The next generation neutrino observatory proposed by the LBNO collaboration will address fundamental questions in particle and astroparticle physics. The experiment consists of a far detector, in its first stage a 20 kt LAr double phase TPC and a magnetised iron calorimeter, situated at 2300 km from CERN and a near detector based on a highpressure argon gas TPC. The long baseline provides a unique opportunity to study neutrino flavour oscillations over their 1st and 2nd oscillation maxima exploring the L/E behaviour, and distinguishing effects arising from δ CP and matter.
In this paper we have reevaluated the physics potential of this setup for determining the mass hierarchy (MH) and discovering CP-violation (CPV), using a conventional neutrino beam from the CERN SPS with a power of 750 kW. We use conservative assumptions on the knowledge of oscillation parameter priors and systematic uncertainties. The impact of each systematic error and the precision of oscillation prior is shown. We demonstrate that the first stage of LBNO can determine unambiguously the MH to > 5σ C.L. over the whole phase space. We show that the statistical treatment of the experiment is of very high importance, resulting in the conclusion that LBNO has ~ 100% probability to determine the MH in at most 4-5 years of running. Since the knowledge of MH is indispensable to extract δ CP from the data, the first LBNO phase can convincingly give evidence for CPV on the 3σ C.L. using today’s knowledge on oscillation parameters and realistic assumptions on the systematic uncertainties.
A. Stahl et al., Expression of Interest for a very Longc Baseline Neutrino Oscillation experiment (LBNO), CERN-SPSC-2012-021 (2012).
S.K. Agarwalla, T. Li and A. Rubbia, An incremental approach to unravel the neutrino mass hierarchy and CP-violation with a long-baseline Superbeam for large θ 13, JHEP 05 (2012) 154 [arXiv:1109.6526] [INSPIRE].
Z. Maki, M. Nakagawa and S. Sakata, Remarks on the unified model of elementary particles, Prog. Theor. Phys. 28 (1962) 870 [INSPIRE].
B. Pontecorvo, Neutrino experiments and the problem of conservation of leptonic charge, Sov. Phys. JETP 26 (1968) 984 [Zh. Eksp. Teor. Fiz. 53 (1967) 1717] [INSPIRE].
G. Fogli, E. Lisi, A. Marrone, D. Montanino, A. Palazzo et al., Global analysis of neutrino masses, mixings and phases: entering the era of leptonic CP-violation searches, Phys. Rev. D 86 (2012) 013012 [arXiv:1205.5254] [INSPIRE].
L. Wolfenstein, Neutrino oscillations in matter, Phys. Rev. D 17 (1978) 2369 [INSPIRE].
J. Arafune, M. Koike and J. Sato, CP violation and matter effect in long baseline neutrino oscillation experiments, Phys. Rev. D 56 (1997) 3093 [Erratum ibid. D 60 (1999) 119905] [hep-ph/9703351] [INSPIRE].
C. Rubbia, The liquid argon time projection chamber: a new concept for neutrino detectors, CERN-EP-INT-77-08 (1977).
A. Rubbia et al., Underground neutrino detectors for particle and astroparticle science: the Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER), J. Phys. Conf. Ser. 171 (2009) 012020 [arXiv:0908.1286] [INSPIRE].
A. Cervera, A. Laing, J. Martin-Albo and F. Soler, Performance of the MIND detector at a Neutrino Factory using realistic muon reconstruction, Nucl. Instrum. Meth. A 624 (2010) 601 [arXiv:1004.0358] [INSPIRE].
A. Rubbia, A CERN-based high-intensity high-energy proton source for long baseline neutrino oscillation experiments with next-generation large underground detectors for proton decay searches and neutrino physics and astrophysics, arXiv:1003.1921 [INSPIRE].
K. Elsener et al., The CERN Neutrino beam to Gran Sasso (NGS): conceptual technical design, CERN, Switzerland (1998).
E. Shaposhnikova et al., Recent intensity increase in the CERN accelerator chain, CERN-AB-2005-029 (2005).
B. Goddard et al., Chamonix 2012 workshop on LHC performance, CERN-ATS-2012-069 (2012).
Y. Papaphilippou et al., Design options of a high-power proton synchrotron for LAGUNA-LBNO, in the proceedings of the 4th International Particle Accelerator Conference (IPAC13), May 12-17, Shangai, China (2013).
B. Goddard et al., Non-local Fast Extraction from the CERN SPS at 100 and 440 GeV, in the proceedings of the 4th International Particle Accelerator Conference (IPAC13), May 12-17, Shangai, China (2013).
A.M. Dziewonski and D.L. Anderson, Preliminary reference earth model, Phys. Earth Planet. Interiors 25 (1981) 297 [INSPIRE].
KM3NeT collaboration, P. Kooijman, ORCA status report, talk given at the 33rd International Conference of Cosmic Rays (IRC2013), July 2-9, Rio de Janeiro, Brazil (2013).
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ArXiv ePrint: 1312.6520
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The LAGUNA-LBNO collaboration., Agarwalla, S., Agostino, L. et al. The mass-hierarchy and CP-violation discovery reach of the LBNO long-baseline neutrino experiment. J. High Energ. Phys. 2014, 94 (2014). https://doi.org/10.1007/JHEP05(2014)094
- Neutrino Detectors and Telescopes
- CP violation