ISSN:
1434-6052
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract. We update our previous work on an analysis of the electroweak data by including new and partly preliminary data available up to the 1996 summer conferences. The new results on the $Z$ partial decay widths into $b$ and $c$ hadrons now offer a consistent interpretation of all data in the minimal standard model. The value extracted for the strong interaction coupling constant $\alpha_s(m_Z)$ agrees well with determinations in other areas. New constraints on the universal parameters $S$ , $T$ and $U$ are obtained from the updated measurements. No signal of new physics is found in the $S$ , $T$ , $U$ analysis once the SM contributions with $m_t \sim 175$ GeV and those of not a too heavy Higgs boson are accounted for. The naive QCD-like technicolor model is now ruled out at the 99% CL even for the minimal model with ${\rm SU(2)_{TC}}$ . In the absence of a significant new physics effect in the electroweak observables, constraints on masses of the top quark, $m_t$ , and Higgs boson, $m_H$ , are derived as a function of $\alpha_s$ and the QED effective coupling $\bar{\alpha}(m_Z^2)$ . The preferred range of $m_H$ depends rather strongly on the actual value of $m_t$ : $m_H〈360 {\rm GeV}$ for $m_t=170{\rm GeV}$ , while $m_H〉130{\rm GeV}$ for $m_t=180{\rm GeV}$ at 95% CL. Prospects due to forthcoming improved measurements of asymmetries, the mass of the weak boson $W$ $m_W$ , $m_t$ and $\bar{\alpha}(m_Z^2)$ are discussed. Anticipating uncertainties of 0.00020 for $\bar s^2(m^2_Z )$ , 20 MeV for $m_W$ , and 2 GeV for $m_t$ , the new physics contributions to the $S$ , $T$ , $U$ parameters will be constrained more severely, and, within the SM, the logarithm of the Higgs mass can be constrained to about $\pm 0.35$ . The better constraints on $S$ , $T$ , $U$ and on $m_H$ within the minimal SM should be accompanied with matching precision in $\bar{\alpha}(m_Z^2)$ .
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100520050126
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