Flavor specific <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:mi>U</mml:mi><mml:msub><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mn>1</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>q</mml:mi></mml:mrow></mml:msub><mml:mo linebreak="badbreak" linebreakstyle="after">−</mml:mo><mml:msub><mml:mrow><mml:mi>L</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msub></mml:math> gauge model for muon g − 2 and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"><mml:mi>b</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>s</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover><mml:mi>μ</mml:mi></mml:math> anomalies

Abstract

The muon (g−2)μ and b→sμ¯μ induced B anomalies as hints of new physics beyond the standard model (SM) have attracted much attention. These two anomalies indicate that there may exist new interaction specifically related to muon. A lot of theoretical ideas have been proposed to explain these anomalies. Gauged flavor specific U(1)Bq−Lμ is among the promising ones. The new gauge boson Z′ from U(1)Bq−Lμ interacts with muon and provides necessary ingredient to solve the (g−2)μ anomaly. The Z′-quark coupling can generate flavor changing interactions after diagonalization of quark mass matrix between weak eigen-state and mass eigen-state basis. We revisit challenges for such models attempting to explain the (g−2)μ and B anomalies separately or simultaneously. We find although for U(1)Bq−Lμ models there is still parameter space to provide solutions for separately explaining the (g−2)μ and B anomalies, there exists no parameter space for such models to solve both the anomalies simultaneously, after taking into account existing constraints from τ→μγ, τ→3μ, neutrino trident and Bs−B¯s data. Among them leptonic processes restrict Z′ mass to be less than a few hundred MeV if required to solve the (g−2)μ anomaly, which causes conflict between data from Bs−B¯s, D0−D¯0 mixing and also hadron decays with Z′ in the final states. The effects of U(1)Y and U(1)Bq−Lμ kinetic mixing on these anomalies are also studied. We find that neither can these effects do much to bring the two anomalies together to be solved simultaneously.

Topics & Concepts