QCD axion, color-mediated neutrino masses, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msup> <mml:mi>B</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo stretchy="false">→</mml:mo> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>+</mml:mo> <mml:msub> <mml:mi>E</mml:mi> <mml:mrow> <mml:mi>miss</mml:mi> </mml:mrow> </mml:msub> </mml:math> anomaly
Chandan Hati, Julio Leite, Newton Nath, J. W. F. Valle
Abstract
Motivated by the recent Belle II result indicating a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mn>2.7</a:mn> <a:mi>σ</a:mi> </a:math> excess of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msup> <c:mi>B</c:mi> <c:mo>+</c:mo> </c:msup> <c:mo stretchy="false">→</c:mo> <c:msup> <c:mi>K</c:mi> <c:mo>+</c:mo> </c:msup> <c:mo>+</c:mo> <c:msub> <c:mi>E</c:mi> <c:mrow> <c:mi>miss</c:mi> </c:mrow> </c:msub> </c:math> events compared to the Standard Model (SM) prediction for <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"> <f:msup> <f:mi>B</f:mi> <f:mo>+</f:mo> </f:msup> <f:mo stretchy="false">→</f:mo> <f:msup> <f:mi>K</f:mi> <f:mo>+</f:mo> </f:msup> <f:mi>ν</f:mi> <f:mover accent="true"> <f:mi>ν</f:mi> <f:mo stretchy="false">¯</f:mo> </f:mover> </f:math> , we explore an explanation to this anomaly based on a Kim-Shifman-Vainshtein-Zakharov-type QCD axion model featuring a Peccei-Quinn (PQ) symmetry breaking at high scale, which can provide a solution to the strong <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>C</k:mi> <k:mi>P</k:mi> </k:math> problem with dark matter relic abundance. The model contains a PQ-charged scalar leptoquark which can interact with the SM quarks only via mass mixing of the latter with vectorlike quarks. The mixing between SM and vectorlike quarks is determined by the PQ mass scales and can explain the excess <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:msup> <m:mi>B</m:mi> <m:mo>+</m:mo> </m:msup> <m:mo stretchy="false">→</m:mo> <m:msup> <m:mi>K</m:mi> <m:mo>+</m:mo> </m:msup> <m:mo>+</m:mo> <m:msub> <m:mi>E</m:mi> <m:mrow> <m:mi>miss</m:mi> </m:mrow> </m:msub> </m:math> events while respecting other flavor constraints. The same PQ-charged scalar leptoquarks and vectorlike quarks also mediate the two-loop radiative neutrino masses.