2020/03/23 by Aliaksei Kachanovich, Ulrich Nierste, Ivan Nišandžić · 1 citation
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #Dark Matter and Cosmic Phenomena #Dark matter #Elementary particle #Higgs boson #Large Hadron Collider #Mixing (physics) #Particle physics theoretical and experimental studies #Phenomenology (philosophy) #Physics beyond the Standard Model #Standard Model (mathematical formulation) #Vertex (graph theory) #hep-ph
paper · pdf · doi:10.1140/epjc/s10052-020-8240-z
9 pages, 4 figures. v.2: minor clarifications, added Table 1, added references, acknowledgements extended
openalex created_date 2020/03/13 · arxiv created 2020/03/23 · openalex publication_date 2020/07/01 · arxiv updated 2020/08/26 · openalex updated_date 2026/08/05
Abstract We consider a Higgs portal model in which the 125-GeV Higgs boson mixes with a light singlet mediator h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> coupling to particles of a Dark Sector and study potential b→ s h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>b</mml:mi><mml:mo>→</mml:mo><mml:mi>s</mml:mi><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> decays in the Belle II experiment. Multiplying the gauge-dependent off-shell Standard-Model b - s -Higgs vertex with the sine of the Higgs mixing angle does not give the correct b - s - h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> vertex. We clarify this issue by calculating the b - s - h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> vertex in an arbitrary Rξ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>R</mml:mi><mml:mi>ξ</mml:mi></mml:msub></mml:math> gauge and demonstrate how the ξ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ξ</mml:mi></mml:math> dependence cancels from physical decay rates involving an on-shell or off-shell h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> . Then we revisit the b→ s h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>b</mml:mi><mml:mo>→</mml:mo><mml:mi>s</mml:mi><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> phenomenology and point out that a simultaneous study of B→ K^* h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>B</mml:mi><mml:mo>→</mml:mo><mml:msup><mml:mi>K</mml:mi><mml:mo>∗</mml:mo></mml:msup><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> and B→ K h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>B</mml:mi><mml:mo>→</mml:mo><mml:mi>K</mml:mi><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> helps to discriminate between the Higgs portal and alternative models of the Dark Sector. We further advocate for the use of the h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> lifetime information contained in displaced-vertex data with h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> decaying back to Standard-Model particles to better constrain the h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> mass or to reveal additional h2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>h</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> decay modes into long-lived particles.