Neutrino-nucleus cross-section measurements are critical for future neutrino oscillation analyses. However, our models to describe them require further refinement, and a deeper understanding of the underlying physics is essential for future neutrino oscillation experiments to realize their ambitious physics goals. Current neutrino cross-section measurements provide clear deficiencies in neutrino interaction modeling, but almost all are reported averaged over broad neutrino fluxes, rendering their interpretation challenging. Using the DUNE-PRISM concept (Deep Underground Neutrino Experiment Precision Reaction Independent Spectrum Measurement) – a movable near detector that samples multiple off-axis positions – neutrino interaction measurements can be used to construct narrow virtual fluxes (less than 100 MeV wide). These fluxes can be used to extract charged-current neutrino-nucleus cross sections as functions of outgoing lepton kinematics within specific neutrino energy ranges. Based on a dedicated simulation with realistic event statistics and flux-related systematic uncertainties, but assuming an almost-perfect detector, we run a feasibility study demonstrating how DUNE-PRISM data can be used to measure muon neutrino charged-current integrated and differential cross sections over narrow fluxes. We find that this approach enables a model independent reconstruction of powerful observables, including energy transfer, typically accessible only in electron scattering measurements, but that large exposures may be required for differential cross-section measurements with few-% statistical uncertainties.

In high energy Gamma-Ray Astronomy with shower arrays the most discriminating signature of the photon-induced showers against the background of hadron-induced cosmic-ray is the content of muons in the observed events. In the electromagnetic $\gamma$-showers the muon production is mainly due to the photo-production of pions followed by the decay $\pi\to\mu\nu$. In high energy photo-production process the photon exhibits an internal structure which is very similar to that of hadrons. Indeed, photon-hadron interactions can be understood if the physical photon is viewed as a superposition of a bare photon and an accompanying small hadronic component which feels conventional hadronic interactions. Information on photo-production $\gamma$p and $\gamma\gamma$ cross-sections are limited to $\sqrt{s}\leq$ 200 GeV from data collected at HERA. Starting from $E_{lab}\approx$100 TeV the difference between different extrapolations of the cross sections increases to more than 50\% at $E_{lab}\approx$10$^{19}$ eV, with important impact on a number of shower observables and on the selection of the photon-initiated air showers. Recently, the LHAASO experiment opened the PeV-sky to observations detecting 40 PeVatrons in a background-free regime starting from about $E_{lab}\approx$ 100 TeV. This result provides a beam of pure high energy primary photons allowing to measure for the first time the photo-production cross section even at energies not explored yet. The future air shower array SWGO in the Southern Hemisphere, where the existence of Super-Pevatrons emitting photons well above the PeV is expected, could extend the study of the hadron nature of the photons in the PeV region. In this contribution the opportunity for a measurement of the photo-production cross section with air shower arrays is presented and discussed.

Since the science white paper of the Large High Altitude Air Shower Observatory (LHAASO) published on arXiv in 2019 [e-Print: 1905.02773 (astro-ph.HE)], LHAASO has completed the transition from a project to an operational gamma-ray astronomical observatory LHAASO is a new generation multi-component facility located in Daocheng, Sichuan province of China, at an altitude of 4410 meters. It aims at measuring with unprecedented sensitivity the spectrum, composition, and anisotropy of cosmic rays in the energy range between 10$^{12}$ and 10$^{18}$~eV, and acting simultaneously as a wide aperture (one stereoradiant) continuously operating gamma-ray telescope in the energy range between 10$^{11}$ and $10^{15}$~eV with the designed sensitivity of 1.3\% of the Crab Unit (CU) above 100 TeV. LHAASO's capability of measuring simultaneously different shower components (electrons, muons, and Cherenkov/fluorescence light), will allow it to investigate the origin, acceleration, and propagation of CR through measurement of the energy spectrum, elemental composition, and anisotropy with unprecedented resolution. The remarkable sensitivity of LHAASO will play a key role in CR physics and gamma-ray astronomy for a general and comprehensive exploration of the high energy universe and will allow important studies of fundamental physics (such as indirect dark matter search, Lorentz invariance violation, quantum gravity) and solar and heliospheric physics. The LHAASO Collaboration organized an editorial working group and finished all editorial work of this science book, to summarize the instrumental features and outline the prospects of scientific researches with the LHAASO experiment.

