Spin-flavour conversion of neutrinos in loop quantum gravity

Lambiase, Gaetano

doi:10.1088/0264-9381/20/19/306

Cited by 10 publications

(5 citation statements)

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“…[209] (see the beginning of Subsection F). On the basis of the above formalism with working set of parametrization constants and by comparing theoretical results with NO data and with the spectrum of cosmic rays of extragalactic origin, the following problems were also considered: the energy dependence of NO length [269], constraints on the intermediate scale (L 10 −18 eV −1 [269,270]) and the working constant [270], and a novel mechanism [271] for generating the primary cosmological asymmetry of the Universe originating from the density difference of neutrinos and antineutrinos caused by the above distinction in signs for the linear-in-momentum contribution to function F in Eq. (11).…”

Section: F Violation Of Lorentz Invariance and Equivalence Principle ...mentioning

confidence: 99%

CPT invariance and neutrino physics

Tsukerman

2010

Preprint

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CPT invariance in neutrino physics has attracted attention after the revival of the hypothetical idea that neutrino and antineutrino might have nonequal masses (m ν = m ν ) when realizing neutrino oscillations as a new sensitive phenomenon to search for the violation of this fundamental symmetry. Moreover, the profound relation between the CPT and Lorentz symmetries turns the studies of CPT and Lorentz invariance violations into the one two-sided problem. We present a guide for non-experts through the literature on neutrino physics. The basic works are reviewed thoroughly while for the other papers only current results or discussion issues are quoted. The review covers, mostly, oscillations of neutrinos, resonant change of their flavors and cosmic neutrino physics to systematize possible evidences of CPT/Lorentz violation in this sector of the Standard Model. ContentsIntroduction 1. The CPT theorem (quotations) 2. Theoretical and experimental status of the CPT 3. General consequences of hypothetical CPT and Lorentz invariance violation in neutrino physics A. CPT and neutrino physics B. Extension of the Standard Model: spontaneous violation of Lorentz invariance and СPТ C. Perturbation-theory formalism for violation of Lorentz invariance, CPT and equivalence principle D. 'Non-standard' violating mechanisms (quantum decoherence, modified dispersion relations) 4. Experimental and observational consequences of CPT and Lorentz invariance violation in neutrino physics E. Perturbative violation of Lorentz invariance and CPT F. Violation of Lorentz invariance and equivalence principle in terrestrial and cosmic neutrino physics G. Manifestations of Lorentz invariance and CPT with 'non-standard' mechanisms in neutrino physics 5. Interpretations of neutrino oscillations based on CPT violation H. False CPT-odd effects in matter I. Neutrino oscillations due to violation of Lorentz invariance J. CPT non-invariant 'ether', quantum decoherence, and LSND anomaly K. Antineutrino vs neutrino oscillation parameters; LSND-anomaly models with m ν = m ν Conclusion References 0 The early version of this article has been published in the Russian journal Uspekhi Fizicheskikh Nauk : U F N , 175, 863 (2005). Although the English translation in Physics-Uspekhi, 48, 825 (2005) was performed by nonexperts, the author has not got possibility to check up proofs carefully because of strict time schedule imposed by the editorial board. Now we present a revised and updated article in English.21 However as it is mentioned, Hawking has stated in his talk at the GR17 (17th Intern. Conf. on General Relativity and Gravitation, Dublin, July 2004) that information is not lost during formation and evaporation of black holes because in all likelihood the true (not the apparent) horizon is never formed. Hawking's claims are discussed in the literature -by the author of [20,21] also within the reference number six in his invited talk of Ref.[108] and, in details, in one of his recent theoretical works (see Section I of Ref. [161]) as well as in Hawking's pape...

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Section: F Violation Of Lorentz Invariance and Equivalence Principle ...mentioning

confidence: 99%

CPT invariance and neutrino physics

Tsukerman

2010

Preprint

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“…An interesting consequence of MDR in LV quantum gravity theories is associated with modifications to the well-known phenomenon of spin-flavour conversion in ν interactions [69]. To be specific, we shall consider an example of a MDR for ν provided by a Loop Gravity approach to quantum gravity.…”

Section: Lorentz Non Invariance Mdr and ν Spin-flavor Conversionmentioning

confidence: 99%

“…It has been noted in [69] that such a modification in the dispersion relation will affect the form of the spin-flavour conversion mechanism. Indeed, it is well known through the Mikheyev-Smirnov-Wolfenstein (MSW) effect [70] that Weak interaction Effects of ν propagating in a medium result in an energy shift √ 2G F (2n e − n n ), where n e (n n )'s denote electron (neutron) densities.…”

