Please, stop the LHC.
Although I agree with the necessity of having such a petition, I can't support it. If you want people to support your petition you must spell the words correctly and you must find powerful arguments. Such an argument could be the following fact: even if the scientists who participated in this project are the most entitled to assure us about its safety, the LHC and the experiments are not at all exempt from failure. The proof lays in several problems of LHC: cooling failure, magnet explosion, etc. In general, there are a lot of cases in history when experiments went wrong, even if they were conducted by the most brilliant minds.
All the scientists admit there's a worst case scenario which can actually happen at LHC, although the probability is low. The problem is, if this worst case scenario happens it has disastrous consequences for the whole planet. In this case, is the experiment really necessary NOW? Or could we wait until more knowledge can confirm 100% safety?