Oscillation Channels Research Articles

Light sterile neutrinos: a critical overview

Light sterile neutrinos, first proposed after the results of the LSND experiment, have been a polemical topic for the last decades after seemingly contradictory data appeared from different experiments. In this overview, I review the experimental hints that point towards sterile neutrinos as well as their statistical compatibility. Even though the muon neutrino disappearance experiments strongly rule out vanilla sterile neutrinos, each oscillation channel remains internally mostly consistent. In any case, in the near future a series of independent and precise experiments should finally settle down this issue.

Effect of final state interactions on neutrino energy reconstruction at DUNE

We quantitatively study the percentage of fake events present in CCQE and CCRes interactions and the impact of final state interactions on the neutrino oscillation parameters at DUNE. The effect of final-state interactions for DUNE oscillation physics is analyzed in an ideal and realistic detector scenario. Resonance interaction will be the most dominant interaction in the oscillation sensitive region of DUNE. The νμ-disappearance oscillation channel is studied using LAr detector. We find that nuclear effects and detector threshold play a significant role in CCQE and CCRes interactions and these nuclear effects induce a significant bias in the determination of atmospheric neutrino oscillation parameters. The impression of nuclear effects on the determination of θ23 is quantified in this work, which will help in reducing the systematic error at DUNE.

Study of nonstandard charged-current interactions at the MOMENT experiment

MuOn-decay MEdium baseline NeuTrino beam experiment (MOMENT) is a next-generation accelerator neutrino experiment looking for more physics study. We try to simulate neutrino oscillations confronting with Charged-Current\&Non-Standard neutrino Interactions(CC-NSIs) at MOMENT. These NSIs could alter neutrino production and detection processes and get involved in neutrino oscillation channels. We separate a perturbative discussion of oscillation channels at near and far detectors, and analyze parameter correlations with the impact of CC-NSIs. Taking $\delta_{cp}$ and $\theta_{23}$ as an example, we find that CC-NSIs can induce bias in precision measurements of standard oscillation parameters. In addition, a combination of near and far detectors using Gd-doped water cherenkov technology at MOMENT is able to provide good constraints of CC-NSIs happening at the neutrino production and detection processes.

A novel MIMO‐GFDM receiver for next generation communication

AbstractOrthogonal frequency‐division multiplexing is not suitable for fifth‐generation applications such as machine‐type communication, tactile internet, and internet of things. Generalized frequency‐division multiplexing (GFDM) is presented to address these requirements on the basis of the pulse‐shaping filter architecture, which makes GFDM have lower out‐of‐band emission and relatively less cyclic prefix and a become candidate for fifth‐generation systems. Because of the filter architecture, the subcarrier is nonorthogonal, which leads to serious intercarrier interference and is sensitive to carrier frequency offset (CFO). For reducing the intercarrier interference, we propose a 2‐path conjugate transmission scheme in the transmitter, and an adaptive receiver based on the modified phase rotated conjugate cancellation scheme is derived. By maximizing the carrier‐to‐interference ratio, we derive the optimal phase rotation and present an adaptive normalized block least mean squared algorithm to search the ideal result. With the proposed adaptive receiver, the CFO variation due to mismatch oscillator frequency and channel effect can be tracked effectively without feeding back the estimated information to the transmitter. In this paper, we propose a novel receiver with channel equalization and CFO compensation for multiple‐input–multiple‐output–GFDM systems in time‐varying channels. So far, no related research works exist. In the simulations, we compare the proposed receiver with several existing schemes in different time‐varying channels and modulations. The proposed scheme outperforms the existing schemes.

Tunable Gunn oscillations in a top-gated planar nanodevice

The frequency of a Gunn diode is usually determined by the length of its oscillation channel, hard to be change after the device has been fabricated. We show that in a top-gated planar nanodevice the frequency of Gunn oscillations can be conveniently increased, i.e. tuned by the top-gate bias. Ensemble Monte Carlo (EMC) simulations indicate that the achieved maximum frequency reaches 1 THz, about three times of that of an un-gated device. Moreover, the tunable frequency-range also increases with the length of the top-gate, resulting in a widest range of ∼0.7 THz. Detailed analysis of the Gunn-domain dynamics shows that this tunable effect is related to the simultaneous formation of multi-domains, which are excited by the top-gate induced non-uniformed electricfield along the oscillation channel.

