Baseline Neutrino Experiment Research Articles

Octant Degeneracy and Quadrant of Leptonic CPV Phase at Long BaselineνExperiments and Baryogenesis

In a recent work by us, we have studied how CP violation discovery potential can be improved at long baseline neutrino experiments (LBNE/DUNE), by combining with its ND (near detector) and reactor experiments. In this work, we discuss how this study can be further analysed to resolve entanglement of the quadrant of leptonic CPV phase and octant of atmospheric mixing angleθ23, at LBNEs. The study is done for both NH (normal hierarchy) and IH (inverted hierarchy), HO (higher octant), and LO (lower octant). We show how baryogenesis can enhance the effect of resolving this entanglement and how possible values of the leptonic CP violating phaseδCPcan be predicted in this context. With respect to the latest global fit data of neutrino mixing angles, we predict the values ofδCPfor different cases. In this context we present favoured values ofδCP(δCPrange at ≥2σ) constrained by the latest updated BAU range and also confront our predictions ofδCPwith an up-to-date global analysis of neutrino oscillation data. We find that some region of the favouredδCPparameter space lies within the best fit values aroundδCP≃1.3π–1.4π. A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in this framework within the nonsupersymmetric SO(10)models.

ICARUS T600: physics results and future activities

The ICARUS T600 detector has proven the effectiveness of Liquid Argon TPC technology with a successful three-year long run at the INFN Gran Sasso National Laboratories (LNGS).ICARUS T600 LNGS data strongly contributed to the global effort in searching for neutrino oscillations mediated by sterile states. A definitive clarification of the sterile neutrino puzzle will come from the new multi-station, Short Baseline Neutrino (SBN) experiment at the Booster Neutrino Beam (BNB) at Fermilab, where a refurbished T600 will act as Far Detector.Presently the T600 detector is located at CERN, undergoing a major overhauling which will allow its participation in the 5 years program of the Fermilab upcoming SBN project. Moreover, ICARUS T600 is also foreseen to collect data with the NUMI Beam to be later exploited in the wider picture of the DUNE Long-Baseline project, recently undertaken by the United States community.This contribution will report the present physics results obtained by the ICARUS Collaboration, as well as describe the overhauling activities and the physics program for the detector in its future deployment at Fermilab.

Search for space charge effects in the ICARUS T600 LAr-TPC

Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The pres- ence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), record- ing cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown.

The new experiment WAGASCI for water to hydrocarbon neutrino cross section measurement using the J-PARC beam

The T2K (Tokai-to-Kamioka) is a long baseline neutrino experiment designed to study various parameters that rule neutrino oscillations, with an intense beam of muon neutrinos. A near detector complex (ND280) is used to constrain non-oscillated flux and hence to predict the expected number of events in the far detector (Super-Kamiokande). The difference in the target material between the far (water) and near (scintillator, hydrocarbon) detectors leads to the main non-canceling systematic uncertainty for the oscillation analysis. In order to reduce this uncertainty a new water grid and scintillator detector, WAGASCI, has been proposed. The detector will be operated at the J-PARC neutrino beam line with the main physics goal to measure the charged current neutrino cross section ratio between water and hydrocarbon with a few percent accuracy. Further physics program may include high-precision measurements of different charged current neutrino interaction channels. The concept of the new detector will be covered together with the actual construction plan.

Large Scale Monte Carlo Simulation of Neutrino Interactions Using the Open Science Grid and Commercial Clouds

Modern long baseline neutrino experiments like the NOvA experiment at Fermilab, require large scale, compute intensive simulations of their neutrino beam fluxes and backgrounds induced by cosmic rays. The amount of simulation required to keep the systematic uncertainties in the simulation from dominating the final physics results is often 10x to 100x that of the actual detector exposure. For the first physics results from NOvA this has meant the simulation of more than 2 billion cosmic ray events in the far detector and more than 200 million NuMI beam spill simulations. Performing these high statistics levels of simulation have been made possible for NOvA through the use of the Open Science Grid and through large scale runs on commercial clouds like Amazon EC2. We details the challenges in performing large scale simulation in these environments and how the computing infrastructure for the NOvA experiment has been adapted to seamlessly support the running of different simulation and data processing tasks on these resources.

Mechanical Properties of Photomultiplier Tube Glasses for Neutrino Detection

Photomultiplier tubes (PMT) are one of the primary components of water Cherenkov neutrino detection for the Long Baseline Neutrino Experiment (LBNE). Thousands of 10‐ to 12‐inch diameter PMT bulbs are placed in the inner wall of a detection tank or a reservoir (e.g., deep mine) filled with 10,000 gallons of high purity water with a resistivity of 11–18.24 MΩ‐cm. Long‐term service of PMTs is vital to the success of neutrino detection projects. We report our results of our investigation on mechanical properties of PMT glasses from two vendors and the effect of ion exchange on their mechanical strength. Vickers indentation, four‐point bend test, and ring‐on‐ring biaxial flexural strength test were used for evaluation of the mechanical strength. Chemical (potassium–sodium ion exchange) strengthening results show increased strength of 46% in one vendor glass and a 57% increase in the other, with no significant reduction in optical transmission in the ultraviolet‐visible range of the electromagnetic spectrum that is critical to neutrino detection. Our results also show narrowing of the distribution of strength calculated using Weibull statistics with chemical strengthening for comparable exchange depths of 22–28 μm.

