Purely leptonic decays of heavy-flavored charged mesons

We study the purely leptonic decays of heavy-flavored charged pseudoscalar (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>P</a:mi></a:mrow></a:math>) and vector (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>V</c:mi></c:math>) mesons (<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msubsup><e:mi>D</e:mi><e:mrow><e:mo stretchy="false">(</e:mo><e:mi>s</e:mi><e:mo stretchy="false">)</e:mo></e:mrow><e:mrow><e:mo stretchy="false">(</e:mo><e:mo>*</e:mo><e:mo stretchy="false">)</e:mo><e:mo>+</e:mo></e:mrow></e:msubsup></e:math>, <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:msubsup><k:mi>B</k:mi><k:mrow><k:mo stretchy="false">(</k:mo><k:mi>c</k:mi><k:mo stretchy="false">)</k:mo></k:mrow><k:mrow><k:mo stretchy="false">(</k:mo><k:mo>*</k:mo><k:mo stretchy="false">)</k:mo><k:mo>+</k:mo></k:mrow></k:msubsup></k:math>) in the relativistic independent quark (RIQ) model based on an average flavor-independent confining potential in an equally mixed scalar-vector harmonic form. We first compute the mass spectra of the ground-state-mesons and fix the model parameters necessary for the present analysis. Using the meson wave functions derivable in the RIQ model, and model parameters so fixed from hadron spectroscopy, we predict the decay constants: <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:msub><q:mi>f</q:mi><q:mrow><q:mi>P</q:mi><q:mo stretchy="false">(</q:mo><q:mi>V</q:mi><q:mo stretchy="false">)</q:mo></q:mrow></q:msub></q:math>, ratios of decay constants: <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:msub><u:mi>f</u:mi><u:mi>V</u:mi></u:msub><u:mo>/</u:mo><u:msub><u:mi>f</u:mi><u:mi>P</u:mi></u:msub></u:math>, <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:msub><w:mi>f</w:mi><w:msub><w:mi>P</w:mi><w:mn>1</w:mn></w:msub></w:msub><w:mo>/</w:mo><w:msub><w:mi>f</w:mi><w:msub><w:mi>P</w:mi><w:mn>2</w:mn></w:msub></w:msub></w:math>, <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:msub><y:mi>f</y:mi><y:msub><y:mi>V</y:mi><y:mn>1</y:mn></y:msub></y:msub><y:mo>/</y:mo><y:msub><y:mi>f</y:mi><y:msub><y:mi>V</y:mi><y:mn>2</y:mn></y:msub></y:msub></y:math>, and the branching fractions (BFs): <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:mi mathvariant="script">B</ab:mi><ab:mo stretchy="false">(</ab:mo><ab:mi>P</ab:mi><ab:mo stretchy="false">(</ab:mo><ab:mi>V</ab:mi><ab:mo stretchy="false">)</ab:mo><ab:mo stretchy="false">→</ab:mo><ab:msup><ab:mi>l</ab:mi><ab:mo>+</ab:mo></ab:msup><ab:msub><ab:mi>ν</ab:mi><ab:mi>l</ab:mi></ab:msub><ab:mo stretchy="false">)</ab:mo></ab:math>, <ib:math xmlns:ib="http://www.w3.org/1998/Math/MathML" display="inline"><ib:mi>l</ib:mi><ib:mo>=</ib:mo><ib:mi>e</ib:mi></ib:math>, <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mrow><kb:mi>μ</kb:mi></kb:mrow></kb:math>, <mb:math xmlns:mb="http://www.w3.org/1998/Math/MathML" display="inline"><mb:mrow><mb:mi>τ</mb:mi></mb:mrow></mb:math>, which agree with the available experimental data and other Standard Model (SM) predictions. For the unmeasured decay constants, especially in the purely leptonic decays of the charged vector mesons, our predictions could be tested in the upcoming Belle-II, SCTF, CEPC, FCC-ee, and LHCb experiments in the near future.