An excellent question! If you look in Section 4 of OPERA’s manuscript (the arXiv link above), they describe their measurement of the distance between the origin of the Neutrino Beam and the OPERA Detector (they even take into account continental drift!). This distance is measured with a precision of 20 centimeters. The OPERA team acknowledges this 20 centimeter uncertainty has an affect on their measurement, and takes this into account by attributing what’s known as a “systematic uncertainty” to their measurement. Light would take 0.67 nanoseconds to travel this distance. So the OPERA Collaboration adds, in quadrature, these 0.67 nanoseconds as a systematic uncertainty on their time of flight measurement; as can be seen in Table 2 on page 24 of the OPERA Manuscript (again see arXiv Link above).

So yes, the distance used in OPERA’s Calculation could be off by 20 centimeters at most. But the uncertainty in time due to this is only 0.67 nanoseconds. Since this time is two orders of magnitude less than OPERA’s Results, we can say that this 20 centimeter uncertainty in the path length does not affect the result significantly.

Hope this helps,
-Brian

Update: Just now realized this was not my post giving an update on the OPERA measurement, please see this post regarding the issue: http://www.quantumdiaries.org/2011/11/18/an-update-from-opera/

The purpose of this blog post was to publicize the latest update from the OPERA Collaboration regarding their recent muon-neutrino time of flight measurement. If you’ll look in the press release quote I posted above, you’ll see that the OPERA Collaboration has indeed submitted their manuscript to a peer review journal, the Journal of High Energy Physics, just this past week. I anticipate the reviewers at JHEP will be in correspondence with the OPERA Collaboration in the near future (i.e. we will know if it is published soon).

Additionally, large scientific collaborations such as OPERA, CMS, DZero, etc… all conduct their own internal peer-review process before releasing any results to the public, or the rest of the scientific community. This is an additional level of the peer-review process that ensures top quality results are published by scientific experiments.

Hope this helps.

Best,
-Brian