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A. Pritchard

Publications and source records attributed to A. Pritchard.

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Atomtronic Many-Body Transport using Husimi Driving

Quantum systems with exact analytic solutions are rare - challenging the realisation of excitation-free transport methods for many-body systems. Husimi's 1953 treatment of linearly driven harmonic oscillators constitutes an important exception, describing a wavepacket which is spatially translated but otherwise unperturbed by the driving. In this work, we experimentally demonstrate the application of Husimi's solution to an interacting many-body system, namely optically- and magnetically-trapped Bose-Einstein condensates subject to resonant and off-resonant linear magnetic driving potentials. The observed centre-of-mass motion is consistent with theory and shows minimal excitation of the displaced condensate - a highly desirable property of any condensate manipulation technique. We demonstrate transport 72 times faster than adiabatic rates, and a novel Husimi driving-based trap frequency measurement. We finally propose future applications based on our experimental results: an atom interferometry scheme, and methods for extended transport and precision control of one-body, few-body, and many-body systems via Husimi driving.

cond-mat.quant-gas

Evaluation of Gadolinium's Action on Water Cherenkov Detector Systems with EGADS

Used for both proton decay searches and neutrino physics, large water Cherenkov (WC) detectors have been very successful tools in particle physics. They are notable for their large masses and charged particle detection capabilities. While current WC detectors reconstruct charged particle tracks over a wide energy range, they cannot efficiently detect neutrons. Gadolinium (Gd) has the largest thermal neutron capture cross section of all stable nuclei and produces an 8 MeV gamma cascade that can be detected with high efficiency. Because of the many new physics opportunities that neutron tagging with a Gd salt dissolved in water would open up, a large-scale R&D program called EGADS was established to demonstrate this technique's feasibility. EGADS features all the components of a WC detector, chiefly a 200-ton stainless steel water tank furnished with 240 photo-detectors, DAQ, and a water system that removes all impurities in water while keeping Gd in solution. In this paper we discuss the milestones towards demonstrating the feasibility of this novel technique, and the features of EGADS in detail.

physics.ins-det

Mapping the material in the LHCb vertex locator using secondary hadronic interactions

Precise knowledge of the location of the material in the LHCb vertex locator (VELO) is essential to reducing background in searches for long-lived exotic particles, and in identifying jets that originate from beauty and charm quarks. Secondary interactions of hadrons produced in beam-gas collisions are used to map the location of material in the VELO. Using this material map, along with properties of a reconstructed secondary vertex and its constituent tracks, a $p$-value can be assigned to the hypothesis that the secondary vertex originates from a material interaction. A validation of this procedure is presented using photon conversions to dimuons.

physics.ins-det

TITUS: the Tokai Intermediate Tank for the Unoscillated Spectrum

The TITUS, Tokai Intermediate Tank for Unoscillated Spectrum, detector, is a proposed Gd-doped Water Cherenkov tank with a magnetised muon range detector downstream. It is located at J-PARC at about 2 km from the neutrino target and it is proposed as a potential near detector for the Hyper-Kamiokande experiment. Assuming a beam power of 1.3 MW and 27.05 x 10^{21} protons-on-target the sensitivity to CP and mixing parameters achieved by Hyper-Kamiokande with TITUS as a near detector is presented. Also, the potential of the detector for cross sections and Standard Model parameter determination, supernova neutrino and dark matter are shown.

physics.ins-det