revisions to several prominent theories posed as alternatives to the Standard Model of particle physics tagged posts

In this artist’s representation, an electron travels between two lasers in an experiment. The electron is spinning about its axis as a cloud of other subatomic particles are constantly emitted and reabsorbed. Some theories in particle physics predict particles, as yet undetected, that would cause the cloud to appear very slightly pear shaped when seen from a distance. With the support of the National Science Foundation, ACME researchers created an experiment setup look at that shape with extreme precision. To the limits of their experiment, they saw a perfectly round sphere, implying that certain types of new particles, if they exist at all, have properties different from those theorists expected.
Credit: Nicolle R. Fuller, NSF