I don't know how to say it, but in the TV dominatrices and the popular science books we see the string theory as "the best theory to explain everything", and as "the only game in town"… etc. And yet, in CERN -The largest physics laboratory-, they are just using the Standard Model (SM) as the only way to find the theory of everything (ToE), and sometimes they call it: "theory of almost everything".
Also, they didn't even mention anything about string theory. (as if it doesn't exist!)
So my question is:
Why? Isn't it easier for them to take the string theory as a Theory of Everything?
Also, the Standard Model is not able to explain the gravitational force from the SM equation! So, the SM is essentially incomplete! Why do they keep working on the SM? Am I missing something here?
-P.S.: I'm an engineer, not a physicist! So, I don't know much about the details.
Best Answer
As with many discussions about string theory, it is sometimes good to recall some reality:
It was over 50 years ago that the Higgs mechanism was proposed. Compared to fully-fledged theories such as string theory, the Higgs mechanism is a tiny add-on to the observed standard model (as it was then). It took 50 years for experiment to get to the point of seeing it, and in fact so far just a first glimpse of it. For 50 years, the Higgs mechanism was speculation not confirmed by experiment. It had all theoretical backing behind it, theory all pointed to it being true, but it couldn't be checked experimentally for 50 long years. For 50 years, you were free to make TV documentaries about particle physics without mentioning the Higgs mechanism, if you thought it was too outlandish a proposal to have a chance of being confirmed. Then finally experiment reached its energy scale and there it was. 50 years later.
As you all know, there are scenarios thinkable where more beyond-the-standard-model-physics is right around the corner, but nothing to rule out that it takes another 50 years to see the next piece of "new physics". That's just a fact of our short life.
But that's not necessarily as bad as it may sound. While "new physics" may remain specuative for a long time to come, here is a well-kept secret to take note of: even old physics isn't fully understood yet. And string theory can help here, and theorists know (though TV stations may not yet have gotten the message).
For instance, computation of scattering amplitudes even in the known and confirmed standard model is still a challenge, if only you are ambitious enough. String theory has helped with understanding some subtle points in plain Yang-Mills perturbation theory. See the links at string theory applied elsewhere -- QCD scattering amplitudes. In particular check out the remarkable story linked to there, told by Matthew Strassler in his post From string theory to the large hadron collider, which is about how string theory insights into QCD scattering amplitudes helped raise the precision of loop computations to the level that it was possible in the first place to separate signal from background in the LHC. He cites people who were involved as saying that without these string theory insights the Higgs might have been produced, but not identified at the LHC. Have a look, it's an interesting story.
Another thing may be worthwhile to remember from time to time: while we are all fond of proclaiming that we understand fundamental particle physics via quantum Yang-Mills theory, fact is that quantum Yang-Mills theory is still an open theoretical problem. We know that we don't understand some very fundamental facts about qauntum Yang-Mills. It's a "Millennium problem" Yang-Mills existence and the mass gap.
Now, one thing that string theory has become after its "second revolution" is something like a map of the space of Yang-Mills like-field theories and various "dual" theories. Via D-brane physics, KK-reduction, AdS/CFT, etc. Yang-Mills like theories appear in various guises in various corners of string theory, and their embedding into string theory geometrically explains subtle equivalences between these, such as electric/magnetic duality, etc. If you haven't seen it before, check out at http://ncatlab.org/nlab/show/gauge+theory+from+AdS-CFT+--+table at least part of this string-theoretic "map" of the space of quantum field theories related to Yang-Mills theory. While this hasn't solved the mass gap problem yet, clearly, one may start to feel that the deeper nature of Yang-Mills theory is slowly but surely being probed here.
The punchline here is the following: besides being a framework for models of quantum gravity and gauge unification, string theory is a piece of theoretical physics that sheds light on the nature of quantum field theory as such. While experimentalists and public media are busy with indulging in the Higgs physics now that they waited for half a century, maybe theoreticians can use the time before the next accelerator to step back and think a bit more about the still open more fundamental issues of quantum physics. That's where string theory has already helped, and I think will help in the future. Of course you won't see this on public TV.
(Generally, it is surprising these days how not only the public media but also the broad community's attention is consistently attracted to the shallow and ignoring the deep advances that do happen in fundamental physics. For instance there is loads of excitement about, say, the firewall essay contest, but the really interesting advances, such as for instance in genuine mathematical characterization of string theory vacua here remains a topic among a tiny group of specialists. At the same time everybody has an opinion about the "landscape", and everbody else has the opposite opinion. What is needed instead is more decent theoretical work on the foundations of quantum field theory and, inevitably then, string theory.)