Flavor anomalies from asymptotically safe gravity
Kamila Kowalska, Enrico Maria Sessolo, Yasuhiro Yamamoto
Abstract
Abstract We use the framework of asymptotically safe quantum gravity to derive predictions for scalar leptoquark solutions to the $$b\rightarrow s$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>b</mml:mi> <mml:mo>→</mml:mo> <mml:mi>s</mml:mi> </mml:mrow> </mml:math> and $$b\rightarrow c$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>b</mml:mi> <mml:mo>→</mml:mo> <mml:mi>c</mml:mi> </mml:mrow> </mml:math> flavor anomalies. The presence of an interactive UV fixed point in the system of gauge and Yukawa couplings imposes a set of boundary conditions at the Planck scale, which allows one to determine low-energy values of the leptoquark Yukawa matrix elements. As a consequence, the allowed leptoquark mass range can be significantly narrowed down. We find that a consistent gravity-driven solution to the $$b\rightarrow s$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>b</mml:mi> <mml:mo>→</mml:mo> <mml:mi>s</mml:mi> </mml:mrow> </mml:math> anomalies predicts a leptoquark with the mass of 4–7 $$\,\mathrm {TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mspace/> <mml:mi>TeV</mml:mi> </mml:mrow> </mml:math> , entirely within the reach of a future hadron-hadron collider with $$\sqrt{s}=100\,\mathrm {TeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>100</mml:mn> <mml:mspace/> <mml:mi>TeV</mml:mi> </mml:mrow> </mml:math> . Conversely, in the case of the $$b\rightarrow c$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>b</mml:mi> <mml:mo>→</mml:mo> <mml:mi>c</mml:mi> </mml:mrow> </mml:math> anomalies the asymptotically safe gravity framework predicts a leptoquark mass at the edge of the current LHC bounds. Complementary signatures appear in flavor observables, namely the (semi)leptonic decays of B and D mesons and kaons.