Detractors of string theory have been deriding it for years, claiming that there is no way to test it. However, with a paper published in 麻豆淫院ical Review Letters titled 鈥淔alsifying Models of New 麻豆淫院ics via WW Scattering鈥�, that could change. Coauthors Jacques Distler at the University of Austin in Texas, Benjamin Grinstein from the University of California, San Diego, and Rafael A. Porto and Ira Z. Rothstein at Carnegie-Mellon University in Pittsburgh, Pennsylvania, address a way of falsifying some models of string theory in their Letter.

鈥淓verybody wants to find an experimental test that proves what you thought before was wrong,鈥� Distler tells 麻豆淫院Org.com. 鈥淥ur aim is to suggest something that would rule out some ultraviolet completions of known physics. The physics that we know is described by an 鈥楨ffective Field Theory.鈥欌€� But that EFT breaks down at some energy, where it must be replaced by something else 鈥� perhaps another EFT. 鈥淯ltimately,鈥� says Distler, 鈥渙ne wants to find a theory that's good to arbitrary energies. That's what we call a 鈥楿V completion.鈥欌€�

鈥淧article physicists grew up assuming that, whatever the UV completion is, it would have certain properties, and it is these properties of the presumptive UV completion that lead to our bounds. String theory arose as a way to satisfy those assumptions,鈥� Distler adds.

Distler says that the test proposed would possibly be performed with information from the Large Hadron Collider (LHC), which is scheduled to go online in Switzerland this year. However, he believes that the up-and-coming International Linear Collider (ILC), which is in the early planning stages still doesn鈥檛 even have an announced location, will likely offer more insight.

鈥淥ne of the things measured will be the unknown parameters of the EFT,鈥� explains Distler. 鈥淚f they turn out to lie in a region forbidden by our bounds, that says something about profound about high energy physics.鈥� (More on how the test would work can be found in another )

Distler is fairly certain that when the test is applied, generic models of string theory will, in fact, hold up. However, if string theory is ruled out, the test would mean that there is more hope for what Distler terms 鈥渃onceivable alternative theories鈥� like loop quantum gravity. 鈥淭his would still offer insight into important fundamentals,鈥� he says. 鈥淲hat we鈥檙e probing is whether the UV completion satisfies axioms we think it ought to.鈥�

There is a caveat to this string theory test, though. 鈥淚f a light Higgs [boson] is discovered, we鈥檇 have to redo all our calculations.鈥� While the Higgs particle is suggested in theory, it still has yet to be discovered, and therefore its mass is not known, making it difficult to include in this calculation, Distler explains. 鈥淏ut,鈥� he adds, 鈥渢he idea will still be there and we will have set out the procedure. A similar calculation, including the Higgs, will still be possible, even if this specific analysis won鈥檛 be applicable.鈥�

Even with this limitation, however, the work by Distler and his colleagues offers something profound 鈥� a way to actually test string theory. 鈥淲e are pointing out what experimentalists should look for,鈥� he says, 鈥渁nd I am of the opinion that these bounds will be satisfied.鈥� He pauses before continuing: 鈥淏ut even if they鈥檙e not, at least I鈥檒l be somewhat mentally prepared.鈥�

By Miranda Marquit, Copyright 2007 麻豆淫院Org.com.
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