4 research outputs found

    Search for heavy Majorana neutrinos in e±e± and e±Ό± final states via WW scattering in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search for heavy Majorana neutrinos in scattering of same-sign W boson pairs in proton–proton collisions at √s = 13 TeV at the LHC is reported. The dataset used corresponds to an integrated luminosity of 140 fb−1, collected with the ATLAS detector during 2015–2018. The search is performed in final states including a same-sign ee or eÎŒ pair and at least two jets with large invariant mass and a large rapidity difference. No significant excess of events with respect to the Standard Model background predictions is observed. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. New constraints are set on the values of the |VeN|2 and |VeN V*ÎŒN| parameters for heavy Majorana neutrino masses between 50 GeV and 20 TeV, where VℓN is the matrix element describing the mixing of the heavy Majorana neutrino mass eigenstate with the Standard Model neutrino of flavour ℓ = e, ÎŒ. The sensitivity to the Weinberg operator is investigated and constraints on the effective ee and eÎŒ Majorana neutrino masses are reported. The statistical combination of the ee and eÎŒ channels with the previously published ΌΌ channel is performed

    Carbon in Meteoroids: Wild 2 Dust Analyses, IDPs and Cometary Dust Analogues

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    Assuming that similar organic components as in comet 81P/Wild 2 are present in incoming meteoroids, we try to anticipate the observable signatures they would produce for meteor detection techniques. In this analysis we consider the elemental and organic components in cometary aggregate interplanetary dust particles and laboratory analyses of inter- and circumstellar carbon dust analogues. On the basis of our analysis we submit that (semi) quantitative measurements of H, N and C produced during meteor ablation will open an entire new aspect to using meteoroids as tracers of these volatile element abundances in active comets and their contributions to the mesospheric metal layers

    Cometary Dust

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