Search for Light $H^{+}$ via $e^{+}{e}^{-}\to H^{+}{H}^{-}\to c\bar{b}\bar{c}b$ @ ILC500

Abstract

Our current {\it impasse}: no new physics seen beyond the $h(125)$ boson. We advocate the {\it general} two Higgs doublet model without $Z_2$ symmetry, allowing extra Yukawa couplings, where we present 5 clear merits. We report on the search effort at LHC for $pp\to tt\bar{c}$, then on the new effort of $pp\to b{H}^{+}\to bt\bar{b}$ search for $H^{+}$, and comment on our \underline{\bf Decadal Mission} program in Taiwan. Finally, we turn to the $e^{+}{e}^{-}\to H^{+}{H}^{-}\to c\bar{b}\bar{c}b$ program at ILC500 as a {\it what-if} situation at the LHC, demonstrating light $H^{+}$ reconstruction without $c$-tagging. We then end with discussion and conclusion.

Comments: 6 pages, 5 figures. Talk presented at LCWS2024 held at Tokyo University, to appear in proceedings