Asking regarding potential questions I might pose soon. While asking a well formulated question about tachyons in special relativity is allowed (as I did last week), I’m wondering how far that goes.

I’ll be specific: I want to ask about more obscure hypotheticals. Specifically graviphotons and graviscalar particles in higher dimensional hypotheses.

To avoid wild speculation, should I cite specific academic papers or is naming the model in question ok. Or, since such higher-dimensional models are not part of currently accepted physics (thus, unlike Special Relativity), so such questions don’t belong here.

Thanks in advance! Want to make sure I don’t break the rules nor turn this place into a science fiction forum! I’m perfectly fine asking such questions elsewhere.


1 Answer 1


Asking about the detection status of specific quanta that are predicted in theories of beyond-the-standard-model physics should be fine. Looking for new particles is, of course, a major activity in experimental particle physics. Moreover, there are also secondary observables that are also indicative of the presence of new physics. (For example, the mass of the top quark had already been "measured" to within about 15%, even before it was detected directly in 1995, because of the top's outside influence as a virtual contributor to certain lower-energy particle processes.) When one has a particular quantum field theory model in hand, it is often straightforward to determine what new effects we would expect to see in that model, as a function of its parameters.

Such predictions can also be turned around and combined with experimental data to place constraints on the models (assuming that the new particles they predict have not actually been seen). For example, while supersymmetric extensions of the standard model have a number of very attractive theoretical features, we have never seen the superpartner of a standard model particle. Over the last several decades, increasingly energetic and precise experiments have led to region of the SUSY parameter space that is phenomenalistically viable continuing to shrink—to the point where many feel that relatively-low-scale SUSY is no longer even a theoretically attractive option. There is an extensive literature on these kinds of constraints for SUSY theories and other kinds of extensions of the standard model, and they surely fall within the heading of "mainstream physics."

  • $\begingroup$ Excellent, thank you! So just to be clear: so long as I constrain my questions to the status of such particles, how much has the possibility of them being found shrunk, and their hypothetical properties as predicted by mainstream physics (that we could detect experimentally of course), I am fine? $\endgroup$
    – Hokon
    Commented Aug 26, 2023 at 23:22
  • 2
    $\begingroup$ @HokonCazalet Yes, I would say so. If you have particular theory (or family of theories) in mind and want to ask about specific experimental consequences, that is a very standard activity in theoretical particle physics. $\endgroup$
    – Buzz Mod
    Commented Aug 26, 2023 at 23:25

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