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Collapsed version of the two-loop diagram shown in Fig. 2 in the heavy ϕ limit. The various labels and indices are the same as those in Fig. 2.
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We consider the decoherence effects in the propagation of neutrinos in a background composed of a scalar particle and a fermion due to the nonforward neutrino scattering processes. Using a simple model for the coupling of the form f¯RνLϕ, we calculate the contribution to the imaginary part of the neutrino self-energy arising from the nonforward neu...
Contexts in source publication
Context 1
... follows from Eq. (3.2), the following identity is readily derived (see Appendix A): ...
Citations
... For some forms of DðρÞ derived from first principles, see[50,51].3 If neutrinos are only affected by the MSW effect, it is possible for ν μ and ν τ to oscillate to each other. ...
Quantum decoherence effects in neutrinos, described by the open quantum systems formalism, serve as a gateway to explore potential new physics, including quantum gravity. Previous research extensively investigated these effects across various neutrino sources, imposing stringent constraints on the spontaneous loss of coherence. In this study, we demonstrate that even within the supernovae environment, where neutrinos are released as incoherent states, quantum decoherence could influence the flavor equipartition of 3ν mixing. Additionally, we examine the potential energy dependence of quantum decoherence parameters (Γ=Γ0(E/E0)n) with different power laws (n=0,2,5/2). Our findings indicate that future-generation detectors (DUNE, Hyper-K, and JUNO) can significantly constrain quantum decoherence effects under different scenarios. For a supernova located 10 kpc away from Earth, if no quantum decoherence is observed, DUNE could potentially establish 3σ bounds of Γ≤6.2×10−14 eV in the normal mass hierarchy (NH) scenario, while Hyper-K would impose a 2σ limit of Γ≤3.6×10−14 eV for the inverted mass hierarchy (IH) with n=0—assuming no energy exchange between the neutrino subsystem and nonstandard environment. These limits become even more restrictive for a closer supernova. When we relax the assumption of energy exchange, for a 10 kpc distance, DUNE could establish a 3σ limit of Γ8≤4.2×10−28 eV for NH, while Hyper-K could constrain Γ8≤1.3×10−27 eV for IH (n=0) with 2σ, which would be orders of magnitude stronger than the bounds reported to date. Furthermore, we examine the impact of neutrino loss during propagation for future supernova detection.
... For some forms of D(ρ) derived from first principles, see[46,47]. ...
Quantum decoherence effects in neutrinos, described by the open quantum systems formalism, serve as a gateway to explore potential new physics, including quantum gravity. Previous research extensively investigated these effects across various neutrino sources, imposing stringent constraints on spontaneous loss of coherence. In this study, we demonstrate that even within the Supernovae environment, where neutrinos are released as incoherent states, quantum decoherence could influence the flavor equipartition of $3\nu$ mixing. Additionally, we examine the potential energy dependence of quantum decoherence parameters ($\Gamma = \Gamma_0 (E/E_0)^n$) with different power laws ($n = 0, 2, 5/2$). Our findings indicate that future-generation detectors (DUNE, Hyper-K, and JUNO) can significantly constrain quantum decoherence effects under different scenarios. For a Supernova located 10 kpc away from Earth, DUNE could potentially establish $3\sigma$ bounds of $\Gamma \leq 6.2 \times 10^{-14}$ eV in the normal mass hierarchy (NH) scenario, while Hyper-K could impose a $2\sigma$ limit of $\Gamma \leq 3.6 \times 10^{-14}$ eV for the inverted mass hierarchy (IH) scenario with $n=0$ - assuming no energy exchange between the neutrino subsystem and non-standard environment ($[H,V_p] = 0$). These limits become even more restrictive for a closer Supernova. When we relax the assumption of energy exchange ($[H,V_p] \neq 0$), DUNE can establish a $3\sigma$ limit of $\Gamma_8 \leq 4.2 \times 10^{-28}$ eV for NH, while Hyper-K could constrain $\Gamma_8 \leq 9.3 \times 10^{-28}$ eV for IH ($n=0$) with the same significance, representing the most stringent bounds reported to date. Furthermore, we examine the impact of neutrino loss during propagation for future Supernova detection.
