Exact solutions for a nonstandard viscous Cahn—Hilliard system

The one-dimensional version of a nonstandard viscous Cahn–Hilliard system (proposed by Colli et al.) for the order parameter and chemical potential with a generally asymmetric polynomial double-well potential is considered. For this system, an exact travelling wave solution, which describes the advancing front of a phase transformation in an infinite domain, is found.Розглянуто одновимірний варіант нестандартної системи рівнянь Кана—Хілліарда (запропонованої Colli et al.) для параметра порядку і хімічного потенціалу з асиметричним поліномним двоямним потенціалом. Для цієї системи знайдено точне розв’язання вигляду рухомої хвилі, що описує рух фронту фазового перетворення в нескінченній області.Рассмотрен одномерный вариант нестандартной системы уравнений Кана—Хиллиарда (предложенной Colli et al.) для параметра порядка и химического потенциала с асимметричным полиномиальным двуямным потенциалом. Для этой системы найдено точное решение вида бегущей волны, которое описывает движение фронта фазового превращения в бесконечной области

Registration of high-intensity electron and x-ray fields with polycrystalline CVD diamond detectors

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Signal selection and model-independent extraction of the neutrino neutral-current single π + cross section with the T2K experiment

This article presents a study of single π + production in neutrino neutral-current interactions (NC1π +) using the FGD1 hydrocarbon target of the ND280 detector of the T2K experiment. We report the largest sample of such events selected by any experiment, providing the first new data for this channel in over four decades and the first using a sub-GeV neutrino flux. The signal selection strategy and its performance are detailed together with validations of a robust cross section extraction methodology. The measured flux-averaged integrated cross-section is σ = (6.07 ± 1.22) × 10−41 cm2 /nucleon, 1.3 σ above the NEUT v5.4.0 expectation

First differential measurement of the single π+ production cross section in neutrino neutral-current scattering

Since its first observation in the 1970s, neutrino-induced neutral-current single positive pion production (NC1π +) has remained an elusive and poorly understood interaction channel. This process is a significant background in neutrino oscillation experiments and studying it further is critical for the physics program of next-generation accelerator-based neutrino oscillation experiments. In this Letter we present the first double-differential cross-section measurement of NC1π + interactions using data from the ND280 detector of the T2K experiment collected in ν-beam mode. The measured flux-averaged integrated cross-section is σ = (6.07±1.22)×10−41 cm2 /nucleon. We compare the results on a hydrocarbon target to the predictions of several neutrino interaction generators and final-state interaction models. While model predictions agree with the differential results, the data shows a weak preference for a cross-section normalization approximately 30% higher than predicted by most models studied in this Letter

Scintillator ageing of the T2K near detectors from 2010 to 2021

The T2K experiment widely uses plastic scintillator as a target for neutrino interactions and an active medium for the measurement of charged particles produced in neutrino interactions at its near detector complex. Over 10 years of operation the measured light yield recorded by the scintillator based subsystems has been observed to degrade by 0.9–2.2% per year. Extrapolation of the degradation rate through to 2040 indicates the recorded light yield should remain above the lower threshold used by the current reconstruction algorithms for all subsystems. This will allow the near detectors to continue contributing to important physics measurements during the T2K-II and Hyper-Kamiokande eras. Additionally, work to disentangle the degradation of the plastic scintillator and wavelength shifting fibres shows that the reduction in light yield can be attributed to the ageing of the plastic scintillator. The long component of the attenuation length of the wavelength shifting fibres was observed to degrade by 1.3–5.4% per year, while the short component of the attenuation length did not show any conclusive degradation