Erratum to “Z′ bosons in supersymmetric E6 models confront electroweak data” [Nucl. phys. B 531 (1998) 65]

Cho, Gi-Chol; Hagiwara, Kaoru; Umeda, Yoshiaki

doi:10.1016/s0550-3213(99)00382-x

Cited by 29 publications

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“…The latest data on the Z parameters [37] and the W -boson mass [34] are studied in the framework of the MSSM in Ref. [29] and we use them here. We also consider the external constraints (Table 5), Set 2 (Table 6) and Set 3 (Table 7) (m W ) new = 0.118 ± 0.057, (6.4c) where the correlation between the first-two errors is ρ corr = 0.80.…”

Section: Constraints On the Sfermion Sector By The Electroweak Precismentioning

confidence: 99%

“…6, we will show our numerical results of the e − e + → W − W + helicity amplitudes, and we will examine in which case the sfermion effects become substantial. The sfermion effects on the e − e + → W − W + cross section are then discussed under the constraint from the direct search experiments and the electroweak precision measurements [28,29]. In Sec.…”

Section: Introductionmentioning

confidence: 99%

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One-loop sfermion corrections toe−e+→W−
Alam
¹
,
Hagiwara
²
,
Kanemura
³

et al. 2000
Phys. Rev. D
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We study one-loop effects of sfermions on helicity amplitudes for e − e + → W − W + in the Minimal Supersymmetric Standard Model. The one-loop contributions are calculated in the MS renormalization scheme. In order to verify the validity of the analytic calculation and the numerical program, the following tests are performed. (i) The BRS sum rules hold exactly among the analytic expressions of the form factors of the e − e + → W − W + amplitude and those of the amplitudes where the external W ± bosons are replaced by the corresponding Goldstone bosons χ ± , hence they hold within the expected accuracy of the numerical program. (ii) The one-loop sfermion contribution to the amplitudes decouple in the heavy mass limit. This property is used to test the overall normalization of the amplitudes. In order to observe the analytically exact decoupling, the amplitudes are expanded by the MS couplings of the Standard Model. (iii) The high-energy analytic formulas of the helicity amplitudes, which are verified by using the equivalence theorem analytically, are used for the numerical test of the high energy behavior of the amplitudes. We then investigate the magnitude of the one-loop effects on each helicity amplitude which may be measured by experiments at future linear colliders. Under the constraint from available precision data, the one-loop corrections to a few helicity amplitudes (for example, the longitudinal-W -pair production) can be at most from −0.8% to +0.6% in magnitude in the observables. The corrections in the helicity-summed cross sections are smaller, typically a few times ±0.1% at large scattering angles.

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Section: Constraints On the Sfermion Sector By The Electroweak Precismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

One-loop sfermion corrections toe−e+→W−
Alam
¹
,
Hagiwara
²
,
Kanemura
³

et al. 2000
Phys. Rev. D
Self Cite
15
1
24
0
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“…First we consider the case when all the squarks are so heavy that their effects on low-energy physics disappears. In our actual numerical calculation, we set all the squark masses and the extra Higgs boson masses at 1 TeV such that they do not make worse the fit to the electroweak data [10,12] and the b → sγ rate [13].…”

mentioning

confidence: 99%

“…Light left-handed sleptons make S Z negative but keep T Z essentially unchanged. It has been shown that if the chargino mass is close to its lower mass bound from the LEP2 experiment, m χ − 1 ∼ 100 GeV, and the squarks and sleptons are sufficiently heavy, say 1 TeV, the total χ 2 in the MSSM is slightly better than that in the standard model [10]:…”

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confidence: 99%

Muon g−2 and precision electroweak physics in the MSSM

2000

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The minimal supersymmetric extension of standard model (MSSM) is examined by analyzing its quantum effects on the precision electroweak measurements and the muon g − 2. We examine carefully the effects of light charginos and neutralinos that are found to improve the fit to the electroweak data. We identify two distinct regions on the (µ, M 2 )-plane that fit well to the electroweak data and give significant contribution to muon g − 2.

