Oscillation Maximum Research Articles

The ESS𝜈SB+ Project

The European Spallation Source neutrino Super Beam (ESS𝜈SB) is a long-baseline neutrino project that will measure the CP-violation in the leptonic sector at the second, rather than the first, oscillation maximum, where the sensitivity of the experiment is ∼3 times higher. The physics simulations have shown that the ESS𝜈SB, after 10 years of data taking, will be able to cover more than 70% of the CP-violating phase, δCP , parameterrange with 5 σ C.L. to reject the no-CP-violation hypothesis. The expected measurement error of δCP is smaller than 8° for all δCP values, making it the most precise proposed experiment in the field by a large margin. The extension project, ESS𝜈SB+ to be performed between 2023 and 2026, aims in measuring the neutrino-nucleus cross-section (the dominant term of the systematic uncertainty) in the energy range of 0.2 – 0.6 GeV, using a Low Energy nuSTORM (LEnuSTORM) and a Low Energy Monitored Neutrino Beam (LEMNB) facilities.

The ESSnuSB Design Study: Overview and Future Prospects

ESSnuSB is a design study for an experiment to measure the CP violation in the leptonic sector at the second neutrino oscillation maximum using a neutrino beam driven by the uniquely powerful ESS linear accelerator. The reduced impact of systematic errors on sensitivity at the second maximum allows for a very precise measurement of the CP violating parameter. This review describes the fundamental advantages of measurement at the second maximum, the necessary upgrades to the ESS linac in order to produce a neutrino beam, the near and far detector complexes, and the expected physics reach of the proposed ESSnuSB experiment, concluding with the near future developments aimed at the project realization.

The design of the ESS neutrino Super Beam ESS[formula omitted]SB for leptonic CP violating measurement and the plans for its further development ESS[formula omitted]SB+

A EC-supported conceptual design study ESSνSB has been carried out during the years 2018–2022 of how the 5 MW linear proton accelerator of the European Spallation Source, currently under construction in Lund, Sweden, can be used to generate a world-uniquely intense neutrino Super Beam for precision measurement of the leptonic CP violating phase δCP. Support for a continuation of this study 2023–2026 has recently been granted by EC. The uniquely high power of the ESS proton linac will allow for the neutrino oscillation measurements to be made at the second oscillation maximum, rather than at the first maximum where other experiments measure, and thereby for a more precise measurement to be made of δCP. This paper describes the results of the conceptual design of ESSνSB lay-out, infrastructure and components as well as of the evaluation of the physics performance for leptonic CP violation discovery and, in particular, for the precision in the measurement if the CP violation phase δCP as well as the plans for the continuation of the work, which will include design studies of a Low energy nuSTORM and an Low Energy Monitored Neutrino Beam.

Towards a sub-percent precision measurement of sin2θ13 with reactor antineutrinos

Measuring the neutrino mixing parameter sin2θ13 to the sub-percent precision level could be necessary in the next ten years for the precision unitary test of the PMNS matrix. In this work, we discuss the possibility of such a measurement with reactor antineutrinos. We find that a single liquid scintillator detector on a reasonable scale could achieve the goal. We propose to install a detector of ∼ 10% energy resolution at about 2.0 km from the reactors with a JUNO-like overburden. The integrated luminosity requirement is about 150 kton · GW · year, corresponding to 4 years’ operation of a 4 kton detector near a reactor complex of 9.2 GW thermal power like Taishan reactor. Unlike the previous θ13 experiments with identical near and far detectors, which can suppress the systematics especially the rate uncertainty by the near-far relative measurement and the optimal baseline is at the first oscillation maximum of about 1.8 km, a single-detector measurement prefers to offset the baseline from the oscillation maximum. At low statistics ≲ 10 kton · GW · year, the rate uncertainty dominates the systematics, and the optimal baseline is about 1.3 km. At higher statistics, the spectral shape uncertainty becomes dominant, and the optimal baseline shifts to about 2.0 km. The optimal baseline keeps being ∼ 2.0 km for an integrated luminosity up to 106 kton · GW · year. Impacts of other factors on the precision sin2θ13 measurement are also discussed. We have assumed that the TAO experiment will improve our understanding of the spectral shape uncertainty, which gives the highest precision measurement of reactor antineutrino spectrum for neutrino energy in the range of 3–6 MeV. We find that the optimal baseline is ∼ 2.9 km with a flat input spectral shape uncertainty provided by the future summation or conversion methods’ prediction. The shape uncertainty would be the bottleneck of the sin2θ13 precision measurement. The sin2θ13 precision is not sensitive to the detector energy resolution and the precision of other oscillation parameters.

