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We examine the role of refractory organics as a major C carrier in the outer protosolar nebula and its implications for the compositions of large Kuiper Belt objects (KBOs) and CI chondrites. By utilizing Rosetta measurements of refractory organics in comet 67P/Churyumov–Gerasimenko, we show that they would make up a large fraction of the protosolar C inventory in the KBO-forming region based on the current widely adopted solar abundances. However, this would free up too much O to form water ice, producing solid material that is not sufficiently rock-rich to explain the uncompressed density of the Pluto–Charon system and other large KBOs; the former has been argued as the most representative value we have for the bulk composition of large KBOs. This inconsistency further highlights the solar abundances problem—an ongoing challenge in reconciling spectroscopically determined heavy-element abundances with helioseismology constraints. By employing a new data set from solar CNO neutrinos and solar wind measurements of C, N, and O, we show that the uncompressed density of the Pluto–Charon system can be reproduced over a wide range of scenarios. We show that a lack of sulfates in Ryugu and Bennu samples implies a lower amount of water ice initially accreted into CI chondrite parent bodies than previously thought. These data are found to be consistent with the solar C/O ratio implied by the new data set. Our predictions can be tested by future neutrino, helioseismology, and cosmochemical measurements. [ABSTRACT FROM AUTHOR]

We analytically determine neutrino transitional probabilities and abundance ratios at various distances from the source of creation in several astrophysical contexts, including the Sun, supernovae and cosmic rays. In doing so, we determine the probability of a higher-order transition state from ν τ → ν λ , where ν λ represents a more massive generation than Standard Model neutrinos. We first calculate an approximate cross-section for high-energy neutrinos which allows us to formulate comparisons for the oscillation distances of solar, supernova and higher-energy cosmic ray neutrinos. The flavor distributions of the resulting neutrino populations from each source detected on Earth are then compared via fractional density charts. [ABSTRACT FROM AUTHOR]

Cygnus is a proposed global network of large-scale gas time projection chambers (TPCs) with the capability of directionally detecting nuclear and electron recoils at ≳ keV energies. The primary focus of Cygnus so far has been the detection of dark matter, with directional sensitivity providing a means of circumventing the so-called "neutrino fog". However, the excellent background rejection and electron/nuclear recoil discrimination provided by the 3-dimensional reconstruction of ionisation tracks could turn the solar neutrino background into an interesting signal in its own right. For example, directionality would facilitate the simultaneous spectroscopy of multiple different flux sources. Here, we evaluate the possibility of measuring solar neutrinos using the same network of gas TPCs built from 10 m 3 -scale modules operating under conditions that enable simultaneous sensitivity to both dark matter and neutrinos. We focus in particular on electron recoils, which provide access to low-energy neutrino fluxes like pp, pep, 7 Be, and CNO. An appreciable event rate is already detectable in experiments consisting of a single 10 m 3 module, assuming standard fill gases such as CF 4 mixed with helium at atmospheric pressure. With total volumes around 1000 m 3 or higher, the TPC network could be complementary to dedicated neutrino observatories, whilst entering the dark-matter neutrino fog via the nuclear recoil channel. We evaluate the required directional performance and background conditions to observe, discriminate, and perform spectroscopy on neutrino events. We find that, under reasonable projections for planned technology that will enable 10–30-degree angular resolution and ∼ 10 % fractional energy resolution, Cygnus could be a competitive directional neutrino experiment. [ABSTRACT FROM AUTHOR]

In this work, first of all, a number of hidden aspects of the concept of particle oscillations are analyzed. The key element of this concept, which does not comply with the principle of least action, is the notion of a mixture of particles, introduced by Gell–Mann, and Pais for neutral K$K$‐mesons. It is proven that the law of conservation of energy‐momentum in the processes of electron neutrino production does not allow solving the problem of solar neutrinos based on the assumption of Gribov and Pontecorvo about their oscillations. It is established that the consequences of Wolfenstein's equation contradict the results of the SNO and Super‐Kamiokande collaborations and that the assertion by Mikheev and Smirnov on the conversion of solar neutrinos is erroneous. Another part of the work is devoted to a logically clear solution to this problem based on the hypothesis of the existence of a new interaction, the carrier of which is a massless pseudoscalar boson, which has a Yukawa coupling with electron neutrinos and nucleons. At each act of interaction of an electron neutrino with the nucleons of the Sun, caused by such interaction, the handedness of the neutrino changes from left to right and vice versa, and also the neutrino energy decreases. The hypothesis provides good agreement between the theoretical and experimental values of the rates of all five observed processes with solar neutrinos. This serves as a significant criterion for both the confidence of such a solution to the problem of solar neutrinos and the confidence of the existence of a new interaction. The problem of solar neutrinos discovered by Davis allows for one of two fundamentally different solutions. The neutrino oscillation assumption, put forward by Gribov and Pontecorvo, considers electron neutrinos as mixtures of two new massive neutrinos. The notion of a mixture of particles, introduced earlier by Gell–Mann, and Pais, contradicts the principles of classical logic. The Gribov–Pontecorvo assumption is not confirmed by numbers reflecting a comparison of theoretical and experimental results for each of the five observed processes with solar neutrinos. Another solution is based on the hypothesis about the existence of a new interaction involving electron neutrinos and nucleons. In its implementation, logically clear methods of classical quantum field theory are used. The obtained good agreement between theoretical and experimental numbers for all five observed processes. [ABSTRACT FROM AUTHOR]

