Neutrino decoherence in an electron and nucleon background
José F. Nieves, Sarira Sahu
备注：
27 Pages, 2 Figures, Typographical errors in Eqs. (6.5) and (6.11) of the PRDpublished version have been corrected. arXiv admin note: text overlap with arXiv:1909.11271
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 our 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 Lindblad 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 decoherence terms for different background conditions, and point out some of the salient features in particular the neutrino energy dependence. To establish contact wih 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 non-standard contributions to the decoherence terms.
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Lomonosov Moscow State University（莫斯科国立罗蒙诺索夫大学）；Branch of Lomonosov Moscow State University in Sarov（莫斯科国立罗蒙诺索夫大学萨罗夫分院）；National Centre for Physics and Mathematics（国家物理数学中心）
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Impact of different neutrino decoherence formalisms at the future long-baseline Experiments
Nabarangpur College（纳巴朗格布尔学院）；School of Physics, University of Hyderabad（海德拉巴大学物理学院）；Center of Excellence for Advanced Materials and Sensing Devices, Ruđer Bošković Institute（鲁德·博什科维奇研究所先进材料与传感设备卓越中心）
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