Study on the Influencing Factors of the Response Characteristics of the Slide Valve-Type Direct-Acting Relief Valve with External Orifice

The slide valve-type direct-acting relief valve with external orifice (SVTDARVWEO) is widely used in hydraulic systems, and its response characteristics are influenced by key factors. It is of great significance to carry out research on the influencing factors of the response characteristics of the SVTDARVWEO. The working principle of the SVTDARVWEO is analyzed in the present study. The simulation model of the SVTDARVWEO is established using AMESim. The influence of the orifice diameter, viscosity coefficient, valve element mass, spring stiffness, oil seal length, and valve element diameter on the response characteristics of the SVTDARVWEO is studied. The results show that: (1) The smaller the orifice diameter is, the smaller the oscillation frequency, amplitude and maximum overshoot of pressure, flowrate, displacement and velocity are. (2) When the viscosity coefficient is 50 N/(m/s), 55 N/(m/s) and 60 N/(m/s), the pressure, flowrate, displacement and velocity oscillate periodically, but the amplitude of the oscillation decreases gradually, and the oscillation frequency is 250 Hz. When the viscosity coefficient is 60 N/(m/s), the pressure, flowrate, displacement and velocity will reach their respective stable values earlier. (3) When the valve element mass is 0.01 kg, 0.015 kg and 0.02 kg, the pressure, flowrate, displacement and velocity oscillate periodically, but the amplitude of oscillation decreases gradually. When the valve element mass is 0.01 kg, the pressure, flowrate, displacement and velocity will reach the stable value earlier. (4) The smaller the spring stiffness is, the greater the maximum overshoot of pressure, flowrate, displacement and velocity is, and the higher the number of oscillations to reach the stable value are, in addition to more time being required. (5) With the increase in oil seal length, the maximum overshoot of pressure and velocity, stability value of displacement also increase correspondingly. (6) With the increase in the valve element diameter, the stable value of pressure decreases, and the oscillation frequency of pressure, flowrate, displacement and velocity increase, but the oscillation amplitude decreases.

Surface-oxide-controlled InGaAs/InAlAs inverted-type metal-oxide-semiconductor high electron mobility transistors for sub-THz high-power amplifiers

Herein, we successfully improved the maximum oscillation frequency and maximum stable gain (MSG) across a wide bias range of surface-oxide-controlled (SOC) InGaAs/InAlAs inverted-type metal-oxide-semiconductor high-electron-mobility transistors (inverted MOS-HEMTs) by reducing the gate leakage current and drain conductance (g d). H2O vapor treatment selectively decreased the narrow band gap indium oxide at the surface of the In-based epitaxial layer via the SOC process before the gate oxide deposition. Furthermore, the calculation of band profiles indicated that the gd reduction was possibly attributed to the suppression of impact ionization in the InGaAs channel by inverted MOS-HEMTs. Consequently, SOC-inverted MOS-HEMTs demonstrated a high MSG of >12 dB at 100 GHz across a wide bias range.

