More Like this

1. Probing superheavy dark matter through lunar radio observations of ultrahigh-energy neutrinos and the impacts of neutrino cascades

   https://doi.org/10.1103/PhysRevD.111.083007  

   Das, Saikat; Carpio, Jose Alonso; Murase, Kohta (April 2025, Physical Review D)

   Ultrahigh-energy neutrinos ( $\mathrm{UHE}\nu$s) can be used as a valuable probe of superheavy dark matter above $\sim {10}^9\mathrm{GeV}$, the latter being difficult to probe with collider and direct detection experiments due to the feebly interacting nature. Searching for radio emissions originating from the interaction of $\mathrm{UHE}\nu$s with the lunar regolith enables us to explore energies beyond ${10}^{12}\mathrm{GeV}$, which astrophysical accelerators cannot achieve. Taking into account the interaction of $\mathrm{UHE}\nu$s with the cosmic neutrino background and resulting standard neutrino cascades to calculate the neutrino flux on Earth, for the first time, we investigate sensitivities of such lunar radio observations to very heavy dark matter. We also examine the impacts of cosmogenic neutrinos that have the astrophysical origin. We show that the proposed ultralong wavelength lunar radio telescope, as well as the existing low-frequency array, can provide the most stringent constraints on decaying or annihilating superheavy dark matter with masses at $\gtrsim {10}^{12}\mathrm{GeV}$. The limits are complementary to or even stronger than those from other $\mathrm{UHE}\nu$detectors, such as the IceCube-Gen2 radio array and the Giant Radio Array for Neutrino Detection. 

   more » « less
2. First Indication of Solar ${}^8\mathrm{B}$ Neutrinos via Coherent Elastic Neutrino-Nucleus Scattering with XENONnT

   https://doi.org/10.1103/PhysRevLett.133.191002  

   Aprile, E; Aalbers, J; Abe, K; Ahmed_Maouloud, S; Althueser, L; Andrieu, B; Angelino, E; Antón_Martin, D; Arneodo, F; Baudis, L; et al (November 2024, Physical Review Letters)

   We present the first measurement of nuclear recoils from solar ${}^8\mathrm{B}$neutrinos via coherent elastic neutrino-nucleus scattering with the XENONnT dark matter experiment. The central detector of XENONnT is a low-background, two-phase time projection chamber with a 5.9 t sensitive liquid xenon target. A blind analysis with an exposure of $3.51\mathrm{t}\times \mathrm{yr}$resulted in 37 observed events above 0.5 keV, with ( ${26.4}_{-1.3}^{+1.4}$) events expected from backgrounds. The background-only hypothesis is rejected with a statistical significance of $2.73\sigma$. The measured ${}^8\mathrm{B}$solar neutrino flux of $\left({4.7}_{-2.3}^{+3.6}\right)\times {10}^6{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$is consistent with results from the Sudbury Neutrino Observatory. The measured neutrino flux-weighted $\mathrm{CE}\nu \mathrm{NS}$cross section on Xe of $\left({1.1}_{-0.5}^{+0.8}\right)\times {10}^{-39}{\mathrm{cm}}^2$is consistent with the Standard Model prediction. This is the first direct measurement of nuclear recoils from solar neutrinos with a dark matter detector. Published by the American Physical Society2024 

   more » « less
3. Ultrahigh-energy Cosmic Rays from Neutrino-emitting Tidal Disruption Events

   https://doi.org/10.3847/1538-4357/adef3b  

   Plotko, Pavlo; Winter, Walter; Lunardini, Cecilia; Yuan_袁, Chengchao_成 超 (December 2025, The Astrophysical Journal)

   Abstract We revisit ultrahigh-energy cosmic-ray (UHECR) production in tidal disruption events (TDEs) in light of recent evidence of neutrino-TDE associations. We use an isotropically emitting source-propagation model, which has been developed to describe the neutrino production in AT2019dsg, AT2019fdr, and AT2019aalc. These TDEs have strong dust echoes in the infrared (IR) range, which are potentially linked to the neutrino production. A mechanism where neutrinos originate from cosmic-ray (CR) scattering on IR photons implies CRs in the ultrahigh-energy range, thus suggesting a natural connection with the observed UHECR. We extrapolate the three TDE associations to a population of neutrino- and UHECR-emitting TDEs, and postulate that these TDEs power the UHECRs. We then infer the source composition, population parameters, and local rates that are needed to describe UHECR data. We find that UHECR data point toward a mix of light to mid-heavy injection isotopes, which could be found, e.g., in oxygen-neon-magnesium white dwarfs, and to a contribution of at least two groups of TDEs with different characteristics, dominated by AT2019aalc-type events. The required local TDE rates of $\mathcal{O}\left(10^2\right){\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$, however, are more indicative of the disruption of main-sequence stars. We propose an enhanced efficiency in the acceleration of heavier nuclei that could address this discrepancy. The predicted diffuse neutrino fluxes suggest a population of astrophysical neutrino sources that can be observed by future radio neutrino detection experiments. The derived source parameters are consistent with those expected from the individual neutrino observations. 

   more » « less
4. Limits on Astrophysical Antineutrinos with the KamLAND Experiment

   https://doi.org/10.3847/1538-4357/ac32c1  

   Abe, S.; Asami, S.; Gando, A.; Gando, Y.; Gima, T.; Goto, A.; Hachiya, T.; Hata, K.; Hayashida, S.; Hosokawa, K.; et al (January 2022, The Astrophysical Journal)

   Abstract We report on a search for electron antineutrinos ( ${\overline{\nu }}_e$) from astrophysical sources in the neutrino energy range 8.3–30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60–110 cm⁻²s⁻¹(90% confidence level, CL) in the analysis range and present a model-independent flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improve on the upper probability limit of⁸B solar neutrinos converting into ${\overline{\nu }}_e$, $P_{{\nu }_e\to {\overline{\nu }}_e}<3.5\times {10}^{-5}$(90% CL) assuming an undistorted ${\overline{\nu }}_e$shape. This corresponds to a solar ${\overline{\nu }}_e$flux of 60 cm⁻²s⁻¹(90% CL) in the analysis energy range. 

   more » « less
5. First Measurement of the Muon Neutrino Interaction Cross Section and Flux as a Function of Energy at the LHC with FASER

   https://doi.org/10.1103/PhysRevLett.134.211801  

   Abraham, Roshan Mammen; Ai, Xiaocong; Anders, John; Antel, Claire; Ariga, Akitaka; Ariga, Tomoko; Atkinson, Jeremy; Bernlochner, Florian U; Boeckh, Tobias; Boyd, Jamie; et al (May 2025, Physical Review Letters)

   This Letter presents the measurement of the energy-dependent neutrino-nucleon cross section in tungsten and the differential flux of muon neutrinos and antineutrinos. The analysis is performed using proton-proton collision data at a center-of-mass energy of 13.6 TeV and corresponding to an integrated luminosity of $(65.6\pm 1.4){\mathrm{fb}}^{-1}$. Using the active electronic components of the FASER detector, $338.1\pm 21.0$charged current muon neutrino interaction events are identified, with backgrounds from other processes subtracted. We unfold the neutrino events into a fiducial volume corresponding to the sensitive regions of the FASER detector and interpret the results in two ways: (i) we use the expected neutrino flux to measure the cross section, and (ii) we use the predicted cross section to measure the neutrino flux. Both results are presented in six bins of neutrino energy, achieving the first differential measurement in the TeV range. The observed distributions align with standard model predictions. Using this differential data, we extract the contributions of neutrinos from pion and kaon decays. Published by the American Physical Society2025 

   more » « less