In an extraordinary feat of precision physics, CMS measures the mass of the W boson, and finds it to be in good agreement with the prediction by the Standard Model of particle physics.
In the most precise measurement of its kind ever obtained at the…
The CMS Collaboration at CERN has conducted an analysis to explore the differences between tau leptons and muons, the two heavier cousins of the electron, and both also fundamental particles in the Standard Model (SM) of particle physics.…
Our current understanding of the nature of elementary particles and their interactions is encapsulated in what is known as the Standard Model (SM) of particle physics. Particles and interactions introduced in the SM have been measured with…
A fundamental parameter of the Standard Model, the electroweak mixing angle plays a key role in the “Higgs mechanism”, when the W and Z gauge bosons get their masses through electroweak symmetry breaking. CMS has now reported a new measurement of…
Even if the standard model of particle physics (SM) describes Nature incredibly well, it fails in providing insight to a number of observations such as the existence of dark matter. How do we get a better (and bigger) model than the SM? From the…
In quantum electrodynamics (QED), the quantum theory of electromagnetic interactions, the magnetic dipole moment of a particle acquires quantum corrections originating from interactions with virtual photons and other particles, often referred to as…
A proton-proton collision at a centre-of-mass energy of 13 TeV, recorded by CMS, compatible with the production of a Higgs boson decaying to a J/ψ meson, which decays to two muons (red lines), and a high-energy photon (green box, top). Try to zoom…
At the subatomic level, interactions between particles are mediated through the exchange of special particles, the force carriers. In the case of electromagnetism, the force is transmitted by photons. They connect particles with electric charge (…
Among all the elementary particles, quarks and gluons (partons) are the only ones that cannot be observed in isolation. In high-energy collisions, such as those occurring at the Large Hadron Collider (LHC), partons undergo a few stages between their…
The CMS Collaboration has recently reported a new study of ZZ+jets production, a process described by the Standard Model of particle physics. The goal of such measurements is to compare the observed results with the theoretical predictions; any…
Bosons are elementary particles in the field of particle physics, distinguished by having a spin quantum number with an integer value. They play a crucial role in mediating the fundamental forces of nature, including the electromagnetic force and…
Quarks and gluons are the elementary particles that make up protons and neutrons, which are in turn the building blocks of the nucleus of every atom. Gluons are the particles that mediate the strong nuclear force, which is responsible for “gluing”…