Simultaneous ion sputter polishing and deposition

Results of experiments to study ion beam sputter polishing in conjunction with simultaneous deposition as a mean of polishing copper surfaces are presented. Two types of simultaneous ion sputter polishing and deposition were used in these experiments. The first type utilized sputter polishing simultaneous with vapor deposition, and the second type utilized sputter polishing simultaneous with sputter deposition. The etch and deposition rates of both techniques were studied, as well as the surface morphology and surface roughness

IceCube Flavor Ratios with Identified Astrophysical Sources: Towards Improving New Physics Testability

Motivated by the discovery of the first high-energy astrophysical neutrino source, the blazar TXS 0506+056, we revisit the IceCube flavor ratio analysis. Assuming large statistics from identified blazars, collected in the forthcoming years by the IceCube detector and its successor IceCube-Gen2, we demonstrate that the constraints on several new physics scenarios in which the baseline dependent terms in neutrino oscillation probabilities are not averaged, can be improved. As a representative case, we consider pseudo-Dirac neutrinos while neutrino decay is also discussed.Comment: 17 pages, 5 figure

A New Probe of Relic Neutrino Clustering using Cosmogenic Neutrinos

We propose a new probe of cosmic relic neutrinos (C$\nu$B) using their resonant scattering against cosmogenic neutrinos. Depending on the lightest neutrino mass and the energy spectrum of the cosmogenic neutrino flux, a Standard Model vector meson (such as a hadronic $\rho$) resonance can be produced via $\nu\bar{\nu}$ annihilation. This leads to a distinct absorption feature in the cosmogenic neutrino flux at an energy solely determined by the meson mass and the neutrino mass, apart from redshift. By numerical coincidence, the position of the $\rho$-resonance overlaps with the originally predicted peak of the Greisen-Zatsepin-Kuzmin (GZK) neutrino flux, which offers an enhanced absorption effect at higher redshifts. We show that this absorption feature in the GZK neutrino flux may be observable in future radio-based neutrino observatories, such as IceCube-Gen2 radio, provided there exists a large overdensity in the C$\nu$B distribution. This therefore provides a new probe of C$\nu$B clustering at large redshifts, complementary to the laboratory probes (such as KATRIN) at zero redshift.Comment: 8 pages, 4 figures, corrected prefactor in Eq. (5

Dark Sector Studies with Neutrino Beams

An array of powerful neutrino-beam experiments will study the fundamentalproperties of neutrinos with unprecedented precision in the coming years. Alongwith their primary neutrino-physics motivations, there has been growingrecognition that these experiments can carry out a rich program of searches fornew, light, weakly-coupled particles that are part of a dark sector. In thiswhite paper, we review the diverse theoretical motivations for dark sectors andthe capabilities of neutrino beam experiments to probe a wide range of modelsand signatures. We also examine the potential obstacles that could limit theseprospects and identify concrete steps needed to realize an impactful darksector search program in this and coming decades.<br

Dark Sector Studies with Neutrino Beams

An array of powerful neutrino-beam experiments will study the fundamentalproperties of neutrinos with unprecedented precision in the coming years. Alongwith their primary neutrino-physics motivations, there has been growingrecognition that these experiments can carry out a rich program of searches fornew, light, weakly-coupled particles that are part of a dark sector. In thiswhite paper, we review the diverse theoretical motivations for dark sectors andthe capabilities of neutrino beam experiments to probe a wide range of modelsand signatures. We also examine the potential obstacles that could limit theseprospects and identify concrete steps needed to realize an impactful darksector search program in this and coming decades.<br

Neutrino Self-Interactions: A White Paper

Neutrinos are the Standard Model (SM) particles which we understand theleast, often due to how weakly they interact with the other SM particles.Beyond this, very little is known about interactions among the neutrinos, i.e.,their self-interactions. The SM predicts neutrino self-interactions at a levelbeyond any current experimental capabilities, leaving open the possibility forbeyond-the-SM interactions across many energy scales. In this white paper, wereview the current knowledge of neutrino self-interactions from a vast array ofprobes, from cosmology, to astrophysics, to the laboratory. We also discusstheoretical motivations for such self-interactions, including neutrino massesand possible connections to dark matter. Looking forward, we discuss thecapabilities of searches in the next generation and beyond, highlighting thepossibility of future discovery of this beyond-the-SM physics.<br

Theory of Neutrino Physics -- Snowmass TF11 (aka NF08) Topical Group Report

This is the report for the topical group Theory of Neutrino Physics (TF11/NF08) for Snowmass 2021. This report summarizes the progress in the field of theoretical neutrino physics in the past decade, the current status of the field, and the prospects for the upcoming decade.Comment: 26 pages, 5 figure

The Forward Physics Facility at the High-Luminosity LHC

High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential