Related Experiment Video
Updated: May 10, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Determination of the X(3872) meson quantum numbers
R Aaij1, C Abellan Beteta, B Adeva
1Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands.
Abstract:
The quantum numbers of the X(3872) meson are determined to be J(PC)=1(++) based on angular correlations in B(+)→X(3872)K(+) decays, where X(3872)→π(+)π(-)J/ψ and J/ψ→μ(+)μ(-). The data correspond to 1.0 fb(-1) of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements J(PC)=2(-+) is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state.
Related Concept Videos
Quantum Numbers
The Pauli Exclusion Principle
Electronic Structure of Atoms
An atom comprises protons and neutrons, which are contained inside the dense, central core called the nucleus, with electrons present around the nucleus. Taking into account the wave–particle duality of electrons and the uncertainty in position around the nucleus, quantum mechanics provides a more accurate model for the atomic structure. It describes atomic orbitals as the regions around the nucleus where electrons of discrete energy exist, characterized by four quantum numbers: n, l, ml, and...
Electron Configurations
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p, 4s,...
The Aufbau Principle and Hund's Rule
Atomic Number and Mass Number

