Precision Higgs Constraints in U(1) Extensions of the Standard Model with a Light <i>Z</i>′-Boson

Anomaly-free <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></semantics></math></inline-...

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Bibliographic Details
Main Authors: Zoltán Péli, Zoltán Trócsányi
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Universe
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Online Access:https://www.mdpi.com/2218-1997/11/1/12
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Summary:Anomaly-free <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></semantics></math></inline-formula> extensions of the standard model (SM) predict a new neutral gauge boson <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>Z</mi><mo>′</mo></msup></semantics></math></inline-formula>. When <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>Z</mi><mo>′</mo></msup></semantics></math></inline-formula> obtains its mass from the spontaneous breaking of the new <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></semantics></math></inline-formula> symmetry by a new complex scalar field, the model also predicts a second real scalar <i>s</i>, and the search for the new scalar and the search for the new gauge boson become intertwined. We present the computation of production cross sections and decay widths of such a scalar <i>s</i> in models with a light <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>Z</mi><mo>′</mo></msup></semantics></math></inline-formula> boson when the decay <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>h</mi><mo>→</mo><msup><mi>Z</mi><mo>′</mo></msup><msup><mi>Z</mi><mo>′</mo></msup></mrow></semantics></math></inline-formula> may have a sizeable branching ratio. We show how the Higgs signal strength measurement in this channel can provide stricter exclusion bounds on the parameters of the model than those obtained from the total signal strength for Higgs boson production.
ISSN:2218-1997