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1. Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

   https://doi.org/10.1140/epjc/s10052-021-09007-w  

   Abi, B. ; Acciarri, R. ; Acero, M. A. ; Adamov, G. ; Adams, D. ; Adinolfi, M. ; Ahmad, Z. ; Ahmed, J. ; Alion, T. ; Monsalve, S. Alonso ; et al ( April 2021 , The European Physical Journal C)

   null (Ed.)

   Abstract The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE’s sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach. 

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2. Development of ultra-pure gadolinium sulfate for the Super-Kamiokande gadolinium project

   https://doi.org/10.1093/ptep/ptac170  

   Hosokawa, K. ; Ikeda, M. ; Okada, T. ; Sekiya, H. ; Fernández, P. ; Labarga, L. ; Bandac, I. ; Perez, J. ; Ito, S. ; Harada, M. ; et al ( December 2022 , Progress of Theoretical and Experimental Physics)

   This paper reports the development and detailed properties of about 13 metric tons of gadolinium sulfate octahydrate, $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$, which has been dissolved into Super-Kamiokande (SK) in the summer of 2020. We evaluate the impact of radioactive impurities in $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ on diffuse supernova neutrino background searches and solar neutrino observation and confirm the need to reduce radioactive and fluorescent impurities by about three orders of magnitude from commercially available high-purity $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$. In order to produce ultra-high-purity $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$, we have developed a method to remove impurities from gadolinium oxide, Gd2O3, consisting of acid dissolution, solvent extraction, and pH control processes, followed by a high-purity sulfation process. All of the produced ultra-high-purity $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ is assayed by inductively coupled plasma mass spectrometry and high-purity germanium detectors to evaluate its quality. Because of the long measurement time of high-purity germanium detectors, we have employed several underground laboratories for making parallel measurements including the Laboratorio Subterráneo de Canfranc in Spain, Boulby in the UK, and Kamioka in Japan. In the first half of production, the measured batch purities were found to be consistent with the specifications. However, in the latter half, the $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ contained one order of magnitude more 228Ra than the budgeted mean contamination. This was correlated with the corresponding characteristics of the raw material Gd2O3, in which an intrinsically large contamination was present. Based on their modest impact on SK physics, they were nevertheless introduced into the detector. To reduce 228Ra for the next stage of gadolinium loading to SK, a new process has been successfully established.

    

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3. Harvesting BAT-GUANO with NITRATES (Non-Imaging Transient Reconstruction and Temporal Search): Detecting and Localizing the Faintest Gamma-Ray Bursts with a Likelihood Framework

   https://doi.org/10.3847/1538-4357/ac9d38  

   DeLaunay, James ; Tohuvavohu, Aaron ( December 2022 , The Astrophysical Journal)

   The detection of the gravitational wave (GW) counterpart GRB 170817A, underluminous compared to the cosmological gamma-ray burst (GRB) population by a factor of 10,000, motivates significant effort in detecting and localizing a dim, nearby, and slightly off-axis population of short GRBs. Swift’s Burst Alert Telescope (BAT) is one of the most sensitive GRB detectors in operation, and the only one that regularly localizes GRBs to arcminute precision, critical to rapid follow-up studies. However, the utility of BAT in targeted subthreshold searches had been historically curtailed by the unavailability of the necessary raw data for analysis. The new availability of time-tagged event data from the GUANO system motivates a renewed focus on developing sensitive targeted search analysis techniques to maximally exploit these data. While computationally cheap, we show that the typical coded-mask deconvolution imaging is limited in its sensitivity due to several factors. We formalize a maximum likelihood framework for the analysis of BAT data wherein signals are forward modeled through the full instrument response, and—coupled with the development of new response models—demonstrate its superior sensitivity to typical imaging via archival comparisons, injection campaigns, and a large number of low-latency GRB discoveries and confirmed arcminute localizations to date. We also demonstrate independent localization of some out-of-field-of-view GRBs for the first time. NITRATES’s increased sensitivity boosts the discovery rate of GRB 170817A–like events in BAT by a factor of at least 3−4×, along with enabling joint analyses and searches with other GRB, GW, neutrino, and FRB instruments. We provide public access to the response functions and search pipeline code.

    

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4. Theoretical Constraints on Neutron-Mirror-Neutron Oscillation

   https://doi.org/doi.org/10.3390/sym140407/31  

   K. S. Babu and R. N. Mohapatra ( April 2022 , Symmetry)

   Mirror models lead to the possibility that neutron (n) can oscillate into its mirror partner (n′), inspiring several experimental searches for this phenomenon. The condition for observability of this oscillation is a high degree of degeneracy between the n and n′ masses, which can be guaranteed if there is exact parity symmetry taking all particles to their mirror partners. However, consistency of these models with big-bang nucleosynthesis requires that this parity symmetry be broken in the early universe in a scenario called asymmetric inflation. In this paper, we study the consistency of an observable n − n′ oscillations signal with asymmetric inflation and derive various theoretical constraints. In particular, we find that the reheat temperature after inflation should lie below 2.5 TeV, and we predict a singlet fermion with a mass below 100 GeV. In simple models, where the right-handed neutrino is a mediator of baryon-number-violating interactions, we find that the light neutrinos are Dirac fermions with their masses arising radiatively through one-loop diagrams 

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5. Squeezing the Parameter Space for Lorentz Violation in the Neutrino Sector with Additional Decay Channels

   https://doi.org/10.3390/particles3030041  

   Jentschura, Ulrich D. ( September 2020 , Particles)

   null (Ed.)

   The hypothesis of Lorentz violation in the neutrino sector has intrigued scientists for the last two to three decades. A number of theoretical arguments support the emergence of such violations, first and foremost for neutrinos, which constitute the “most elusive” and “least interacting” particles known to mankind. It is of obvious interest to place stringent bounds on the Lorentz-violating parameters in the neutrino sector. In the past, the most stringent bounds have been placed by calculating the probability of neutrino decay into a lepton pair, a process made kinematically feasible by Lorentz violation in the neutrino sector, above a certain threshold. However, even more stringent bounds can be placed on the Lorentz-violating parameters if one takes into account, additionally, the possibility of neutrino splitting, i.e., of neutrino decay into a neutrino of lower energy, accompanied by “neutrino-pair Čerenkov radiation.” This process has a negligible threshold and can be used to improve the bounds on Lorentz-violating parameters in the neutrino sector. Finally, we take the opportunity to discuss the relation of Lorentz and gauge symmetry breaking, with a special emphasis on the theoretical models employed in our calculations. 

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