Attenuation effect and neutrino oscillation tomography

The attenuation effect is the effect of weakening contributions to the oscillation signal from remote structures of the matter density profile. The effect is a consequence of integration over the neutrino energy within the energy resolution interval. Structures of a density profile situated at distances larger than the attenuation length, ${\ensuremath{\lambda}}_{\mathrm{att}}$, are not ``seen'' at the level $\ensuremath{\epsilon}\ensuremath{\equiv}2EV/\mathrm{\ensuremath{\Delta}}{m}^{2}$, where $V$ is the matter potential. We show that the origins of attenuation are (i) the averaging of oscillations in certain layer(s) of matter, (ii) the smallness of the matter effect: $\ensuremath{\epsilon}\ensuremath{\ll}1$, and (iii) the specific initial and final states on neutrinos. We elaborate on the graphic description of the attenuation that allows us to compute explicitly the effects in the ${\ensuremath{\epsilon}}^{2}$ order for various density profiles and oscillation channels. The attenuation in the case of partial averaging is described. The effect is crucial for the interpretation of oscillation data and for the oscillation tomography of the Earth with low energy (solar, supernova, atmospheric, etc.) neutrinos.

Probing direct and indirect unitarity violation in future accelerator neutrino facilities

The possible existence of light and heavy sterile neutrinos may give rise to direct and indirect unitarity violation of the 3×3 lepton mixing matrix respectively. In the current work we study the potential of future accelerator neutrino facilities in probing the unitarity violation effects. Taking DUNE, T2HK and a low-energy Neutrino Factory (LENF) as working examples of future accelerator neutrino facilities, we study the distinct effects of direct and indirect unitarity violation on the discovery reach of the leptonic CP violation and precision measurements of θ23 in the three neutrino framework. In addition, constraints on the additional mixing parameters of direct and indirect unitarity violation are also discussed. Finally, we stress that the combination of experiments with different oscillation channels, different neutrino beams and different detector techniques will be an effective solution to the parameter degeneracy problem and give the robust measurement of leptonic CP violation even if the direct and indirect unitarity violation are taken into account.

Multiple angles on the sterile neutrino – a combined view of cosmological and oscillation limits

The possible existence of sterile neutrinos is an important unresolved question for both particle physics and cosmology. Data sensitive to a sterile neutrino is coming from both particle physics experiments and from astrophysical measurements of the Cosmic Microwave Background. In this study, we address the question whether these two contrasting data sets provide complementary information about sterile neutrinos. We focus on the muon disappearance oscillation channel, taking data from the MINOS, ICECUBE and Planck experiments, converting the limits into particle physics and cosmological parameter spaces, to illustrate the different regions of parameter space where the data sets have the best sensitivity. For the first time, we combine the data sets into a single analysis to illustrate how the limits on the parameters of the sterile-neutrino model are strengthened. We investigate how data from a future accelerator neutrino experiment (SBN) will be able to further constrain this picture.

Fast-thermal coupled cores in zero power reactors: A demonstration of feasibility and pertinence for the ZEPHYR project

The development of GEN-IV fast reactor technology at an industrial scale will need significant improvement of nuclear data and related uncertainties to cope with awaited target uncertainties (Palmiotti and Salvatores, 2011). However, GEN-IV dedicated Zero Power Facilities are now sparse. In France, both the MASURCA Zero Power Reactor (ZPR) and the future ZEPHYR multipurpose ZPR to be built in Cadarache belong to this type of facilities. For this latest one, fast/thermal coupled configurations performed in MINERVE during the 1970’s have been recently revisited using modern calculation tools. The principle of a fast zone fed by a thermal booster, known from decades as the concept of coupled cores regained interest in recent years. This paper describes the concept of fast/thermal coupled core, a deeper description of the physical characteristics of the adaptation zone, and its use in the improvement of fast-spectrum nuclear data thanks to integral experiments. An optimized configuration is then presented. The preliminary design phase is performed using deterministic tools, a posteriori validated against a full Monte Carlo calculation. Particular attention is paid on the impact of the buffer zone on the spectral characteristics in the oscillation channel, as well as the sample mass characteristics required to ensure a proper signal analysis. Moreover, preliminary studies dedicated to the experimental realization of such a configuration are described, including the reactivity stability in case of an accidental flooding of the fast central zone.

The stabilization system of primary oscillation for a micromechanical gyroscope

The mode of primary oscillations of a micromechanical gyroscope (MMG) sensor is provided by an electrostatic comb-drive actuator in which the interaction between the micromechanical structures and electronics occurs by means of a single or differential capacitive sensor. Two pairs of capacitive sensors are traditionally used for frequency stabilization of MMG primary oscillations. The first pair of capacitive sensors excites primary oscillations, while the second measures the amplitude of primary oscillations. The stabilization system provides a continuous frequency tuning of primary oscillations that increases the duration of transition processes, the time of operational readiness, and the instability of the output signal from the secondary oscillation channel of the MMGs. This paper presents a new approach to the primary oscillation control system of the two-component MMG. The method of calculating the natural resonant frequency is based on measurements of the total current passing through the comb-driver actuator capacitances, and a lock-in detection is suggested. This paper consists of the results of the numerical analysis, the description of the proposed approach to the frequency control of the primary MMG oscillations, and the Simulink model of the behaviour of the MMG stabilization system, depending on its mechanical-and-physical properties with regard to a 2% shift of the natural resonant frequency. The frequency control of the primary oscillations at 2% frequency detuning is performed within 0.11 s.