... The effect is actively studied in different neutrino experiments in reactor and solar fluxes (see, for example, [5,6,7]). We also highlight the recent theoretical studies dedicated to neutrino quantum decoherence [8,9,10,11]. Previously, we have studied neutrino quantum decoherence in supernovae fluxes [12]. ...
We developed the previously proposed theoretical framework based on the quantum field theory of open systems applied to neutrinos. Within this framework we have considered the neutrino evolution and neutrino flavour oscillations taking into account for the decay of a heavier neutrino state to a lighter neutrino state and to a massless particle, namely photons, dark photons, axion-like particles and gravitons. We have shown that the neutrino evolution accounting for the decays will be governed by the Lindblad master equation, in which the decoherence parameters are proportional to the neutrino decay rate.
... Various aspects of neutrino-DM interactions have been studied in the literature [6][7][8][9][57][58][59][60][61][62][63][64]]. An encyclopedia of interactions of neutrinos with ultralight scalar DM leading to an effective vertex ν-ν-φ-φ * can be found in ref. [6]. ...
A bstract
High energy astrophysical neutrinos interacting with ultralight dark matter (DM) can undergo flavour oscillations that induce an energy dependence in the flavour ratios. Such a dependence on the neutrino energy will reflect in the track to shower ratio in neutrino telescopes like IceCube or KM3NeT. This opens up a possibility to study DM density profiles of astrophysical objects like AGN, GRB etc., which are the suspected sources of such neutrinos.
... The operator D½ρ encodes the decoherence effects in the system. In many existing studies simple forms for this operator have been assumed with manageable numbers of free parameters to test against experimental data, although in some cases the decoherence effects have been derived from first principals (see e.g., [54,56,58]). In this week we seek to determine the form of D½ρ representing the distance fluctuations we are considering, and ultimately produce the damping effects we observe. ...
One of the most common expectations of a quantum theory of gravity is that spacetime is uncertain or fluctuating at microscopic scales, making it a stochastic medium for particle propagation. Particles traversing this spacetime may experience fluctuations in travel times or velocities, together referred to as lightcone fluctuations, with even very small effects potentially accumulating into observable signals over large distances. In this work we present a heuristic model of lightcone fluctuations and study the resulting modifications to neutrino propagation, including neutrino decoherence and arrival time spread. We show the expected scale of such effects due to “natural” Planck scale physics and consider how they may be observed in neutrino detectors, and compare the potential of neutrinos to γ-ray astronomy. Using simulations of neutrino mass states propagating in a fluctuating environment, we determine an analytic decoherence operator in the framework of open quantum systems to quantitatively evaluate neutrino decoherence resulting from lightcone fluctuations, allowing experimental constraints on neutrino decoherence to be connected to Planck scale fluctuations in spacetime and γ-ray results.
... In previous works we have presented various calculations related to the propagation of neutrinos in that kind of background [14][15][16]. In Ref. [14] we considered the real part of the self-energy of a neutrino that propagates in a medium consisting of fermions and scalars, with a coupling of the form given in Eq. (1.1). ...
... In Ref. [16] we noted that those couplings can induce decoherence effects, of the form discussed in recent works [17][18][19][20][21], due to the neutrino non-forward-scattering process ν a þ x → ν b þ x, where x ¼ f; ϕ. As observed in Ref. [16], the contribution to Γ due to these processes can be determined from the two-loop calculation of Σ i . ...
... In Ref. [16] we noted that those couplings can induce decoherence effects, of the form discussed in recent works [17][18][19][20][21], due to the neutrino non-forward-scattering process ν a þ x → ν b þ x, where x ¼ f; ϕ. As observed in Ref. [16], the contribution to Γ due to these processes can be determined from the two-loop calculation of Σ i . Thus, in that reference we performed the two-loop calculation of Σ i and Γ or the case in which the background contains only the fermions f, assuming that the ϕ particle is heavy enough and the conditions are such that there are no ϕ particles in the background. ...