Hadron Production Measurements from NA61/SHINE

We report on measurements of hadron yields in proton-carbon interactions at 31 GeV/c recorded by the NA61/SHINE experiment at CERN. Results aim to improve the precision of flux predictions for the T2K long baseline neutrino experiment in Japan. Recent measurements based on the 2009 data have reduced uncertainties and extend the kinematic coverage in momentum and polar angle. Results cover the full phase-space of importance to T2K.

The Beamline DAQ System for the T2K Experiment

The T2K (Tokai-to-Kamioka) experiment is a long baseline neutrino experiment designed to observe oscillations from mu neutrinos to electron neutrinos. Through 2013, the system showed stable operation, with 230 kW of beam power and $1.2\times{10^{14}}$ protons per bunch, the highest intensity in the world. This manuscript describes the data acquisition system used to monitor the high-intensity proton beam that produces the neutrino beam. This paper describes the data acquisition system for the monitoring of the primary proton beam and the secondary muon beam.

Performance and Results of the LBNE 35 Ton Membrane Cryostat Prototype

We report on the performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI). LBNE has designed and fabricated the supporting cryogenic system infrastructure and successfully commissioned and operated the first membrane cryostat. Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the purity requirements in a membrane cryostat without evacuation; to demonstrate that we can achieve and maintain the purity requirements of the liquid argon using mol sieve and copper filters. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion (ppt) oxygen equivalent. LBNE is planning the design and construction of a large liquid argon detector. This presentation will present requirements, design and construction of the LBNE 35 ton membrane cryostat prototype, and detail the commissioning and performance. The experience and results of this prototype are extremely important for the development of the LBNE detector.

The LAGUNA-LBNO Project

LAGUNA-LBNO is a Design Study funded by the European Commission to develop the design of a large and deep underground neutrino observatory; its physics program involves the study of neutrino oscillations at long baselines, the investigation of the Grand Unification of elementary forces and the detection of neutrinos from astrophysical sources. Building on the successful format and on the findings of the previous LAGUNA Design Study, LAGUNA-LBNO is more focused and is specifically considering Long Baseline Neutrino Oscillations (LBNO) with neutrino beams from CERN. Two sites, Fréjus (in France at 130km) and Pyhäsalmi (in Finland at 2300km), are being considered. Three different detector technologies are being studied: Water Cherenkov, Liquid Scintillator and Liquid Argon. Recently the LAGUNA-LBNO consortium has submitted an Expression of Interest for a very long baseline neutrino experiment, selecting as a first priority the option of a Liquid Argon detector at Pyhäsalmi. Detailed potential studies have been curried out for the determination of the neutrino Mass Hierarchy and the discovery of the CP-violation, using a conventional neutrino beam from the CERN SPS with a power of 750kW.

Beyond Standard Model Searches in the MiniBooNE Experiment

The MiniBooNE experiment has contributed substantially to beyond standard model searches in the neutrino sector. The experiment was originally designed to test theΔm2~1 eV2region of the sterile neutrino hypothesis by observingνe(ν-e) charged current quasielastic signals from aνμ(ν-μ) beam. MiniBooNE observed excesses ofνeandν-ecandidate events in neutrino and antineutrino mode, respectively. To date, these excesses have not been explained within the neutrino standard model (νSM); the standard model extended for three massive neutrinos. Confirmation is required by future experiments such as MicroBooNE. MiniBooNE also provided an opportunity for precision studies of Lorentz violation. The results set strict limits for the first time on several parameters of the standard-model extension, the generic formalism for considering Lorentz violation. Most recently, an extension to MiniBooNE running, with a beam tuned in beam-dump mode, is being performed to search for dark sector particles. This review describes these studies, demonstrating that short baseline neutrino experiments are rich environments in new physics searches.

NOvA experiment in light of largeθ13

NOvA is an off-axis long baseline neutrino experiment searching for νμ → νe oscillations using an upgraded NuMI neutrino beam from Fermilab, Batavia, IL. The main physics goal is a measurement of the CP violation and establishing the neutrino masses hierarchy. A large 14 kton Far detector, comprised of liquid scintillator contained in extruded PVC cells, will also provide an opportunity for other non-accelerator physics searches. While civil construction at the far detector is underway, a smaller prototype near detector has been assembled at Fermilab and is being studied.