Composition measurement of cosmic rays (CRs) around the knee of the CR energy spectrum is crucial for studying the processes of particle acceleration and propagation of Galactic CRs. The Square Kilometer Array (KM2A) of the Large High Altitude Air Shower Observatory (LHAASO) can provide precise measurement of the muonic and electromagnetic (em) components in CR-induced extensive air showers, and hence a good chance to disentangle the CR composition. Here we propose an approach of decomposing CR compositions with the number ratio between muons and em particles (N-mu/N-e) observed by LHAASOKM2A: We reconstruct the energy spectra of individual CR compositions by fitting the N-mu /N-e distributions in each reconstructed energy bin using the template shapes of the N-mu/N-e distributions of individual CR compositions based on Monte Carlo (MC) simulation. We evaluate the performance of this approach with MC tests where mock data of LHAASO-KM2A are generated by MC simulation. We show that the input composition model can be well recovered in this approach, independent of the CR composition model adopted in the MC simulation for the template distributions. The uncertainties of the reconstructed spectra at <20 PeV, mainly limited by simulation statistics, are <= 7% for the proton, He, and, Fe groups, and <= 8% and <= 16% for the carbon-nitrogen-oxygen and MgAlSi groups, respectively.

The fields of cosmic ray astrophysics, gamma-ray astrophysics, and neutrino astrophysics have diverged somewhat. But for the air showers in the GeV and TeV energy ranges, the ground-based detector techniques have considerable overlaps. VHE gamma-ray astronomy is the observational study measuring the directions, flux, energy spectra, and time variability of the sources of these gamma rays. With the low flux of gamma rays, and the background of charged particle cosmic rays, the distinguishing characteristic of gamma-ray air shower detectors is large size and significant photon to charge particle discrimination. Air shower telescopes for gamma-ray astronomy consist of an array of detectors capable of measuring the passage of particles through the array elements. To maximize signal at energies of a TeV or so, the array needs to be built at high altitude as the maximum number of shower particles is high in the atmosphere. These detectors have included sparse arrays of shower counters, dense arrays of scintillators or resistive plate counters (RPC), buried muon detectors in concert with surface detectors, or many-interaction-deep Water Cherenkov Detectors (WCD). In general these detectors are sensitive over a large field of view, the whole of the sky is a typical sensitivity and perhaps 2/3 of the sky selected for clean analysis, but with only moderate resolution in energy, typically due to shower-to-shower fluctuations and the intrinsic sampling of the detector. These telescopes though, operate continuously, despite weather, moonlight, day or night, and without needing to be pointed to a specific target for essentially a 100% duty cycle. In this chapter we will examine the performance and characteristics of such detectors. These are contrasted with the Imaging Air Cherenkov Telescopes which also operate in this energy range, and both current and future proposed experiments are described.

The recent discovery of PeV gamma-ray emission especially from the LHAASO observatory, located in the Northern hemisphere, boosted the relevance of observing the Southern sky at such energies. SWGO (SouthernWide-Field Gamma-Ray Observatory) is the largest proposed detector with sensitivity in the 100 TeV-1 PeV energy range. The baseline SWGO idea is a km^2 array of water tanks to be placed above 4,400ma.s.l. in the Andes, South America. In this contribution, we have studied the particle content and the morphology of Extensive Air Showers (EAS) generated by photons and protons in the 0.1 to 10 PeV energy range. We have simulated over 106 gamma-rays and proton induced showers respectively with primary energy in the 0.1-10 PeV energy range. We also show the particle distribution at ground, the lateral profile, the muon content and the average particle properties at ground.

The origin of cosmic ray (CR) spectral knee around ∼4 PeV is unknown. Composition studies around the knee can provide information on the CR sources and propagation. LHAASO-KM2A is capable of simultaneously measuring the EM and muonic components in extensive air showers. The triggered events of LHAASO-KM2A are dominated by CRs of higher energies at larger zenith angles because of the increasing atmospheric attenuation. In this work, we use the KM2A observed spectrum of muon-to-electron number ratio to constrain CR composition around the knee. The muon-to-electron number ratio spectra are compared between Monte Carlo (MC) simulation and experiment data over a wide zenith angle range. We report a MC excess at large zenith angles, which sets an upper limit on CR Fe flux at PeVs. Systematic uncertainties of interaction models and atmospheric models are briefly discussed.

