4 uncertainties related to the modeling of power corrections corresponding to weak annihilation effects and the chirally-enhanced power corrections to hard spectator scattering. Therefore the numerical results for the direct CP asymmetries are not reliable. Several of these observables like FB asymmetry in B → K ∗ l + l − [39], CP asymmetry in B$_{s}$ → ψφ [40] and the decay rate of K$_{L}$ → π $^{0}$ν ¯ ν [41] have also been studied before, as well as many other interesting aspects of SM4 by Hou and collaborators [42–45], see also [46]. However, their analysis was generally restricted to m$_{t}$ ′ of ∼ 300 GeV . On the other hand, our analysis seems to favor m$_{t}$ ′ in the range of (400 - 600) GeV to explain the observed CP asymmetries in the B, B$_{s}$ decays. We note also that recent analysis by Chanowitz seems to disfavor most of the parameter space they have used [34] whereas our parameter space is largely unaffected [47]. We identify several processes wherein SM4 causes large deviations from the expectations of SM3; for example, B → X$_{s}$ν ¯ ν , B$_{s}$ → µ $^{+}$µ − , A$_{SL}$ ( B$_{s}$ → X$_{s}$ℓν ), a$_{CP}$ ( B → πK ), a$_{CP}$ ( B → π $^{0}$π$^{0}$), K$_{L}$ → π $^{0}$ν ¯ ν and of course mixing-induced CP in B$_{s}$ → ψφ etc. These observables will be measured with higher statistics at the upcoming high intensity K, B, B$_{s}$ experiments at CERN, FERMILAB, JPARC facilities etc and in particular at the LHCb experiment and possibly also at the Super-B factories and hence may provide further indirect evidence for an additional family of quarks. The paper is arranged as follows. After the introduction, we provide constraints on the 4 × 4 CKM matrix by incorporating oblique corrections along with experimental data from important observables involving Z, B and K decays as well as B$_{d}$ and B$_{s}$ mixings etc. In Sec. III, we present the estimates of many useful observables in the SM4. Finally in Sec. IV, we present our summary. In our previous article [15], to find the limits on V$_{CKM}$$_{4}$ elements, we concentrated mainly on the constraints that will come from vertex correction to Z → b ¯ , Br ( B → X$_{s}$γ ), Br ( B → X$_{s}$ l $^{+}$l − ), B$_{d}$ − ¯ B$_{d}$ and B$_{s}$ − ¯ B$_{s}$ mixing, Br ( K + → π $^{+}$νν ) and indirect CP violation in K$_{L}$ → ππ described by | ϵ$_{k}$ | . We did not consider ϵ ′ /ϵ as a constraint because of its large hadronic uncertainties. Chanowitz [34] has shown that as m$_{t}$ ′ becomes very large more important constraint is from non decoupling oblique corrections rather than the vertex correction to II. CONSTRAINTS ON THE CKM4 MATRIX ELEMENTS