The Borexino experiment has developed, in its 32 years of activity, techniques and methods that allow for unprecedented radiopurity levels, which continue to be the current state of the art. These pioneering techniques and methods represent a new standard for ultra-low-background physics, a legacy that Borexino leaves to future experiments studying low-energy neutrinos and searching for rare events with detectors operating deep underground. The Borexino experiment leaves an equally influential scientific legacy with its discoveries and precise measurements of the nuclear processes that cause the Sun and stars to shine. Thanks to its unparalleled low background in the energy window of ∼150 keV to ∼15 MeV, the Borexino experiment also has contributed significantly to the understanding of neutrino oscillations with the observation of the energy-dependent matter to vacuum-dominated flavor conversion probability of solar neutrinos. Along with this textbook-quality body of solar neutrino results, the Borexino experiment has contributed to the study of the Earth's mantle radioactivity with background-free measurements of geoneutrinos. This article presents an overview of the long-lasting Borexino results and of the experimental efforts required to achieve them. [ABSTRACT FROM AUTHOR]

This study investigates the clustering and bias of Luminous Red Galaxies (LRG) in the BOSS-LOWZ, -CMASS, -COMB, and eBOSS samples, using two types of simulated lightcones: (i) high-fidelity lightcones from Uchuu N -body simulation, employing SHAM technique to assign LRG to (sub)haloes, and (ii) 16 000 covariance lightcones from GLAM-Uchuu N -body simulations, including LRG using HOD data from Uchuu. Our results indicate that Uchuu and glam lightcones closely replicate BOSS/eBOSS data, reproducing correlation function and power spectrum across scales from redshifts 0.2 to 1.0, from 2 to |$150 \,h^{-1}\,\mathrm{Mpc}$| in configuration space, from 0.005 to |$0.7\, h\,\mathrm{Mpc}^{-1}$| in Fourier space, and across different LRG stellar masses. Furthermore, comparing with existing MD-Patchy and EZmock BOSS/eBOSS lightcones based on approximate methods, our GLAM-Uchuu lightcones provide more precise clustering estimates. We identify significant deviations from observations within |$20 \,h^{-1}\,\mathrm{Mpc}$| scales in MD-Patchy and EZmock , with our covariance matrices indicating that these methods underestimate errors by between 10 per cent and 60 per cent. Lastly, we explore the impact of cosmology on galaxy clustering. Our findings suggest that, given the current level of uncertainties in BOSS/eBOSS data, distinguishing models with and without massive neutrino effects on large-scale structure (LSS) is challenging. This paper highlights the Uchuu and GLAM-Uchuu simulations' robustness in verifying the accuracy of Planck cosmological parameters, providing a strong foundation for enhancing lightcone construction in future LSS surveys. We also demonstrate that generating thousands of galaxy lightcones is feasible using N -body simulations with adequate mass and force resolution. [ABSTRACT FROM AUTHOR]

Low fluxes of astrophysical neutrinos at TeV energies, and the overwhelming background of atmospheric neutrinos below that, render the current paradigm of neutrino astronomy a severely statistics-limited one. While many hints have emerged, all the evidence gathered by IceCube and ANTARES, over the course of almost a decade and a half of operation, has fallen short of providing any conclusive answer to the puzzle of the origin of high-energy cosmic rays and neutrinos. The advancement of the field is thus closely associated with not only the neutrino observatories coming online in the next few years, but also on the coordinated efforts of the EM, GW and cosmic ray communities to develop dedicated channels and infrastructure that allow for the swift and comprehensive multi-messenger follow-up of relevant events detected in any of these sectors. This paper highlights the strides that have been already taken in that direction and the fruits that they have borne, as well as the challenges that lie ahead. [ABSTRACT FROM AUTHOR]

Solar energetic particles (SEPs) are bursts of high-energy particles that originate from the Sun and can last for hours or even days. The aim of this study is to understand how the characteristics of energetic particles ware affected by the characteristic parameters of corotating interaction regions (CIRs). In particular, the particle intensity distribution with time and space in CIRs with different characteristics were studied. The propagation and acceleration of particles were described by the focused transport equation (FTE). We used a three-dimensional magnetohydrodynamic (MHD) model to simulate the background solar wind with CIRs. By changing the inner boundary conditions, we constructed CIRs with different solar wind speeds, angles between the polar axis and rotation axis, and the azimuthal widths of the fast streams. Particles were impulsively injected at the inner boundary of the MHD model. We then studied the particle propagation and compression acceleration in different background solar wind. The results showed that the CIR widths are related to the solar wind speed, tilt angles, and the azimuthal widths of the fast stream. The acceleration of particles in the reverse and forward compression regions are mainly influenced by the solar wind speed difference and the slow solar wind speed, respectively. Particles with lower energy (sub-MeV) are more sensitive to the solar wind speed difference and the tilt angle. The particle intensity variation with time and the radial distance is mainly influenced by the solar wind speed. The longitudinal distribution of particle intensity is affected by the solar wind speed, tilt angles, and the azimuthal widths of the fast stream. [ABSTRACT FROM AUTHOR]

