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arXiv · 1909.08571

A Standard Model explanation for the excess of electron-like events in MiniBooNE

A. Ioannisian
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Abstract

We study the dependence of neutral current (NC) neutrino-induced $π^0$/photon production ($ν_μ+ A \to ν_μ+1π^0 / γ+ X$) on the atomic number of the target nucleus, A, at 4-momentum transfers relevant to the MiniBooNE experiment: $Δ$ resonance mass region. Our conclusion is based on experimental data for photon-nucleus interactions from the A2 collaboration at the Mainz MAMI accelerator. We work in the approximation that decays of $Δ$ resonance unaffected by its production channel, via photon or Z boson. $1π^0+X$ production scales as A$^{2/3}$, the surface area of the nucleus. Meanwhile the photons created in $Δ$ decays will leave the nucleus, and that cross section will be proportional to the atomic number of the nucleus. Thus the ratio of photon production to $π^0$ production is proportional to A$^{1/3}$. For carbon $^{12}$C this factor is $\approx$2.3. MiniBooNE normalises the rate of photon production to the measured $π^0$ production rate. The reduced neutral pion production rate would yield at least twice as many photons as previously expected, thus significantly lowering the number of unexplained electron-like events.

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A. Ioannisian. 2019-09-26. A Standard Model explanation for the excess of electron-like events in MiniBooNE. https://arxiv.org/abs/1909.08571

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