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1. Solar neutrinos and ${\nu }_2$ visible decays to ${\nu }_1$

   https://doi.org/10.1103/PhysRevD.109.013003  

   de_Gouvêa, André; Weill, Jean; Sen, Manibrata (January 2024, Physical Review D)

   Experimental bounds on the neutrino lifetime depend on the nature of the neutrinos and the details of the potentially new physics responsible for neutrino decay. In the case where the decays involve active neutrinos in the final state, the neutrino masses also qualitatively impact how these manifest themselves experimentally. In order to further understand the impact of nonzero neutrino masses, we explore how observations of solar neutrinos constrain a very simple toy model. We assume that neutrinos are Dirac fermions and there is a new massless scalar that couples to neutrinos such that a heavy neutrino— ${\nu }_2$ with mass $m_2$ —can decay into a lighter neutrino— ${\nu }_1$ with mass $m_1$ —and a massless scalar. We find that the constraints on the new physics coupling depend, sometimes significantly, on the ratio of the daughter-to-parent neutrino masses and that, for large-enough values of the new physics coupling, the “dark side” of the solar neutrino parameter space— ${\sin }^2{\theta }_{12}\sim 0.7$ —provides a reasonable fit to solar neutrino data, if only ${}^8\mathrm{B}$ or ${}^7\mathrm{Be}$ neutrino data alone are considered, but no allowed region is found in the combined analysis. Our results generalize to other neutrino-decay scenarios, including those that mediate ${\nu }_2\to {\nu }_1{\overline{\nu }}_3{\nu }_3$ when the neutrino mass ordering is inverted mass and $m_2>m_1\gg m_3$ , the mass of ${\nu }_3$ . Published by the American Physical Society2024 

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2. First Measurement of ${\nu }_e$ and ${\nu }_{\mu }$ Interaction Cross Sections at the LHC with FASER’s Emulsion Detector

   https://doi.org/10.1103/PhysRevLett.133.021802  

   Abraham, Roshan Mammen; Anders, John; Antel, Claire; Ariga, Akitaka; Ariga, Tomoko; Atkinson, Jeremy; Bernlochner, Florian U; Boeckh, Tobias; Boyd, Jamie; Brenner, Lydia; et al (July 2024, Physical Review Letters)

   The first results of the study of high-energy electron neutrino ( ${\nu }_e$ ) and muon neutrino ( ${\nu }_{\mu }$ ) charged-current interactions in the $\mathrm{FASER}\nu$ emulsion-tungsten detector of the FASER experiment at the LHC are presented. A 128.8 kg subset of the $\mathrm{FASER}\nu$ volume was analyzed after exposure to $9.5{\mathrm{fb}}^{-1}$ of $\sqrt{s}=13.6\mathrm{TeV}$ $pp$ data. Four (eight) ${\nu }_e$ ( ${\nu }_{\mu }$ ) interaction candidate events are observed with a statistical significance of $5.2\sigma$ ( $5.7\sigma$ ). This is the first direct observation of ${\nu }_e$ interactions at a particle collider and includes the highest-energy ${\nu }_e$ and ${\nu }_{\mu }$ ever detected from an artificial source. The interaction cross section per nucleon $\sigma /E_{\nu }$ is measured over an energy range of 560–1740 GeV (520–1760 GeV) for ${\nu }_e$ ( ${\nu }_{\mu }$ ) to be $\left({1.2}_{-0.7}^{+0.8}\right)\times {10}^{-38}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$ [ $(0.5\pm 0.2)\times {10}^{-38}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$ ], consistent with standard model predictions. These are the first measurements of neutrino interaction cross sections in those energy ranges. Published by the American Physical Society2024 

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3. Measurement of ${\nu }_{\mu }$ charged-current inclusive ${\pi }^0$ production in the NOvA near detector

   https://doi.org/10.1103/PhysRevD.107.112008  

   Acero, M. A.; Adamson, P.; Agam, G.; Aliaga, L.; Alion, T.; Allakhverdian, V.; Altakarli, S.; Anfimov, N.; Antoshkin, A.; Asquith, L.; et al (June 2023, Physical Review D)
4. First measurement of ${\nu }_{\mu }$ charged-current ${\pi }^0$ production on argon with the MicroBooNE detector

   https://doi.org/10.1103/PhysRevD.99.091102  

   Adams, C.; Alrashed, M.; An, R.; Anthony, J.; Asaadi, J.; Ashkenazi, A.; Auger, M.; Balasubramanian, S.; Baller, B.; Barnes, C.; et al (May 2019, Physical Review D)
5. $E_6$ models in light of precision $M_W$ measurements

   https://doi.org/10.1103/PhysRevD.107.075005  

   Barger, Vernon; Hauptmann, Cash; Huang, Peisi; Keung, Wai-Yee (April 2023, Physical Review D)