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Jefferson Lab physicists identify two unexpected subatomic structures in exotic particle search

Researchers seeking the Y(2175) particle with a high-energy photon beam instead detected two distinct signals at nearby masses.

Updated Sep 2, 2026 · 06:18 UTC1 reports

The short version

  • Physicists using Jefferson Lab's GlueX experiment sought the exotic particle Y(2175) via photoproduction but found two previously unobserved structures instead.
  • The detected structures, named Y(2240) and X(1830), appeared at roughly 2.24 GeV and 1.82 GeV, respectively.
  • The findings provide an upper limit on Y(2175) photoproduction and present new data for theorists modeling exotic quark and gluon configurations.

Key facts

  • The GlueX Collaboration conducted a photoproduction experiment by firing high-energy photons at a proton target to search for the exotic particle Y(2175).[ScienceDaily]
  • Rather than observing Y(2175), researchers detected two separate candidate structures: Y(2240) at roughly 2.24 GeV and X(1830) at approximately 1.82 GeV.[ScienceDaily]
  • The Y(2240) signal reached a statistical significance of five sigma (5-sigma), or a confidence level of roughly 99.9994%.[ScienceDaily]
  • The X(1830) signal achieved a three-sigma (3-sigma) significance level, corresponding to a confidence level of approximately 99.7%.[ScienceDaily]
  • The research was published in Physical Review Letters by the GlueX Collaboration.[ScienceDaily]

What remains uncertain

  • The exact internal quark and gluon configurations of the Y(2240) and X(1830) structures remain unknown pending further theoretical modeling and follow-up measurements.[ScienceDaily]
  • At three sigma, the signal for X(1830) carries lower statistical certainty than Y(2240) and may require additional data to definitively confirm.[ScienceDaily]

Sources