Further evidence of an entirely new particle, called X17, could rewrite the Standard Model of particle physics. Story: [Mysterious 'Particle X17' Could Carry a Newfound Fifth Force of Nature, But Most Experts Are Skeptical](https://www.livescience.com/fifth-force-could-exist.html) Credit: Live Science / produced & edited by [Steve Spaleta](http://www.twitter.com/stevespaleta)