The interaction of solar neutrinos with the 128Te and 130Te isotopes was studied taking into account the resonance structure of charge-exchange strength functions S(E). An analysis was made of both experimental data on the strength functions S(E) obtained in the reactions (3He, t) and the strength functions S(E) calculated in the microscopic theory of finite Fermi systems. The resonance structure of the S(E) strength function was investigated, and the Gamow–Teller, analog, and pygmy resonances were identified. The capture cross sections σ(E) of solar neutrinos by the two isotopes were calculated with consideration of the resonance structure of the strength function S(E), and the influence of the resonances on the energy dependence σ(E) was analyzed. It was shown that, when calculating the cross section σ(E), the resonance structure of the strength function S(E) should be taken into account. [ABSTRACT FROM AUTHOR]

We present a study on the superconducting properties of 500 nm thick NbTiN films grown by reactive co-sputtering on silicon substrates at room temperature. The samples exhibit a chemical composition with Nb (50 at.%) and Ti (50 at.%), revealing a polycrystalline structure characterized by columnar growth and an average lateral grain size of approximately 40 nm. The superconducting critical temperature (Tc) was measured at 13.8 K, and the upper critical field extrapolated to zero temperature reached 22 T, resulting in a coherence length (ξ) of 3.8 nm. The penetration depth (λ) was determined through local magnetic force microscopy measurements conducted at temperatures of 4.25 and 6 K. The obtained values were 400 (15) nm at 4.25 K and 430 (15) nm at 6 K. Extrapolating these measurements to zero temperature, we obtained an estimated value of 380 nm. A comparison was made with samples that underwent thermal annealing at 700 °C, resulting in a reduction of disorder at the nanoscale and an increase in Tc to 14.2 K. Despite this enhancement, the coherence length ξ (0) remained at approximately 3.8 nm, with no appreciable changes in the λ values. Our findings contribute to understanding fundamental superconducting parameters in nitride thin films, with potential applications ranging from resonant accelerator cavities to Josephson junctions and radiation detectors. [ABSTRACT FROM AUTHOR]

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Isabella Stengers' book "Virgin Mary and the Neutrino: Reality in Trouble" explores the intersection of science, belief, and capitalism, highlighting the challenges of scientific practice and public concerns. Stengers emphasizes the importance of humility in scientific endeavors, using the example of neutrinos to illustrate the complexities of scientific discovery and the sociological realities that shape knowledge. She also draws parallels between scientific practices and pilgrimages to the Virgin Mary, advocating for an inclusive understanding of reason that values diverse perspectives. Stengers' work encourages readers to critically engage with the complexities of scientific progress and societal concerns, offering valuable insights for those interested in the philosophy of science. [Extracted from the article]

We present a set of 1194 Type-1 Rosseland-mean opacity tables for four different metallicity mixtures. These new Los Alamos OPLIB atomic radiative opacity tables are an order of magnitude larger in number than any previous opacity table release, and span regimes where previous opacity tables have not existed. For example, the new set of opacity tables expands the metallicity range to Z = 10−6 to Z = 0.2, which allows improved accuracy of opacities at low and high metallicity, increases the table density in the metallicity range Z = 10−4 to Z = 0.1 to enhance the accuracy of opacities drawn from interpolations across neighboring metallicities, and adds entries for hydrogen mass fractions between X = 0 and X = 0.1 including X = 10−2, 10−3, 10−4, 10−5, 10−6 that can improve stellar models of hydrogen deficient stars. We implement these new OPLIB radiative opacity tables in MESA and find that calibrated solar models agree broadly with previously published helioseismic and solar neutrino results. We find differences between using the new 1194 OPLIB opacity tables and the 126 OPAL opacity tables range from ≈20% to 80% across individual chemical mixtures, up to ≈8% and ≈15% at the bottom and top of the solar convection zone respectively, and ≈7% in the solar core. We also find differences between standard solar models using different opacity table sources that are on par with altering the initial abundance mixture. We conclude that this new, open-access set of OPLIB opacity tables does not solve the solar modeling problem, and suggest the investigation of physical mechanisms other than the atomic radiative opacity. [ABSTRACT FROM AUTHOR]

The large-scale structure of the Universe is distributed in a cosmic web. Studying the distribution and clustering of dark matter particles and haloes may open up a new horizon for studying the physics of the dark Universe. In this work, we investigate the nearest neighbour statistics and spherical contact function in cosmological models with massive neutrinos. For this task, we use the relativistic N -body code, gevolution, and study particle snapshots at three different redshifts. In each snapshot, we find the haloes and evaluate the letter functions for them. We show that a generic behaviour can be found in the nearest neighbour, G (r), and spherical contact functions, F (r), which makes these statistics promising tools to constrain the total neutrino mass. [ABSTRACT FROM AUTHOR]