Extracting the best physics sensitivity from T2HKK: A study on optimal detector volume

T2HK is an upcoming long-baseline experiment in Japan which will have two water Cherenkov detector tanks of 187 kt volume each at a distance of 295 km from the source. An alternative project, T2HKK is also under consideration where one of the water tanks will be moved to Korea at a distance of 1100 km. The flux at 295 km will cover the first oscillation maximum and the flux at 1100 km will mainly cover the second oscillation maximum. As physics sensitivity at the dual baseline relies on variation in statistics, the dependence of systematic uncertainty, the effect of the second oscillation maximum and matter density, 187 kt detector volume at 295 km and 187 kt detector volume at 1100 km may not be the optimal configuration of T2HKK. Therefore, in this work we have tried to optimize the ratio of the detector volume at both the locations by studying the interplay between the above mentioned parameters. For the analysis of neutrino mass hierarchy, octant of ${\ensuremath{\theta}}_{23}$ and $CP$ precision, we have considered two values of ${\ensuremath{\delta}}_{CP}$ as 270\ifmmode^\circ\else\textdegree\fi{} and 0\ifmmode^\circ\else\textdegree\fi{} and for $CP$ violation we have considered the value of ${\ensuremath{\delta}}_{CP}=270\ifmmode^\circ\else\textdegree\fi{}$. These values are motivated by the current best-fit values of this parameter as obtained from the experiments T2K and $\mathrm{NO}\ensuremath{\nu}\mathrm{A}$. Interestingly we find that if the systematic uncertainty is negligible then the T2HK setup i.e., when both the detector tanks are placed at 295 km gives the best results in terms of hierarchy sensitivity at ${\ensuremath{\delta}}_{CP}=270\ifmmode^\circ\else\textdegree\fi{}$, octant sensitivity, $CP$ violation sensitivity, and $CP$ precision sensitivity at ${\ensuremath{\delta}}_{CP}=0\ifmmode^\circ\else\textdegree\fi{}$. For current values of systematic errors, we find that neither T2HK, nor T2HKK setup is giving better results for hierarchy, $CP$ violation and $CP$ precision sensitivity. The optimal detector volume which is in the range between 255 kt to 345 kt at 1100 km gives better results in the above mentioned parameters.

A New Battery Selection System and Charging Control of a Movable Solar-Powered Charging Station for Endless Flying Killing Drones

This paper provides a design, a charging control, and energy management of a movable Photo Voltaic (PV) charging station with an Automatic Battery Replacement (ABR) system to enable drones for ongoing missions. The paper represents the first stage of a three-staged project titled Fall Armyworm (FAW) insect killer. The other two stages involve the flight control of drones and detecting and killing FAW insects. Without chemical methods, the project aims to eliminate harmful FAW insects that are rapidly spreading in Africa and Asia. The power source is a hybrid PV system with energy storage devices (batteries and supercapacitors). The maximum power from PV panels is tracked using three different online methods (PSO, IC, and P&O), and the best method with the highest accuracy is selected. The experimental and simulation results approved that PSO is the recommended method used in this project among the studied methods because of its high target reach (about 97%) and low steady-state oscillation (maximum 2.15%). An intelligent energy management system is investigated and designed to efficiently utilize solar power with a constant-current constant-voltage charger for LiPo batteries. A new Battery Selection System (BSS) is designed and verified to efficiently utilize the harvested energy and increase the mission time. The BSS targets to manage the selection of the appropriate battery to charge and control its charging rate. The system performance is tested using MATLAB software. Then, an experimental setup for the system is built to validate simulation results. The results of simulations and experiments proved the reliability of BSS in different operating cases with an efficiency higher than 97%.

Physics reach of the ESSnuSB experiment

ESSnuSB is a unique future proposed long-baseline experiment in Sweden to study neutrino oscillation by probing the second oscillation maximum. In this proceeding, we update the flux and efficiencies and re-calculate the sensitivity of ESSnuSB in the standard three flavour scenario. We find that it has excellent sensitivity to the Dirac CP phase δCP, moderate sensitivity to the mass hierarchy of the neutrinos and limited sensitivity to measure the octant of the atmospheric mixing angle θ 23. We also find that it has a very good sensitivity to constrain the atmospheric mass squared difference .

