This Is Why The ‘X17’ Particle And A New, Fifth Force Probably Don’t Exist
“You cannot be afraid to make a mistake in science, but you must be aware that mistakes are common, can come from unexpected sources, and — as a responsible scientist — our job is not to sensationalize our most wishful thinking about what might be true, but to subject it to the most careful, skeptical scrutiny we can muster. Only with that mindset can we responsibly take a look at the experimental evidence in question.
If we want to give these new results a proper analysis, we need to make sure we’re asking the right questions. How was the experiment set up? What was the raw data? How was the analysis of the data performed? Was it verified independently? Is this data consistent with all the other data we’ve taken? What are the plausible theoretical interpretations, and how confident are we they’re correct? And finally, if it all holds up, how can we verify whether this really is a new particle with a new force?”
If you’ve been around the particle physics block before, there’s a lesson you should have learned by now: your default assumption should be that the Standard Model is correct. If an experiment contradicts what the Standard Model predicts, you should immediately be spending your energy wondering what’s wrong with the experiment, not leaping to fantastic, speculative conclusions about all of physics being wrong.
What should you make about the Atomki Anomaly, the X17 particle, and the idea of a new, fundamental force? To say “be skeptical” is a gross understatement. Get the story today.
This One ‘Anomaly’ Is Driving Physicists To Search For Light Dark Matter
“If the result is robust, one potential explanation is the existence of a new particle with a specific mass: about 0.017 GeV/c^2. This particle would be heavier than the electron and all of the neutrinos, but lighter than every other massive, fundamental particle ever discovered. Many different theoretical scenarios have been proposed to account for this measurement, and various ways to look for an experimental signature have also been devised.
When you hear about experiments looking for a dark photon, a light vector boson, a protophobic particle, or the force-carrying particle for a new, fifth force, they’re all looking for variants that could explain this Atomki anomaly. Not only that, but many of them also seek to solve one of the big puzzles with this particle: the dark matter puzzle. There’s no harm in shooting for the Moon, but every measurement has met with the same disappointment: null results.”
You have to go where the data point you, even if there’s every reason to believe that what you’re undertaking is nothing but a fool’s errand. There has been an enormous increase in the experiments that are deciding to search for light dark matter: dark matter particles heavier than an electron but lighter than the other Standard Model particles. We’ve been probing this energy range for decades, finding nothing, but there’s one nuclear physics experiment that indicated an anomaly back in 2015-2016, and that’s enough evidence to alter the direction of a field!
If you’ve ever wondered why physicists care about light dark matter, this is one read you won’t want to miss. It’s all null results so far, but that’s just further motivation to deepen the search.