"e. , the implementation . (3) idealizing, i. e. , the model is supposed to deviate from the original and as long as there is a good reason for that one doesn't worry. Software process models are in an idealizing reference mode to the actually realized software process. As the software process model describes how software shall be developed under ideal conditions there is no reason to be worried if one deviates from the model because the real conditions are not ideal. More Magazine Model Search (4) constituting, i. e. "

" These are either fermionic baryons composed of three quarks (the proton and neutron being the most familiar example) or bosonic mesons composed of a quark-antiquark pair (such as pions). The mass of such aggregates exceeds that of the components due to their binding energy. Tests and predictions The Standard Model predicted the existence of W and Z bosons, the gluon, the top quark and the charm quark before these particles had been observed. Their predicted properties were experimentally confirmed with good precision. The Large Electron-Positron collider at CERN tested various predictions about the decay of Z bosons, and found them confirmed. To get an idea of the success of the Standard Model a comparison between the measured and the predicted values of some quantities are shown in the following table: Quality Measured (GeV) SM prediction (GeV) Mass of W boson 80,4120±0,0420 80,3900±0,0180 Mass of Z boson 91,1874±0,0021 91,1874±0,0021 Challenges to the Standard Model Although the Standard Model has had great success in explaining experimental results, it has never been accepted as a complete theory of fundamental physics. This is because it has two important defects: The model contains 19 free parameters, such as particle masses, which must be determined experimentally (plus another 10 for neutrino masses). Model Search 2006 These parameters cannot be independently calculated. The model does not describe the gravitational interaction. "