The paper studies the electron irradiation at an energy of 30 keV affecting the diffuse-reflectance spectra and integrated absorption coefficient of solar irradiance of the micron-sized mZnO powder modified by adding nY2O3 nanoparticles in the amount of 0.1 to 10 wt.%. The best content of nanoparticles is found to be 3 wt.%, when the diffuse-reflectance spectra and the integrated absorption coefficient of the modified powder are 1.41 times lower than in the initial powder. It is shown that free electrons forming during the powder irradiation, make the highest contribution to the powder degradation. [ABSTRACT FROM AUTHOR]

The Hyper-Kamiokande (Hyper-K) project is the world's leading international neutrino and nucleon decay experiment comprising a next-generation underground water Cherenkov detector and upgraded Japan Proton Accelerator Research Complex (J-PARC) neutrino beam. It will provide an enormous potential to discover the leptonic charge-parity violation, to investigate the Grand Unified Theory by proton decay exploration, and to determine the neutrino mass ordering. Further, Hyper-K will significantly enhance the capability to observe solar neutrinos and neutrinos from other astronomical sources in comparison with its predecessors. After the budget approval in January 2020, the Hyper-K project officially began, and the operation is expected to start in 2027. The excavations of a 2.0 km long access tunnel and the tunnels for the detector facility have been completed. In October 2022 it was started the excavation of one of the world's largest underground caverns to suite the HK detector. This article discusses the status and the prospects of the Hyper-K detector construction. [ABSTRACT FROM AUTHOR]

The sequence for overcoming the threshold values of a number of physical characteristics for proton event forecasting in real time is discussed. Each characteristic adds a new physical meaning that refines the forecast. To take into account all the characteristics, the following continuous patrol observations are necessary: (1) the magnetic field of the active region (ascent of the flux) and the total magnetic field of the Sun, which can predict the onset of flare activity several days prior to main events; (2) soft X-ray radiation in two channels to calculate the temperature (T) and emission measure of plasma, which can show preheating to T > 10 MK required to begin proton acceleration (the first few minutes before the start of hard X-ray (HXR) radiation with energies >100 keV); (3) HXR radiation >100 keV or microwave radiation (>3 GHz), which indicates the intensity and duration of operation of the electron accelerator (a few to tens of minutes before the arrival of protons with energies >100 MeV); (4) radio emission at plasma frequencies (<1000 MHz), showing the development of the flare process upward into the corona and leading to a coronal mass ejection (CME) several minutes before the onset of type II and IV radio bursts (the first tens of minutes before the appearance of a CME in the field of view of the coronagraph); (5) the direction and velocity of CME propagation, which determine the conditions to release accelerated protons into the heliosphere. These stages of solar proton flares are illustrated by observations of proton events on August 2–9, 2011. To quantitatively predict the onset time, maximum and magnitude of the proton flux, as well as its fluence, it is necessary to create statistical regression models based on all of the listed characteristics of past solar proton events. [ABSTRACT FROM AUTHOR]

The results of studying the fluxes of solar protons with energies greater than 5 MeV in near-Earth space on March 13–23, 2023, are presented. The features of the period under study are no visible solar flare with which the beginning of the event could be associated and an untypical time profile of proton fluxes, as well as a long duration of the existence of solar proton fluxes in near-Earth space. An attempt was made to explain the sources of the observed different variations in particle fluxes and to understand what happened on the Sun and in the near-Earth space. The source of solar protons on March 13, 2023, was an explosive process on the back side of the Sun from the Earth, registered as a coronal mass ejection of very high power. The reason for the long and complex time profile of solar protons was the contribution of particle acceleration processes on the Sun and in the interplanetary medium, as well as the modulation of particle fluxes by the structures of the interplanetary magnetic field. A possible scenario has been proposed to explain the existence of increased fluxes of solar particles on March 15–23, 2023: the formation of a heliospheric structure, this being a closed trap region formed by two interplanetary coronal mass ejections and regions of interaction of high-speed and slow solar wind streams. The study uses experimental data obtained from the Solar Orbiter spacecraft and from spacecraft located near the L1 point of the Earth–Sun system (ACE and DSCOVR) and in geostationary orbit (GOES-16). [ABSTRACT FROM AUTHOR]

A solar still is a device that uses sun energy to convert brackish or salted water into drinkable water and its distillate output is lower. In addition, it is the primary issue with the solar still; thus, researchers are looking for fresh ideas to raise the distillate output. The primary goal of this study is to examine the effects of mixing different weight concentrations (5%, 10%, 15%, and 20%) of toner waste powder (TWP) nanoparticles with black paint on distillate output and energy–exergy efficiency analysis. Two solar stills of similar dimensions have been used in the current study from February to March 2023 at Palanpur, Gujarat, India. Basin water, inner glass surface temperature, distillate output, and intensity of solar radiation are all monitored hourly for solar stills. This research indicates that the application of TWP coating to absorber plates increased the distillate output, and the highest distillate output of 955 ml was achieved at 10 wt. % concentration of nanoparticles, which is 40.03% higher than a conventional solar still (CSS) and 33.38%, 10.40%, and 30.64% higher than 5, 15, and 20 wt. % concentrations of nanoparticles at the same water depth, respectively. In addition, it was discovered that adding TWP to the solar still enhanced energy and exergy efficiency. Based on this research, it can be concluded that TWP is a suitable, inexpensive resource to boost energy and exergy efficiency and distillate output of solar still. [ABSTRACT FROM AUTHOR]

