Xenon doping of liquid argon in ProtoDUNE single phase

The Deep Underground Neutrino Experiment (DUNE) will be the next generation long-baseline neutrino experiment. The far detector is designed as a complex of four LAr-TPC (Liquid Argon Time Projection Chamber) modules with 17 kt of liquid argon each. The development and validation of the first far detector technology is pursued through ProtoDUNE Single Phase (ProtoDUNE-SP), a 770 t LAr-TPC at CERN Neutrino Platform. Crucial in DUNE is the photon detection system that will ensure the trigger of non-beam events — proton decay, supernova neutrino burst and BSM searches — and will improve the timing and calorimetry for neutrino beam events. Doping liquid argon with xenon is a known technique to shift the light emitted by argon (128 nm) to a longer wavelength (178 nm) to ease its detection. The largest xenon doping test ever performed in a LAr-TPC was carried out in ProtoDUNE-SP. From February to May 2020, a gradually increasing amount of xenon was injected to also compensate for the light loss due to air contamination. The response of such a large TPC has been studied using the ProtoDUNE-SP Photon Detection System (PDS) and a dedicated setup installed before the run. With the first it was possible to study the light collection efficiency with respect to the track position, while with the second it was possible to distinguish the xenon light (178 nm) from the LAr light (128 nm). The light shifting mechanism proved to be highly efficient even at small xenon concentrations (<20 ppm in mass) furthermore it allowed recovering the light quenched by pollutants. The light collection improved far from the detection plane, enhancing the photon detector response uniformity along the drift direction and confirming a longer Rayleigh scattering length for 178 nm photons, with respect to 128 nm ones. The charge collection by the TPC was monitored proving that xenon up to 20 ppm does not impact its performance.

Neutrino beam driven instability of magnetosonic waves in the presence of obliquemagnetic field and ion-neutral collisional effect in plasmas

The neutrino beam driven instability of fast and slow magnetosonic waves with oblique applied magnetic field in multi-component ion, electron, and neutrino beam plasma is studied. The dissipation effects of ion-neutral collisions are also included in the model. The neutrino and electron interactions through electro-weak force are included. It is found that the dissipation of ion collisions has significant effect on the phase velocity of the wave propagation and growth rate of the neutrino beam driven instability. The analytical expression of the growth rate of the fast and slow magnetosonic waves instability is found under the weak neutrino beam approximation and in the absence of ions and neutrals (atoms) collision effect. The numerical illustration of growth rates of the fast and slow magnetosonic waves are also presented with variations of magnetic field angle, neutrino beam energy, neutrino beam density, magnetic field intensity. It is found that the growth rate of the fast magnetosonic wave is maximum in case of the perpendicular directed magnetic field to the direction of wave propagation, while growth rate of slow magnetosonic wave is minimum in that case. It is also noticed that growth rate of fast magnetosonic wave comes out to be larger (of the order tens) than the slow magnetosonic wave case, which is quite different from earlier published results of Type II core-collapse supernova.

Deep Underground Neutrino Experiment (DUNE) Near Detector Conceptual Design Report

The Deep Underground Neutrino Experiment (DUNE) is an international, world-class experiment aimed at exploring fundamental questions about the universe that are at the forefront of astrophysics and particle physics research. DUNE will study questions pertaining to the preponderance of matter over antimatter in the early universe, the dynamics of supernovae, the subtleties of neutrino interaction physics, and a number of beyond the Standard Model topics accessible in a powerful neutrino beam. A critical component of the DUNE physics program involves the study of changes in a powerful beam of neutrinos, i.e., neutrino oscillations, as the neutrinos propagate a long distance. The experiment consists of a near detector, sited close to the source of the beam, and a far detector, sited along the beam at a large distance. This document, the DUNE Near Detector Conceptual Design Report (CDR), describes the design of the DUNE near detector and the science program that drives the design and technology choices. The goals and requirements underlying the design, along with projected performance are given. It serves as a starting point for a more detailed design that will be described in future documents.

Neutrino beam-dump experiment with FASER at the LHC

The neutrino physics program at the LHC, which will soon be initiated by the FASER experiment, will provide unique opportunities for precision studies of neutrino interaction vertices at high energies. This will also open up the possibility to search for beyond the standard model (BSM) particles produced in such interactions in the specific high-energy neutrino beam-dump experiment. In this study, we illustrate the prospects for such searches in models with the dipole or Z′ portal to GeV-scale heavy neutral leptons. To this end, we employ both the standard signature of new physics that consists of a pair of oppositely-charged tracks appearing in the decay vessel, and the additional types of searches. These include high-energy photons and single scattered electrons. We show that such a variety of experimental signatures could significantly extend the sensitivity reach of the future multi-purpose FASER 2 detector during the High-Luminosity phase of the LHC.

