Combined explanation of LHC multilepton, diphoton, and top-quark excesses

Abstract

In this article, we propose the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi mathvariant="normal">Δ</a:mi><a:mn>2</a:mn><a:mi>HDM</a:mi><a:mi mathvariant="normal">S</a:mi></a:mrow></a:math> as a combined explanation of several excesses and anomalies observed at the LHC. Especially, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>t</e:mi><e:mover accent="true"><e:mi>t</e:mi><e:mo stretchy="false">¯</e:mo></e:mover></e:math> differential distributions point towards the associated production of new electroweak scale Higgs bosons decaying into bottom quarks and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>W</i:mi></i:math> bosons (<k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mo>&gt;</k:mo><k:mn>5</k:mn><k:mi>σ</k:mi></k:math>) with masses consistent with the diphoton excesses at <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mo>≈</m:mo><m:mn>95</m:mn><m:mtext> </m:mtext><m:mtext> </m:mtext><m:mi>GeV</m:mi></m:math> and <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:mo>≈</o:mo><o:mn>151.5</o:mn><o:mtext> </o:mtext><o:mtext> </o:mtext><o:mi>GeV</o:mi></o:math> (<q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:mn>3.8</q:mn><q:mi>σ</q:mi></q:math> and <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mn>4.9</s:mn><s:mi>σ</s:mi></s:math>, respectively). Furthermore, CMS found indications for resonant <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:mi>t</u:mi><u:mover accent="true"><u:mi>t</u:mi><u:mo stretchy="false">¯</u:mo></u:mover></u:math> production at <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:mo>≈</y:mo><y:mn>400</y:mn><y:mtext> </y:mtext><y:mtext> </y:mtext><y:mi>GeV</y:mi></y:math> (<ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:mn>3.5</ab:mn><ab:mi>σ</ab:mi></ab:math>) and both ATLAS and CMS reported elevated four-top and <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mi>t</cb:mi><cb:mover accent="true"><cb:mi>t</cb:mi><cb:mo stretchy="false">¯</cb:mo></cb:mover><cb:mi>W</cb:mi></cb:math> cross sections. The <gb:math xmlns:gb="http://www.w3.org/1998/Math/MathML" display="inline"><gb:mrow><gb:mi mathvariant="normal">Δ</gb:mi><gb:mn>2</gb:mn><gb:mi>HDM</gb:mi><gb:mi mathvariant="normal">S</gb:mi></gb:mrow></gb:math> is obtained by supplementing the SM Higgs (<kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:msub><kb:mi>H</kb:mi><kb:mn>2</kb:mn></kb:msub></kb:math>) with a second scalar doublet (<mb:math xmlns:mb="http://www.w3.org/1998/Math/MathML" display="inline"><mb:msub><mb:mi>H</mb:mi><mb:mn>1</mb:mn></mb:msub></mb:math>), real scalar singlet (<ob:math xmlns:ob="http://www.w3.org/1998/Math/MathML" display="inline"><ob:mi>S</ob:mi></ob:math>), and a Higgs triplet with zero hypercharge (<qb:math xmlns:qb="http://www.w3.org/1998/Math/MathML" display="inline"><qb:mi mathvariant="normal">Δ</qb:mi></qb:math>). We fix the masses of the neutral tripletlike and the singletlike scalars by the diphoton excesses, i.e., <tb:math xmlns:tb="http://www.w3.org/1998/Math/MathML" display="inline"><tb:msub><tb:mi>m</tb:mi><tb:msup><tb:mi mathvariant="normal">Δ</tb:mi><tb:mn>0</tb:mn></tb:msup></tb:msub><tb:mo>=</tb:mo><tb:mn>151.5</tb:mn><tb:mtext> </tb:mtext><tb:mtext> </tb:mtext><tb:mi>GeV</tb:mi></tb:math> and <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:msub><wb:mi>m</wb:mi><wb:mi>S</wb:mi></wb:msub><wb:mo>=</wb:mo><wb:mn>95</wb:mn><wb:mtext> </wb:mtext><wb:mtext> </wb:mtext><wb:mi>GeV</wb:mi></wb:math>, respectively. <yb:math xmlns:yb="http://www.w3.org/1998/Math/MathML" display="inline"><yb:mrow><yb:mi>H</yb:mi></yb:mrow></yb:math>, the <ac:math xmlns:ac="http://www.w3.org/1998/Math/MathML" display="inline"><ac:mi>C</ac:mi><ac:mi>P</ac:mi></ac:math>-even component of <cc:math xmlns:cc="http://www.w3.org/1998/Math/MathML" display="inline"><cc:msub><cc:mi>H</cc:mi><cc:mn>1</cc:mn></cc:msub></cc:math>, is produced via gluon fusion from a top-loop and decays dominantly to <ec:math xmlns:ec="http://www.w3.org/1998/Math/MathML" display="inline"><ec:mi>S</ec:mi><ec:mo>+</ec:mo><ec:msup><ec:mi mathvariant="normal">Δ</ec:mi><ec:mn>0</ec:mn></ec:msup></ec:math> whose subsequent decays to <hc:math xmlns:hc="http://www.w3.org/1998/Math/MathML" display="inline"><hc:msup><hc:mi>W</hc:mi><hc:mo>+</hc:mo></hc:msup><hc:msup><hc:mi>W</hc:mi><hc:mo>−</hc:mo></hc:msup></hc:math> and <jc:math xmlns:jc="http://www.w3.org/1998/Math/MathML" display="inline"><jc:mi>b</jc:mi><jc:mover accent="true"><jc:mi>b</jc:mi><jc:mo stretchy="false">¯</jc:mo></jc:mover></jc:math> explain the differential <nc:math xmlns:nc="http://www.w3.org/1998/Math/MathML" display="inline"><nc:mi>t</nc:mi><nc:mover accent="true"><nc:mi>t</nc:mi><nc:mo stretchy="false">¯</nc:mo></nc:mover></nc:math> distributions for <rc:math xmlns:rc="http://www.w3.org/1998/Math/MathML" display="inline"><rc:mi>σ</rc:mi><rc:mo stretchy="false">(</rc:mo><rc:mi>p</rc:mi><rc:mi>p</rc:mi><rc:mo stretchy="false">→</rc:mo><rc:mi>H</rc:mi><rc:mo stretchy="false">→</rc:mo><rc:mi>S</rc:mi><rc:msup><rc:mi mathvariant="normal">Δ</rc:mi><rc:mn>0</rc:mn></rc:msup><rc:mo stretchy="false">)</rc:mo><rc:mo>≈</rc:mo><rc:mn>5</rc:mn><rc:mtext> </rc:mtext><rc:mtext> </rc:mtext><rc:mi>pb</rc:mi></rc:math>. Choosing the top-Yukawa of <yc:math xmlns:yc="http://www.w3.org/1998/Math/MathML" display="inline"><yc:msub><yc:mi>H</yc:mi><yc:mn>1</yc:mn></yc:msub></yc:math> accordingly, the <ad:math xmlns:ad="http://www.w3.org/1998/Math/MathML" display="inline"><ad:mi>C</ad:mi><ad:mi>P</ad:mi></ad:math>-odd Higgs boson <cd:math xmlns:cd="http://www.w3.org/1998/Math/MathML" display="inline"><cd:mi>A</cd:mi></cd:math> turns out to have the right production cross section to account for the resonant <ed:math xmlns:ed="http://www.w3.org/1998/Math/MathML" display="inline"><ed:mi>t</ed:mi><ed:mover accent="true"><ed:mi>t</ed:mi><ed:mo stretchy="false">¯</ed:mo></ed:mover></ed:math> excess at 400 GeV, while the top-associated production of <id:math xmlns:id="http://www.w3.org/1998/Math/MathML" display="inline"><id:mi>H</id:mi></id:math> and <kd:math xmlns:kd="http://www.w3.org/1998/Math/MathML" display="inline"><kd:mi>A</kd:mi></kd:math> results in new physics pollution of Standard Model <md:math xmlns:md="http://www.w3.org/1998/Math/MathML" display="inline"><md:mi>t</md:mi><md:mover accent="true"><md:mi>t</md:mi><md:mo stretchy="false">¯</md:mo></md:mover><md:mi>W</md:mi></md:math> and <qd:math xmlns:qd="http://www.w3.org/1998/Math/MathML" display="inline"><qd:mi>t</qd:mi><qd:mover accent="true"><qd:mi>t</qd:mi><qd:mo stretchy="false">¯</qd:mo></qd:mover><qd:mi>t</qd:mi><qd:mover accent="true"><qd:mi>t</qd:mi><qd:mo stretchy="false">¯</qd:mo></qd:mover></qd:math> cross sections, as preferred by the data. Published by the American Physical Society 2024