Addendum to: Invisible neutrino decay: first vs second oscillation maximum

Addendum to: Invisible neutrino decay: first vs second oscillation maximum

Physics prospects with the second oscillation maximum at the Deep Underground Neutrino Experiment

Current long-baseline neutrino-oscillation experiments such as NO$\nu$A and T2K are mainly sensitive to physics in the neighbourhood of the first oscillation maximum of the $\nu_\mu \to \nu_e$ oscillation probability. The future Deep Underground Neutrino Experiment (DUNE) utilizes a wide-band beam tune optimized for CP violation sensitivity that fully covers the region of the first maxima and part of the second. In the present study, we elucidate the role of second oscillation maximum in addressing issues pertaining to unknowns in the standard three flavour paradigm. We consider a new DUNE beam tune optimized for coverage of the region of the second oscillation maxima which could be realized using proposed accelerator upgrades that provide multi-MW of power at proton energies of 8 GeV. We find that addition of the multi-MW 8 GeV beam to DUNE wide-band running leads to modest improvement in sensitivity to CP violation, mass hierarchy, the octant of $\theta_{23}$ as well as the resolution of $\delta$ and the Jarlskog invariant. Significant improvements to the DUNE neutrino energy resolution yield a much larger improvement in performance. We conclude that the standard DUNE wide-band beam when coupled with excellent detector resolution capabilities is sufficient to resolve $\delta$ to better than $\sim 12^\circ$ for all values of $\delta$ in a decade of running. For second maxima (8 GeV 3MW) beam running concurrently with the standard wide-band (80 GeV 2.2 MW) beam for 5 of the 10 years, it is found that $\delta$ can be further resolved better than $\sim 10^\circ$ for all values of $\delta$.

Resection of bone by sagittal saw: Investigation of effects of blade speed, feed rate, and irrigation on temperature rise.

Heat generation during bone cutting by sagittal saw may lead to temperature rise and possible incidence of thermal necrosis. The aim of the present research is to examine the effect of saw blade oscillation rate, blade feed rate, and irrigation by physiological saline solution on the bone temperature rise during sawing in order to determine the desired conditions for reducing the extent of thermal damage. For this purpose, empirical tests of bovine femur cutting were performed in 15 states, including five levels for the blade oscillation rate (10,000-18,000 cpm with 2000 cpm intervals) and three levels for the feed rate (10-30 mm.min-1 with 10 mm.min-1 intervals) for dry conditions; and five states, including five levels for the blade oscillation rate (10,000-18,000 cpm with 2000 cpm intervals) and one level in feed rate of 20 mm.min-1 for the irrigation conditions. The results indicated that the bone temperature rise had a direct relationship with the blade oscillation rate and an inverse relationship with its feed rate. In the state of no cooling, the minimum temperature rise (ΔT = 65.45°C) occurred at the blade speed of 10,000 cpm and feed rate of 30 mm.min-1, while in the state of sawing with irrigation, the temperature rise almost did not exceed the allowable range (ΔT ≤ 10°C). The results suggested that to lower the possibility of incidence of osteonecrosis in the bone resection by sagittal saw, cooling with physiological saline solution or application of the minimum blade oscillation rate and maximum feed rate is recommended.

Impact of high energy beam tunes on the sensitivities to the standard unknowns at DUNE

Even though neutrino oscillations have been conclusively established, there are a few unanswered questions pertaining to leptonic Charge Parity violation (CPV), mass hierarchy (MH) and $\theta_{23}$ octant degeneracy. Addressing these questions is of paramount importance at the current and future neutrino experiments including the Deep Underground Neutrino Experiment (DUNE) which has a baseline of 1300 km. In the standard mode, DUNE is expected to run with a {\textit{low energy}} (LE) tuned beam which peaks around the first oscillation maximum ($2-3$ GeV) (and then sharply falls off as we go to higher energies). However, the wide band nature of the beam available at long baseline neutrino facility (LBNF) allows for the flexibility in utilizing beam tunes that are well-suited at higher energies as well. In this work, we utilize a beam that provides high statistics at higher energies which is referred to as the {\textit{medium energy}} (ME) beam. This opens up the possibility of exploring not only the usual oscillation channels but also the $\nu_{\mu} \to \nu_{\tau}$ oscillation channel which was otherwise not accessible. Our goal is to find an optimal combination of beam tune and runtime (with the total runtime held fixed) distributed in neutrino and antineutrino mode that leads to an improvement in the sensitivities of these parameters at DUNE. In our analysis, we incorporate all the three channels ($\nu_{\mu} \to \nu_{e}, \nu_{\mu} \to \nu_{\mu}, \nu_{\mu} \to \nu_{\tau}$) and develop an understanding of their relative contributions in sensitivities at the level of $\Delta \chi^2$. Finally, we obtain the preferred combination of runtime using both the beam tunes as well as neutrino and antineutrino mode that lead to enhanced sensitivity to the current unknowns in neutrino oscillation physics i.e., CPV, MH and $\theta_{23}$ octant.

