Winos from natural SUSY at the high luminosity LHC

Abstract

In natural supersymmetric models defined by no worse than a part in thirty electroweak fine-tuning, winos and binos are generically expected to be much heavier than Higgsinos. Moreover, the splitting between the Higgsinos is expected to be small, so that the visible decay products of the heavier Higgsinos are soft, rendering the Higgsinos quasi-invisible at the LHC. Within the natural supersymmetry (SUSY) framework, heavy electroweak gauginos decay to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>W</a:mi></a:math>, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>Z</c:mi></c:math> or <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>h</e:mi></e:math> bosons plus Higgsinos in the ratio <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:mo>∼</g:mo><g:mn>2</g:mn><g:mo>∶</g:mo><g:mn>1</g:mn><g:mo>∶</g:mo><g:mn>1</g:mn></g:mrow></g:math>, respectively. This is in sharp contrast to models with a binolike lightest superpartner and very heavy Higgsinos, where the charged (neutral) wino essentially always decays to a <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>W</i:mi></i:math> (<k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mi>h</k:mi></k:math>) boson and an invisible bino. Wino pair production at the LHC, in natural SUSY, thus leads to <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mi>V</m:mi><m:mi>V</m:mi></m:math>, <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:mi>V</o:mi><o:mi>h</o:mi></o:math> and <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:mi>h</q:mi><q:mi>h</q:mi><q:mo>+</q:mo><q:msub><q:menclose notation="updiagonalstrike" other="updiag1"><q:mi>E</q:mi></q:menclose><q:mi>T</q:mi></q:msub></q:math> final states (<u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:mrow><u:mi>V</u:mi><u:mo>=</u:mo><u:mi>W</u:mi></u:mrow></u:math>, <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:mrow><w:mi>Z</w:mi></w:mrow></w:math>) where, for TeV scale winos, the vector bosons and <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:mi>h</y:mi></y:math> daughters are considerably boosted. We identify eight different channels arising from the leptonic and hadronic decays of the vector bosons and the decay <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:mi>h</ab:mi><ab:mo stretchy="false">→</ab:mo><ab:mi>b</ab:mi><ab:mover accent="true"><ab:mi>b</ab:mi><ab:mo stretchy="false">¯</ab:mo></ab:mover></ab:math>, each of which offers an avenue for wino discovery at the high luminosity LHC (HL-LHC). By combining the signal in all eight channels we find, assuming <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:msqrt><fb:mi>s</fb:mi></fb:msqrt><fb:mo>=</fb:mo><fb:mn>14</fb:mn><fb:mtext> </fb:mtext><fb:mtext> </fb:mtext><fb:mi>TeV</fb:mi></fb:math> and an integrated luminosity of <hb:math xmlns:hb="http://www.w3.org/1998/Math/MathML" display="inline"><hb:mn>3000</hb:mn><hb:mtext> </hb:mtext><hb:mtext> </hb:mtext><hb:msup><hb:mi>fb</hb:mi><hb:mrow><hb:mo>−</hb:mo><hb:mn>1</hb:mn></hb:mrow></hb:msup></hb:math>, that the discovery reach for winos extends to <jb:math xmlns:jb="http://www.w3.org/1998/Math/MathML" display="inline"><jb:mi>m</jb:mi><jb:mo stretchy="false">(</jb:mo><jb:mi>w</jb:mi><jb:mi>i</jb:mi><jb:mi>n</jb:mi><jb:mi>o</jb:mi><jb:mo stretchy="false">)</jb:mo><jb:mo>∼</jb:mo><jb:mn>1.1</jb:mn><jb:mtext> </jb:mtext><jb:mtext> </jb:mtext><jb:mi>TeV</jb:mi></jb:math>, while the 95% CL exclusion range extends to a wino mass of almost 1.4 TeV. We also identify “Higgsino specific channels” which could serve to provide <nb:math xmlns:nb="http://www.w3.org/1998/Math/MathML" display="inline"><nb:mn>3</nb:mn><nb:mi>σ</nb:mi></nb:math> evidence that winos lighter than 1.2 TeV decay to light Higgsinos rather than to a binolike lightest supersymmetric particle, should a wino signal appear at the HL-LHC. Published by the American Physical Society 2024

Topics & Concepts