941 research outputs found

    Probing nonstandard lepton number violating interactions in neutrino oscillations

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    We discuss lepton number violating processes in the context of long-baseline neutrino oscillations. We summarise and compare neutrino flavour oscillations in quantum mechanics and quantum field theory, both for standard oscillations and for those that violate lepton number. When the active neutrinos are Majorana in nature, the required helicity reversal gives a strong suppression by the neutrino mass over the energy, (mν/Eν)2(m_{\nu}/E_{\nu})^{2}. Instead, the presence of non-standard lepton number violating interactions incorporating right-handed lepton currents at production or detection alleviate the mass suppression while also factorising the oscillation probability from the total rate. Such interactions arise from dimension-six operators in the low energy effective field theory of the Standard Model. We derive general and simplified expressions for the lepton number violating oscillation probabilities and use limits from MINOS and KamLAND to place bounds on the interaction strength in interplay with the unknown Majorana phases in neutrino mixing. We compare the bounds with those from neutrinoless double beta decay and other microscopic lepton number violating processes and outline the requirements for future short- and long-baseline neutrino oscillation experiments to improve on the existing bounds.Comment: 33 pages, 9 figure

    Probing New Physics with Long-Range Neutrino Interactions: An Effective Field Theory Approach

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    We investigate forces induced by the exchange of two light neutrinos between Standard Model (SM) fermions in the presence of effective operators parametrising physics beyond the SM. We first set up a general framework in which we derive the long-range potential mediated by weakly interacting neutrinos in the SM, retaining both spin-independent and spin-dependent terms. We then derive neutrino-mediated potentials when there are vector, scalar and tensor non-standard interactions present as well as an exotic neutrino magnetic moment. Examining the phenomenology of such long-range potentials in atomic scale laboratory experiments, we derive upper bounds on the Wilson coefficients of the effective operators and compare these to those from processes such as charged lepton flavour violation.Comment: 60 pages, 6 figure

    Neutrinoless double beta decay via light neutralinos in R-parity violating supersymmetry

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    We perform a study of neutrinoless double beta (0νββ) decay mediated by the lightest neutralino of arbitrary mass in the minimal supersymmetric Standard Model (MSSM) under the presence of R-parity violating trilinear interactions. In this scenario, the exchange of the lightest neutralino can result in 0νββ decay of either long-range or short-range behaviour, depending on the neutralino mass. Using nuclear matrix elements calculated in the interacting boson model, we use an interpolation between the long- and short-range behaviours with an approximate formula. The non-observation of 0νββ decay is then used to place constraints on the supersymmetry parameter space, compatible with constraints from collider experiments. We compare these constraints to bounds from pion decays, CKM unitarity and big bang nucleosynthesis

    Probes of Heavy Sterile Neutrinos

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    We review probes of heavy sterile neutrinos, focusing on direct experimental searches and neutrinoless double beta decay. Working in a phenomenological parametrization, we emphasize the importance of the nature of sterile neutrinos in interpreting neutrinoless double beta decay searches. While current constraints on the active-sterile neutrino mixing are already stringent, we highlight planned future efforts that will probe regimes motivated by the lightness of active neutrinos

    Executive Compensation and Risk Taking

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    Probing active-sterile neutrino transition magnetic moments with photon emission from CEνNS

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    In the presence of transition magnetic moments between active and sterile neutrinos, the search for a Primakoff upscattering process at coherent elastic neutrino-nucleus scattering (CEνNS) experiments can provide stringent constraints on the neutrino magnetic moment. We show that a radiative upscattering process with an emitted photon in the final state can induce a novel coincidence signal at CEνNS experiments that can also probe neutrino transition magnetic moments beyond existing limits. Furthermore, the differential distributions for such a radiative mode can also potentially be sensitive to the Dirac vs Majorana nature of the sterile state mediating the process. This can provide valuable insights into the nature and mass generation mechanism of the light active neutrinos

    Probing Active-Sterile Neutrino Transition Magnetic Moments with Photon Emission from CEν\nuNS

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    In the presence of transition magnetic moments between active and sterile neutrinos, the search for a Primakoff upscattering process at coherent elastic neutrino-nucleus scattering (CEν\nuNS) experiments can provide stringent constraints on the neutrino magnetic moment. We show that a radiative upscattering process with an emitted photon in the final state can induce a novel coincidence signal at CEν\nuNS experiments that can also probe neutrino transition magnetic moments beyond existing limits. Furthermore, the differential distributions for such a radiative mode can also potentially be sensitive to the Dirac vs. Majorana nature of the sterile state mediating the process. This can provide valuable insights into the nature and mass generation mechanism of the light active neutrinos.Comment: 38 pages, 9 figures; expanded discussion of constraints, matches published versio

    Surface Attachment of Active Antimicrobial Coatings Onto Conventional Plastic Based Laminates and Performance Assessment of These Materials on the Storage Life of Vacuum Packaged Beef Sub-Primals

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    Two antimicrobial coatings, namely Sodium octanoate and Auranta FV (a commercial antimicrobial composed of bioflavonoids, citric, malic, lactic, and caprylic acids) were used. These two antimicrobials were surface coated onto the inner polyethylene layer of cold plasma treated polyamide films using beef gelatin as a carrier and coating polymer. This packaging material was then used to vacuum pack beef sub-primal cuts and stored at 4 °C. A control was prepared using the non-coated commercial laminate and the same vacuum packaged sub-primal beef cuts. During storage, microbial and quality assessments were carried out. Sodium octanoate treated packages significantly (p \u3c 0.05) reduced microbial counts for all bacteria tested with an increase of 7 and 14 days, respectively compared to control samples. No significant effect on pH was observed with any treatment. The results suggested that these food grade antimicrobials have the potential to be used in antimicrobial active packaging applications for beef products
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