(Fig.1) They cannot separate Higgs, quark from accelerator = unreal.
We need only protons and electrons in atoms and molecules in our real world. Other doubtful particles are unnecessary for our daily lives.
So it's safe to say that only protons and electrons are real, and all other elusive Higgs, quarks .. are unreal particles.
What's the crucial difference between real and unreal (= virtual ) particles ?
Real protons and electrons are so stable that we can isolate them from other irrelevant particles to put them to practical use in our real world.
On the other hand, Higgs and quarks are too unstable and too rare to confirm. We cannot separate them from infinite irrelevant particles inside collider.
Unless you can isolate pure Higgs and quarks from other irrelevant particles, these particles can neither be confirmed as real nor be useful.
(Fig.2) ↓ Doubtful Higgs remains mixed with other irrelevant particles.
Higgs and quarks are very doubtful, because they cannot detect these particles directly, instead, only detect other irrelevant particles to estimate its existence.
In large hadron collider (= LHC ), they collide protons with each other, and they argue one Higgs creation needs as many as trillion collisions !
They can neither isolate Higgs nor detect Higgs directly. All they can do is detect final products such as light and electrons as "Higgs decay".
So it is very hard to say these very rare, unstable Higgs and quarks are real particles.
(Fig.3) Purify Higgs → confirm and use Higgs are impossible
If some particle remains hidden in other infinite amounts of irrelevant particles, you cannot confirm their property, and it remains useless.
Very unstable and rare particles such as Higgs and quraks can neither be isolated from other irrelevant particles nor be detected directly.
So it's safe to say these doubtful particles are unreal.
For example, you can purify real particles such as protons and electrons to confirm their physical properties and put them to practical use.
Unreal particles such as Higgs and quarks lack this important process to confirm they are real (= ② ③ in Fig.3 ).
Staying with other different particles, a new particle is so easily scattered by other particles that we cannot know its mass (= how they behave under magnetic field ).
(Fig.4) Antimatter is too rare, only one in "millions" of proton collisions !?
Producing rare anti-matter depends on very disordered experiments where they claim millions of collisions between protons and metal generate only a few anti-protons.
In these infinite unrelated particles, some of them "look like" unreal anti-particles due to "multi-particle scattering" or something.
So the doubtful anti-hydrogen is just the result of their misinterpretation of spectrum from a pair of real proton and electron.
They just pick up only convenient fake data from a mixture of many kinds of unrelated high-energy particles and gamma rays using artificial simulation.
So as long as they cannot extract pure anti-matter only from pure light, anti-matter is just a statistical artifact of other unrelated particles.
(Fig.5) Higgs, quarks cannot be islolated from collider. = unreal particles
What's the definition of "real" elementary particles ? To confirm they are new real particles, purifying them of other irrelevant particles is indispensble.
Because if a new particle remains together with infinite amount of other irrelevant particles, it's impossible to know its own physical property to distinguish them.
Protons, electrons and lights can be purified and confirmed as real.
Higgs, quarks, weak boson, supersymmetry are too unstable, too doubtful, and cannot be isolated from other irrelevant particles !
So these "transient" particles can be said to be unreal and unneeded for our real world.
2017/5/19 updated. Feel free to link to this site.