W W V (V =γ , Z ) vertex in the Georgi-Machacek model
Abstract
The C P -even static form factors Δ κV' and Δ QV (V =γ , Z ) associated with the W W V vertex are studied in the context of the Georgi-Machacek model (GMM), which predicts nine new scalar bosons accommodated in a singlet, a triplet, and a fiveplet. General expressions for the one-loop contributions to Δ κV' and Δ QV arising from neutral, singly, and doubly charged scalar bosons are obtained in terms of both parametric integrals and Passarino-Veltman scalar functions, which can be numerically evaluated. It is found that the GMM yields 15 (28) distinct contributions to Δ κγ' and Δ Qγ (Δ κZ' and Δ QZ), though several of them are naturally suppressed. A numerical analysis is done in the region of parameter space still consistent with current experimental data and it is found that the largest contributions to Δ κV' arise from Feynman diagrams with two nondegenerate scalar bosons in the loop, with values of the order of a =g2/(96 π2) reached when there is a large splitting between the masses of these scalar bosons. As for Δ QV, it reaches values as large as 10-2a for the lightest allowed scalar bosons, but it decreases rapidly as one of the masses of the scalar bosons becomes large. Among the new contributions of the GMM to the Δ κV' and Δ QV form factors are those induced by the H5±W∓Z vertex, which arises at the tree level and is a unique prediction of this model.
- Publication:
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Physical Review D
- Pub Date:
- November 2016
- DOI:
- 10.1103/PhysRevD.94.095006
- arXiv:
- arXiv:1610.04911
- Bibcode:
- 2016PhRvD..94i5006A
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 27 pages, 10 figures