Research outputs:

• T2K
• SBN
• DUNE

• PhD theses

For developers:
Note: Links to private GitHub repositories not live without access permissions to the VALOR GitHub organisation.

• Mailing list
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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 [6]([9]) , Maria Antonova [4], Thomas Dealtry [5] ([7,9]), Rhiannon Jones [10]([6]), Tereza Kroupova [8], Jaiden Parlone [6], Davide Sgalaberna [3] ([2]), and Bethany Slater [6].

(Past authors: Dom Barker [10], Francis Bench [6], Christopher Barry [6], Andrew Chappell [11], Steve Dennis [1] ([9,11];[6]) , Lorena Escudero [4];[1], Nick Grant [9];[5];[11], Frank Thomas Ham [6], and Raj Shah [7,9].)

[1] University of Cambridge, Cavendish Laboratory, Cambridge, UK
[2] CERN European Organization for Nuclear Research, Geneve, Switzerland
[3] ETH Zurich, Institute for Particle Physics and Astrophysics, Zurich, Switzerland
[4] Instituto de Física Corpuscular (IFIC), Valencia, Spain
[5] Lancaster University, Physics Department, Lancaster, UK
[6] University of Liverpool, Physics Department, Liverpool, UK
[7] University of Oxford, Subdepartment of Particle Physics, Oxford, UK
[8] University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, PA 19104, USA
[9] UK Research and Innovation, Science and Technology Facilities Council,
     Rutherford Appleton Laboratory, Particle Physics Department, Harwell, UK
[10] University of Sheffield, Physics Department, Sheffield, UK
[11] University of Warwick, Physics Department, Coventry UK


For all communications: c.andreopoulos \at cern.ch

Statement on the distribution of VALOR codes

Currently, all generic and experiment-specific source codes and wikis are hosted in a number of private GitHub repositories, and they are not freely accessible.

The VALOR group has medium-term plans to license and distribute the VALOR Software Development Kit (SDK) to the community. The SDK implements a highly configurable and efficent neutrino data analysis procedure, that is employed in several state-of-the-art oscillation analyses (that have produced world-leading measurements of oscillation parameters) as well as in detailed sensitivity studies. Currently, all our T2K, HyperK and DUNE 3-flavour oscillation and systematics constraint fits, as well as our SBN and NuStorm 3+N oscillation and systematics constraint fits, are implemented on top of that common SDK. It provides key analysis abstractions and workflows (honed over many successive analysis cycles) allowing one to easily develop complex joint fits of arbitrary sets of kinematical distributions corresponding to different observed event topologies from different experiments, detectors and/or beam running conditions, considering different physics hypotheses and entirely-customisable systematic error model, doing little more that providing appropriate definitions through a series of XML files. 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

VALOR led oscillation analyses of T2K data collected in several running periods, with different conditions and exposures [T2K-1]. The source codes listed in square brackets below correspond to different branches of the VALOR-SDK (framework) and VALOR-T2K-LBL (T2K-specific oscillation analysis code) git repositories. The TeX source for each technical note lives in different branches of the VALOR-T2K-DOCS git repository, named after the technical note ID. The repository URLs are listed in [T2K-2].