Most ionospheric models cannot sufficiently reproduce the observed electron density profiles in the E-region ionosphere, since they usually underestimate electron densities and do not match the profile shape. Mitigation of these issues is often addressed by increasing the solar soft X-ray flux which is ineffective for resolving data-model discrepancies. We show that low-resolution cross sections and solar spectral irradiances fail to preserve structure within the data, which considerably impacts radiative processes in the E-region, and are largely responsible for the discrepancies between observations and simulations. To resolve data-model inconsistencies, we utilize new high-resolution (0.001 nm) atomic oxygen (O) and molecular nitrogen (N2) cross sections and solar spectral irradiances, which contain autoionization and narrow rotational lines that allow solar photons to reach lower altitudes and increase the photoelectron flux. This work improves upon Meier et al. (2007, https://doi.org/10.1029/2006gl028484) by additionally incorporating high-resolution N2 photoionization and photoabsorption cross sections in model calculations. Model results with the new inputs show increased O+ production rates of over 500%, larger than those of Meier et al. (2007, https://doi.org/10.1029/2006gl028484) and total ion production rates of over 125%, while N2+ production rates decrease by ~15% in the E-region in comparison to the results obtained using the cross section compilation from Conway (1988, https://apps.dtic.mil/sti/pdfs/ADA193866.pdf). Low-resolution molecular oxygen (O2) cross sections from the Conway compilation are utilized for all input cases and indicate that O2+ is a dominant contributor to the total ion production rate in the E-region. Specifically, the photoionization contributed from longer wavelengths is a main contributor at ~120 km. [ABSTRACT FROM AUTHOR]

Ultra-low-radioactivity titanium alloys are promising materials for the manufacture of low-background detectors which are being developed for experiments in astroparticle physics and neutrino astrophysics. Structural titanium is manufactured on an industrial scale from titanium sponge. The ultra-low-background titanium sponge can be produced on an industrial scale with a contamination level of less than 1 mBq/kg of uranium and thorium isotopes. The pathways of contaminants during the industrial production of structural titanium were analyzed. The measurements were carried out using two methods: inductively coupled plasma mass spectroscopy (ICP-MS) and gamma spectroscopy using high-purity germanium detectors (HPGes). It was shown that the level of contamination with radioactive impurities does not increase during the remelting of titanium sponge and mechanical processing. We examined titanium alloy samples obtained at different stages of titanium production, namely an electrode compaction, a vacuum arc remelting with a consumable electrode, and a cold rolling of titanium sheets. We found out that all doped samples that were studied would be a source of uranium and thorium contamination in the final titanium alloys. It has been established that the only product allowed obtaining ultra-low-background titanium was the commercial VT1-00 alloy, which is manufactured without master alloys addition. The master alloys in the titanium production process were found cause U/Th contamination. [ABSTRACT FROM AUTHOR]

In the past decade, dual-phase xenon time projection chambers (Xe-TPCs) have emerged as some of the most powerful detectors in the fields of astroparticle physics and rare-event searches. Developed primarily towards the direct detection of dark matter particles, experiments presently operating deep underground have reached target masses at the multi-tonne scale, energy thresholds of approximately 1 keV and radioactivity-induced background rates similar to those from solar neutrinos. These unique properties, together with demonstrated stable operation over several years, allow for the exploration of new territory via high-sensitivity searches for a plethora of ultra-rare interactions. These include searches for particle dark matter, for second-order weak decays, and the observation of astrophysical neutrinos. We first review some properties of xenon as a radiation detection medium and the operation principles of dual-phase Xe-TPCs together with their energy calibration and resolution. We then discuss the status of currently running experiments and of proposed next-generation projects, describing some of the technological challenges. We end by looking at their sensitivity to dark matter candidates, to second-order weak decays and to solar and supernova neutrinos. Experiments based on dual-phase Xe-TPCs are difficult and, like all good experiments, they are constantly pushed to their limits. Together with many other endeavours in astroparticle physics and cosmology they will continue to push at the borders of the unknown, hopefully to reveal profound new knowledge about our cosmos. This article is part of the theme issue 'The particle-gravity frontier'. [ABSTRACT FROM AUTHOR]

