Tevatron’s mystery signal grows stronger with more data

New Scientist : In April, Fermilab’s CDF experiment team announced that an unexpected bump in the data showing a W boson and two jets of quarks might indicate the presence of a particle not predicted by the standard model. At that point the result was at a three–sigma level of certainty; there was a one in a thousand chance that the bump was a statistical fluke. With the analysis of more data since then, the result is at 4.8 sigma—very close to the five–sigma standard of formal discoveries in particle physics. The CDF team is checking to see if the anomaly is the result of a system or detector effect or if it indicates a new particle. Fermilab’s DZero team is running an independent check as well and is expected to publish its results in the next few weeks.