  • 2010 (Run 1) 2-flavour νμ disappearance
        → VALOR technical note: T2K/TN-036
        → VALOR source codes: SDK [n/a] - T2K-LBL [2010_v1.0.0]
  • 2010 (Run 1-2) 2-flavour νμ disappearance
        → VALOR contribution to: Phys.Rev. D85 (2012) 031103
        → VALOR technical note: T2K/TN-064
        → VALOR source codes: SDK [n/a] - T2K-LBL [2010_v2.1.0]
  • 2010 (Run 1-2) 3-flavour νμ disappearance
        → VALOR technical note: T2K/TN-087
        → VALOR source codes: SDK [n/a] - T2K-LBL [2010_v3.0.0]
  • 2012 (Run 1-3) 3-flavour νμ disappearance
        → VALOR contribution to: Phys.Rev.Lett. 111 (2013) 211803
        → VALOR contribution to: Phys.Rev.Lett. 112 (2014) 061802
        → VALOR technical note: T2K/TN-141
        → VALOR source codes: SDK [n/a] - T2K-LBL [2012_v1.1.0]
  • 2012 (Run 1-3) 3-flavour joint νμ disappearance + νe appearance
        → VALOR technical note: T2K/TN-154
        → VALOR source codes: SDK [n/a] - T2K-LBL [2012_v2.0.0]
  • 2013 (Run 1-4a) 3-flavour νμ disappearance
        → VALOR technical note: T2K/TN-155
        → VALOR source codes: SDK [n/a] - T2K-LBL [2013_v1.0.0]
  • 2013 (Run 1-4) 3-flavour νμ disappearance
        → VALOR contribution to: Phys.Rev.Lett. 112 (2014) 181801
        → VALOR technical note: T2K/TN-183
        → VALOR source codes: SDK [n/a] - T2K-LBL [2013_v2.0.0]
  • 2013 (Run 1-4) 3-flavour joint νμ disappearance + νe appearance
        → VALOR contribution to: Phys.Rev. D91 (2015) 072010
        → VALOR technical note: T2K/TN-175
        → VALOR source codes: SDK [n/a] - T2K-LBL [2013_v3.1.0]
  • 2015 (Run 5-6) 3-flavour νμ disappearance
        → VALOR contribution to: Phys.Rev.Lett. 116 (2016) 181801
        → VALOR technical note: T2K/TN-243
        → VALOR source codes: SDK [v1.0.0] - T2K-LBL [2015_v1.1.0]
  • 2015 (Run 5-6) νe appearance
        → VALOR technical note: T2K/TN-252
        → VALOR source codes: SDK [v1.1.0] - T2K-LBL [2015_v2.0.0]
  • 2016 (Run 1-6 / Run 1-7) νe appearance
        → VALOR technical note: T2K/TN-296
        → VALOR source codes: SDK [v1.2.0] - T2K-LBL [2016_v1.0.0]
  • 2016 (Run 1-6 / Run 1-7) 3-flavour νμ / νμ disappearance
        → VALOR contribution to: Phys.Rev. D96 (2017) no.1, 011102
        → VALOR technical note: T2K/TN-302
        → VALOR source codes: SDK [v1.2.0] - T2K-LBL [2016_v1.0.0]
  • 2016 (Run 1-6 / Run 1-7) 3-flavour joint νμ / νμ disappearance + νe / νe appearance
    using standard single-ring e-like and μ-like samples in neutrino and antineutrino beam modes (4 samples)
        → VALOR contribution to: Phys.Rev.Lett. 118 (2017) no.15, 151801
        → VALOR technical note: T2K/TN-266
        → VALOR source codes: SDK [v1.2.0] - T2K-LBL [2016_v1.0.0]
  • 2016 (Run 1-6 / Run 1-7) 3-flavour joint νμ / νμ disappearance + νe / νe appearance
    with additional (5th) νe CC1π+ event sample
        → VALOR contribution to: Phys.Rev. D96 (2017) no.9, 092006
        → VALOR technical note: T2K/TN-306
        → VALOR source codes: SDK [v1.2.0] - T2K-LBL [2016_v1.0.0]
  • 2017 (Run 1-8) 3-flavour joint (5 sample) νμ / νμ disappearance + νe / νe appearance
        → VALOR contribution to: Phys.Rev.Lett. 121 (2018) no.17, 171802
        → VALOR technical note: T2K/TN-327
        → VALOR source codes: SDK [v1.4.2] - T2K-LBL [2017_v1.0.0]
  • 2018 (Run 1-9) νe appearance
        → VALOR contribution to: Phys. Rev. Lett. 124, 161802 (2020)
        → VALOR technical note: T2K/TN-356
        → VALOR source codes: SDK [] - T2K-LBL []
  • 2018 (Run 1-9) 3-flavour joint (5 sample) νμ / νμ disappearance + νe / νe appearance
        → VALOR contribution to: Nature 580, 339–344 (2020)
        → VALOR contribution to: Phys.Rev.D 103 (2021) 11, 112008
        → VALOR technical note: T2K/TN-360
        → VALOR source codes: SDK [] - T2K-LBL []
  • 2020 (Run 1-10) 3-flavour joint (5 sample) νμ / νμ disappearance + νe / νe appearance
        → VALOR technical note: T2K/TN-394
        → VALOR source codes: SDK [] - T2K-LBL []

[T2K-1] 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), Run 9 (10/2017-05/2018, FHC: 0.204x1020 POT and RHC: 8.788x1020 POT), and Run 10 ().

[T2K-2] The VALOR-SDK, VALOR-T2K-LBL, and VALOR-T2K-DOCS repositories are private repositories hosted in the VALOR GitHub organisation.

VALOR provides a joint sterile neutrino oscillation and systematics constraint fit for SBN. It supports a range of standalone (νμ disappearance, νe appearance, νe disappearance) or joint oscillation analyses in 3+N frameworks, incorporating inclusive or exclusive channels from all SBN LArTPC detectors, and utilises the SBND PRISM concept. A central focus of the VALOR group effort is the development of SBND-driven flux and cross-section tunes and systematic error constraints. We're also exploring use of VALOR for BSM studies on SBND, and have developed sensitivity studies for heavy neutrino decays.

  • 2021 SBN Sterile Neutrino Oscillation Sensitivities
        → VALOR contribution to: SBN Oscillation Sensitivity Technical Note (2021), SBN-doc-27037
        → VALOR source codes: SDK [v?] - SBN [v?]

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.

  • 2017 Near Detector Task Force analysis
        → VALOR contribution to: DUNE Near Detector Task Force report, DUNE-doc-1792
        → VALOR source codes: SDK [v1.4.0] - DUNE-LBL [v3.0.0]

PhD theses with a VALOR analysis.