A joint Fermilab/SLAC publication

Exotic particle of the day: the stringball


Today at the American Physical Society meeting in Washington, DC, Ayana Arce from Duke University spoke about prospects for discovering new physics at the Large Hadron Collider. Among the many theoretically proposed exotica she discussed, the most fun name goes to the stringball. It looks like a mini black hole but it involves what she described as “a democratic decay to a large number of objects per event.” That statement takes a bit of unpacking to understand, but here’s how a stringball could behave in a snapshot:

Imagine a small black hole. The black hole evaporates away through Hawking radiation, getting smaller over time. String theory suggests that when the black hole gets to some critically small size, it transforms into highly excited vibrating string state, which can then disintegrate into a burst of massless radiation. That radiation would appear as jets of particles coming out in every direction in an LHC detector such as ATLAS or CMS.

If stringballs exist, there is a good chance that the LHC could see them when it ramps up its energy and collects sufficient data. As a bonus, the characteristics of a stringball would be determined by any extra dimensions that might exist. It’s a long shot to discover, but it’s a curious example of the exotica that could be created by the Large Hadron Collider.

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