Being one of the most mysterious particles of the Standard Model, neutrinos have opened up new opportunities for astrophysical research. The high penetrating power of neutrinos provides insight into stellar interior and makes it possible to study the mechanisms of the origin of ultra-high energy cosmic rays. When a star explodes, a neutrino flare informs us about this event several hours earlier than electromagnetic radiation. Neutrino also plays a crucial role in cosmology, being the second most abundant known particle in the Universe. In the radiation-dominated epoch, neutrinos together with photons, determine the dynamics of the expansion of the Universe. Later, becoming nonrelativistic, the neutrinos increase the contribution Ωm of nonrelativistic matter, which previously consisted of cold dark matter and baryonic matter. Since neutrinos affect the course of the evolution of the Universe, this fact should be taken into account when determining cosmological parameters. Recently, in addition to relic neutrinos from the Big Bang, antineutrinos of primordial nucleosynthesis have been theoretically predicted. Their detection could be additional evidence for baryon asymmetry of the Universe. Current results from a number of independent experiments indicate the possibility of the existence of a light sterile neutrino (mν ~ 1–3 eV). The presence of such a neutrino is in poor agreement with the predictions of the Standard Cosmological Model, but these contradictions can be removed by its extension, for example, by the existence of a nonzero lepton asymmetry ξν ~ 10−2 of the Universe. Nowadays, there are little doubts about the existence of cosmological neutrinos, but unfortunately it is not yet possible to detect them directly due to the extremely small cross section of their interaction at low energies. However, if this can be done in the future, we will obtain direct information about the first seconds, minutes, and hours of the evolution of the Universe after the Big Bang. A review of key aspects related to the influence of cosmological neutrinos on the evolution of the Universe at different stages from the early Universe (primordial nucleosynthesis and primordial recombination) to present days is given. [ABSTRACT FROM AUTHOR]

We present PEANUTS (Propagation and Evolution of Active NeUTrinoS), an open-source Python package for the automatic computation of solar neutrino spectra and active neutrino propagation through Earth. PEANUTS is designed to be fast, by employing analytic formulae for the neutrino propagation through varying matter density, and flexible, by allowing the user to input arbitrary solar models, custom Earth density profiles and general detector locations. It provides functionalities for a fully automated simulation of solar neutrino fluxes at a detector, as well as access to individual routines to perform more specialised computations. The software has been extensively tested against the results of the SNO experiment, providing excellent agreement with their results. In addition, the present text contains a pedagogical derivation of the relations needed to compute the oscillated solar neutrino spectra, neutrino propagation through Earth and nadir exposure of an experiment. [ABSTRACT FROM AUTHOR]

Nonlinear gravitational evolution induces strong nonlinearities in the observed cosmological density fields, leading to positive off-diagonal correlations in the power spectrum covariance. This has caused the information saturation in the power spectrum, e.g., the neutrino mass constraints from the nonlinear power spectra are lower than their linear counterparts by a factor of ∼2 at z = 0. In this paper, we explore how nonlinear reconstruction methods improve the cosmological information from nonlinear cosmic fields. By applying nonlinear reconstruction to cold dark matter fields from the Quijote simulations, we find that nonlinear reconstruction can improve the constraints on cosmological parameters significantly, nearly reaching the linear theory limit. For neutrino mass, the result is only 12% lower than the linear power spectrum, i.e., the theoretical best result. This makes nonlinear reconstruction an efficient and useful method to extract neutrino information from current and upcoming galaxy surveys. [ABSTRACT FROM AUTHOR]

We present in this paper a public data release of an unprecedentedly large set of core-collapse supernova (CCSN) neutrino emission models, comprising 100 detailed 2D axisymmetric radiation-hydrodynamic simulations evolved out to as late as ∼5 s post-bounce and spanning an extensive range of massive-star progenitors. The motivation for this paper is to provide a physically and numerically uniform benchmark data set to the broader neutrino detection community to help it characterize and optimize subsurface facilities for what is likely to be a once-in-a-lifetime galactic supernova burst event. With this release, we hope to (1) help the international experiment and modelling communities more efficiently optimize the retrieval of physical information about the next galactic CCSN, (2) facilitate the better understanding of core-collapse theory and modelling among interested experimentalists, and (3) help further integrate the broader supernova neutrino community. [ABSTRACT FROM AUTHOR]

The trimaximal mixing scheme is one of the widely studied neutrino mixing schemes. However, the predicted solar neutrino mixing angle θ 1 2 and the reactor neutrino mixing angle θ 1 3 cannot simultaneously realize their best-fit values. To address this issue, a minimal modification to the trimaximal mixing scheme is proposed. The modified trimaximal mixing scheme can simultaneously predict the best-fit values of θ 1 2 and θ 1 3 using an additional real parameter introduced via the modification. [ABSTRACT FROM AUTHOR]

We explore the complementarity of direct detection (DD) and spallation source (SS) experiments for the study of sterile neutrino physics. We focus on the sterile baryonic neutrino model: an extension of the Standard Model that introduces a massive sterile neutrino with couplings to the quark sector via a new gauge boson. In this scenario, the inelastic scattering of an active neutrino with the target material in both DD and SS experiments gives rise to a characteristic nuclear recoil energy spectrum that can allow for the reconstruction of the neutrino mass in the event of a positive detection. We first derive new bounds on this model based on the data from the COHERENT collaboration on CsI and LAr targets, which we find do not yet probe new areas of the parameter space. We then assess how well future SS experiments will be able to measure the sterile neutrino mass and mixings, showing that masses in the range ~15 − 50 MeV can be reconstructed. We show that there is a degeneracy in the measurement of the sterile neutrino mixing that substantially affects the reconstruction of parameters for masses of the order of 40 MeV. Thanks to their lower energy threshold and sensitivity to the solar tau neutrino flux, DD experiments allow us to partially lift the degeneracy in the sterile neutrino mixings and considerably improve its mass reconstruction down to 9 MeV. Our results demonstrate the excellent complementarity between DD and SS experiments in measuring the sterile neutrino mass and highlight the power of DD experiments in searching for new physics in the neutrino sector. [ABSTRACT FROM AUTHOR]

