SM extension with a gauged flavor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>U</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>1</mml:mn><mml:msub><mml:mo stretchy="false">)</mml:mo><mml:mi>F</mml:mi></mml:msub></mml:math> symmetry
Physical review. D/Physical review. D.