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“…It should be noted that not only in the littlest Higgs model but also in the SUSY E 6 models, the extra neutral gauge boson can mix with the SM Z boson after the electroweak symmetry breaking. Such mixing is, however, severely constrained from the experimental data of the electroweak precision measurements at the Z-pole [10], and we assume that the mixing is small enough to neglect in our study. Now let us examine theoretical predictions of extra gauge boson in each model at the linear collider.…”

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confidence: 99%

Search for a light extra gauge boson in the littlest Higgs model at a linear collider

Cho

Omote

2004

Phys. Rev. D

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Littlest Higgs model predicts some extra particles beyond the Standard Model. Among them, an extra neutral gauge boson AH is lightest and its mass could be a few hundred GeV. We study production and decay of AH at future e + e − linear collider and compare them with those of Z ′ bosons in supersymmetric (SUSY) E6 models. We find that, if the extra gauge boson mass is smaller than √ s of the linear collider, the forward-backward asymmetries of b-and c-quarks at the AH pole differ significantly from those given by the Z ′ bosons, and are useful to test the littlest Higgs model and SUSY E6 models.Little Higgs [1,2,3] is an attractive idea to solve the gauge hierarchy problem. In this class of models, the electroweak Higgs boson appears as a pseudo-goldstone boson of a certain global symmetry breaking at a scale Λ ∼ 10 TeV so that the Higgs boson mass can be as light as O(100 GeV). The light Higgs boson mass is protected from the 1-loop quadratic divergence by gauging a part of global symmetry, and introducing a few extra heavy particles whose typical mass scale is of order f ≡ Λ/4π, where f is a decay constant of the pseudo-goldstone boson.One of the simplest models based on this idea is known as Littlest Higgs Model [4], which has a global SU(5) and gauged [SU(2) × U(1)] 2 symmetries at ultra-violet regime. At the scale Λ, the global symmetry is broken to SO(5) while the gauge symmetry is broken to that of the Standard Model (SM), SU(2) L ×U(1) Y . Such symmetry breaking allows that the littlest Higgs model has four massive gauge bosons below Λ, and they are mixed with the SM gauge bosons after the electroweak symmetry breaking. As a result, the set of extra gauge bosons at the weak scale consists of electrically neutral states (A H , Z H ) and charged states (W ± H ). The mass scale of the extra gauge bosons are given by m AH ∼ g Y f and m ZH ≈ m WH ∼ gf , where g Y and g are U(1) Y and SU(2) L gauge couplings, respectively. In addition to the extra gauge bosons, the littlest Higgs model predicts a triplet scalar Φ and a vector-like quark T in order to stabilize the Higgs boson mass against the radiative corrections. The scalar Φ cancels the 1-loop quadratic divergence by the Higgs self-interaction, while the extra quark T cancels one by the top-quark Yukawa interaction. Up to the order one coefficients, the masses of Φ and T are roughly given by the decay constant f [5]. Among the extra particles in the littlest Higgs model, therefore, A H is lightest one, so that it is expected to be discovered at future collider experiments rather early. In hadron collider experiments, A H is produced in the Drell-Yan process, pp (or pp) → A H → µ + µ − X, and shows a peak of the invariant mass distribution of muon pair in the final state [5,6].Since such an experimental signature of the A H boson is quite similar to a Z ′ boson in models which have an extra U(1) gauge symmetry, it is very important to identify the models if an extra neutral gauge boson is discovered in hadron collider experiments such as Tevatron Run-II or LH...

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Erratum to “Z′ bosons in supersymmetric E6 models confront electroweak data” [Nucl. phys. B 531 (1998) 65]

Cited by 29 publications

References 0 publications

One-loop sfermion corrections toe−e+→W−
Alam
¹
,
Hagiwara
²
,
Kanemura
³

et al. 2000
Phys. Rev. D
Self Cite
15
1
24
0
View full text Add to dashboard Cite

One-loop sfermion corrections toe−e+→W−
Alam
¹
,
Hagiwara
²
,
Kanemura
³

et al. 2000
Phys. Rev. D
Self Cite
15
1
24
0
View full text Add to dashboard Cite

Muon g−2 and precision electroweak physics in the MSSM

Search for a light extra gauge boson in the littlest Higgs model at a linear collider

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Erratum to “Z′ bosons in supersymmetric E6 models confront electroweak data” [Nucl. phys. B 531 (1998) 65]

Cited by 29 publications

References 0 publications

One-loop sfermion corrections toe−e+→W−Alam1, Hagiwara2, Kanemura3 et al. 2000Phys. Rev. DSelf Cite151240View full textAdd to dashboardCite

One-loop sfermion corrections toe−e+→W−Alam1, Hagiwara2, Kanemura3 et al. 2000Phys. Rev. DSelf Cite151240View full textAdd to dashboardCite

Muon g−2 and precision electroweak physics in the MSSM

Search for a light extra gauge boson in the littlest Higgs model at a linear collider

Contact Info

Product

Resources

About

One-loop sfermion corrections toe−e+→W−
Alam
¹
,
Hagiwara
²
,
Kanemura
³

et al. 2000
Phys. Rev. D
Self Cite
15
1
24
0
View full text Add to dashboard Cite

One-loop sfermion corrections toe−e+→W−
Alam
¹
,
Hagiwara
²
,
Kanemura
³

et al. 2000
Phys. Rev. D
Self Cite
15
1
24
0
View full text Add to dashboard Cite