Direct production of light scalars in the type-I two-Higgs-doublet model at the lifetime frontier of the LHC

This is the authors' abstract. We don't add key points for this paper.

A light pseudoscalar <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>A</a:mi></a:mrow></a:math> in the sufficient large <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>tan</c:mi><c:mi>β</c:mi></c:math> region of type-I two-Higgs-doublet model can be naturally a long-lived particle. We focus on <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msup><e:mi>H</e:mi><e:mo>±</e:mo></e:msup><e:mi>A</e:mi></e:math>, <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>H</g:mi><g:mi>A</g:mi></g:math>, and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>A</i:mi><i:mi>A</i:mi></i:math> pair productions via the electroweak processes mediated by the bosons at the LHC, including <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mrow><k:mi>p</k:mi><k:mi>p</k:mi><k:mo stretchy="false">→</k:mo><k:msup><k:mrow><k:mi>W</k:mi></k:mrow><k:mrow><k:mo>±</k:mo></k:mrow></k:msup><k:mo>/</k:mo><k:mi>Z</k:mi><k:mo stretchy="false">→</k:mo><k:msup><k:mrow><k:mi>H</k:mi></k:mrow><k:mrow><k:mo>±</k:mo></k:mrow></k:msup><k:mo>/</k:mo><k:mi>H</k:mi><k:mi>A</k:mi></k:mrow></k:math> and <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:mi>p</o:mi><o:mi>p</o:mi><o:mo stretchy="false">→</o:mo><o:mi>h</o:mi><o:mo stretchy="false">→</o:mo><o:mi>A</o:mi><o:mi>A</o:mi></o:math> at the 14 TeV LHC. The possibility of probing <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mi>A</s:mi></s:math> as a LLP at the FASER-2, FACET, MoEDAL-MAPP-2, and MATHUSLA is discussed. We find that FASER-2 fails to probe any parameter space within <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:mrow><u:mn>0.2</u:mn><u:mtext> </u:mtext><u:mtext> </u:mtext><u:mi>GeV</u:mi><u:mo><</u:mo><u:msub><u:mi>m</u:mi><u:mi>A</u:mi></u:msub><u:mo><</u:mo><u:mn>10</u:mn><u:mtext> </u:mtext><u:mtext> </u:mtext><u:mi>GeV</u:mi></u:mrow></u:math> for all the considered processes. For <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:mrow><w:mn>130</w:mn><w:mo><</w:mo><w:msub><w:mrow><w:mi>m</w:mi></w:mrow><w:mrow><w:mi>H</w:mi><w:mo>±</w:mo></w:mrow></w:msub><w:mo>=</w:mo><w:msub><w:mrow><w:mi>m</w:mi></w:mrow><w:mrow><w:mi>H</w:mi></w:mrow></w:msub><w:mo><</w:mo><w:mn>400</w:mn><w:mtext> </w:mtext><w:mtext> </w:mtext><w:mi>GeV</w:mi></w:mrow></w:math>, FACET, MoEDAL-MAPP-2, and MATHUSLA can probe <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:mi>tan</y:mi><y:mi>β</y:mi><y:mo>≲</y:mo><y:msup><y:mn>10</y:mn><y:mrow><y:mn>4</y:mn><y:mo>−</y:mo><y:mn>6</y:mn></y:mrow></y:msup></y:math> for <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:msub><ab:mi>m</ab:mi><ab:mi>A</ab:mi></ab:msub><ab:mo>≲</ab:mo><ab:mn>3</ab:mn><ab:mtext> </ab:mtext><ab:mtext> </ab:mtext><ab:mi>GeV</ab:mi></ab:math>, and <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mi>tan</cb:mi><cb:mi>β</cb:mi><cb:mo>≲</cb:mo><cb:msup><cb:mn>10</cb:mn><cb:mrow><cb:mn>6</cb:mn><cb:mo>−</cb:mo><cb:mn>8</cb:mn></cb:mrow></cb:msup></cb:math> for <eb:math xmlns:eb="http://www.w3.org/1998/Math/MathML" display="inline"><eb:mrow><eb:mn>3</eb:mn><eb:mtext> </eb:mtext><eb:mtext> </eb:mtext><eb:mi>GeV</eb:mi><eb:mo>≲</eb:mo><eb:msub><eb:mi>m</eb:mi><eb:mi>A</eb:mi></eb:msub><eb:mo><</eb:mo><eb:mn>10</eb:mn><eb:mtext> </eb:mtext><eb:mtext> </eb:mtext><eb:mi>GeV</eb:mi></eb:mrow></eb:math> from <gb:math xmlns:gb="http://www.w3.org/1998/Math/MathML" display="inline"><gb:mi>p</gb:mi><gb:mi>p</gb:mi><gb:mo stretchy="false">→</gb:mo><gb:msup><gb:mi>W</gb:mi><gb:mo>±</gb:mo></gb:msup><gb:mo>/</gb:mo><gb:mi>Z</gb:mi><gb:mo stretchy="false">→</gb:mo><gb:msup><gb:mi>H</gb:mi><gb:mo>±</gb:mo></gb:msup><gb:mo>/</gb:mo><gb:mi>Z</gb:mi><gb:mi>A</gb:mi></gb:math> processes. And <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mi>p</kb:mi><kb:mi>p</kb:mi><kb:mo stretchy="false">→</kb:mo><kb:mi>h</kb:mi><kb:mo stretchy="false">→</kb:mo><kb:mi>A</kb:mi><kb:mi>A</kb:mi></kb:math> process covers similar parameter space. All processes can surpass the current limits. Published by the American Physical Society 2024