New mechanism for the top-bottom mass hierarchy

Journal Article · Wed Sep 01 04:00:00 EDT 2004 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.70.055006· OSTI ID:20705160

Hashimoto, Michio ^[1]; Kanemura, Shinya ^[2]

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1. Department of Physics, Pusan National University, Pusan 609-735 (Korea, Republic of)
2. Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

We propose a mechanism to generate hierarchy between masses of the top and bottom quarks without fine-tuning of the Yukawa coupling constants in the context of the two Higgs doublet model (THDM). In the THDM with a discrete symmetry, there exists the vacuum where only the top quark receives the mass of the order of the electroweak symmetry breaking scale v({approx_equal}246 GeV), while the bottom quark remains massless. By introducing a small soft-breaking parameter m{sub 3}{sup 2} of the discrete symmetry, the bottom quark perturbatively acquires a nonzero mass. We show a model in which the small m{sub 3}{sup 2}[{approx}v{sup 2}/(4{pi}){sup 2}] is generated by the dynamics above the cutoff scale of the THDM. The ratio tan{beta} of the two vacuum expectation values is necessarily very large, i.e., tan{beta}{approx}m{sub t}/m{sub b}. We also find a salient relation, 1/tan{beta}{approx_equal}m{sub 3}{sup 2}/m{sub H}{sup 2}, where m{sub H} is the mass of the extra CP-even Higgs boson. Our scenario yields some specific features that can be tested in future collider experiments.

• OSTI ID: 20705160
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 5 Vol. 70; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
B QUARKS
CP INVARIANCE
GEV RANGE
HIGGS BOSONS
HIGGS MODEL
REST MASS
SYMMETRY
SYMMETRY BREAKING
T QUARKS
WEINBERG-SALAM GAUGE MODEL
YUKAWA POTENTIAL