Archaeological evidence for the Xia dynasty is very scant. There is evidence that a state did exist during the purported time period of the Xia dynasty but this evidence is far from definitive. Thus archaeologists and historians cannot definitively say that it did exist.However, I must point out that the Xia Dynasty (if it existed at all) is VERY old! To a Chinese scholar from the Three Kingdoms period, the Xia Dynasty was even older than the Three Kingdoms period is to us today! No civilization is stagnant. As various Chinese states evolved, they grew in population and in complexity. So we shouldn’t expect the Xia Dynasty period to have had elaborate palaces or massive urban sites with ruins that are still easily visible today.Also, early Chinese civilization developed in the Yellow River valley and the North China plain. This region has endured countless floods, earthquakes, and outside invasions over the past several millennia. In addition to such disasters, this region was also very conducive for urban development and redevelopment. If the Xia Dynasty existed, then a considerable portion of the evidence might lie deep underneath modern cities.So the answer is that we don’t have strong evidence for the existence of the Xia Dynasty so we cannot say that it was real; but given the purported age of the Xia Dynasty along with the geography and the history of the region, evidence is very difficult to come by.