Classically, it shouldn’t have happened:
Another of the team’s proposals hinges not on extra particles, but on extra spatial dimensions. Physicists have long speculated that in addition to the three dimensions we see, more dimensions could lie curled up at the subatomic scale. If these dimensions are large enough, energy from the interiors of stars could leak into them.
“You can think of these large extra dimensions as Tupperware containers,” says Ronald Gamble, a postdoc at the National Strategic Research Institute who studies extensions of general relativity and was not involved with the new work. “After you’ve finished your main meal that exists in the three dimensions, you can put your leftover food in them to save for later. That’s what we believe gravity may be doing.”
In contrast to hidden particles carrying energy away from the star, the extra dimensions would hide energy within the star, but the result would be the same: Both the lower and upper bounds of the mass gap would increase.
A third possibility, modified gravity, would overturn an assumption held by both Isaac Newton and Albert Einstein. The inherent strength of gravity, instead of being constant throughout the entire universe, could depend on the cosmic environment. So different regions in space would have different mass gaps. In regions where gravity is stronger, both pair-instability supernovae and the shortcut taken by the largest stars would kick in at lower masses, putting the mysterious black holes above the local mass gap rather than within it.
All these beyond-the-Standard-Model ideas excite Fishbach. “It’s really cool that we’re constraining fundamental physics by measuring black hole masses,” she says. “Unfortunately, astrophysics is really messy, so we have to disentangle the fundamental physics from the astrophysics.”
Scott Herschberger, “Physics at tiniest scale could explain ‘impossible’ black holes” at Symmetry
It’s great copy, really