Motivated by recent progress of theory and experiment on the anomalous magnetic moment of the electron, ae, we update the hadronic contributions to ae. Using our up-to-date compilation of ...e+e−→hadrons data, we find the leading order hadronic contribution aehad,LO,VP=(1.866±0.010exp±0.005rad)⋅10−12 and the next-to-leading order hadronic contribution aehad,NLO,VP=(−0.2234±0.0012exp±0.0007rad)⋅10−12, where the first and second errors are from the error of the experimental data and the uncertainty in the treatment of radiative corrections, respectively. These values are compatible with earlier evaluations by other groups, but have significantly improved uncertainties due to the more precise input data used. We also update the leading order hadronic contribution to the ground state hyperfine splitting of muonium, obtaining ΔνMuhad,VP=(232.68±1.25exp±0.72rad) Hz. This value is consistent with the most precise evaluation in the literature and reduces its error by a factor of two.
We calculate the Standard Model (SM) prediction for the muon anomalous magnetic moment. By using the latest experimental data for
e
+
e
-
→ hadrons as input to dispersive integrals, we obtain the ...values of the leading order (LO) and the next-to-leading-order (NLO) hadronic vacuum polarisation contributions as a
had, LO VP
μ
= (693:27 ± 2:46) × 10-
10
and a
had, NLO VP
μ
= (_9.82 ± 0:04) × 1010-
10
, respectively. When combined with other contributions to the SM prediction, we obtain a
μ
(SM) = (11659182:05 ± 3.56) × 10-
10
; which is deviated from the experimental value by Δa
μ
(exp) _ a
μ
(SM) = (27.05 ± 7.26) × 10-
10
. This means that there is a 3.7 σ discrepancy between the experimental value and the SM prediction. We also discuss another closely related quantity, the running QED coupling at the Z-pole, α(M
2
Z
). By using the same
e
+
e
-
→ hadrons data as input, our result for the 5-flavour quark contribution to the running QED coupling at the Z pole is Δ
(5)
had
(M
2
Z
) = (276.11 ± 1.11) × 10-
4
, from which we obtain Δ(M
2
Z
) = 128.946 ± 0.015.
We update the electroweak study of the predictions of the Minimal Super-symmetric Standard Model (MSSM) including the recent results on the muon anomalous magnetic moment, the weak boson masses, and ...the final precision data on the Z boson parameters from LEP and SLC. We find that the region of the parameter space where the slepton masses are a few hundred GeV is favored from the muon g − 2 for tan β ~ 10, whereas for tan β ≃ 50 heavier slepton mass up to ~ 1000 GeV can account for the reported 3.2 σ difference between its experimental value and the Standard Model (SM) prediction. As for the electroweak measurements, the SM gives a good description, and the sfermions lighter than 200 GeV tend to make the fit worse. We find, however, that sleptons as light as 100 to 200 GeV are favored also from the electroweak data, if we leave out the jet asymme-try data that do not agree with the leptonic asymmetry data. We extend the survey of the preferred MSSM parameters by including the constraints from the b → sγ transition, and find favorable scenarios in the minimal supergravity, gauge-, and mirage-mediation models of supersymmetry breaking.
Motivated by the possibility that the right-handed top-quark (
t
R
) is composite, we discuss the effects of dimension-six operators on the Higgs boson production at the LHC. When
t
R
is the only ...composite particle among the Standard Model (SM) particles, the (
V
+
A
) ⊗ (
V
+
A
) type four-top-quark contact interaction is expected to have the largest coefficient among the dimension-six operators, according to the Naive Dimensional Analysis (NDA). We find that, to lowest order in QCD and other SM interactions, the cross section of the SM Higgs boson production via gluon fusion does not receive corrections from one insertion of the new contact interaction vertex. We also discuss the effects of other dimension-six operators whose coefficients are expected to be the second and the third largest from NDA. We find that the operator which consists of two
t
R
’s and two SM Higgs boson doublets can recognizably change the Higgs boson production cross section from the SM prediction if the cut-off scale is ∼ 1TeV.
Following updates in the compilation of e + e − → hadrons data, this work presents reevaluations of the hadronic vacuum polarization contributions to the anomalous magnetic moments of the electron ( ...a e ), muon ( a μ ) and tau lepton ( a τ ), to the ground-state hyperfine splitting of muonium and also updates the hadronic contributions to the running of the QED coupling at the mass scale of the Z boson, α ( M 2 Z ) . Combining the results for the hadronic vacuum polarization contributions with recent updates for the hadronic light-by-light corrections, the electromagnetic and the weak contributions, the deviation between the measured value of a μ and its Standard Model prediction amounts to Δ a μ = ( 28.02 ± 7.37 ) × 10 − 10 , corresponding to a muon g − 2 discrepancy of 3.8 σ.