Disentangling genuine from matter-induced CP violation in neutrino oscillations

We prove [1] that, in any flavor transition, neutrino oscillation CP violating asymmetries in matter have two disentangled components: (a) a CPT-odd T-invariant term, non-vanishing iff there are interactions with matter; (b) a T-odd CPT-invariant term, non-vanishing iff there is genuine CP violation. As function of the baseline, these two terms are distinct L-even and L-odd observables, respectively. In the experimental region of terrestrial accelerator neutrinos, we calculate [2] their approximate expressions from which we prove that, at medium baselines, the CPT-odd component is small and nearly (δ-independent, so it can be subtracted from the experimental CP asymmetry as a theoretical background, provided the hierarchy is known. At long baselines, on the other hand, we find that (i) a Hierarchy-odd term in the CPT-odd component dominates the CP asymmetry for energies above the first oscillation node, and (ii) the CPT-odd term vanishes, independent of the CP phase δ, at E = 0.92 GeV(L/1300 km) near the second oscillation maximum, where the T-odd term is almost maximal and proportional to sin δ. A measurement of the CP asymmetry in these energy regions would thus provide separate information on (i) the neutrino mass ordering, and (ii) direct evidence of genuine CP violation in the lepton sector.

Neutrino CP Violation with the European Spallation Source neutrino Super Beam project

After measuring in 2012 a relatively large value of the neutrino mixing angle θ 13, the door is now open to observe for the first time a possible CP violation in the leptonic sector. The measured value of θ 13 also privileges the 2nd oscillation maximum for the discovery of CP violation instead of the usually used 1st oscillation maximum. The sensitivity at this 2nd oscillation maximum is about three times higher than for the 1st oscillation maximum inducing a lower influence of systematic errors. Going to the 2nd oscillation maximum necessitates a very intense neutrino beam with the appropriate energy. The world’s most intense pulsed spallation neutron source, the European Spallation Source (ESS), will have a proton linac with 5 MW power and 2 GeV energy. This linac, under construction, also has the potential to become the proton driver of the world’s most intense neutrino beam with very high potential to discover a neutrino CP violation. The physics performance of that neutrino Super Beam in conjunction with a megaton underground Water Cherenkov neutrino detector installed at a distance of about 500 km from ESS has been evaluated. In addition, the choice of such detector will extent the physics program to proton–decay, atmospheric neutrinos and astrophysics searches. The ESS proton linac upgrades, the accumulator ring needed for proton pulse compression, the target station optimization and the physics potential are described. In addition to neutrinos, this facility will also produce at the same time a copious number of muons which could be used by a muon collider. The ESS neutron facility will be fully ready by 2023 at which moment the upgrades for the neutrino facility could start.

Anomalous thermal fluctuation distribution sustains proto-metabolic cycles and biomolecule synthesis.

An environment far from equilibrium is thought to be a necessary condition for the origin and persistence of life. In this context we report open-flow simulations of a non-enzymic proto-metabolic system, in which hydrogen peroxide acts both as oxidant and driver of thermochemical cycling. We find that a Gaussian perturbed input produces a non-Boltzmann output fluctuation distribution around the mean oscillation maximum. Our main result is that net biosynthesis can occur under fluctuating cyclical but not steady drive. Consequently we may revise the necessary condition to "dynamically far from equilibrium".

