<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>B</mml:mi></mml:mrow></mml:math> anomalies in a two-Higgs-doublet model with flavor symmetry

The long-standing flavor anomalies in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>b</a:mi><a:mo stretchy="false">→</a:mo><a:mi>s</a:mi><a:msup><a:mo>ℓ</a:mo><a:mo>+</a:mo></a:msup><a:msup><a:mo>ℓ</a:mo><a:mo>−</a:mo></a:msup></a:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mi>b</d:mi><d:mo stretchy="false">→</d:mo><d:mi>c</d:mi><d:mo>ℓ</d:mo><d:mi>ν</d:mi></d:math> persist. In this work, we explore a specific flavor-gauged two-Higgs-doublet model (FG2HDM) extended by a scalar singlet, with an imposed <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>U</g:mi><g:mo stretchy="false">(</g:mo><g:mn>1</g:mn><g:mo stretchy="false">)</g:mo></g:math> flavor symmetry. Compared to the standard model (SM), four additional scalars and one neutral gauge boson <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:msup><k:mi>Z</k:mi><k:mo>′</k:mo></k:msup></k:math> are added to the particle spectrum. The special Yukawa coupling matrices, due to the <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mi>U</m:mi><m:mo stretchy="false">(</m:mo><m:mn>1</m:mn><m:mo stretchy="false">)</m:mo></m:math> symmetry, lead to flavor-changing neutral Higgs interactions uniquely occurring in the down-type quark sector, while the new gauge boson <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:msup><q:mi>Z</q:mi><q:mo>′</q:mo></q:msup></q:math> induces flavor-changing neutral current interactions in the down-type quark sector as well. The two distinct types of anomalies can be accommodated simultaneously in such a model. Incorporating scalar and vector contributions to <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mi>b</s:mi><s:mo stretchy="false">→</s:mo><s:mi>s</s:mi><s:msup><s:mo>ℓ</s:mo><s:mo>+</s:mo></s:msup><s:msup><s:mo>ℓ</s:mo><s:mo>−</s:mo></s:msup></s:math>, <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:msub><v:mi>B</v:mi><v:mi>s</v:mi></v:msub><v:mo stretchy="false">→</v:mo><v:msup><v:mi>μ</v:mi><v:mo>+</v:mo></v:msup><v:msup><v:mi>μ</v:mi><v:mo>−</v:mo></v:msup></v:math>, and <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:msubsup><y:mi>B</y:mi><y:mi>s</y:mi><y:mn>0</y:mn></y:msubsup><y:mo>−</y:mo><y:msubsup><y:mover accent="true"><y:mi>B</y:mi><y:mo stretchy="false">¯</y:mo></y:mover><y:mi>s</y:mi><y:mn>0</y:mn></y:msubsup></y:math> mixing, charged Higgs contributions to <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mi>b</cb:mi><cb:mo stretchy="false">→</cb:mo><cb:mi>c</cb:mi><cb:mo>ℓ</cb:mo><cb:mi>ν</cb:mi></cb:math>, along with electroweak precision observables and Higgs fermionic decays, we investigate the parameter space in FG2HDM and find substantial room in the solution space. Specifically, in the SM-like model setup, the data suggest that <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:msub><fb:mi>m</fb:mi><fb:msup><fb:mi>Z</fb:mi><fb:mo>′</fb:mo></fb:msup></fb:msub><fb:mo>&lt;</fb:mo><fb:mn>450</fb:mn><fb:mtext> </fb:mtext><fb:mtext> </fb:mtext><fb:mi>GeV</fb:mi></fb:math>, <hb:math xmlns:hb="http://www.w3.org/1998/Math/MathML" display="inline"><hb:mi>tan</hb:mi><hb:mi>β</hb:mi><hb:mo>&lt;</hb:mo><hb:mn>28</hb:mn></hb:math>, and <jb:math xmlns:jb="http://www.w3.org/1998/Math/MathML" display="inline"><jb:msup><jb:mi>g</jb:mi><jb:mo>′</jb:mo></jb:msup><jb:mo>/</jb:mo><jb:msub><jb:mi>m</jb:mi><jb:msup><jb:mi>Z</jb:mi><jb:mo>′</jb:mo></jb:msup></jb:msub><jb:mo>&gt;</jb:mo><jb:mn>3.5</jb:mn><jb:mo>×</jb:mo><jb:msup><jb:mn>10</jb:mn><jb:mrow><jb:mo>−</jb:mo><jb:mn>4</jb:mn></jb:mrow></jb:msup><jb:mtext> </jb:mtext><jb:mtext> </jb:mtext><jb:msup><jb:mrow><jb:mi>GeV</jb:mi></jb:mrow><jb:mrow><jb:mo>−</jb:mo><jb:mn>1</jb:mn></jb:mrow></jb:msup></jb:math>, while there are fewer constraints on heavy scalars, which can be further tested by a combination of other observables.