Predicting transport effects of scintillation light signals in large-scale liquid argon detectors

Liquid argon is being employed as a detector medium in neutrino physics and Dark Matter searches. A recent push to expand the applications of scintillation light in Liquid Argon Time Projection Chamber neutrino detectors has necessitated the development of advanced methods of simulating this light. The presently available methods tend to be prohibitively slow or imprecise due to the combination of detector size and the amount of energy deposited by neutrino beam interactions. In this work we present a semi-analytical model to predict the quantity of argon scintillation light observed by a light detector with a precision better than $$10\%$$ 10 % , based only on the relative positions between the scintillation and light detector. We also provide a method to predict the distribution of arrival times of these photons accounting for propagation effects. Additionally, we present an equivalent model to predict the number of photons and their arrival times in the case of a wavelength-shifting, highly-reflective layer being present on the detector cathode. Our proposed method can be used to simulate light propagation in large-scale liquid argon detectors such as DUNE or SBND, and could also be applied to other detector mediums such as liquid xenon or xenon-doped liquid argon.

Measurements of $\overline{\nu}_{\mu}$ and $\overline{\nu}_{\mu} + \nu_{\mu}$ charged-current cross-sections without detected pions or protons on water and hydrocarbon at a mean anti-neutrino energy of 0.86 GeV

We report measurements of the flux-integrated $\overline{\nu}_\mu$ and $\overline{\nu}_\mu+\nu_\mu$ charged-current cross-sections on water and hydrocarbon targets using the T2K anti-neutrino beam with a mean beam energy of 0.86 GeV. The signal is defined as the (anti-)neutrino charged-current interaction with one induced $\mu^\pm$ and no detected charged pion or proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton Module. The phase space of muons is restricted to the high-detection efficiency region, $p_{\mu}&gt;400~{\rm MeV}/c$ and $\theta_{\mu}&lt;30^{\circ}$, in the laboratory frame. An absence of pions and protons in the detectable phase spaces of $p_{\pi}&gt;200~{\rm MeV}/c$, $\theta_{\pi}&lt;70^{\circ}$ and $p_{\rm p}&gt;600~{\rm MeV}/c$, $\theta_{\rm p}&lt;70^{\circ}$ is required. In this paper, both the $\overline{\nu}_\mu$ cross-sections and $\overline{\nu}_\mu+\nu_\mu$ cross-sections on water and hydrocarbon targets and their ratios are provided by using the D’Agostini unfolding method. The results of the integrated $\overline{\nu}_\mu$ cross-section measurements over this phase space are $\sigma_{\rm H_{2}O}=(1.082\pm0.068(\rm stat.)^{+0.145}_{-0.128}(\rm syst.)) \times 10^{-39}\,{\rm cm^{2} / nucleon}$, $\sigma_{\rm CH}=(1.096\pm0.054(\rm stat.)^{+0.132}_{-0.117}(\rm syst.)) \times 10^{-39}\,{\rm cm^{2} / nucleon}$, and $\sigma_{\rm H_{2}O}/\sigma_{\rm CH} = 0.987\pm0.078(\rm stat.)^{+0.093}_{-0.090}(\rm syst.)$. The $\overline{\nu}_\mu+\nu_\mu$ cross-section is $\sigma_{\rm H_{2}O} = (1.155\pm0.064(\rm stat.)^{+0.148}_{-0.129}(\rm syst.)) \times 10^{-39}\,{\rm cm^{2} / nucleon}$, $\sigma_{\rm CH}=(1.159\pm0.049(\rm stat.)^{+0.129}_{-0.115}(\rm syst.)) \times 10^{-39}\,{\rm cm^{2} / nucleon}$, and $\sigma_{\rm H_{2}O}/\sigma_{\rm CH}=0.996\pm0.069(\rm stat.)^{+0.083}_{-0.078}(\rm syst.)$.

A high precision narrow-band neutrino beam: The ENUBET project

The knowledge of the initial flux, energy and flavor of current neutrino beams is the main limitation for a precise measurement of neutrino cross-sections. The ENUBET ERC project is studying a facility based on a narrow-band neutrino beam capable of constraining the neutrino fluxes normalization through the monitoring of the associated charged leptons in an instrumented decay tunnel. In ENUBET, the identification of large-angle positrons from [Formula: see text] decays at single particle level can potentially reduce the [Formula: see text] flux uncertainty at the level of 1%. This setup would allow for an unprecedented measurement of the [Formula: see text] cross-section at the GeV scale. This input would be highly beneficial to reduce the budget of systematic uncertainties in the next long baseline oscillation projects. Furthermore, in narrow-band beams, the transverse position of the neutrino interaction at the detector can be exploited to determine a priori with significant precision the neutrino energy spectrum without relying on the final state reconstruction. This contribution will present the advances in the design and simulation of the hadronic beam line. Special emphasis will be given to a static focusing system of secondary mesons that can be coupled to a slow extraction proton scheme. The consequent reduction of particle rates and pile-up effects makes the determination of the [Formula: see text] flux through a direct monitoring of muons after the hadron dump viable, and paves the way to a time-tagged neutrino beam. Time-coincidences among the lepton at the source and the neutrino at the detector would enable an unprecedented purity and the possibility to reconstruct the neutrino kinematics at source on an event-by-event basis. We will also present the performance of positron tagger prototypes tested at CERN beamlines, a full simulation of the positron reconstruction chain and the expected physics reach of ENUBET.