On the polarization of the final nucleon in NC elastic $\nu _\mu (\bar \nu _\mu )$ -N scattering

New short baseline neutrino experiments open new possibilities of high precision study of different neutrino processes. We present here results of the calculation of the polarization of final nucleon in elastic NC \nu_\mu (\bar\nu_\mu)-nucleon scattering. In a numerical analysis the sensitivity to the different choices of the axial and axial strange form factors is examined. Measurements of the polarization of the final proton in elastic e-p scattering drastically changed our knowledge about the electromagnetic form factors of the proton. From measurement of the nucleon polarization in the NC elastic scattering a new additional information about the axial G_A(Q^2} and the strange axial G^s_A(Q^2) form factors of the nucleon could be inferred.

The Sanford Underground Research Facility at Homestake

The Sanford Underground Research Facility (SURF) at Homestake is presented. The Davis campus is described in detail including the two laboratory modules at the 4850-foot level (>4200 mwe). These modules house the LUX dark matter and MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiments. The Long Baseline Neutrino Experiment plans to place their far detector at SURF. The facility is managed for the US Department of Energy (DOE) by Lawrence Berkeley National Laboratory. The South Dakota Science and Technology Authority (SDSTA) owns and operates the facility. SURF is a dedicated science facility with significant expansion capability.

Photon detection in the Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN)

The Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN) is being built at Los Alamos National Laboratory. A hexagonal time projection chamber (TPC) with a 1 m drift length will be constructed inside a cryostat containing 7,700L of liquid argon. CAPTAIN will be used to test interactions using beams of neutrons and neutrinos. It will serve as a test bed for various options for the Long Baseline Neutrino Experiment (LBNE) including in the photon detection system. The current photon detection system will be described and future options discussed. The system is composed of sixteen R8520-500 Hamamatsu photomultiplier tubes with a wavelength shifting coating on acrylic in front of the PMT. Various wavelength shifting coatings can be examined with the current default of tetraphenyl butadiene.

Polarization of the final nucleon in quasi-elastic neutrino scattering and the axial form factor of the nucleon

Measurements of the polarization of the final proton in elastic e–p scattering drastically changed our knowledge about the electromagnetic form factors of the proton. Here we present our results of the calculation of the polarization of the final nucleon in charged current quasi-elastic neutrino nucleon scattering. Relations which connect the axial form factor with the polarization, the cross section and the electromagnetic form factors of the nucleon are derived. Measurements of the polarization of the nucleon in high-statistics short baseline neutrino experiments (or in near detectors of long baseline experiments) could provide important information on the axial form factor of the nucleon.

DAEδALUS: A Path to [formula omitted] Using Cyclotron Decay-at-Rest Neutrino Sources

DAEδALUS is a proposed phased neutrino experiment to search for evidence of CP violation in the neutrino sector, which also provides a rich physics program at each stage of development. The final experiment will comprise several cyclotron-based accelerator units located at three different distances from a single, large underground detector such as LENA, MEMPHYS, or Hyper-K and search for evidence of CP violation in the oscillation probability of muon antineutrinos to electron antineutrinos over baselines of ∼ 20 km. This novel type of search will complement and extend the reach of conventional experiments designed to search for CP violation in neutrino oscillations such as the Long Baseline Neutrino Experiment (LBNE). IsoDAR is a separate proposed experiment possible at an early stage in the development of DAEδALUS. It is a definitive search for sterile neutrinos, capable of ruling out the parameter space allowed by global fits to the Reactor, SAGE, and GALLEX anomalies at 20σ(5σ) in 5 years (4 months).

Long-baseline neutrino oscillation projects and neutrino CP violation in Europe

The discovery that the last mixing angle, θ13, is non-zero, has opened the possibility to address crucial open questions in the coming future: if the CP symmetry is conserved in the leptonic sector; what the neutrino mass ordering is and what the precise values of the mixing parameters are. Long baseline neutrino experiments will be the strategy of choice to answers these questions. We review the theoretical issues for these type of experiments and the ambitious future experimental program which is underway or at the R&D stage in Europe.

Status of 3+N Sterile Neutrino Fits

Tension among recent short baseline neutrino experiments has pointed toward the possible need for one or more additional mass splittings in the existing neutrino oscillation framework. This would require the addition of at least one sterile (non-interacting) neutrino to the current model. This work summarizes fits to world data of models which include one, two, and three sterile neutrinos in the ∼1 eV2 range and provides motivation for future short baseline searches.

Recent results of the OPERA experiment

OPERA is a long baseline neutrino experiment aiming at the first direct observation of the tau neutrino appearance in an almost pure muon neutrino beam. The detector, installed in the hall C of the Gran Sasso National Laboratory, 730 km away from the beam source, is a hybrid apparatus combining nuclear emulsion based detector units together with electronic trackers. Furthermore two spectrometers are used in order to reconstruct charge and momentum of penetrating muon particles. In the first 4 years of data taking OPERA collected 14.2×1019 protons on target (p.o.t.) and 13377 neutrino interactions. In this paper the status of the analysis will be presented together with the oscillation search results.