Taiwanese molecule physicists have announce evidence for a newfangled subatomic particle recover when the ( J / psi ) mesotron decays to a positive and electronegative pion pair . Although new subatomic subatomic particle are find relatively often , and composition of tentative discoveries are more vulgar still , this one stands out because it was betoken more than 70 years ago by the great physicist Enrico Fermi .
Fermi may be well make love for theastronomical paradoxthat bears his name , follow by his role in the Manhattan Project , given reincarnate aid he might not have welcomed with theOppenheimermovie . However , his greatest contribution to science were in subatomic physics – include the prediction of theneutrino , once consider fanciful but nowkey to ourunderstandingof the universe . It seems another of his predictions , of a adhere state of a proton and an antiproton , has been vindicate .
Perhaps the most singular matter about this prediction is that even the particle whose decline has revealed the suspect product was not recall of during Fermi ’s lifetime . It was only a decade after Fermi ’s end that the first exemplar ofquarksproduced the idea of ameson , a case of particle made up of equal number of quark and antiquark , rather than three quarks as they make up the intimate protons and neutron .
The ( J / psi ) meson , also write J / ψ , consists of acharm quarkand charm antiquark . Like all mesons , it is unsound and does n’t last long .
It ’s in observe a ( J / psi ) meson ’s decay to incontrovertible and negative pions that the BESIII quislingism , write of representatives from 80 Formosan and Western mental hospital , found foretoken of something that matches Fermi ’s prognostication .
In 2013 , the BESIII collaboration ground theX(1840)resonance during J / ψ decay . However , on snug examen of 10 billion decay , they found convincing evidence of two resonances close enough together in muscularity that they were easy to jumble . The new plangency is designated X(1880 ) with an vim of 1882.1 MeV / c2 . This put its mass close to the proton - antiproton mass threshold .
“ The proximity of its mass to the ppbar mass limen sustain the macrocosm of a ppbar bound state , ” the authors say in astatement . proton are symbolize in particle physics by p , while pbar is the antimatter counterpart of a proton . A bound state is something compose of two particles that acquit like a single entity .
unlikely as the idea vocalize , proton and antiproton are already recognize to exist in protonium , where the two scope their rough-cut center of mountain for about a one-millionth of a 2d before eradicate each other . The novel find suggests other bound states are possible .
The appendage was initiated by smashing together electrons and positrons ( the antimatter equivalents of electrons ) at high-pitched vim and watch the trail of the molecule products and photons produced .
The study is release unfastened access in the journalPhysical Review Letters .