A comparative study between ESSnuSB and T2HK in determining the leptonic CP phase

In this paper, we perform a comparative analysis between the future proposed long-baseline experiments ESSnuSB and T2HK in measuring the leptonic CP phase [Formula: see text]. In particular, we study the effect of the neutrino mass ordering degeneracy and the leptonic mixing angle [Formula: see text] octant degeneracy in the measurement of leptonic CP violation and precision for both experiments. Since the ESSnuSB (T2HK) experiment probes the second (first) oscillation maximum to study neutrino oscillations, the effect of these degeneracies are significantly different in both experiments. Our main conclusion is that for the ESSnuSB experiment, the information on the neutrino mass ordering does not play a major role in the determination of [Formula: see text], which is not the case for the T2HK experiment. However, the information on the true octant compromises the CP sensitivity of the ESSnuSB experiment as compared to T2HK if [Formula: see text] lies in the lower octant. These conclusions are true for both the 540 km and 360 km baseline options for the ESSnuSB experiment. In addition, we investigate the effect of different running times in neutrino and antineutrino modes and the effect of [Formula: see text] precision in measuring [Formula: see text].

Physics potential of ESS\u03bdSB in the presence of a light sterile neutrino

ESSνSB is a proposed neutrino super-beam project at the ESS facility. We study the performance of this setup in the presence of a light eV-scale sterile neutrino, considering 540 km baseline with 2 years (8 years) of ν ( overline{nu} ) run-plan. This baseline offers the possibility to work around the second oscillation maximum, providing high sensitivity towards CP-violation (CPV). We explore in detail its capability in resolving CPV generated by the standard CP phase δ13, the new CP phase δ14, and the octant of θ23. We find that the sensitivity to CPV induced by δ13 deteriorates noticeably when going from 3ν to 4ν case. The two phases δ13 and δ14 can be reconstructed with a 1σ uncertainty of ∼ 150 and ∼ 350 respectively. Concerning the octant of θ23, we find poor sensitivity in both 3ν and 4ν schemes. Our results show that a setup like ESSνSB working around the second oscillation maximum with a baseline of 540 km, performs quite well to explore CPV in 3ν scheme, but it is not optimal for studying CP properties in 3+1 scheme.

Precision measurements on \u03b4CP in MOMENT

As it is very promising to expect a discovery of CP violation in the leptonic sector, the precision measurement of the Dirac CP phase δCP is going to be one of the key interests in the future neutrino oscillation experiments. In this work, we examine the physics reach of the proposed medium baseline muon decay experiment MOMENT. In order to identify potential bottlenecks and opportunities to improve CP precision in MOMENT, we investigate the effect of statistical error, systematic uncertainties, fraction of the muon beam polarity, and adjusting the baseline length to match the first or second oscillation maximum on the precision measurement of δCP. We also simulate superbeam experiments T2K, NOνA, T2HK, DUNE and T2HKK in comparison and complementary to MOMENT. To reach the precision of δCP at 12° or better at 1 σ confidence level, we find it sufficient to combine the data of MOMENT, DUNE and T2HK.

Biprobability approach to CP phase degeneracy from non-standard neutrino interactions

Non-standard interactions (NSI) between neutrinos and matter at long-baseline experiments could make determination of the CP-violating phase δ13 ambiguous due to interference with additional complex phases. Such degeneracies are often studied in the context of specific experiments and a few parameter choices, leaving it unclear how to extract a general understanding of when two sets of parameters may be degenerate or how different types of experiments in principle combine to lift such a degeneracy. This work complements detailed simulations of individual experiments by showing how underlying parameters relate to degeneracies as represented on a biprobability plot. We show how a range of energies near the oscillation maximum Δ31=π/2 separates some degenerate probabilities along the CP-conserving direction of biprobability space according to δ+≡δ13+δeτ, while near Δ31=3π/2 degenerate probabilities are separated along the CP-violating direction according to δeτ. We apply this to the experimental hints that suggest δ13∼−π/2 to see that this could also be consistent with δ13,δeτ=0 or π. The baseline and energy range characteristic of DUNE provides some resolution, but a further improvement comes from beams a few degrees off-axis at ≳1000 km baselines, including some proposed sites for T2HKK.