The article claims that "for the first time, string theory is testable," when in reality:
* the tests here concern particles that aren't actually known to exist yet
* lots of variants of string theory can be invalidated by the (non)existence of particles at particular masses or with particular properties
* moreover, this kind of invalidation has already happened on many occasions
* as usual it's only some models of string theory that are ruled out
So the headline and article are both kind of rubbish. In this case I wouldn't even say it's just a misleading headline because the article acts as though some (or even lots of) models of string theory getting hypothetically ruled out by a particle having a certain mass is a brand new thing.
* the tests here concern particles that aren't actually known to exist yet * lots of variants of string theory can be invalidated by the (non)existence of particles at particular masses or with particular properties * moreover, this kind of invalidation has already happened on many occasions * as usual it's only some models of string theory that are ruled out
So the headline and article are both kind of rubbish. In this case I wouldn't even say it's just a misleading headline because the article acts as though some (or even lots of) models of string theory getting hypothetically ruled out by a particle having a certain mass is a brand new thing.