Search for pp → ttc(bar), ttt(bar) and btb(bar) at the LHC as Probe of Top-changing Extra Higgs Bosons

George W.S. Hou^1*

¹Physics, National Taiwan University, Taipei, Taiwan
²School of Physical Sciences, Indian Association for the Cultivation of Science, Kolkata, India

* Presenter:George W.S. Hou, email:wshou@phys.ntu.edu.tw

With the absence of New Physics at the LHC or elsewhere, we argue that a general two Higgs doublet model (g2HDM) with extra Yukawa couplings as the compelling ― and accessible ― New Physics. We argue that the H, A and H+ bosons should be sub-TeV in mass, but well-hidden from our view so far by
1) fermion mass-mixing hierarchy,
2) alignment (small h(125)-H mixing), and
3) (the mysterious) near-diagonal d-type extra Yukawa coupling matrix.
We give a general perspective on search strategies at the LHC, focusing on extra top Yukawa couplings, both top changing and conserving, of the exotic Higgs boson. These couplings connect with electroweak baryogenesis and the electron electric dipole moment, and there is a plethora of other flavor observables. At the LHC, we advocate the cg → ttc, ttt and btb production processes, and urge for experimental search.

Main Reference:
1. “Sub-TeV H+ Boson Production as Probe of Extra Top Yukawa Couplings”,
D. Ghosh, W.-S. Hou, T. Modak,
arXiv:1912.10613 [hep-ph], to appear in PRL.

Supporting References:
2. “Cancellation mechanism for the electron electric dipole moment connected with the baryon asymmetry of the Universe”,
K. Fuyuto, W.-S. Hou, E. Senaha,
PRD 101 (2020) 011901(R) [arXiv:1910.12404 [hep-ph]].
3. “Searching for new scalar bosons via triple-top signature in cg → tS0 → ttt(bar)”,
M. Kohda, T. Modak, W.-S. Hou,
PLB 776 (2018) 379 [arXiv:1710.07260 [hep-ph]].
4. “Electroweak baryogenesis driven by extra top Yukawa couplings”,
K. Fuyuto, W.-S. Hou, E. Senaha,
PLB 776 (2018) 402 [arXiv:1705.05034 [hep-ph]].

Keywords: extra Top Yukawa couplings, extra Higgs bosons, LHC, electroweak baryogenesis, Higgs alignment