Solar nuclear reactions can occasionally produce sub-MeV elusive beyond the Standard Model particles that escape the solar interior without further interactions. This study focuses on massive spin-one particles. We construct the general theoretical framework and identify two crucial mixing sources involving the photon, which facilitate communication between the hidden and visible sectors: kinetic mixing with the photon, and plasma-induced mixing due to thermal electron loops. For both cases, we focus on the second stage of the solar proton-proton chain and evaluate the fluxes of monochromatic 5.49 MeV hidden vectors produced by the p(d,3 He)γ′ nuclear reaction. We then investigate their terrestrial detection via Compton-like scatterings. The incoming fluxes are polarized, and we evaluate the cross sections for Compton-like scatterings for transverse and longitudinal vectors. Finally, we apply this framework to a concrete case by investigating the sensitivity of the forthcoming Jiangmen Underground Neutrino Observatory (JUNO) experiment and identifying parameter space where current terrestrial bounds will be improved. [ABSTRACT FROM AUTHOR]

The development of mutually reinforcing solar‐driven interfacial evaporation (SDIE) and integrated functional materials/systems to achieve efficient production of freshwater and energy/matters simultaneously under extremely high solar utilization is in high demand. Herein, an integrated SDIE reaction system (reduced graphene oxide (rGO)‐palladium (Pd) catalytic evaporator, rGO‐Pd) is first reported, where SDIE and the integrated catalytic reaction are mutually reinforced. The apparent utilization of solar to thermal energy by the integrated SDIE reaction system is a combination of evaporative utilization and catalytic utilization. The reaction heat released by the rGO‐Pd catalytic evaporator enhances its anti‐salt water production performance to a record of 12.7 L m−2 h−1, surpassing the reported performance of other integrated SDIE reaction systems. In the rGO‐Pd catalytic evaporator, the synergetic effect of photothermal and rapid mass transfer significantly increases the catalytic activity (turnover frequency) of Pd catalysts up to a record 125.07 min−1, which is about 3.75 times of the condition without light. This integrated SDIE reaction system can effectively and simultaneously produce freshwater, salt, and catalyzed chemicals after evaporating water to dryness. This study paves the way for SDIE's high‐performance applications in future integrated water, energy, and environmental systems. [ABSTRACT FROM AUTHOR]

The paper provides a general overview of the current state of solar research. [ABSTRACT FROM AUTHOR]

During a few solar energetic particle (SEP) events, solar protons were trapped within the geomagnetic field and reached the outer edge of the inner radiation belt. We reproduced this phenomenon by modeling the proton flux distribution at the Low‐Earth Orbit (LEO) for different geomagnetic conditions during solar particle events. We developed a three‐dimensional relativistic test particle simulation code to compute the 70–180 MeV solar proton Lorentz trajectories in low L‐shell range from 1 to 3. The Tsyganenko model (T01) generated the background static magnetic field with the IGRF (v12) model. We have selected three Dst index values: −7, −150, and −210 nT, to define quiet time, strong, and severe geomagnetic storms and to generate the corresponding inner magnetic field configurations. Our results showed that the simulated solar proton flux was more enhanced in the high‐latitude regions and more expanded toward the lower latitude range as long as the geomagnetic storm was intensified. Satellite observations and geomagnetic cutoff rigidities confirmed the numerical results. Furthermore, the LEO proton flux distribution was deformed, so the structure of the proton flux inside the South Atlantic Anomaly (SAA) became longitudinally extended as the Dst index decreased. Moreover, we have assessed the corresponding radiation environment of the LEO mission. We realized that, for a higher inclined LEO mission during an intense geomagnetic storm (Dst = −210 nT), the probability of the occurrence of the Single Event Upset (SEU) rates increased by 19% and the estimated accumulated absorbed radiation doses increased by 17% in comparison with quiet conditions. Plain Language Summary: Solar energetic particles are high‐energy particles emitted from the Sun during intense activity. When they reach the Earth, they become trapped in its magnetic field. In some cases, these trapped solar particles can penetrate deeper toward the Earth's surface when some fluctuations in the Earth's magnetic field occur. The impact of solar particles on satellite technologies and astronauts is significant and dangerous. In this work, we reproduced this phenomenon by developing a numerical code to calculate the solar proton trajectories inside the Earth's magnetic field according to several geomagnetic conditions. Our new results successfully produced the same physical process and did agree with other methodologies, such as satellite observations. Afterward, we estimated the resulting radiation environment of a Low‐Earth Orbit mission. We found that a satellite could suffer more radiation risks of around 20% if a Solar Energetic Particle event occurred during an intense geomagnetic storm. Key Points: We have numerically modeled the Low‐Earth Orbit proton flux due to precipitated solar protons for different geomagnetic storm conditionsOur test particle simulations reproduced the proton flux enhancement at high latitudes, agreeing with observations and cutoff rigiditiesDuring a stronger geomagnetic storm and solar energetic particle event, a spacecraft that enters the polar cap region would be subject to more radiation risks [ABSTRACT FROM AUTHOR]

