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concordance = is an agreement of values/figures. An equality/agreement between an estimated value and a real value.

So you could also use inequality

If they were expected to be equal and they are not, _discrepancy_ is the most frequently used term in physics.

For decades, the Standard Model has been subjected to thorough experimental scrutiny and has survived several attacks. For example, in the 1990's, the experimental result for the fractional production of bottom anti-bottom (denoted by Rb) through a Z gauge boson differed from the theoretical prediction. However, further experiments and analysis eventually eliminated the discrepancy. The Standard Model has overcome so many of these experimental-theoretical conflicts that particle physicists are almost complacent about deviations and are willing to assume that any problem is merely a statistical fluctuation that will eventually resolve itself.

The CERN collider near Geneva, Switzerland, the SLAC facility in Stanford, California and the proton accelerator at Fermilab near Chicago, Illinois have been the main machines testing the Standard Model. In 1998, a comparison of dozens of quantities revealed no discrepancy between experiment and theory. The Standard Model appeared to be in perfect shape, much to the dismay of inventive theorists, who had hoped to find small imperfections that would indicate new physics such as supersymmetry, compositeness or undiscovered subnuclear forces.

http://www.jupiterscientific.org/sciinfo/smtrouble.html

Charlie Baltay is the co-spokesperson of the highy successful SLD experiment at SLAC. He is joined by Thomas Moore and Homer Neal in the studies of Bs mixing. From 1992 to 1998 the experiment recorded 550K e+e- -> Z decays. Though LEP has a larger data sample SLD has been very competitive because of the high polarization (~75%) of the incident electron beam and the superior vertex resolution due to the CCD vertex detector and the micron-sized beam spots in SLC. In addition to having the most sensitive measurement of Bs mixing, SLD also has the most precise measurement of the VA interference term in the Zbb coupling (Ab) which at the present time is the only known discrepancy with the Standard Model. Though, the actual data collection has come to an end, the wealth of physics oppurtunities provided by the SLD data will take several more years to fully exploit.

http://www.yale.edu/physics/research/exptlparticle2.html

Or simply difference