The Higgs mass in the MSSM infrared fixed point scenario

Casas, J.A.; Espinosa, J. R.; Haber, Howard E.

doi:10.1016/s0550-3213(98)00327-7

Cited by 44 publications

(50 citation statements)

References 71 publications

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“…A reduction of the number of independent parameters in the infrared quasi-fixed point regime made it possible to determine, to a sufficiently high degree of precision, an upper limit on the mass of the lightest CP-even Higgs boson. In the case being considered, comparatively small values of tan β result in that its mass does not exceed 94 ± 5 GeV [11]- [13]. This limit is 25 − 30 GeV lower than the absolute upper limit in the minimal SUSY model.…”

Section: Introductionmentioning

confidence: 82%

Infrared quasifixed solutions in a nonminimal supersymmetric standard model

Nevzorov

Trusov

2001

Phys. Atom. Nuclei

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The considerable part of the parameter space in the MSSM corresponding to the infrared quasi fixed point scenario is almost excluded by LEP II bounds on the lightest Higgs boson mass. In the NMSSM the mass of the lightest Higgs boson reaches its maximum value in the strong Yukawa coupling limit when Yukawa couplings are essentially larger than gauge ones at the Grand Unification scale. In this limit the solutions of the renormalisation group equations are attracted to the infrared and Hill type effective fixed lines or surfaces in the Yukawa coupling parameter space. They are concentrated in the vicinity of quasi fixed points for Y i (0) → ∞. However the solutions are attracted to such points rather weakly. For this reason when all Y i (0) ∼ 1 the solutions of the renormalisation group equations are gathered near a line in the Hill type effective surface. In the paper the approximate solutions for the NMSSM Yukawa couplings are given. The possibility of b-quark and τ -lepton Yukawa coupling unification at the scale M X is also discussed.

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Section: Introductionmentioning

confidence: 82%

Infrared quasifixed solutions in a nonminimal supersymmetric standard model

Nevzorov

Trusov

2001

Phys. Atom. Nuclei

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“…These comparatively small values of tan β lead to much more stringent constraints on the mass of the lightest Higgs boson. A detailed theoretical analysis performed in [3], [4], revealed that, in the case being considered, its mass does not exceed 94 ± 5 GeV, which is 25 − 30 GeV below the absolute upper limit in the minimal SUSY model. It should be noted that the LEP II constraints on the mass of the lightest Higgs boson [6] are such that a considerable fraction of solutions approaching a quasi-fixed point at tan β ∼ 1 have already been ruled out by existing experimental data.…”

