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PhD theses

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VALOR is a neutrino fitting group established within the T2K experiment in 2010 and named after its initial participants (VALencia-Oxford-Rutherford). The VALOR group led numerous flagship T2K oscillation analyses, produced world-leading results on behalf of the T2K collaboration and contributed to most published T2K oscillation papers. The existence of a powerful, flexible, well-validated, and optimised analysis and software framework, enabled the VALOR group to adapt its advanced analysis procedures on several other experiments. Today the group also plays an important role in preparations for the physics exploitation of the Fermilab SBN programme as well as in physics sensitivity and design optimisation studies for the DUNE and HyperK experiments.

VALOR group members

Costas Andreopoulos [1,2] (VALOR coodinator), Maria Antonova [3], Dom Barker [4], Chistopher Barry [1], Francis Bench [1], Andrew Chappell [5], Thomas Dealtry [6], Steve Dennis [1] (VALOR/SBN coordinator), Lorena Escudero [7] (VALOR/DUNE coordinator), Tom Ham [1], Jaggar Henzerling [1], Rhiannon Jones [1], Nick Grant [5], Marco Roda [1], Davide Sgalaberna [8] (VALOR/T2K coordinator), and Julia Tena Vidal [1].

Past authors: Raj Shah [2,9]

[1] University of Liverpool, Physics Department, Oliver Lodge Laboratory, Liverpool L69 7ZE, UK
[2] UK Research and Innovation, Science and Technology Facilities Council,
     Rutherford Appleton Laboratory, Particle Physics Department, Harwell Oxford Campus, OX11 0QX, UK
[3] Instituto de Física Corpuscular (IFIC), Valencia, E-46980 Paterna, Spain
[4] University of Sheffield, Physics Department
[5] University of Warwick, Physics Department, Coventry CV4 7AL, UK
[6] Lancaster University, Physics Department, Lancaster, LA1 4YB, UK
[7] University of Cambridge, Cavendish Laboratory, Cambridge CB3 0HE, UK
[8] CERN, Switzerland
[9] University of Oxford, Subdepartment of Particle Physics, Oxford, OX1 3RH, UK

For all communications: constantinos.andreopoulos \at

Distribution of VALOR code

The VALOR group has medium-term plans to license and distribute to the community the VALOR Software Development Kit (SDK) that was used for implementing our T2K, SBN and DUNE oscillation analyses. The VALOR SDK is a complete software stack for a state-of-the-art oscillation analysis that has produced world-leading measurements of oscillation parameters.

The SDK provides key analysis abstractions (honed over many successive analysis cycles) allowing one to easily develop complex fits combining arbitrary sets of kinematical distributions corresponding to different event topologies from different experiments, detectors and/or beam running conditions. Definitions of a) reconstructed event samples, b) reconstructed and true kinematical spaces of any dimensionality, c) generator-level labels, d) tracked mappings between reconstructed event samples and generator-level labels, e) tracked mappings between reconstructed and true kinematical spaces, f) physics hypotheses, g) systematics parameters and their effects on specific reconstructed samples / generator-level labels / kinematic spaces, and h) the systematic parameter priors, are all flexibly and easiy defined through XML configuration files. Example definitions and XML configuration files (though not proprietary experiment-specific data and MC files) from existing VALOR analyses are provided as part of the SDK. A substantial overlap between the VALOR and GENIE groups allows VALOR to correctly implement analyses that rely on the latest GENIE comprehensive models and tunes. The VALOR SDK is parallelized and it has been tested for fits that involve O(100) event samples and O(1000) systematic parameters.

Research outputs

T2K collected data in several periods with different conditions and proton-on-target (POT) exposures, both in neutrino-enhanced Forward Horn Current (FHC) and antineutrino-enhanced Reversed Horn Current (RHC) modes: Run 1 (01-06/2010, FHC: 0.323x1020 POT), Run 2 (10/2010-03/2011, FHC: 1.108x1020 POT), Run 3 (03-06/2012, FHC: 1.579x1020 POT), Run 4 (10/2012-05/2013, FHC: 3.560x1020 POT), Run 5 (05-06/2014, FHC: 0.242x1020 POT and RHC: 0.506x1020 POT), Run 6 (10/2014-06/2015, FHC: 0.190x1020 POT and RHC: 3.505x1020 POT), Run 7 (02-05/2016, FHC: 0.480x1020 POT and RHC: 3.460x1020 POT), Run 8 (10/2016-04/2017, FHC: 7.170x1020 POT), and Run 9 (10/2017-05/2018, FHC: 0.204x1020 POT and RHC: 8.788x1020 POT)

VALOR provides a joint sterile neutrino oscillation and systematics constraint fit for SBN considering all measured exclusive channels from all three SBN LArTPC detectors (SBND, MicroBooNE, ICARUS). We're also exploring use of VALOR for neutrino interaction cross-section measurements using folded distributions and we're prototyping such analyses for SBND.

  • [new SBN fit using few simulation and reconstruction in progress]

VALOR provides a sensitive joint 3-flavour oscillation and systematics constraint fit for DUNE, and produced the first-ever realistic sensitivity calculations from an end-to-end analysis using full event simulation and reconstruction.

PhD theses with a VALOR analysis.