We study the μ→eγ decay in the Z3-invariant next-to-minimal supersymmetric (SUSY) Standard Model (NMSSM) with superheavy right-handed neutrinos. We assume that the soft SUSY breaking parameters are ...generated at the GUT scale, not universally as in the minimal supergravity scenario but in such a way that those soft parameters which are specific to the NMSSM can differ from the soft parameters which involve only the MSSM fields while keeping the universality at the GUT scale within the soft parameters for the MSSM and right-handed neutrino fields. We call this type of boundary conditions “semi-constrained”. In this model, the lepton-flavor-violating off-diagonal elements of the slepton mass matrix are induced by radiative corrections from the neutrino Yukawa couplings, just like as in the MSSM extended with the right-handed neutrinos, and these off-diagonal elements induce sizable rates of μ→eγ depending on the parameter space. Since this model has more free parameters than the MSSM, the parameter region favored from the Higgs boson mass can slightly differ from that in the MSSM. We show that there is a parameter region in which the μ→eγ decay can be observable in the near future even if the SUSY mass scale is about 4 TeV.
This work presents a complete reevaluation of the hadronic vacuum polarization contributions to the anomalous magnetic moment of the muon, aμhad,VP, and the hadronic contributions to the effective ...QED coupling at the mass of the Z boson, Δαhad(MZ2), from the combination of e+e−→hadrons cross section data. Focus has been placed on the development of a new data combination method, which fully incorporates all correlated statistical and systematic uncertainties in a bias free approach. All available e+e−→hadrons cross section data have been analyzed and included, where the new data compilation has yielded the full hadronic R-ratio and its covariance matrix in the energy range mπ≤s≤11.2 GeV. Using these combined data and perturbative QCD above that range results in estimates of the hadronic vacuum polarization contributions to g−2 of the muon of aμhad,LO VP=(693.26±2.46)×10−10 and aμhad,NLO VP=(−9.82±0.04)×10−10. The new estimate for the Standard Model prediction is found to be aμSM=(11659182.04±3.56)×10−10, which is 3.7σ below the current experimental measurement. The prediction for the five-flavor hadronic contribution to the QED coupling at the Z boson mass is Δαhad(5)(MZ2)=(276.11±1.11)×10−4, resulting in α−1(MZ2)=128.946±0.015. Detailed comparisons with results from similar related works are given.
In our previous study, we used optical coherence tomography (OCT) and reported an increase in signal intensity of depth profiles between euthanasia injection and cardiac arrest (CA), demonstrating ...the potential as a tool for monitoring/diagnosing brain tissue viability Appl. Opt.48, 4354 (2009). Here, for the first time to our knowledge, we measured three-dimensional (3D) OCT images through a thinned skull changing temperatures in the rat brain. The measurements were made at 10 min intervals for 210 min to evaluate correlations of temperature with heart rate and ratios of signal intensity (RSI). The 3D image area was 4 mm × 4 mm × 2.8 mm. When the temperature was decreased from 28°C to 18°C to reduce tissue viability, the heart rate was found to decrease with an increase in RSI. Negative correlation coefficients (CCs) between temperatures and RSIs, and between heart rate and RSIs, were obtained. This indicates that OCT signals increase with reductions of viability caused by decreases in heart rates and temperatures in tissues. These observations correspond to estimations obtained by multiwavelength diffuse reflectance spectroscopy Appl. Opt.47, 4164 (2008). CCs and stationary RSIs would depend upon measured positions in tissues. Without injections for euthanasia, a similar rapid increase in RSI has also been measured before CA.
We show that, in the minimal supersymmetric standard model, the possibility for the lightest CP-even Higgs boson to be lighter than Z boson (as low as about 60 GeV) is, contrary to the usual belief, ...not yet excluded by the CERN LEP2 Higgs search nor any direct searches for supersymmetric particles at high energy colliders. The characteristic of the light Higgs boson scenario (LHS) is that the ZZh coupling and the decay branching ratio Br(h/A-->bb) are simultaneously suppressed as a result of generic supersymmetric loop corrections. Consequently, the W(+/-)H(-/+)h coupling has to be large due to the sum rule of Higgs couplings to weak gauge bosons. We discuss the potential of the Fermilab Tevatron and B factories to test the LHS, and show that the associated neutral and charged Higgs boson production process, pp-->H(+/-)h(A), can completely probe the LHS at the CERN Large Hadron Collider.
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