Sensitivity of ATLAS at HL-LHC to flavour changing neutral currents in top quark decays t → cH, with H → γγ

ATL-PHYS-PUB-2013-012

30 September 2013

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Abstract
The sensitivity of a search for flavour changing neutral currents in top quark decays t → cH, with H → γγ at HL-LHC, using the ATLAS detector is estimated. The analysis extrapolates the preliminary result obtained by ATLAS with the 7 TeV and the 8 TeV data. It is based on tt ̄ events in which one top decays to cH, the other decays to bW, and both the hadronic and the leptonic decay modes of the W are used and combined. An expected upper limit on the branching ratio of about 1.5 $\cdot10^{-4}$ at the 95% confidence level is obtained.
Figures
Figure 01:
Distribution of the invariant masses of the Top1 combinations, for all selected events before mass cuts (four entries per event).

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Figure 02:
Distribution of the invariant masses of the Top2 combinations, for all events where the corresponding Top1 combination falls into the selection window.

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Figure 03:
For the leptonic selection, distribution of the invariant masses of the Top2 combinations, for all events where the corresponding Top1 combination falls into the selection window.

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Figure 04:
Evolution of CLs as a function of Br for the expectation in the absence of signal. The dashed line corresponds to the conservative estimate of the background (see text). The corresponding limits with looser cuts on jet pT are also shown (in blue / (dash-dotted)

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2024-03-19 01:28:31