Section: Introductionmentioning

confidence: 89%

Quasifixed-point scenario in a modified nonminimal supersymmetric standard model

Nevzorov

Trusov

2002

Phys. Atom. Nuclei

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The simplest extension of the MSSM that does not contradict LEP II experimental bound on the lightest Higgs boson mass at tan β ∼ 1 is the modified Next-toMinimal Supersymmetric Standard Model (MNSSM). We investigate the renormalization of Yukawa couplings and soft SUSY breaking terms in this model. The possibility of b-quark and τ -lepton Yukawa coupling unification at the Grand Unification scale M X is studied. The particle spectrum is analysed in the vicinity of the quasi-fixed point where the solutions of renormalization group equations are concentrated at the electroweak scale. IntroductionA rapid development of experimental high-energy physics over the last decades of the XX century gave impetus to intensive investigations of various extensions of the Standard Model. Its supersymmetric generalization known as the Minimal Supersymmetric Standard Model (MSSM) is one of the most popular extensions of the Standard Model. The Higgs sector of the MSSM includes two doublets of Higgs fields, H 1 and H 2 . Upon a spontaneous breakdown of gauge symmetry, each of them develops a vacuum expectation value; we denote the corresponding vacuum expectation values by v 1 and v 2 . The sum of the squares of the vacuum expectation values of the Higgs fields is v 2 = (246 GeV) 2 , the ratio of the expectation values being determined by the angle β. By definition, β = arctan(v 2 /v 1 ). The value of tan β is not fixed experimentally. It is varied within a wide interval, from 1.3−1.8 to 50−60. Within supersymmetric (SUSY) models, the upper and lower limits on tan β arise under the assumption that perturbation theory is applicable up to the scale at which gauge coupling constants are unified, M X = 3 · 10 16 GeV -that is, under the assumption that there is no Landau pole in solutions to relevant renormalization group equations.The spectrum of the Higgs sector of the MSSM contains four massive states. Two of them are CP-even, one is CP-odd, and one is charged. The presence of a light Higgs boson in the CP-even sector is an important distinguishing feature of SUSY models. Its mass is constrained from above aswhere M Z is the Z-boson mass (M Z ≈ 91.2 GeV) and ∆ stands for the contribution of loop corrections. The magnitude of these corrections is proportional to m 4 t (m t is the running mass of the t-quark), depends logarithmically on the supersymmetry breakdown scale M S , and is virtually independent of the choice of tan β. An upper limit on the mass of the light CP-even Higgs boson within the MSSM grows with increasing tan β and, for tan β ≫ 1, reaches 125 − 128 GeV in realistic SUSY models with M S ≤ 1000 GeV.At the same time it is known from [1] that, for tan β ≪ 50 − 60, solutions to the renormalization group equations for the t-quark Yukawa coupling constant h t (t) are concentrated in the vicinity of the quasi-fixed pointwherewith g i being the gauge constants of the Standard Model group. The variable t is defined in the standard way: t = ln(M 2 X /q 2 ). Its value at the electroweak scale is t 0 = 2 ln(M X /M pole ...

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“…Since µ eff , B 0 , and y have been found we investigate the dependence of the Higgs boson spectrum on A, m 0 , and µ ′ using the relations (16). For the masses of CP-odd states one can get an exact analytical result:…”

Section: The Procedures Of the Analysismentioning

confidence: 99%

“…It has been shown that in the vicinity of this point the b − τ Yukawa coupling unification is realised [13]. In the recent publications (see [15][16][17]) the value of tan β that corresponds to quasi-fixed point regime has been calculated. It is restricted between 1.3 and 1.8.…”

Section: Introductionmentioning

confidence: 98%

“…Such comparatively low values of tan β yield more stringent bound on the lightest Higgs boson mass in the MSSM. So, it does not exceed 94 ± 5 GeV [15,16]. The obtained theoretical bound on m h has to be compared with the lower experimental one in the SM since it was computed for the SUSY breaking scale M S of order of 1 TeV when all other Higgs bosons and superparticles are heavy enough.…”

Section: Introductionmentioning

confidence: 99%

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Higgs bosons in the simplest SUSY models

2002

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Nowadays in the MSSM the moderate values of tan β are almost excluded by LEP II lower bound on the lightest Higgs boson mass. In the Next-to-Minimal Supersymmetric Standard Model the theoretical upper bound on it increases and reaches maximal value in the strong Yukawa coupling limit when all solutions of renormalization group equations are concentrated near the quasi-fixed point. For calculation of Higgs boson spectrum the perturbation theory method can be applied. We investigate the particle spectrum in the framework of the modified NMSSM which leads to the self-consistent solution in the strong Yukawa coupling limit. This model allows one to get m h ∼ 125 GeV at values of tan β ≥ 1.9. In the investigated model the lightest Higgs boson mass does not exceed 130.5 ± 3.5 GeV. The upper bound on the lightest CP-even Higgs boson mass in more complicated supersymmetric models is also discussed.

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The Higgs mass in the MSSM infrared fixed point scenario

Cited by 44 publications

References 71 publications

Infrared quasifixed solutions in a nonminimal supersymmetric standard model

Infrared quasifixed solutions in a nonminimal supersymmetric standard model

Quasifixed-point scenario in a modified nonminimal supersymmetric standard model

Higgs bosons in the simplest SUSY models

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