Muon Neutrino Beam Research Articles

The CNGS neutrino beam

The CNGS (CERN Neutrinos to Gran Sasso) project aims to produce a muon neutrino beam for the investigation of the oscillations of neutrinos. The beam is directed from CERN SPS accelerator to the Gran Sasso National Laboratory (LNGS) of the INFN in Italy, 730 km from CERN, where the OPERA experiment is designed to search for the appearance of tau neutrinos in the beam. Construction of the beam started in September 2000 and commissioning ended in early August 2006. The beam was first sent to Gran Sasso on August 17, 2006. An overview of the CNGS project and of the commissioning is provided.

Resolving the eightfold neutrino parameter degeneracy by two identical detectors with different baselines

We have shown in a previous paper that two identical detectors with each fiducial mass of 0.27 megaton water, one in Kamioka and the other in Korea, which receive the (anti-) muon neutrino beam of 4 MW power from J-PARC facility have potential of determining the neutrino mass hierarchy and discovering $CP$ violation by resolving the degeneracies associated with them. In this paper, we point out that the same setting has capability of resolving the ${\ensuremath{\theta}}_{23}$ octant degeneracy in region where ${sin}^{2}2{\ensuremath{\theta}}_{23}\ensuremath{\lesssim}0.97$ at 2 standard deviation confidence level even for very small values of ${\ensuremath{\theta}}_{13}$. Altogether, it is demonstrated that one can solve all the eightfold neutrino parameter degeneracies in situ by using the Tokai-to-Kamioka-Korea setting if ${\ensuremath{\theta}}_{13}$ is within reach by the next generation superbeam experiments. We also prove the property called ``decoupling between the degeneracies'', which is valid to first-order in perturbation theory of the earth matter effect, that guarantees approximate independence between analyses to solve any one of the three different type of degeneracies.

K2K and T2K

K2K is the first accelerator experiment to investigate neutrino oscillation in the Δm2 region of atmospheric neutrinos. The observed energy dependent disappearance of νµ leads, with a preliminary analysis of the full statistics, to the determination of sin22θ = 1.19±0.23 and Δm2 = (2.55±0.40)×10−3 eV2. The T2K experiment, follow-up of K2K, will start data taking in 2009. T2K will use the new high intensity muon neutrino beam now under construction at JPARC. Neutrino interactions will be detected, as for K2K, in SuperKamiokande at a distance of 295 km. Main goals of the experiment are a high sensitivity search for νe appearance and a study of νµ with precision δ(Δm223) ∼ 1 × 10−4eV2 and δ(sin22θ23) ∼ 0.01.

Search for neutrino-induced charged current coherent pion production with carbon in a 1.3 GeV wide band muon neutrino beam

The search for charged-current coherent pion production induced by neutrinos with a mean energy of 1.3 GeV is discussed. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed and an upper limit of 0.60 × 10 − 2 is set on the cross section ratio of coherent pion production to the total charged current interaction at the 90% confidence level.

Calculation of intervention doses for the CNGS facility

The purpose of the CNGS (CERN Neutrinos to Gran Sasso) project is to generate at CERN a powerful artificial muon–neutrino beam aimed at the Gran Sasso Laboratory in Italy. There, detectors will detect those neutrinos and try to disentangle those, which on their 730 km trip have changed their flavour. During the operating lifetime of the neutrino beam facility some interventions are required. These maintenance operations have to be planned in advance to define the guidelines of design and operational procedures in order to keep the doses received by personnel As Low As Reasonably Achievable (ALARA-principle). A calculational method developed for the Monte Carlo simulation program FLUKA has been used, which allows one to compute dose equivalent rates from induced radioactivity for different cooling times in the regions of the human intervention. In this paper the method of calculation is described, the results of dose equivalent rate in the areas of interventions are summarized and discussed and finally, these results are applied to estimate doses received by personnel during interventions.

Measurement of single [formula omitted] production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam

Neutral current single π0 production induced by neutrinos with a mean energy of 1.3 GeV is measured using a 1000 ton water Cherenkov detector in the K2K long baseline neutrino experiment. The cross section for this process relative to the total charged current cross section is measured to be 0.064±0.001(stat.)±0.007(sys.). The momentum distribution of neutral current π0s from a water target is measured with high statistics for the first time.

Evidence for Muon Neutrino Oscillation in an Accelerator-Based Experiment

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).

