Speaker
Ms
Yilin Zhou
(Fudan University)
Description
The CMS experiment reports the observation of three structures in the 𝐽/𝜓𝐽/𝜓→𝜇+𝜇−𝜇+𝜇− channel — 𝑋(6600), 𝑋(6900), and 𝑋(7100) — each with a significance well above 5𝜎, confirming and extending the earlier Run 2 results. Strong interference effects among them, also above 5𝜎, indicate they share the same quantum numbers. A complementary search in the 𝐽/𝜓𝜓(2𝑆) channel reveals two structures consistent with 𝑋(6900) and 𝑋(7100). A spin–parity analysis favors a 𝐽𝑃𝐶=2++ assignment, a rare quantum number among known hadrons. Together, these findings strongly support the interpretation of these states as a family of all-charm tetraquarks, offering new insights into the dynamics of exotic resonances.
Primary author
Ms
Yilin Zhou
(Fudan University)
