By Ron Cowen
Call off the guard dogs. No one — yet — has to worry about researchers drastically tinkering with the standard model of particle physics, the wildly successful theory that describes how elementary particles interact and form the building blocks of matter.
But in sifting through the ashes of a short-lived subatomic particle called the kaon, physicists have found new hints that the theory might one day need to be modified.
Ideas for a possible alteration range from a new type of force to a new family of elementary particles.