Can we probe intrinsic CP and T violations and nonunitarity at long baseline accelerator experiments?

One of the fundamental parameters entering neutrino oscillation framework is the leptonic CP phase $\delta_{13}$ and its measurement is an important goal of the planned long baseline experiments. It should be noted that ordinary matter effects complicate the determination of this parameter and there are studies in literature that deal with separation of intrinsic versus extrinsic CP violation. It is important to investigate the consequences of new physics effects that can not only hamper the measurement of $\delta_{13}$, but also impact the consequences of discrete symmetries such as CP, T and unitarity in different oscillation channels. In the present work, we explore these discrete symmetries and implications on unitarity in presence of two new physics scenarios (non-standard interaction in propagation and presence of sterile neutrinos) that serve as good examples of going beyond the standard scenario in different directions. We uncover the impact of new physics scenarios on disentangling intrinsic and extrinsic CP violation.

Latest results of OPERA

OPERA is a long baseline neutrino experiment which took data between 2008 and 2012 having for goal the observation of the νμ→ντ transition in appearance mode i.e. detecting the τ lepton. The detector was located in the underground Gran Sasso laboratory, 730 km away from the CNGS neutrino beam production at CERN. The collaboration observed 5 ντ candidates which, considering the very low expected background of 0.25 events, allowed for a discovery claim of neutrino oscillation in appearance mode at the level of 5.1 σ. Additional analyses were performed aiming at the possible observation of the νμ→νe transition, and at the search for anomalies related to the possible existence of a sterile neutrino. In this paper, after a short introduction describing the detector, the different results are presented on both oscillation channels including standard 3 flavour scenario and possible new physics.

Results from the OPERA experiment

The OPERA neutrino experiment was designed to perform a unique v τ appearance measurement in the v μ CNGS beam to confirm the oscillation mechanism in the atmospheric sector v μ → v τ . The detection of v τ leptons produced in v τ CC interactions and of their decays is accomplished exploiting the high spatial resolution of nuclear emulsions. Five v τ candidate events have been detected in the full data sample from 2008-2012 CNGS runs, with an expected background of 0.25 events. The background only hypothesis is rejected with a significance larger than 5 σ. The analysis of the tau neutrino sample in the framework of the 3+1 neutrino model is also presented. Furthermore OPERA good capabilities in detecting electron neutrino interactions allow setting limits on the v μ → v e oscillation channel.

Robust Training Symbol Assisted Least Squares Estimation for Direct Conversion Receivers with Oscillator IQ-Imbalance

The direct conversion receiver is attractive for being able to provide low-cost and compact receiver design for wireless communications. However, the oscillator imbalance in the in-phase and quadrature components of its mixing sinusoid introduces additional self-image interference, which is a non-linear effect to the received signal. Relying on just one OFDM training symbol, we formulate the joint estimation of oscillator imbalance, DC offset, and channel response as a linear model. A low-complexity least squares (LS) estimation method is then proposed. The transformation matrix in our model is shown to be of full rank with probability 1, which allows our LS approach to be realizable for a variety of training OFDM symbols. Justified by simulation results, our method outperforms the other three LS methods in the literature.

Electric ion dispersion as a new type of mass spectrometer

At the 2014 Fields-MPrime Industrial Problem Solving Workshop, PerkinElmer presented a design problem for mass spectrometry. Traditionally, mass spectrometry is done via three methods: using magnetic fields to deflect charged particles whereby different masses bend differently; using a time-of-flight procedure where particles of different mass arrive at different times at a target; and using an electric quadrupole that filters out all masses except for one very narrow band. The challenge posed in the problem was to come up with a new design for mass spectrometry that did not involve magnetic fields and where mass fractions could be measured in an entire sample on a continuous basis. We found that by sending the sample particles down a channel of line charges oscillations would be induced with a spatial wavelength being mass dependent thereby allowing different masses to be separated spatially and potentially detected on a continuous basis, without the use of magnetic fields. In this paper, we present the analysis of our design and illustrate how this principle could be used for mass spectrometry.

Constraining the nonstandard interaction parameters in long baseline neutrino experiments

In this article we investigate the prospects for probing the strength of the possible non-standard neutrino interactions (NSI) in long baseline neutrino oscillation experiments. We find that these experiments are sensitive to NSI couplings down to the level of 0.01-0.1 depending on the oscillation channel and the baseline length, as well as on the detector's fiducial mass. We also investigate the interference of the leptonic CP angle $\delta_{CP}$ with the constraining of the NSI couplings. It is found that the interference is strong in the case of the $\nu_{e}\leftrightarrow\nu_{\mu}$ and $\nu_{e}\leftrightarrow\nu_{\tau}$ transitions but not significant in other transitions. In our numerical analysis we apply the GLoBES software and use the LBNO setup as our benchmark.