Water-Cherenkov detectors (WCD) have been manufactured in Australia by the company AQUA-MATE as part of the RD activities for SWGO. They consist of a steel tank frame with a bladder on its interior satisfying the SWGO double-layer tank design. Tanks and bladders have been custom designed to optimally accommodate the bladder inside the tank and with minimal material usage. They are delivered in compact boxes that are easy to transport. These boxes are designed to fit 24 tanks in a 20-foot container. The double-layer tank design has introduced new features to improve the discrimination between gamma-rays and cosmic rays. Some of these features created challenges for the manufacturing. Some units have been delivered to one of Peru’s candidate sites at 4800 m and to Mexico (the HAWC Observatory, 4100 m) for prototype tests in real conditions. In this contribution we will describe manufacturing and construction details of the first SWGO prototype WCD. These details were envisaged to facilitate: the transport of the units, the assembly, the deployment and maintenance activities of the detectors. Furthermore, the units need to be resistant to strong winds, rain, snow and earthquakes.The costs are scalable with the detector volume. This information could be of interest to other Observatories that are in RD phase, such as the Global Cosmic Ray Observatory (GCOS) for the study of the highest-energy particles in the Universe and the Tau Air Shower Mountain-Based Observatory (TAMBO) for the search of PeV neutrinos.

The SWGO Collaboration is evaluating the possibility of deploying Water Cherenkov Detectors (WCD) in a high-altitude natural lake. For that, the first challenge is to build a bladder strong enough that could be used as a WCD inside a natural lake. A prototype bladder has been designed for SWGO and two bladders, made of different films, have been deployed for testing at Sibinacocha lake, in Peru, at 5000 masl. In order to monitor the wave intensity in the lake, a low-cost oceanographic buoy was developed using an acceleration sensor MPU6050 and a liquid sensor DS18B20. The development platform used was the Arduino Mega 2560 with some out-of-the shelf modules to achieve a functional and autonomous prototype. A code was developed in Python to process the data and convert the acceleration values into position, allowing estimation of height variations, as a function of time, less than 1 cm. To reduce the environmental impact of the floating structure, the use of metallic materials was minimized and mostly wood, cotton, and PVC pipes were used. This buoy has been installed next to SWGO prototype bladders at the Sibinacocha lake in Peru. In this contribution we will present the details of a low-cost oceanographic buoy built to monitor lake wave intensity.

Current cosmic ray anisotropy experiments have shown a significant swing in both the direction and the amplitude of the dipole at energies around tens of TeV. Due to the charged nature of these particles, and the presence of magnetic fields in our galaxy, an underlying composition-dependent dipole swing is expected. For this reason, combining measurements of the composition and the distribution of arrival directions is essential for unveiling the astrophysical origin of this structure. In this work, we study the potential of the upcoming Southern Wide-field Gamma-ray Observatory (SWGO) in contributing to these anisotropy studies. We present a template-based method developed for reconstructing the number of muons and separating primary cosmic rays. Preliminary resolutions of $5-30\%$ in the number of muons and an accuracy of $70-90\%$ in the species separation are found. A clear improvement is seen by considering a dedicated muon-counter layer in a detector, highlighting the future potential of SWGO.

The performance of the proposed MATHUSLA detector as an instrument for studying the physics of cosmic rays by measuring extensive air showers is presented. The MATHUSLA detector is designed to observe and study the decay of long-lived particles produced at the pp interaction point of the CMS detector at CERN during the HL-LHC data-taking period. The proposed MATHUSLA detector will be composed of many layers of long scintillating bars that cannot measure more than one hit per bar and correctly report the hit coordinate in case of multiple hits. This study shows that adding a layer of RPC detectors with both analogue and digital readout significantly enhances the capabilities of MATHUSLA to measure the local densities and arrival times of charged particles at the front of air showers. We discuss open issues in cosmic-ray physics that the proposed MATHUSLA detector with an additional layer of RPC detectors could address and conclude by comparing with other air-shower facilities that measure cosmic rays in the PeV energy range.

We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.

The Southern Wide-field Gamma-ray Observatory (SWGO) is an international collaboration working on a ground-based gamma-ray observatory that will be located in the southern hemisphere. A crucial step in the analysis is to identify the showers produced by gamma rays and separate them from the abundant background of hadronic showers. In this work, we propose to adapt the observable $S_b$ used successfully to composition studies in the Pierre Auger Observatory to the SWGO detector. This observable takes into account the signal and the position of each triggered detector. It characterizes the shape of the lateral distribution of the signal, which depends on the nature of the primary particle. The value of $S_b$ is therefore suited to identify gamma induced showers and to reject the more frequent hadronic showers. This analysis has been performed using a scaling factor to link the observable $S_b$ between the central and outrigger array. Also we explore how this new observable improves the separation of primary proton and gamma-induced air showers in terms of the merit factor.

