Neutrino physics studies in the Fermilab Short Baseline Neutrino (SBN) programme

Neutrinos are the most abundant massive particle in the universe. Since their discovery, neutrinos played an important role in many areas of physics: They were used to study the weak nuclear force, to illuminate the quark structure of hadrons, and to confirm our models of astrophysical phenomena. With the discovery that neutrinos have mass, they took centre stage as the object of study. The study of neutrino properties allows us to probe origin of neutrino mass, the matter-antimatter asymmetry of the universe, and the existence of new particles and forces.

The Short-Baseline Near Detector (SBND) will be one of three liquid Argon Time Projection Chamber (LArTPC) neutrino detectors positioned along the axis of the Booster Neutrino Beam (BNB) at Fermilab, as part of the Short-Baseline Neutrino (SBN) Program. SBND construction and commissioning has been completed, and the experiment now collects physics quality data. SBND is characterised by superb imaging capabilities and will record over a million neutrino interactions per year. Thanks to its unique combination of measurement resolution and statistics, SBND will carry out a rich program of neutrino interaction measurements and novel searches for physics beyond the Standard Model (BSM). It will enable the potential of the overall SBN sterile neutrino program by performing a precise characterisation of the unoscillated event rate, and by constraining BNB flux and neutrino-Argon cross-section systematic uncertainties. In this talk, the physics reach, current status, and future prospects of SBND are discussed.

The University of Liverpool is a founding member of the SBND collaboration. Liverpool physicists played pivotal roles in the construction, commissioning, and preparation for the physics exploitation of the detector. In addition, Liverpool PhD students have made significant contributions to both the detector and its physics goals. We invite applications for a new PhD student to join in our leading physics activities.

Liverpool is leading the development of the VALOR oscillation analysis for SBN and SBND. VALOR enables a detailed description of systematic uncertainties and it allows the efficient joint analysis of many event samples. Is this thus well suited for the systematics limited SBN measurements, and for the joint analysis of the many distinct event topologies that will be observed by SBND. The analysis also incorporates `SBND-PRISM’, i.e. the idea that we can exploit that different portions of the SBND detector see a different flux (the peak energy is shifted by around 100 MeV between the on-axis and extreme off-axis directions) to lift systematic parameter degeneracies, and it performs a joint fit of samples from a range of different angular slices  within SBND. Using VALOR, the succesful candidate will characterise and constrain modelling uncertainties and produce systematically robust SBND-driven spectrum extrapolations to the ICARUS baseline. They will incorporate the SBND constraints into the VALOR SBN oscillation analysis, exercise the full analysis chain, and make comprehensive evaluations of the impact of physics uncertainties on the SBN oscillation program. Through this effort, the successful candidate will help instigate targeted new SBND measurement campaigns providing the inputs to improve the modelling of neutrino interactions. Particularly emphasis will be given in the improvement, tuning and uncertainty estimation of the Liverpool-led GENIE neutrino event simulation. Finally, they will perform sensitive multi-channel sterile neutrino oscillation searches with VALOR and contribute to some of the highest-profile SBN publications.

 

The successful candidate will join the Particle Physics group at the University of Liverpool is one of the UKs largest Particle Physics groups, holding research grants of around £22M and operating research infrastructure facilities worth £30M. With a staff complement of 65 leading academics, physicists, engineers and technologists, it trains around 60 post graduate research students at any time. Particle Physics is a major theme for the University of Liverpool and the group has strong support at the School and Faculty levels. The group is active at CERN (ATLAS, LHC-b, FASER, MUonE), at J-PARC (T2K, Super-K, Hyper-K), at JUNO, at SNOLAB (SNO+), at Fermilab (g-2, mu2e, SBND, DUNE), at PSI (mu3e, muEDM) and in astroparticle physics (CTA), Dark Matter (LZ, Darkside-20k) and the use of quantum technology for fundamental physics (AION, MAGIS-100). In recent years the group has delivered the ATLAS Silicon Endcap-C, the LHC-b VeLo and VeLo pixel upgrade, the ND280 ECAL for T2K, cathode planes for the SBND TPC, and tracker stations the FNAL g-2 experiment. Currently the group is developing and building detectors and other systems for the ATLAS HL-LHC Inner tracker upgrades, for the Mu2e and Mu3e experiments, for Hyper-K, for MAGIS-100 and for DUNE.

Besides receiving targeted training in Particle Physics, the successful candidate would have the option to join LIV.INNO as an associate. LIV.INNO the Liverpool Centre for Doctoral Training for Innovation in Data Intensive Sciences and would have access to targeted training on data science. Information about LIV.INNO can be found in: https://www.liverpool.ac.uk/centre-for-doctoral-training-for-innovation-in-data-intensive-science/

 

The candidate will be based at Liverpool, with frequent travel in the UK and in overseas institutes to collaborate with SBND scientists. There would be frequent travel to Fermilab, as well as an opportunity for a long-term attachment, to participate in SBND data-taking operations.

 


 

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