Results from the OPERA experiment

The OPERA neutrino experiment was designed to perform a unique appearance measurement in the CNGS beam to confirm the oscillation mechanism in the atmospheric sector. Runs were successfully carried out from 2008 to 2012. The detection of τ leptons produced in ντ CC interactions and of their decays is accomplished exploiting the high spatial resolution of nuclear emulsions. Furthermore OPERA has good capabilities in detecting electron neutrino interactions, setting limits on the νμ→νe oscillation channel. The status of the analysis is reported together with updated results on both oscillation channels.

Systematic uncertainties in long-baseline neutrino oscillations for largeθ13

We study the physics potential of future long-baseline neutrino oscillation experiments at large $\theta_{13}$, focusing especially on systematic uncertainties. We discuss superbeams, \bbeams, and neutrino factories, and for the first time compare these experiments on an equal footing with respect to systematic errors. We explicitly simulate near detectors for all experiments, we use the same implementation of systematic uncertainties for all experiments, and we fully correlate the uncertainties among detectors, oscillation channels, and beam polarizations as appropriate. As our primary performance indicator, we use the achievable precision in the measurement of the CP violating phase $\deltacp$. We find that a neutrino factory is the only instrument that can measure $\deltacp$ with a precision similar to that of its quark sector counterpart. All neutrino beams operating at peak energies $\gtrsim 2$ GeV are quite robust with respect to systematic uncertainties, whereas especially \bbeams and \thk suffer from large cross section uncertainties in the quasi-elastic regime, combined with their inability to measure the appearance signal cross sections at the near detector. A noteworthy exception is the combination of a $\gamma=100$ \bbeam with an \spl-based superbeam, in which all relevant cross sections can be measured in a self-consistent way. This provides a performance, second only to the neutrino factory. For other superbeam experiments such as \lbno and the setups studied in the context of the \lbne reconfiguration effort, statistics turns out to be the bottleneck. In almost all cases, the near detector is not critical to control systematics since the combined fit of appearance and disappearance data already constrains the impact of systematics to be small provided that the three active flavor oscillation framework is valid.

Golden channel at a neutrino factory revisited: Improved sensitivities from a magnetized iron neutrino detector

This paper describes the performance and sensitivity to neutrino mixing parameters of a Magnetised Iron Neutrino Detector at a Neutrino Factory with a neutrino beam created from the decay of 10 GeV muons. Specifically, it is concerned with the ability of such a detector to detect muons of the opposite sign to those stored (wrong-sign muons) while suppressing contamination of the signal from the interactions of other neutrino species in the beam. A new, more realistic simulation and analysis, which improves the efficiency of this detector at low energies, has been developed using the GENIE neutrino event generator and the GEANT4 simulation toolkit. Low-energy neutrino events down to 1 GeV were selected, while reducing backgrounds to the ${10}^{\ensuremath{-}4}$ level. Signal efficiency plateaus of $\ensuremath{\sim}60%$ for ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ and $\ensuremath{\sim}70%$ for ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ events were achieved starting at $\ensuremath{\sim}5\text{ }\text{ }\mathrm{GeV}$. Contamination from the ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ oscillation channel was studied for the first time and was found to be at the level between 1% and 4%. Full response matrices are supplied for all the signal and background channels from 1 GeV to 10 GeV. The sensitivity of an experiment involving a Magnetised Iron Neutrino Detector detector of 100 ktons at 2000 km from the Neutrino Factory is calculated for the case of ${sin}^{2}2{\ensuremath{\theta}}_{13}\ensuremath{\sim}{10}^{\ensuremath{-}1}$. For this value of ${\ensuremath{\theta}}_{13}$, the accuracy in the measurement of the $CP$-violating phase is estimated to be $\ensuremath{\Delta}{\ensuremath{\delta}}_{CP}\ensuremath{\sim}3\ifmmode^\circ\else\textdegree\fi{}--5\ifmmode^\circ\else\textdegree\fi{}$, depending on the value of ${\ensuremath{\delta}}_{CP}$, the $CP$ coverage at $5\ensuremath{\sigma}$ is 85% and the mass hierarchy would be determined with better than $5\ensuremath{\sigma}$ level for all values of ${\ensuremath{\delta}}_{CP}$.

Probing the neutrino mass hierarchy with Super-Kamiokande

We show that for recently discovered large values of theta(13), a superbeam with an average neutrino energy of ~ 5 GeV, such as those being proposed at CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino mass hierarchy at 5 sigma in less than two years irrespective of the true hierarchy and CP phase. The measurement relies on the near resonant matter effect in the numu to nue oscillation channel, and can be done counting the total number of appearance events with just a neutrino beam.