × 10 − 6 > 1 . 4 × 10 − 10 3 years < 2 . 6 × 10 − 6 > 2 . 5 × 10 − 10 10 years PFdS, S. Pastor, C.A. Ternes, T. Thakore, M. T´ ortola, arXiv:1810.10916 H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 12
Contribution from different topologies H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 13
Effect on standard oscillation parameters Filled colors : standard ( α 3 = 0) Lines : marginalizing α 3 2.6 2 ] -3 eV 31 [10 2.5 ★ ★ 2 ∆ m 2.4 3 years 10 years 95,99% C.L. 0.4 0.5 0.6 0.4 0.5 0.6 2 θ 23 2 θ 23 sin sin Small effect only in the first octant H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 14
Effect on mass ordering determination 10 NO 10 years 3 years IO 2 √ ∆χ 5 0 0.1 1 10 100 1000 -6 eV 2 ] α 3 [10 Around the region of interest ( α 3 ∼ 10 − 6 eV 2 ) the neutrino mass ordering sensitivity is robust H2020 Oscillation physics Workshop P.F. de Salas - neutrino decay sensitivity with ORCA 15
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