What are the theoretical puzzles and/or experimental results that superstring theory can explain, but Standard Models can't?

Question

From what I understand by reading this answer and this answer, Superstring theory can't directly explain all of the arbitrary "input parameters" in the Standard Model much like how Newtonian Laws of Gravity can't exactly explain stuffs unexplained by Ptolmey model, and it also fails to reduce the number of arbitrary input parameters in Standard Model:

When Newton's mechanics was new, people expected a theory of the solar system to produce better descriptions for the stuff left unexplained by Ptolmey: the equant distances, the main-cycle periods, and epicycle locations. Newton's theory didn't do much there--- it just traded in the Ptolmey parameters for the orbital parameters of the planets.

However the hope is that:

That string theory will lead to a specific model that incorporates gravity also, from which the structure of the Standard Model will come out naturally, with fewer constants than the descriptive ones needed now,

If I read correctly, this means that Superstring theory can reproduce Standard Models and much more, if we specify the correct "boundary conditions", ie: a few other arbitrary parameters ( less than the number of arbitrary parameters we need to specify in Standard Model).

Is my understanding correct?If yes, what are the theoretical puzzles and/or experimental results that superstring theory can explain, but Standard Models can't?

Why is it being put on hold? I thought my question should be sufficiently clear and narrow-scoped? — Graviton, Jun 19 '18 at 09:21
Yeah, it'd be nice to see some guidance on what specifically could be improved. — Don Branson, Jun 19 '18 at 23:53
The title question (v1) seems unclear what you're asking/too broad (i.e. explaining what issue exactly?), and polemic/primarily opinion-based (i.e. "How good is..."). — Qmechanic, Jun 20 '18 at 10:58
There are precisely zero experimental results that superstring theory can explain, that the SM can't. — knzhou, Jun 21 '18 at 01:16
As for theoretical puzzles, I think that's already covered pretty well in the two questions you linked. Can you specify exactly what about those answers you find incomplete? — knzhou, Jun 21 '18 at 01:17
@knzhou, as for the theoretical puzzles, maybe the answers I cite do contain the information, but I read them a few times and still couldn't wrap my head around them. — Graviton, Jun 21 '18 at 01:32
@Graviton Then you should narrow your question by asking about a specific thing you don't understand. — knzhou, Jun 21 '18 at 01:33
@knzhou I would say "gravity" is an experimental result SST can explain, and that the SM can't :-) — AccidentalFourierTransform, Jul 05 '18 at 21:24

score 2 · Accepted Answer · answered Jun 21 '18 at 11:48

To my knowledge, there are zero instances where any string theory has made a prediction, the approach using the standard model has made a different prediction or no prediction, and the string theory prediction has turned out to match the data.

The closest to this that I'm aware of came about fifteen years ago, when string theorists realized that, if one or two of the proposed extra spatial dimensions were large, gravity would depart from the Newtonian $1/r^2$ behavior when the distance between two masses approached the compactification length scale of the extra dimensions. In response, experimentalists developed a program of torsion pendulum measurements sensitive to deviations from $1/r^2$ gravity all the way down to micrometer lengths. There aren't any: any "large" extra dimension in string theory is still microscopic. The experimental challenge in going to shorter distances is the mechanical challenge of separating the test masses, and I think the experimentalists have moved on to other, less glamorous fifth-force sorts of tests.

What are the theoretical puzzles and/or experimental results that superstring theory can explain, but Standard Models can't?

1 Answers1