Charm physics with neutrinos

High energy neutrino interactions induce charmed hadron production at the level of a few percent and therefore they constitute a powerful tool to study charm physics. Recently the CHORUS experiment has published new results on charm physics with the muon neutrino beam at CERN, profiting of the possibility to identify the charm production and decay vertexes with nuclear emulsions. These results are reviewed and included in the general picture of charm physics with neutrinos.

Neutral Current π0 Interactions at MiniBooNE

MiniBooNE, the Mini Booster Neutrino Experiment at Fermilab, will search for the appearance of electron neutrinos in a beam of muon neutrinos, and in the process will accumulate more neutrino interactions in the 0 − 2 GeV energy range than all past experiments. This work presents preliminary results from the neutral current π0 analysis at MiniBooNE, with comparisons of the NUANCE, NEUGEN, and NEUT neutrino cross section Monte Carlos. Also presented are comparisons of three Monte Carlo simulations with MiniBooNE data taken during the running period from September, 2002, to September, 2003.

Testing the Maximal Nature of Muon Neutrino Flavor Mixing

The small difference between the survival probabilities of muon neutrino and antineutrino beams, traveling through Earth matter in a long baseline experiment such as MINOS, is shown to be an important measure of any possible deviation from maximality in the flavor mixing of those states.

The NuMI off-axis long baseline experiment

Several different experiments have now established that neutrinos do oscillate or may have presented experimental evidence that can be explained by neutrino oscillations [1,2,3,4,5]. The purpose of future experiments is now to measure with high precision the parameters of the neutrino mixing or so-called MNS matrix. One of those experiments is planned at the powerful NuMI neutrino beam line. The experiment is especially designed to obtain a high sensitivity for electron neutrino appearance in a muon neutrino beam. This measurement is related to the mixing angle Θ13, which is so far undetermined from previous measurements. This article will report on possible technology choices and the physics reach of the experiment.

Measurement of the Z/A dependence of neutrino charged-current total cross-sections

A relative measurement of total cross-sections is reported for polyethylene, marble, iron, and lead targets for the inclusive charged-current reaction νμ + N → μ- + X. The targets, passive blocks of ∼ 100 kg each, were exposed simultaneously to the CERN SPS wide-band muon-neutrino beam over a period of 18 weeks. Systematic effects due to differences in the neutrino flux and detector efficiency for the different target locations were minimised by changing the position of the four targets on their support about every two weeks. The relative neutrino fluxes on the targets were monitored within the same experiment using charged-current interactions in the calorimeter positioned directly downstream of the four targets. From a fit to the Z/A dependence of the total cross-sections a value is deduced for the effective neutron-to-proton cross-section ratio.

Experimental Highlights from Gran Sasso Laboratory

The Gran Sasso National Laboratory of the INFN has given important contributions to the discovery of the phenomenon of neutrino oscillations with experiments both on electron neutrinos from the Sun and muon neutrinos indirectly produced by cosmic rays interactions in the atmosphere. Other experiments in the laboratory give the best limits on electron neutrino effective Majorana mass with two different isotopes. We appear to have entered a new physics domain in which the study of neutrinos may lead us to discover new phenomena, corresponding to energy scales by much higher than those of the present accelerators. Underground laboratories are showing their relevance complementary to the colliders for the advance of basic physics. The physics program at the Gran Sasso Laboratory that we are defining will be focussed on neutrino physics with a complementary set of experiments on the muon neutrino beam from CERN (CNGS project), on solar neutrinos, on atmospheric neutrinos and on neutrinos from Supernova explosion. The relevant thermonuclear cross-sections will be measured. The Majorana vs. Dirac nature of electron neutrinos will be explored with the search for neutrino-less double beta decays in different isotopes.

A method for detecting ν τ appearance in the spectra of quasielastic CC events

A method for detecting the transition ν μ→ν τ in long-baseline accelerator experiments, that consists in comparing the far-to-near ratios of the spectra of quasielastic CC events generated by high- and low-energy beams of muon neutrinos, is proposed. The test may be accessible to big water Cherenkov detectors and iron-scintillator calorimeters, and is limited by statistics rather than systematics. In the NuMI program with the MINOS detector, only the Δ m 2 values above some 4×10 −3 eV 2 can be probed.

