From:
Mann, W. Anthony <Anthony Mann tufts edu>
Date: Tuesday, July 8, 2025 at 3:59 PM
To: neutrino cosmos phy tufts edu <neutrino cosmos phy tufts edu>
Subject: [Tufts-Nu] Tufts-Neutrinos: Meeting this week, Friday July11th at 12:30 pm
Dear Tuftons,
For tomorrow’s Friday Meeting, we have one Talk scheduled:
Alternate Geometries for the Dune TMS
Luke Miller
I have heard informally of possible updates from others, but have not
yet received a confirmation.
I have just learned from Hugo Beauchemin that ATLAS has confirmed and earlier
observation of a top-antitop bound state (i.e. toponium). The folk lore for many decades
has been that the top quark decays too quickly to permit the formation of bound states,
but it appears now that for t t-bars produced nearly at rest in the CM frame, entanglement
via gluon exchange is possible.
The first ``onium” system to be observed was charmonium (circa 1973). Its discovery
established the reality of quarks as fermionic particles and heralded the emergence of the
Standard Model. The first state to be observed was the
2S+1LJ
= 3S1 state;
the lowest energy state, the eta_c which is 1S0 was discovered later.
It will be interesting
to learn the quantum numbers of this toponium state. Just imagine, a non-relativistic QCD
bound state which is likely amendable to an ``atomic” description, much as we learn in
a first course in quantum mechanics.
Sincerely,
T
