<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>D</mml:mi> </mml:mrow> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mo>*</mml:mo> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> and survival of the fittest scalar leptoquark

Abstract

Motivated by the long-standing discrepancy in lepton flavor universality ratios <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msub> <a:mi>R</a:mi> <a:mi>D</a:mi> </a:msub> </a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msub> <c:mi>R</c:mi> <c:msup> <c:mi>D</c:mi> <c:mo>*</c:mo> </c:msup> </c:msub> </c:math> we assess the status of scalar leptoquark states <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msub> <e:mi>R</e:mi> <e:mn>2</e:mn> </e:msub> </e:math> , <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msub> <g:mover accent="true"> <g:mi>R</g:mi> <g:mo stretchy="false">˜</g:mo> </g:mover> <g:mn>2</g:mn> </g:msub> </g:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:msub> <k:mi>S</k:mi> <k:mn>1</k:mn> </k:msub> </k:math> which can in principle provide a desired enhancement of <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mi mathvariant="script">B</m:mi> <m:mo stretchy="false">(</m:mo> <m:mi>B</m:mi> <m:mo stretchy="false">→</m:mo> <m:msup> <m:mi>D</m:mi> <m:mrow> <m:mo stretchy="false">(</m:mo> <m:mo>*</m:mo> <m:mo stretchy="false">)</m:mo> </m:mrow> </m:msup> <m:mi>τ</m:mi> <m:mi>ν</m:mi> <m:mo stretchy="false">)</m:mo> </m:math> in a minimal setup with two Yukawa couplings only. We consider unavoidable low-energy constraints, <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"> <u:mi>Z</u:mi> </u:math> -pole measurements as well as high- <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"> <w:msub> <w:mi>p</w:mi> <w:mi>T</w:mi> </w:msub> </w:math> constraints. After setting the mass of each leptoquark to 1.5 TeV we find that of all considered states only <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"> <y:msub> <y:mi>S</y:mi> <y:mn>1</y:mn> </y:msub> </y:math> leptoquark, coupled to both chiralities of leptons and quarks, is still a completely viable solution while the scenario with <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"> <ab:msub> <ab:mi>R</ab:mi> <ab:mn>2</ab:mn> </ab:msub> </ab:math> is in growing tension with <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"> <cb:mi mathvariant="normal">Γ</cb:mi> <cb:mo stretchy="false">(</cb:mo> <cb:mi>Z</cb:mi> <cb:mo stretchy="false">→</cb:mo> <cb:mi>τ</cb:mi> <cb:mi>τ</cb:mi> <cb:mo stretchy="false">)</cb:mo> </cb:math> and with the LHC constraints on the ditau tails at high- <ib:math xmlns:ib="http://www.w3.org/1998/Math/MathML" display="inline"> <ib:msub> <ib:mi>p</ib:mi> <ib:mi>T</ib:mi> </ib:msub> </ib:math> . We comment on the future experimental tests of the <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"> <kb:msub> <kb:mi>S</kb:mi> <kb:mn>1</kb:mn> </kb:msub> </kb:math> scenario. Published by the American Physical Society 2024

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