Mineral oil tests for the MiniBooNE detector

The MiniBooNE experiment will unambiguously confirm or refute the existence of the neutrino oscillation signal seen by the liquid scintillator neutrino detector (LSND) experiment at Los Alamos National Laboratory. MiniBooNE will search for the appearance of electron neutrinos in a beam of muon neutrinos. The MiniBooNE detector is a 12-m-diameter sphere filled with mineral oil and instrumented with photomultiplier tubes. The properties of the mineral oil chosen to fill this Cerenkov detector will be important to the experiment. The production of scintillation light in the oil, the attenuation of light across the detector, and the index of refraction of the oil are all important properties that must be known in order to properly model the detector. Fluorescence of the oil, optical dispersion, and oil density are also important quantities. The fluorescence spectra for several pure mineral oils as well as mineral oils doped with a small amount of various fluors were measured to determine the expected scintillation spectra from those oils. Index of refraction measurements were made in order to determine the Cerenkov angle and the dispersion for each oil. Attenuation tests were performed to rind an oil with maximal attenuation length and with no abnormal absorption features. This paper presents measurements of some of the oil properties, which are made at Fermilab using several experimental setups. Based on the results of these tests (and a price within budget constraints), Marcol 7 oil was selected for the MiniBooNE experiment.

A novel concept for a /ν neutrino factory: the beta-beam

The evolution of neutrino physics demands new schemes to produce intense, collimated and pure neutrino beams. The current neutrino factory concept implies the production, collection, and storage of muons to produce beams of muon and electron neutrinos at equal intensities at the same time. Research and development addressing its feasibility are ongoing. In the current Letter, a new neutrino factory concept is proposed that could possibly achieve beams of high intensity, known energy spectrum and a single neutrino flavour (electron–antineutrino or electron–neutrino). The scheme relies on existing technology.

Physics beyond the Standard Model: experiments at the Gran Sasso Laboratory

Experiments in underground laboratories have shown strong evidence of physics beyond the Standard Model. The anomalies observed in electron neutrinos from the sun andmuon neutrinos from cosmic rays interacting in the atmosphere can be explained if neutrinos are massive and oscillate. The physics program at the Gran Sasso Laboratory that we are defining will focus on the next phase of neutrino physics with acomplementary set of experiments on the muon-neutrino beam from CERN (CNGS project), on solar neutrinos, on atmospheric neutrinos and on neutrinos from supernova explosions. The relevant thermonuclear cross-sections will be measured. The Majorana vs. Dirac nature of electron neutrinos will be explored with the search for neutrinoless double beta decays in different isotopes. Experiments on non-baryonic dark matter are reaching a sensitivity that brings them close to being able to detect neutralinos in certain optimistic theoretical expectations. The program at Gran Sasso for the next years will include a strong effort to increase further the sensitivity by orders ofmagnitude with different complementary techniques.

Neutrino physics at Gran Sasso Laboratory

Experiments in underground laboratories have shown strong evidence of physics beyond the standard model. The anomalies observed in electron-neutrinos from the sun and muon-neutrinos from cosmic rays interactions in the atmosphere can be explained if neutrino oscillate and are massive. The physics program at the Gran Sasso Laboratory that we are defining will be focussed on the next phase of neutrino physics with a complementary set of experiments on the muon-neutrino beam from CERN (CNGS project), on solar neutrinos, on atmospheric neutrinos and on neutrinos from supernova explosion. The relevant thermonuclear cross-sections will be measured. The Majorana vs. Dirac nature of electron neutrinos will be explored with the search for neutrino-less double beta decays in different isotopes.

Accurate GPS orientation of a long baseline for Neutrino Oscillation Experiments at Fermilab

Recent research in elementary particle physics is concentrating a great amount of effort on neutrino oscillation experiments. These studies require the accurate pointing of neutrino beams between two distant points. The Fermi National Accelerator Laboratory (Fermilab) intends to build a new particle beamline to direct a beam of muon neutrinos from its Main Injector toward a far‐off (735 km away) underground detector capable of searching for non‐zero neutrino mass by looking for neutrino oscillations. This paper describes the GPS work carried out to accurately position the reference ground marks at the two sites from which the spatial orientation of the baseline can be accurately determined. The effect of plate rotations on the absolute orientation of the baseline was also investigated.

Revising neutrino oscillation parameter space with direct flavor-changing interactions

We formulate direct, neutrino flavor-changing interactions in a framework that fits smoothly with the parameterization of two-and three-state mixing of massive neutrino states. We show that even small direct interaction strengths could have important consequences for the interpretation of currently running and proposed oscillation experiments. The oscillation amplitude and the borders of the allowed regions in two-and three-flavor mixing parameter space can be sensitieve to the presence of direct interactions when the transition probability is small. We use extensively the high sensitivity of the NOMAD experiment to illustrate potentially large effects from small, direct flavor violation. In the purely leptonic sector, we find that the clean muon neutrino and electron neutrino beams from a muon collider could provide the sharpest tests of direct flavor violation.