Explaining the $$ {B}_{d,s}\to {K}^{\left(\ast \right)}{\overline{K}}^{\left(\ast \right)} $$ non-leptonic puzzle and charged-current B-anomalies via scalar leptoquarks
Javier M. Lizana, Joaquim Matias, Ben A. Stefanek
Abstract
A bstract We present a model based on S 1 scalar leptoquarks to solve the tension observed in the recently proposed non-leptonic optimized observables $$ {L}_{K^{\ast }{\overline{K}}^{\ast }} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>L</mml:mi> <mml:mrow> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> <mml:msup> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>∗</mml:mo> </mml:msup> </mml:mrow> </mml:msub> </mml:math> and $$ {L}_{K\overline{K}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>L</mml:mi> <mml:mrow> <mml:mi>K</mml:mi> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:msub> </mml:math> . These observables are constructed as ratios of U-spin related decays based on $$ {B}_{d,s}^0\to {K}^{\left(\ast \right)0}{\overline{K}}^{\left(\ast \right)0} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi>d</mml:mi> <mml:mo>,</mml:mo> <mml:mi>s</mml:mi> </mml:mrow> <mml:mn>0</mml:mn> </mml:msubsup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>K</mml:mi> <mml:mrow> <mml:mfenced> <mml:mo>∗</mml:mo> </mml:mfenced> <mml:mn>0</mml:mn> </mml:mrow> </mml:msup> <mml:msup> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mrow> <mml:mfenced> <mml:mo>∗</mml:mo> </mml:mfenced> <mml:mn>0</mml:mn> </mml:mrow> </mml:msup> </mml:math> . The model gives a one-loop contribution to the Wilson coefficient of the chromomagnetic dipole operator needed to explain the tension in both non-leptonic observables, while naturally avoiding large contributions to the corresponding electromagnetic dipoles. The necessary chiral enhancement comes from an O (1) Yukawa coupling with a TeV-scale right-handed neutrino running in the loop. We endow the model with a U(2) flavor symmetry, necessary to protect light-family flavor observables that otherwise would be in tension. Furthermore, we show that the same S 1 scalar leptoquark is capable of simultaneously explaining the hints of lepton flavor universality violation observed in charged-current B -decays. The model therefore provides a potential link between two puzzles in B -physics and TeV-scale neutrino mass generation. Finally, the combined explanation of the B -physics puzzles unavoidably results in an enhancement of $$ \mathcal{B}\left(B\to K\nu \overline{\nu}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> <mml:mfenced> <mml:mrow> <mml:mi>B</mml:mi> <mml:mo>→</mml:mo> <mml:mi>Kν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:mfenced> </mml:math> , yielding a value close to present bounds.