Probing the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>R</mml:mi><mml:msup><mml:mi>K</mml:mi><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mo>*</mml:mo><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:msup></mml:msub></mml:math> anomaly at a muon collider
Guoyuan Huang, Sudip Jana, Farinaldo S. Queiroz, Werner Rodejohann
Abstract
The LHCb measurements of the $\ensuremath{\mu}/e$ ratio in $B\ensuremath{\rightarrow}K\ensuremath{\ell}\ensuremath{\ell}$ decays $({R}_{K})$ indicate a deficit with respect to the Standard Model prediction, supporting earlier hints of lepton universality violation observed in the ${R}_{{K}^{(*)}}$ ratio. Possible explanations of these $B$-physics anomalies include heavy ${Z}^{\ensuremath{'}}$ bosons or scalar and vector leptoquarks mediating $b\ensuremath{\rightarrow}s{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. We note that a muon collider can directly measure this process via ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\rightarrow}b\overline{s}$ and can shed light on the lepton nonuniversality scenario. Investigating currently discussed center-of-mass energies $\sqrt{s}=3$, 6 and 10 TeV, we show that the parameter space of ${Z}^{\ensuremath{'}}$ and leptoquark solutions to the ${R}_{{K}^{(*)}}$ anomalies can be mostly covered. Effective operators explaining the anomalies can be probed with the muon collider setup $\sqrt{s}=6\text{ }\text{ }\mathrm{TeV}$ and integrated luminosity $L=4\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$.