Discovering Long-lived Particles at DUNE

Long-lived particles (LLPs) arise in many theories beyond the Standard Model. These may be copiously produced from meson decays (or through their mixing with the LLP) at neutrino facilities and leave a visible decay signal in nearby neutrino detectors. We compute the expected sensitivity of the DUNE liquid argon (LAr) and gaseous argon (GAr) near detectors (ND) to light LLP decays. In doing so, we determine the expected backgrounds for both detectors, which have been largely overlooked in the literature, taking into account their angular and energy resolution. We show that searches for LLP decays into muon pairs, or into three pions, would be extremely clean. Conversely, decays into two photons would be affected by large backgrounds from neutrino interactions for both near detectors; finally, the reduced signal efficiency for $e^+ e^-$ pairs leads to a reduced sensitivity for ND-LAr. Our results are first presented in a model-independent way, as a function of the mass of the new state and its lifetime. We also provide detailed calculations for several phenomenological models with axion-like particles (coupled to gluons, to electroweak bosons, or to quark currents). Some of our results may also be of interest for other neutrino facilities using a similar detector technology (e.g. MicroBooNE, SBND, ICARUS, or the T2K Near Detector).Comment: 34 pages, 11 Figure

The dynamics of ions on phased radio-frequency carpets in high pressure gases and application for barium tagging in xenon gas time projection chambers

NEXT Collaboration: et al.Radio-frequency (RF) carpets with ultra-fine pitches are examined for ion transport in gases at atmospheric pressures and above. We develop new analytic and computational methods for modeling RF ion transport at densities where dynamics are strongly influenced by buffer gas collisions. An analytic description of levitating and sweeping forces from phased arrays is obtained, then thermodynamic and kinetic principles are used to calculate ion loss rates in the presence of collisions. This methodology is validated against detailed microscopic SIMION simulations. We then explore a parameter space of special interest for neutrinoless double beta decay experiments: transport of barium ions in xenon at pressures from 1 to 10 bar. Our computations account for molecular ion formation and pressure dependent mobility as well as finite temperature effects. We discuss the challenges associated with achieving suitable operating conditions, which lie beyond the capabilities of existing devices, using presently available or near-future manufacturing techniques.The University of Texas at Arlington NEXT group is supported by the Department of Energy, USA under Early Career Award number DE-SC0019054 (BJPJ), by Department of Energy, USA Award DE-SC0019223 (DRN), the National Science Foundation, USA under award number NSF CHE 2004111 (FWF), and the Robert A Welch Foundation, Y-2031-20200401 (FWF). The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under the Advanced Grant 339787-NEXT; the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014–2020) under the Grant Agreements No. 674896, 690575 and 740055; the Ministerio de Economía Competitividad and the Ministerio de Ciencia, Innovación Universidades of Spain under grants FIS2014-53371-C04, RTI2018-095979, the Severo Ochoa Program grants SEV-2014-0398 and CEX2018-000867-S, and the María de Maeztu Program MDM-2016-0692; from Fundacion Bancaria la Caixa (ID 100010434), grant code LCF/BQ/PI19/11690012; the Generalitat Valenciana of Spain under grants PROMETEO/2016/120 and SEJI/2017/011; the Portuguese FCT under project PTDC/FIS-NUC/2525/2014 and under projects UID/FIS/04559/2020 to fund the activities of LIBPhys-UC; the Pazy Foundation (Israel) under grants 877040 and 877041; the US Department of Energy under contracts number DE-AC02-06CH11357 (Argonne National Laboratory, USA), DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A&M). DGD acknowledges support from the Ramón y Cajal program (Spain) under contract number RYC-2015-18820. JM-A acknowledges support from Fundación Bancaria la Caixa (ID 100010434), grant code LCF/BQ/PI19/11690012, and from the Plan GenT program of the Generalitat Valenciana , grant code CIDEGENT/2019/049.Peer reviewe

