Leptons are elementary fermionic particles constituting a fundamental physical system in the Standard Model, characterized by half-integer spin (spin-½), lack of color charge, and participation in electroweak but not strong interactions. They occur in three generations, each comprising a charged lepton (electron, muon, tau) and its associated neutrino, distinguished by lepton flavor quantum numbers. Leptons obey Fermi–Dirac statistics and are subject to conservation laws such as total lepton number and, to high precision, individual flavor numbers in most processes. Their dynamics are described by the electroweak sector’s SU(2)\(_L\)×U(1)\(_Y\) gauge symmetry, with mass eigenstates arising from Yukawa couplings and, for neutrinos, flavor mixing via the PMNS matrix.
Recent research on lightweight particles called neutrinos might have passed you by—much like the more than 10 trillion neutrinos passing through your body each second. Now, our new paper—with 21 countries, more than 60 institutes ...
General Physics
Feb 12, 2025
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In order to find rare processes from collider data, scientists use computer algorithms to determine the type and properties of particles based on the faint signals that they leave in the detector. One such particle is the ...
General Physics
Feb 3, 2025
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Strange "right-handed" neutrinos may be responsible for all the matter in the universe, according to new research.
Astronomy
Jan 16, 2025
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The Large Hadron Collider (LHC) made its groundbreaking discovery of the Higgs boson in 2012, but its ancestry can be traced back more than 60 years to the first electron-positron collision experiment in Italy. Named Anello ...
General Physics
Jan 16, 2025
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Particle physicists have been looking for so-called "sterile neutrinos" for a few decades now. They are a hypothesized particle that would have a tiny mass like the three known neutrinos but would not interact by the weak ...
Scientists working on the Short-Baseline Near Detector (SBND) at Fermi National Accelerator Laboratory have identified the detector's first neutrino interactions.
General Physics
Sep 10, 2024
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A central aim of the ATLAS Higgs physics program is to measure, with increasing precision, the strength of interactions of the Higgs boson with elementary fermions and bosons.
General Physics
Sep 9, 2024
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A team including researchers from the Laboratory for High Energy Physics at the University of Bern has successfully measured the interaction rates of neutrinos at unprecedented energies using the Large Hadron Collider (LHC) ...
General Physics
Jul 16, 2024
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Neutrinos have a quantum mechanical property called "flavor." This flavor can transform as neutrinos move through space. A major challenge is to keep track of both the physical movement of the neutrinos and their change of ...
General Physics
Jul 12, 2024
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400
The Belle II experiment is a large research effort aimed at precisely measuring weak-interaction parameters, studying exotic hadrons (i.e., a class of subatomic particles) and searching for new physical phenomena. This effort ...
