The structure of the f0(980) scalar boson has been a mystery for decades.
A new study, however, appears to show that it is basically a quark-antiquark meson with a valance strange quark and anti-strange quark. In other words, it is strange quark quarkonia. The new study largely rules out tetraquark, meson molecule, and quark-antiquark-gluon hybrid particle alternatives.
13 comments:
Where did you get the flavor content of the f0(980) from? Was there a press release? The paper itself only says q qbar.
From the illustration in the paper reproduced in the post.
Also, while the paper is cautious, a top quark doesn't hadronize and is far too massive. A charm quark and a bottom quark are both too massive. And, if it was an up and anti-up, or a down and anti-down, it would be neutral charged pion (which is generally described as a blend of up and anti-up and down and anti-down states) with less than 140 MeV of mass, yet while it decays to pions, it isn't a pion. By process of elimination, it must be a strange-antistrange meson if it is a simple q-q bar meson. I'm not sure why the authors were unwilling to say so outright in the body text, even though they did put this in the illustration in their paper.
Less definitively, but suggestively, it is more massive than kaons with a single strange quark, and all pseudo-scalar and vector mesons with only up and down quarks (the charged rho, the neutral rho, and the omega meson), but less massive than a spin-1 s-s bar meson (i.e. a Phi meson), and is very similar mass to the pseudo-scalar eta prime meson (u-u bar, d-d bar, s-s bar blend), all of which is consistent with a spin-0 s-s bar assignment. See https://en.wikipedia.org/wiki/List_of_mesons
Of course, the paper doesn't explain the structure of the other light true scalar mesons like the f(500), of the light axial vector mesons like the a(980).
"From the illustration"
OK, I missed that!:-)
Maybe they only said qqbar because their method can't distinguish flavor - to arrive at ssbar they'd have to engage in some extra reasoning.
See also https://dispatchesfromturtleisland.blogspot.com/2020/03/glueball-physics.html
Noting a paper reaching the same conclusion re the f0(980) and concluding that the f0(500) is a u-ubar + d-dbar/sqrt(2) meson, and discussing possible other structures for other light scalar mesons.
Typo: "The structure of the f0(980) scalar boson" should read "meson".
All mesons are also bosons.
No. The word we have been seeking is on the paper: hadron (baryon also works but isn't ideal; my correction also wasn't ideal).
Not boson. Bosons are carrier-particles like the Higgs or like a photon. I do not know of a boson made of quarks.
@Darayvus
By definition, a boson is a particle (subatomic or atomic) with an integer value of total angular momentum (a.k.a. "J" a.k.a. "spin"), which as a result behaves in accordance with Bose-Einstein statistics. It can be fundamental or composite. Mesons are always bosons.
https://en.wikipedia.org/wiki/Boson
https://en.wikipedia.org/wiki/Meson
A "hadron" is a composite particle whose components are bound directly by the strong force of QCD. https://en.wikipedia.org/wiki/Hadron
A meson is not a baryon. A baryon is a hadron that is a fermion, usually with three valance quarks, while a meson is a hadron that is a boson, usually with with a valence quark and a valence anti-quark.
The magic term you used was "composite boson". I was not even aware of such a beast! Thank you Andrew.
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