Breaks in the Perfect Symmetry of the Universe Could Be a Window Into Completely New Physics

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The bible of particle physics is dying for an upgrade. And physicists may have just the thing: Some particles and forces might look in the mirror and not recognize themselves. That, in itself, would send the so-called Standard Model into a tailspin.

By Paul Sutter |

Just about all fundamental reactions between the universe’s subatomic particles look the same when they are flipped around in a mirror. The mirror-image, called parity, is then said to be symmetrical, or to have parity symmetry, in physics speak.

Of course, not everyone follows the rules. We know that, for instance, reactions involving the weak nuclear force, which is also weird for a whole bunch of other reasons, violates parity symmetry. So it stands to reason other forces and particles in the quantum world are also rule-breakers in this area.

Physicists have some ideas about these other hypothetical reactions that wouldn’t look the same in the mirror and hence would violate parity symmetry. These strange reactions could point us toward new physics that could help us move past the Standard Model of particle physics, our current summary of all things subatomic.

Unfortunately, we will never see most of these strange reactions in our atom smashers and laboratories. The interactions are just too rare and weak to detect with our instruments, which are tuned to other kinds of interactions. But there might be some rare exceptions. Researchers at the world’s largest atom smasher, the Large Hadron Collider (LHC), located near Geneva, have been hunting for these rare interactions. So far, they’ve come up empty-handed, but even that result is illuminating. Those negative results help weed out fruitless hypotheses from consideration, allowing physicists to focus on more-promising avenues in the hunt for new physics.

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