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1. Probing long-range forces between neutrinos with cosmic structures

   https://doi.org/10.1103/PhysRevD.111.055019  

   Kaplan, David E; Luo, Xuheng; Rajendran, Surjeet (March 2025, Physical Review D)

   We study the consequences of new long-range forces between neutrinos on cosmic scales. If these forces are a few orders of magnitude stronger than gravity, they can induce perturbation instability in the nonrelativistic cosmic neutrino background in the late time universe. As a result, the cosmic neutrino background may form nonlinear bound states instead of free-streaming. The implications of the formation of nonlinear neutrino bound states include enhancing matter perturbations and triggering star formation. Based on existing measurements of the matter power spectrum and reionization history, we place new constraints on long-range forces between neutrinos with ranges lying in $1\mathrm{kpc}\lesssim m_{\varphi }^{-1}\lesssim 10\mathrm{Mpc}$. Published by the American Physical Society2025 

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2. Measurement of electron neutrino and antineutrino cross sections at low momentum transfer

   https://doi.org/10.1103/PhysRevD.109.092008  

   Henry, S; Su, H; Akhter, S; Ahmad_Dar, Z; Ansari, V; Ascencio, M V; Sajjad_Athar, M; Bashyal, A; Betancourt, M; Bonilla, J L; et al (May 2024, Physical Review D)

   Accelerator based neutrino oscillation experiments seek to measure the relative number of electron and muon (anti)neutrinos at different $L/E$values. However high statistics studies of neutrino interactions are almost exclusively measured using muon (anti)neutrinos since the dominant flavor of neutrinos produced by accelerator based beams are of the muon type. This work reports new measurements of electron (anti)neutrinos interactions in hydrocarbon, obtained by strongly suppressing backgrounds initiated by muon flavor (anti)neutrinos. Double differential cross sections as a function of visible energy transfer, $E_{\text{avail}}$, and transverse momentum transfer, $p_T$, or three momentum transfer, $q_3$are presented. Published by the American Physical Society2024 

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3. Evidence of Coherent Elastic Neutrino-Nucleus Scattering with COHERENT’s Germanium Array

   https://doi.org/10.1103/PhysRevLett.134.231801  

   Adamski, S; Ahn, M; Barbeau, P S; Belov, V; Bernardi, I; Bock, C; Bolozdynya, A; Bouabid, R; Browning, J; Cabrera-Palmer, B; et al (June 2025, Physical Review Letters)

   We report the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) on natural germanium, measured at the Spallation Neutron Source at Oak Ridge National Laboratory. The Ge-Mini detector of the COHERENT collaboration employs large-mass, low-noise, high-purity germanium spectrometers, enabling excellent energy resolution, and an analysis threshold of 1.5 keV electron-equivalent ionization energy. We observe an on-beam excess of ${20.6}_{-6.3}^{+7.1}$counts with a total exposure of 10.22 GWhkg, and we reject the no-CEvNS hypothesis with $3.9\sigma$significance. The result agrees with the predicted standard model of particle physics signal rate within $2\sigma$. Published by the American Physical Society2025 

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4. First Joint Oscillation Analysis of Super-Kamiokande Atmospheric and T2K Accelerator Neutrino Data

   https://doi.org/10.1103/PhysRevLett.134.011801  

   Abe, K; Abe, S; Bronner, C; Hayato, Y; Hiraide, K; Hosokawa, K; Ieki, K; Ikeda, M; Kameda, J; Kanemura, Y; et al (January 2025, Physical Review Letters)

   The Super-Kamiokande and T2K Collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of $19.7\left(16.3\right)\times {10}^{20}$protons on target in (anti)neutrino mode, the analysis finds a $1.9\sigma$exclusion of $CP$conservation (defined as $J_{CP}=0$) and a $1.2\sigma$exclusion of the inverted mass ordering. Published by the American Physical Society2025 

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5. Neutron star cooling with lepton-flavor-violating axions

   https://doi.org/10.1103/PhysRevD.109.103005  

   Zhang, Hong-Yi; Hagimoto, Ray; Long, Andrew J (May 2024, Physical Review D)

   The cores of dense stars are a powerful laboratory for studying feebly coupled particles such as axions. Some of the strongest constraints on axionlike particles and their couplings to ordinary matter derive from considerations of stellar axion emission. In this work we study the radiation of axionlike particles from degenerate neutron star matter via a lepton-flavor-violating coupling that leads to muon-electron conversion when an axion is emitted. We calculate the axion emission rate per unit volume (emissivity) and by comparing with the rate of neutrino emission, we infer upper limits on the lepton-flavor-violating coupling that are at the level of $\left|g_{ae\mu }\right|\lesssim {10}^{-6}$. For the hotter environment of a supernova, such as SN 1987A, the axion emission rate is enhanced and the limit is stronger, at the level of $\left|g_{ae\mu }\right|\lesssim {10}^{-11}$, competitive with laboratory limits. Interestingly, our derivation of the axion emissivity reveals that axion emission via the lepton-flavor-violating coupling is suppressed relative to the familiar lepton-flavor-preserving channels by the square of the plasma temperature to muon mass ratio, which is responsible for the relatively weaker limits. Published by the American Physical Society2024 

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