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arXiv · 1511.00220

Constraints on top quark flavor changing neutral currents using diphoton events at the LHC

Sara Khatibi·Mojtaba Mohammadi Najafabadi
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Abstract

In this paper we show that the diphoton mass spectrum in proton-proton collisions at the LHC is sensitive to the top quark flavor changing neutral current in the vertices of $tuγ$ and $tcγ$. The diphoton mass spectrum measured by the CMS experiment at the LHC at a center-of-mass energy of 8 TeV and an integrated luminosity of 19.5 fb$^{-1}$ is used as an example to set limits on these FCNC couplings. It is also shown that the angular distribution of the diphotons is sensitive to anomalous $tuγ$ and $tcγ$ couplings and it is a powerful tool to probe any value of the branching fraction of top quark rare decay to an up-type quark plus a photon down to the order of $10^{-4}$. We also show that the $tuγ$ FCNC coupling has a significant contribution to the neutron electric dipole moment (EDM) and the upper bound on neutron EDM can be used to constrain the $tuγ$ FCNC coupling.

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Sara Khatibi, Mojtaba Mohammadi Najafabadi. 2016-06-16. Constraints on top quark flavor changing neutral currents using diphoton events at the LHC. https://doi.org/10.1016/j.nuclphysb.2016.06.009

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