Section: Lorentz Non Invariance Mdr and ν Spin-flavor Conversionmentioning

confidence: 99%

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CPT Violation and decoherence in quantum gravity

Mavromatos

2009

J. Phys.: Conf. Ser.

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In this brief review I discuss ways and tests of CPT-Violation in the context of quantum gravity theories with space-time foam vacua, which entail quantum decoherence of matter propagating in such backgrounds. I cover a wide variety of sensitive probes, ranging from cosmic neutrinos to meson factories. I pay particular emphasis on associating the latter with specific, probably unique ("smoking-gun"), effects of this type of CPT Violation, related to a modification of Einstein-Podolsky-Rosen (EPR) correlations in the entangled states of the relevant neutral mesons. I also present some semi-microscopic estimates of these latter effects, in the context of a specific string-inspired model of space-time foam ("D-particle foam"). Introduction: arguments in favour of and against Matter Decoherence in Quantum GravityThe theory of Quantum Gravity (QG) is still elusive, despite considerable effort to formulate mathematically consistent models for the description of quantum fluctuations of space time at microscopic scales (Planck length scales of order 10 −35 m). An important unknown factor in such a formulation is the structure of space time at such scales, which could be entirely different from what we are accustomed to from our low-energy experience. In fact, space-time at Planck scales may not even be continuous or commutative.The traditional approach of considering singular microscopic-scale space-time fluctuations due to the formation and subsequent Hawking evaporation of Planck-size black holes in the vacuum leads to speculations [1] about possible loss of quantum coherence ("decoherence") for matter propagating in such topologically non-trivial space-time vacua. Originally, such properties were thought [2] to be generic features of the space-time foam backgrounds [3].An important issue arising in this context concerns the existence of a well-defined scattering matrix in the presence of microscopic black holes (i.e. in the regime of strong quantum gravity); the information encoded in matter fields may not be delivered intact to asymptotic observers. This will lead to an effective (low-energy) decoherence of matter fields propagating in foamy backgrounds. Basically, the matter quantum system is an open system, interacting with the "environment" of quantum gravitational degrees of freedom, not accessible to low-energy observers performing scattering experiments.There is a rich phenomenology of such decoherence models, especially in the context of particle physics [4], using sensitive particle probes, such as neutron interferometry, neutral mesons [2,5,6,7,8,9] or neutrinos [10,11,12,13,14,15,16,17,18]. In this context, R. Wald has proven [19] a strong form of violation of CPT symmetry in quantum field theories involving decoherence due to quantum gravity, in the sense that in such theories the quantum mechanical operator that generates the CPT transformations is not well-defined. In these cases, CPT "Violation" refers to a rather intrinsic microscopic time irreversibility situation ("intrinsic CPT Violation"), and it s...

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“…To obtain these bounds the author of [69] made the following physically relevant assumptions: (a) Reasonable profiles for solar n e ∼ n 0 e −10.5r/R⊙ , n 0 = 85N A cm . To obtain bounds on κ we need to distinguish two cases: (I) L=universal constant: In this case, we already know from photon dispersion tests on GRB and (AGN) [11,65] that L ∼ 10 −18 eV −1 .…”

Section: Lorentz Non Invariance Mdr and ν Spin-flavor Conversionmentioning

confidence: 99%

CPT Violation and Decoherence in Quantum Gravity

Mavromatos¹

Lecture Notes in Physics

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In these lectures I review, in as much pedagogical way as possible, various theoretical ideas and motivation for violation of CPT invariance in some models of Quantum Gravity, and discuss the relevant phenomenology. Since the subject is vast, I pay particular emphasis on the CPT Violating decoherence scenario for quantum gravity, due to space-time foam. In my opinion this seems to be the most likely scenario to be realised in Nature, should quantum gravity be responsible for the violation of this symmetry. In this context, I also discuss how the CPT Violating decoherence scenario can explain experimental "anomalies" in neutrino data, such as LSND results, in agreement with the rest of the presently available data, without enlarging the neutrino sector.

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Spin-flavour conversion of neutrinos in loop quantum gravity

Cited by 10 publications

References 60 publications

CPT invariance and neutrino physics

CPT invariance and neutrino physics

CPT Violation and decoherence in quantum gravity

CPT Violation and Decoherence in Quantum Gravity

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