Atmospheric Neutrinos

• Yu Seon Jeong (CERN)

Room: 4/3-006 - TH Conference Room We will discuss the atmospheric neutrinos from the heavy flavour hadron decays, known as prompt neutrinos. The flux of prompt neutrinos have large uncertainty unlike the neutrinos from the pion decays. We will talk about main components for evaluating the prompt neutrino flux and its theoretical uncertainties.

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

• Ara Ioannisyan (A.Alikhanyan National Science Laboratory (AM))

Room: 4/3-006 - TH Conference Room We study the dependence of neutral current (NC) neutrino-induced π0/photon production (νμ+A→νμ+1π0/γ+X) on the atomic number of the target nucleus, A, at 4-momentum transfers relevant to the MiniBooNE experiment:|q|=200-500 MeV, 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. 1π0+X production scales as A2/3, 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 π0 production is proportional to A1/3. For carbon 12C this factor is ≈2.3. MiniBooNE normalises the rate of photon production to the measured π0 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.