A shower array exploiting the full coverage approach with a high segmentation of the readout allow to image the front of atmospheric showers with unprecedented resolution and detail. The grid distance determines the energy threshold (small energy showers are lost in the gap between detectors) and the quality of the shower sampling. Therefore, this experimental solution is needed to detect showers with a threshold in the 100 GeV range. The full coverage approach has been exploited in the ARGO-YBJ experiment. In this contribution we will summarise the advantages of this technique and discuss possible applications in new wide field of view detectors.

We present the concept of a shallow, single-layer, multi-PMT water Cherenkov detector (WCD) unit for ground-based gamma-ray astronomy. The design was developed as part of the R&D activities for SWGO, as a candidate WCD unit solution for the future Observatory. The main objective of the proposal is to achieve a low-volume single-layer surface detection unit with good calorimetry and timing of the shower front, and excellent gamma-hadron discrimination capability. The unit name, Mercedes, is derived from its configuration, where 3 PMTs are positioned equidistant from the center of the unit in a 120-deg symmetric azimuthal arrangement. Background rejection, in the TeV range, is based on the asymmetric illumination of the PMTs by energetic muons traversing the water volume. The mechanical implementation is based on rotomolded tanks similar to those used in the Pierre Auger Observatory. For easy deployment, the PMTs may be installed through openings in the lateral walls of the tank, and placed outside water, observing the calorimetric volume through transparent windows in the tank bladders. The highly innovative tank proposal, whose production technique is already patented, and at the commercial stage, has a jacketed- wall structure that houses all electronics and cabling, and a layer of insulating foam to avoid freezing at high-altitude. The mechanical concept was conceived for inexpensive production, easy deployment and maintenance, and to provide a cost-effective solution for high-altitude large array designs with several thousand units, such as in SWGO.

The Southern Wide-field Gamma-ray Observatory (SWGO) is a proposed facility for ground-based gamma-ray astronomy. It will consist of an array of water Cherenkov detectors to detect astrophysical gamma-rays mainly in the range of hundreds of GeV up to the PeV scale. To be constructed in South America, it will feature an approximately two-steradian field of view and a duty cycle close to 100%, which will complement the current generation of instruments by extending survey coverage to the Southern Hemisphere. As part of the development of the SWGO standard reconstruction framework, we employ a Monte Carlo template-based method to estimate the properties of the primary gamma-ray (such as core position and energy). In this method, an observed lateral amplitude distribution of a gamma-ray-induced air shower is fitted to the expected probability distribution stored in the templates. We validate this approach by estimating the energy performance for one of the currently investigated test array and detector unit configurations for SWGO.

This work presents the ASIMOV Prize for scientific publishing, which was launched in Italy in 2016. The prize aims to bring the young generations closer to scientific culture, through the critical reading of popular science books. The books are selected by a committee that includes scientists, professors, Ph.D. and Ph.D. students, writers, journalists and friends of culture, and most importantly, over 800 school teachers. Students are actively involved in the prize, according to the best practices of public engagement: they read, review the books and vote for them, choosing the winner. The experience is quite successful: 12,000 students from 270 schools all over Italy participated in the last edition. The possibility of replicating this experience in other countries is indicated, as was done in Brazil in 2020 with more than encouraging results.

Combining observations of multi-messengers help in boosting the sensitivity of astrophysical source searches, and probe various aspects of the source physics. In this chapter we discuss how LHAASO observations of very high energy (VHE) gamma rays in combination with telescopes for the other messengers can help in solving the origins of VHE neutrinos and galactic and extragalactic cosmic rays.

We report on recent progress and next steps in the design of the proposed MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC as part of the Snowmass 2021 process. Our understanding of backgrounds has greatly improved, aided by detailed simulation studies, and significant R&D has been performed on designing the scintillator detectors and understanding their performance. The collaboration is on track to complete a Technical Design Report, and there are many opportunities for interested new members to contribute towards the goal of designing and constructing MATHUSLA in time for HL-LHC collisions, which would increase the sensitivity to a large variety of highly motivated LLP signals by orders of magnitude.

In order to reveal the nature of dark matter, it is crucial to detect its non-gravitational interactions with the standard model particles. The traditional dark matter searches focused on the so-called weakly interacting massive particles. However, this paradigm is strongly constrained by the null results of current experiments with high precision. Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale. The Large High Altitude Air Shower Observatory (LHAASO) with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale. In this document, we review the theoretical motivations and background of heavy dark matter. We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO, and present the projected sensitivities. We also review the prospects of searching for the axion-like particles, which are a kind of well motivated light pseudo-scalars, through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.