Hadron production measurements to constrain accelerator neutrino beams

A precise prediction of expected neutrino fluxes is required for a long-baseline accelerator neutrino experiment. The flux is used to measure neutrino cross sections at the near detector, while at the far detector it provides an estimate of the expected signal for the study of neutrino oscillations. In the talk several approaches to constrain the neutrino flux are presented. The first is the traditional one when an interaction chain for the neutrino parent hadrons is stored to be weighted later with real measurements. In this approach differential hadron cross sections are used which, in turn, are measured in ancillary hadron production experiments. The approach is certainly model dependent because it requires an extrapolation to different incident nucleon momenta assuming x_F scaling as well as extrapolation between materials having different atomic numbers. In the second approach one uses a hadron production yields off a real target exploited in the neutrino beamline. Yields of neutrino parent hadrons are parametrized at the surface of the target, thus one avoids to trace the particle interaction history inside the target. As in the case of the first approach, a dedicated ancillary experiment is mandatory. Recent results from the hadron production experiments - NA61/SHINE at CERN (measurements for T2K) and MIPP at Fermilab (measurements for NuMI) - are reviewed.Comment: Presented at the Neutrino 2014 conference in Boston, June 201

A High Pressure Time Projection Chamber with Optical Readout

Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these measurements as part of a future long-baseline neutrino oscillation experiment such as the Deep Underground Neutrino Experiment. In this paper we describe the design and operation of the prototype HPTPC with an argon based gas mixture. We report on the successful hybrid charge and optical readout, using four CCD cameras, of signals from Am-241 sources.Comment: 40 pages, 24 figure

Two-particle correlations in azimuthal angle and pseudorapidity in inelastic p + p interactions at the CERN Super Proton Synchrotron

Results on two-particle ΔηΔϕ correlations in inelastic p + p interactions at 20, 31, 40, 80, and 158 GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the Epos and UrQMD models.ISSN:1434-6044ISSN:1434-605

Search for new physics with the SHiP experiment at CERN

The SHiP Collaboration has proposed a general-purpose experimental facility operating in beam dump mode at the CERN SPS accelerator with the aim of searching for light, long-lived exotic particles of Hidden Sector models. The SHiP experiment incorporates a muon shield based on magnetic sweeping and two complementary apparatuses. The detector immediately downstream of the muon shield is optimised both for recoil signatures of light dark matter scattering and for tau neutrino physics, and consists of a spectrometer magnet housing a layered detector system with heavy target plates, emulsion film technology and electronic high precision tracking. The second detector system aims at measuring the visible decays of hidden sector particles to both fully reconstructible final states and to partially reconstructible final states with neutrinos, in a nearly background free environment. The detector consists of a 50 m long decay volume under vacuum followed by a spectrometer and particle identification with a rectangular acceptance of 5 m in width and 10 m in height. Using the high-intensity beam of 400 GeV protons, the experiment is capable of integrating $2\cdot 10^{20}$ protons in five years, which allows probing dark photons, dark scalars and pseudo-scalars, and heavy neutrinos with GeV-scale masses at sensitivities that exceed those of existing and projected experiments. The sensitivity to heavy neutrinos will allow for the first time to probe, in the mass range between the kaon and the charm meson mass, a coupling range for which baryogenesis and active neutrino masses can be explained. The sensitivity to light dark matter reaches well below the elastic scalar Dark Matter relic density limits in the range from a few MeV/$c^2$ up to 200 MeV/$c^2$. Following the review of the Technical Proposal, the CERN SPS Committee recommended in 2016 that the experiment and the beam dump facility studies proceed to a Comprehensive Design Study phase. These studies have resulted in a mature proposal submitted to the European Strategy for Particle Physics Update

Calibrating the SHiP muon-flux using NA61/SHINE

A major concern for the design of the SHiP experiment is the lack of a precise knowledge of the muon flux. This is a proposal to measure the expected muon flux in the SHiP experiment by installing a replica of the SHiP target in a 400 GeV proton beam in front of the NA61/SHINE spectrometer. We propose to do a first measurement in 2017

Application of SiPM arrays for the readout of a scintillator based time-of-flight detector

A feasibility study of replacing a conventional phototube with an array of SiPMs is presented. High gain, low voltage operation and insensitivity to the magnetic field make SiPMs practically useful for the light collection in a physics experiment. In addition, sensors can be assembled in a compact system which is easily scalable. In this study an array of 6 mm x 6 mm area SiPMs was coupled to the end of a plastic scintillator counter with dimensions 150 cm x 6 cm x 1 cm. The principal restriction for applications requiring an accurate evaluation of the photons arrival time is a large SiPM capacitance which results in broadening of the signal rise time. A natural solution of the problem is to read out and amplify the sensors independently, thus essentially isolating the sensor capacitances from each other. For this purpose an 8 channel SiPM anode readout ASIC (MUSIC R1) has been used. Prospects for applications in large-scale particle physics detectors of the SHIP and T2K/ND280 experiments with timing resolution below 100 ps are provided in light of the results

Measurement of the muon flux for the SHiP experiment

We report the results of the measurement of the muon flux emanating from the SHiP target at the CERN SPS. A replica of the SHiP target followed by a $2.4~\rm{m}$ iron hadron absorber was installed in the H4 400 GeV/c proton beamline. To measure the momentum spectrum, a spectrometer consisting of drift tubes and resistive plate chambers (RPCs) was placed around the Goliath magnet. During a three week period a dataset for analysis corresponding to $3.27 \times 10^{11}$ protons on target (POT) was recorded. This amounts to approximatively $1\%$ of a SHiP spill. The amount of accumulated data allows us to make a validation of the results from our Pythia and Geant4 based Monte Carlo (FairShip)

Timepix3 as solid-state time-projection chamber in particle and nuclear physics

Timepix3 devices are hybrid pixel detectors developed within the Medipix3 collaboration at CERN providing a simultaneous measurement of energy (ToT) and time of arrival (ToA) in each of its 256×256 pixels (pixel pitch: 55 µm). The timestamp resolution below 2 ns allows a measurement of charge carrier drift times, so that particle trajectories can be reconstructed in 3D on a microscopic level (z-resolution: 30-60 µm). The 3D trajectory reconstruction methodology developed elsewhere is validated against simulated data providing ground truth information of the incident angles. The detector response functions and the achievable track angular resolutions are determined. For the first time, data taken with Timepix3 in the MoEDAL experiment are presented. After extracting singly charged minimum ionizing particle (MIP) tracks from the mixed radiation field using characteristic track features, their impact angles are evaluated. The directionality of the MIP radiation field is shown in elevation angle (θ) versus azimuthal angle (ϕ) maps, "unfolded" using the simulated detector responses to an omnidirectional radiation field.ISSN:1824-803