Toponium: the smallest bound state and simplest hadron in quantum mechanics

Abstract

We explore toponium, the smallest known quantum bound state of a top quark and its antiparticle, bound by the strong force. With a Bohr radius of $8\times 10^{-18}$~m and a lifetime of $2.5\times 10^{-25}$~s, toponium uniquely probes microphysics. Unlike all other hadrons, it is governed by ultraviolet freedom. This distinction offers novel insights into quantum chromodynamics. Our analysis reveals a toponium signal exceeding $5\sigma$ in the distribution of the cross section ratio between $e^{+}{e}^{-}\to b\bar{b}$ and $e^{+}{e}^{-}\to q\bar{q}$ ($q=b,c,s,d,u$), based on 400~fb${}^{-1}$ of data collected at $\sqrt{s}\approx 341\mathrm{GeV}$. This discovery enables a top quark mass measurement with an uncertainty reduced by a factor of ten compared to current precision levels. Moreover, this method improves the systematic uncertainty by at least a factor of 2.7 compared to any other possible methods.

8 pages, 2 pages; accepted for publication as a Regular Article in Physical Review D

References in corpus (16)

• PYTHIA 6.4 Physics and Manual
• A portrait of the Higgs boson by the CMS experiment ten years after the discovery
• A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery
• The lifetime of the electroweak vacuum and sensitivity to Planck scale physics
• CEPC Technical Design Report -- Accelerator (v2)
• Spin-dependent potentials from lattice QCD
• Evidence for intrinsic charm quarks in the proton
• Observation of quantum entanglement in top-quark pairs using the ATLAS detector
• What is the Top Quark Mass?
• Quantum tops at circular lepton colliders
• Analytic three-loop QCD corrections to top-quark and semileptonic $b\to u$ decays
• Combination of measurements of the top quark mass from data collected by the ATLAS and CMS experiments at $\sqrt{s}$ = 7 and 8 TeV
• Heavy-quark pair production at lepton colliders at NNNLO in QCD
• Top quark mass measurements at the $t\bar{t}$ threshold with CEPC
• Ladder top-quark condensation imprints in supercooled electroweak phase transition
• Novel method for identifying the heaviest QED atom

Cited by in corpus (2)

• Searching for the toponium ${\eta }_t$ with the ${\eta }_t$ $\to$ $W^{+}{W}^{-}$ decay
• Investigating topped hadrons to probe the boundaries of the potential model