We consider the calculation of the thermal self-energy of a neutrino that propagates in a medium composed of fermions and scalars interacting via a Yukawa-type coupling, in the case that the neutrino energy is much larger than the fermion and scalar masses, as well as the temperature and chemical potentials of the background. In this kinematic regime the one-loop contribution to the imaginary part of the self-energy is negligible. We consider the two-loop contribution and we encounter the so-called pinch singularities which are known to arise in higher-loop self-energy calculations in thermal field theory. With a judicious use of the properties and parametrizations of the thermal propagators the singularities are treated effectively and actually disappear. From the imaginary part of the self-energy, we obtain a precise formula for the damping matrix expressed in terms of integrals over the background particle distributions. The formulas predict a specific dependence of the damping terms on the neutrino energy, depending on the background conditions. For guidance in estimating the effects in specific contexts, we compute the damping terms for several limiting cases of the momentum distribution functions of the background particles. We discuss briefly the connection between the results of our calculations for the damping matrix and the decoherence effects described in terms of the Lindblad equation.
... In previous works we have presented various calculations related to the propagation of neutrinos in that kind of backgrounds [14,15,16]. In Ref. [14] we considered the real part of the self-energy of a neutrino that propagates in a medium consisting of fermions and scalars, with a coupling of the form given in Eq. (1.1). ...
... In Ref. [16] we noted that those couplings can induce decoherence effects, of the form discussed in recent works [17,18,19,20,21], due to the neutrino non-forward scattering process ν a + x → ν b + x, where x = f, φ. As observed in Ref. [16], the contribution to Γ due to these processes can be determined from the two-loop calculation of Σ i . ...
... In Ref. [16] we noted that those couplings can induce decoherence effects, of the form discussed in recent works [17,18,19,20,21], due to the neutrino non-forward scattering process ν a + x → ν b + x, where x = f, φ. As observed in Ref. [16], the contribution to Γ due to these processes can be determined from the two-loop calculation of Σ i . Thus, in that reference we performed the two-loop calculation of Σ i and Γ or the case in which the background contains only the fermions f , assuming that the φ particle is heavy enough and the conditions are such that there are no φ particles in the background. ...
We consider the calculation of the thermal self-energy of a neutrino that propagates in a medium composed of fermions and scalars interacting via a Yukawa-type coupling, in the case that the neutrino energy is much larger than the fermion and scalar masses, as well as the temperature and chemical potentials of the background. In this kinematic regime the one-loop contribution to the imaginary part of the self-energy is negligible. We consider the two-loop contribution and we encounter the so-called pinch singularities which are known to arise in higher loop self-energy calculations in Thermal Field Theory. With a judicious use of the properties and parametrizations of the thermal propagators the singularities are treated effectively and actually disappear. From the imaginary part of the self-energy, we obtain a precise formula for the damping matrix expressed in terms of integrals over the background particle distributions. The formulas predict a specific dependence of the damping terms on the neutrino energy, depending on the background conditions. For guidance to estimating the effects in specific contexts, we compute the damping terms for several limiting cases of the momentum distribution functions of the background particles. We discuss briefly the connection between the results of our calculations for the damping matrix and the decoherence effects described in terms of the Lindblad equation.
... Subsequently we pointed out that, in addition to the damping effects, those couplings induce decoherence effects in the propagation of neutrinos due to the neutrino nonforward scattering process [4]. More precisely, we considered various neutrino flavors (ν La ) interacting with a scalar and fermion with a coupling of the form ...
... II we review briefly our strategy to determine the jump operators from the results of the calculation of the absorptive part of the self-energy. This material is based on our previous work [4], and we therefore limit ourselves there to state the main points omitting some details. In Sec. ...
