Jet-Origin Identification and Its Application at an Electron-Positron Higgs Factory

To enhance the scientific discovery power of high-energy collider experiments, we propose and realize the concept of jet-origin identification that categorizes jets into five quark species <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mo stretchy="false">(</a:mo><a:mi>b</a:mi><a:mo>,</a:mo><a:mi>c</a:mi><a:mo>,</a:mo><a:mi>s</a:mi><a:mo>,</a:mo><a:mi>u</a:mi><a:mo>,</a:mo><a:mi>d</a:mi><a:mo stretchy="false">)</a:mo></a:math>, five antiquarks <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mo stretchy="false">(</e:mo><e:mover accent="true"><e:mi>b</e:mi><e:mo stretchy="false">¯</e:mo></e:mover><e:mo>,</e:mo><e:mover accent="true"><e:mi>c</e:mi><e:mo stretchy="false">¯</e:mo></e:mover><e:mo>,</e:mo><e:mover accent="true"><e:mi>s</e:mi><e:mo stretchy="false">¯</e:mo></e:mover><e:mo>,</e:mo><e:mover accent="true"><e:mi>u</e:mi><e:mo stretchy="false">¯</e:mo></e:mover><e:mo>,</e:mo><e:mover accent="true"><e:mi>d</e:mi><e:mo stretchy="false">¯</e:mo></e:mover><e:mo stretchy="false">)</e:mo></e:math>, and the gluon. Using state-of-the-art algorithms and simulated <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mi>ν</s:mi><s:mover accent="true"><s:mi>ν</s:mi><s:mo stretchy="false">¯</s:mo></s:mover><s:mi>H</s:mi><s:mo>,</s:mo><s:mi>H</s:mi><s:mo stretchy="false">→</s:mo><s:mi>j</s:mi><s:mi>j</s:mi></s:math> events at 240 GeV center-of-mass energy at the electron-positron Higgs factory, the jet-origin identification simultaneously reaches jet flavor tagging efficiencies ranging from 67% to 92% for bottom, charm, and strange quarks and jet charge flip rates of 7%–24% for all quark species. We apply the jet-origin identification to Higgs rare and exotic decay measurements at the nominal luminosity of the Circular Electron Positron Collider and conclude that the upper limits on the branching ratios of <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:mrow><x:mi>H</x:mi><x:mo stretchy="false">→</x:mo><x:mi>s</x:mi><x:mover accent="true"><x:mrow><x:mi>s</x:mi></x:mrow><x:mrow><x:mo stretchy="false">¯</x:mo></x:mrow></x:mover><x:mo>,</x:mo><x:mi>u</x:mi><x:mover accent="true"><x:mrow><x:mi>u</x:mi></x:mrow><x:mrow><x:mo stretchy="false">¯</x:mo></x:mrow></x:mover><x:mo>,</x:mo><x:mi>d</x:mi><x:mover accent="true"><x:mrow><x:mi>d</x:mi></x:mrow><x:mrow><x:mo stretchy="false">¯</x:mo></x:mrow></x:mover></x:mrow></x:math> and <gb:math xmlns:gb="http://www.w3.org/1998/Math/MathML" display="inline"><gb:mi>H</gb:mi><gb:mo stretchy="false">→</gb:mo><gb:mi>s</gb:mi><gb:mi>b</gb:mi><gb:mo>,</gb:mo><gb:mi>d</gb:mi><gb:mi>b</gb:mi><gb:mo>,</gb:mo><gb:mi>u</gb:mi><gb:mi>c</gb:mi><gb:mo>,</gb:mo><gb:mi>d</gb:mi><gb:mi>s</gb:mi></gb:math> can be determined to <jb:math xmlns:jb="http://www.w3.org/1998/Math/MathML" display="inline"><jb:mn>2</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:math> to <lb:math xmlns:lb="http://www.w3.org/1998/Math/MathML" display="inline"><lb:mn>1</lb:mn><lb:mo>×</lb:mo><lb:msup><lb:mn>10</lb:mn><lb:mrow><lb:mo>−</lb:mo><lb:mn>3</lb:mn></lb:mrow></lb:msup></lb:math> at 95% confidence level. The derived upper limit for <nb:math xmlns:nb="http://www.w3.org/1998/Math/MathML" display="inline"><nb:mi>H</nb:mi><nb:mo stretchy="false">→</nb:mo><nb:mi>s</nb:mi><nb:mover accent="true"><nb:mi>s</nb:mi><nb:mo stretchy="false">¯</nb:mo></nb:mover></nb:math> decay is approximately 3 times the prediction of the standard model.