Models of particle acceleration in solar eruptive events suggest that roughly equal energy may go into accelerating electrons and ions. However, while previous solar X-ray spectroscopic imagers have transformed our understanding of electron acceleration, only one resolved image of γ-ray emission from solar accelerated ions has ever been produced. This paper outlines a new satellite instrument concept—the large imaging spectrometer for solar accelerated nuclei (LISSAN)—with the capability not only to observe hundreds of events over its lifetime, but also to capture multiple images per event, thereby imaging the dynamics of solar accelerated ions for the first time. LISSAN provides spectroscopic imaging at photon energies of 40 keV–100 MeV on timescales of ≲10 s with greater sensitivity and imaging capability than its predecessors. This is achieved by deploying high-resolution scintillator detectors and indirect Fourier imaging techniques. LISSAN is suitable for inclusion in a multi-instrument platform such as an ESA M-class mission or as a smaller standalone mission. Without the observations that LISSAN can provide, our understanding of solar particle acceleration, and hence the space weather events with which it is often associated, cannot be complete. [ABSTRACT FROM AUTHOR]

In this work, we study the neutrino mixing sum rules arising from discrete symmetries and the class of Littlest Seesaw (LS) neutrino models. These symmetry-based approaches all offer predictions for the cosine of the leptonic CP phase  cos δ  in terms of the mixing angles,  θ 13 ,  θ 12 ,  θ 23 , while the LS models also predict the sine of the leptonic CP phase  sin δ , as well as making other predictions. In particular, we study the solar neutrino mixing sum rules, arising from charged lepton corrections to tri-bimaximal (TB), bimaximal (BM), golden ratio (GR) and hexagonal (HEX) neutrino mixing, and the atmospheric neutrino mixing sum rules, arising from preserving one of the columns of these types of mixing—for example, the first or second column of the TB mixing matrix (TM1 or TM2)—and we confront them with an up-to-date global fit of the neutrino oscillation data. We show that some mixing sum rules, such as an atmospheric neutrino mixing sum rule arising from a version of neutrino golden ratio mixing (GRa1), are already excluded at 3 σ , and we determine the remaining models allowed by the data. We also consider the more predictive LS models (which obey the TM1 sum rules and offer further predictions) based on constrained sequential dominance CSD(n) with  n ≈ 3 . We compare for the first time the three cases  n = 2.5 ,  n = 3  and  n = 1 + 6 ≈ 3.45 , which are favored by theoretical models, using a new type of analysis to accurately predict the observables  θ 12 ,  θ 23  and  δ. We study all the above approaches, solar and atmospheric mixing sum rules and LS models, together so that they may be compared and to give an up-to-date analysis of the predictions of all of these possibilities, when confronted with the most recent global fits. [ABSTRACT FROM AUTHOR]

Low background segmented liquid scintillator detector, doped with an indium as a target for solar neutrino registration, can be used for measuring total solar neutrino spectrum including neutrinos. A detector consisting of small modules filled with liquid scintillator in the volume of 1–2 L is considered. Silicon matrices are used for light collection. The background of indium beta-activity is suppressed by triple coincidences. The detector of such a type can measure Be neutrino flux with high accuracy and independently check the measurement performed by the Borexino Collaboration. [ABSTRACT FROM AUTHOR]

We analyze neutrino fluxes near the surface of a protoneutron star in type II supernova explosions. For magnetorotational explosion mechanism it is shown that effective neutrino collisions in a magnetized nucleon gas caused by the neutral current Gamow–Teller component lead to neutrino acceleration. Such an effect originates from spin-projection asymmetry in phase space volume of outer channel neutrino due to nucleon magnetic moment interaction with magnetic field. Respective increase in a hardness of the energy spectrum is favorable for observations of supernova neutrinos using neutrino telescopes. The possibilities of detecting supernova neutrinos by large-volume Cherenkov observatories—KM3NeT and Baikal-GVD—are discussed. As is demonstrated the upper limits of the distance thresholds for such observations can be increased by a factor of , when employing the -fold coincidence technique in data processing. [ABSTRACT FROM AUTHOR]

The LVD detector, located in the Gran Sasso Laboratory at a depth of 3600 m w.e., is designed for research in the field of neutrino physics, astrophysics, cosmic ray physics and the search for rare processes predicted by theory. The LVD experiment was built in 1991 to detect neutrinos from collapses of stellar nuclei in our galaxy. The background of the detector is atmospheric muons, neutrons generated by muons in the detector material and natural radioactivity underground. The report presents the latest experimental results obtained at LVD: a limit on the frequency of supernova outbreaks, muon variations with a period of 1, 4, 10 years, and also describes the problems of studying the low-energy background underground. [ABSTRACT FROM AUTHOR]