... The following material is borrowed from Ref. [4], which we summarize here for completeness. We denote by u μ the velocity four-vector of the background medium and by k μ the momentum of the propagating neutrino. ...
We consider the decoherence effects in the propagation of active neutrinos due to the nonforward neutrino scattering processes in a matter background composed of electrons and nucleons. We calculate the contribution to the imaginary part of the neutrino self-energy arising from such processes. Since the initial neutrino state is depleted but does not actually disappear (the initial neutrino transitions into a neutrino of a different flavor but does not decay) those processes should be associated with decoherence effects that cannot be described in terms of the coherent evolution of the state vector. Based on the formalism developed in our previous work for treating the nonforward scattering processes using the notion of the stochastic evolution of the state, we identify the jump operators, as used in the context of the master or Lindblad equation, in terms of the results of the calculation of the nonforward neutrino scattering contribution to the imaginary part of the neutrino self-energy. As a guide to estimating the decoherence effects in situations of practical interest we give explicit formulas for the decoherence terms for different background conditions, and point out some of the salient features in particular the neutrino energy dependence. To establish contact with previous works in which the decoherence terms are treated as phenomenological parameters, we consider the solution to the evolution equation in the two-generation case. We give formulas that are useful for estimating the effects of the decoherence terms under various conditions and environments, including the typical conditions applicable to long baseline experiments, where matter effects are important. In those contexts the effects appear to be small, and indicative that if significant decoherence effects were to be found they would be due to nonstandard contributions to the decoherence terms.
... Subsequently we pointed out that, in addition to the damping effects, those couplings induce decoherence effects in the propagation of neutrinos due to the neutrino non-forward scattering process [4]. More precisely, we considered various neutrino flavors (ν La ) interacting with a scalar and fermion with a coupling of the form L int = a λ afR ν La φ + h.c. ...
... In Section 2 we review briefly our strategy to determine the jump operators from the results of the calculation of the absorptive part of the self-energy. This material is based on our previous work [4], and we therefore limit ourselves there to state the main points omitting some details. In Section 3 we proceed to the actual calculation as outlined in Section 2. The end result is a set of formulas for the jump operators, Figure 1: Two-loop diagrams for the damping term in the neutrino thermal self-energy in a matter (electron and nucleon) background. ...
... The following material is borrowed from Ref. [4], which we summarize here for completeness. We denote by u µ the velocity four-vector of the background medium and by k µ the momentum of the propagating neutrino. ...
We consider the decoherence effects in the propagation of active neutrinos due to the non-forward neutrino scattering processes in a matter background composed of electrons and nucleons. We calculate the contribution to the imaginary part of the neutrino self-energy arising from such processes. Since the initial neutrino state is depleted but does not actually disappear (the initial neutrino transitions into a neutrino of a different flavor but does not decay) those processes should be associated with decoherence effects that cannot be described in terms of the coherent evolution of the state vector. Based on the formalism developed in previous work for treating the non-forward scattering processes using the notion of the stochastic evolution of the state, we identify the jump operators, as used in the context of the master or Linblad equation, in terms of the results of the the calculation of the non-forward neutrino scattering contribution to the imaginary part of the neutrino self-energy. As a guide to estimating the decoherence effects in situations of practical interest we give explicit formulas for the jump operators for different background conditions, and point out some of the salient features in particular the neutrino energy dependence. The results can be useful for long baseline experiments, where matter effects are important, and can also serve to guide the generalizations to other situations in which the decoherence effects in the propagation of neutrinos due to the non-forward scattering processes may be important.
Изучено влияние квантовой декогеренции массовых нейтринных состояний на коллективные осцилляции нейтрино для случая трех флейворов. При исследовании использовался метод, основанный на анализе уравнения Линдблада на устойчивость, при этом гамильтониан эволюции нейтрино включал в себя эффекты самодействия. Получены новые аналитические условия возникновения коллективных осцилляций нейтрино при взрыве сверхновой, которые учитывают эффект квантовой декогеренции нейтрино.
