Anomalous Tau Neutrino Appearance from Light Mediators in Short-Baseline Neutrino Experiments

Fuente: arXiv
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Main Authors: Dev, P. S. Bhupal, Dutta, Bhaskar, Han, Tao, Kim, Doojin
Format: Preprint
Published: 2023
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author Dev, P. S. Bhupal
Dutta, Bhaskar
Han, Tao
Kim, Doojin
author_facet Dev, P. S. Bhupal
Dutta, Bhaskar
Han, Tao
Kim, Doojin
contents We point out a new mechanism giving rise to anomalous tau neutrino appearance at the near detectors of beam-focused neutrino experiments, without extending the neutrino sector. The charged mesons ($π^\pm, K^\pm$) produced and focused in the target-horn system can decay to a (neutrino-philic) light mediator via the helicity-unsuppressed three-body decays. If such a mediator carries non-vanishing hadronic couplings, it can also be produced via the bremsstrahlung of the incident proton beam. The subsequent decay of the mediator to a tau neutrino pair results in tau neutrino detection at the near detectors, which is unexpected under the standard three-flavor neutrino oscillation paradigm. We argue that the signal flux from the charged meson decays can be significant enough to discover the light mediator signal at the on-axis liquid-argon near detector of the DUNE experiment, due to the focusing of charged mesons. In addition, we show that ICARUS-NuMI, an off-axis near detector of the NuMI beam, as well as DUNE, can observe a handful of tau neutrino events induced by beam-proton bremsstrahlung.
format Preprint
id arxiv_https___arxiv_org_abs_2304_02031
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Anomalous Tau Neutrino Appearance from Light Mediators in Short-Baseline Neutrino Experiments
Dev, P. S. Bhupal
Dutta, Bhaskar
Han, Tao
Kim, Doojin
High Energy Physics - Phenomenology
High Energy Physics - Experiment
We point out a new mechanism giving rise to anomalous tau neutrino appearance at the near detectors of beam-focused neutrino experiments, without extending the neutrino sector. The charged mesons ($π^\pm, K^\pm$) produced and focused in the target-horn system can decay to a (neutrino-philic) light mediator via the helicity-unsuppressed three-body decays. If such a mediator carries non-vanishing hadronic couplings, it can also be produced via the bremsstrahlung of the incident proton beam. The subsequent decay of the mediator to a tau neutrino pair results in tau neutrino detection at the near detectors, which is unexpected under the standard three-flavor neutrino oscillation paradigm. We argue that the signal flux from the charged meson decays can be significant enough to discover the light mediator signal at the on-axis liquid-argon near detector of the DUNE experiment, due to the focusing of charged mesons. In addition, we show that ICARUS-NuMI, an off-axis near detector of the NuMI beam, as well as DUNE, can observe a handful of tau neutrino events induced by beam-proton bremsstrahlung.
title Anomalous Tau Neutrino Appearance from Light Mediators in Short-Baseline Neutrino Experiments
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2304.02031