The NEXT experiment for neutrinoless double beta decay searches

La desintegración doble beta sin emisión de neutrinos es un hipotético proceso radiactivo en el que un núcleo de número atómico Z y número másico A se transforma en su isóbaro de número atómico Z+2 emitiendo dos electrones. La observación de esta desintegración probaría que el neutrino es una partícula de tipo Majorana (es decir, indistinguible de su antipartícula) y que la ley de conservación del número leptónico total puede violarse en las interacciones físicas, dos hallazgos con profundas implicaciones en cosmología y física de partículas. Hasta la fecha, no se ha obtenido evidencia experimental convincente de la existencia de la desintegración. El campo, no obstante, atraviesa en la actualidad una edad dorada, motivada posiblemente por un controvertido anuncio de descubrimiento en 2001 en el experimento Heidelberg-Moscow, y por la observación, hace ya más de 15 años, de las oscilaciones de neutrinos, que implican que el neutrino tiene masa, condición necesaria para que se produzca la desintegración doble beta sin neutrinos. Los experimentos de la generación actual emplean variadas técnicas de detección y masas de isótopo que oscilan entre unas pocas decenas de kilogramos hasta varios centenares. Tras unos pocos años de operación, estos experimentos alcanzarán sensibilidades a la semi-vida de la desintegración próximas a 1E26 años. Si no observaran ninguna señal, sería preciso expandir los experimentos a la escala de la tonelada para alcanzar sensibilidades superiores a 1E27 años y, así, poder explorar completamente la región correspondiente a la jerarquía inversa de masas del neutrino. El experimento NEXT buscará la desintegración doble beta sin neutrinos usando una cámara de proyección temporal (o TPC, por sus siglas en inglés) llena con 100 kg de xenón gaseoso (enriquecido al 91% en el isótopo Xe-136) a una presión de 15 bares. Dicho detector ofrece dos valiosas prestaciones para un experimento de este tipo: excelente resolución energética (cercana al 0.5% FWHM a 2.5 MeV) y trazado de partículas cargadas para la discriminación de señal y ruido. Además, la tecnología puede ser extrapolada sin demasiados problemas a la escala de la tonelada, permitiendo la exploración completa de la región correspondiente a la jerarquía invertida de masas de los neutrinos. El detector, conocido como NEXT-100, está actualmente en construcción, y su instalación y puesta en marcha en el Laboratorio Subterráneo de Canfranc (LSC), en España, se han previsto para el año 2017. Los dos primeros capítulos de esta tesis tratan los conceptos teóricos básicos de la naturaleza Dirac/Majorana del neutrino y de la desintegración doble beta. En el tercer capítulo se describen los aspectos experimentales más relevantes a considerar en la búsqueda de la desintegración doble beta. En el cuarto se discute la aplicación de una TPC de xenón gaseoso para la búsqueda de la desintegración, y en el quinto capítulo se introduce el experimento NEXT, discutiéndose los principales resultados de la fase inicial de investigación y desarrollo del experimento. El sexto capítulo versa sobre la simulación Monte-Carlo de los detectores de NEXT, esencial para la estimación de la sensibilidad del experimento, discutida en el séptimo capítulo. El octavo capítulo trata el futuro próximo de las búsquedas de la desintegración doble beta. Finalmente, el capítulo nueve resume las conclusiones principales del trabajo

Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Sigma m(nu) = (0.32 +/- 0.11) eV. This result, if con firmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m(beta beta) involved in neutrinoless double beta decay (beta beta 0 nu) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based beta beta 0 nu experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg.year, could already have a sizeable opportunity to observe beta beta 0 nu events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton.year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely.We warmly acknowledge C. González-García and P. Hernández for discussions, help and insight. This work was supported by the Ministerio de Economía y Competitividad of Spain under grants CONSOLIDER-Ingenio 2010 CSD2008-0037 (CUP), FPA2009-13697-C04-04 and FPA2011-29678, and by the Generalitat Valenciana grant PROMETEO/2009/116 and the ITN INVISIBLES (Marie Curie Actions, PITN-GA-2011-289442).Peer reviewe

Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora

International audienceThe Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/$c$ charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$\pm0.6$% and 84.1$\pm0.6$%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation

Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora

International audienceThe Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/$c$ charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$\pm0.6$% and 84.1$\pm0.6$%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation

Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora

International audienceThe Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/$c$ charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$\pm0.6$% and 84.1$\pm0.6$%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation