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.
Neutrinos are among the most enigmatic particles in the universe. They are omnipresent yet interact extremely rarely with matter.
General Physics
Apr 14, 2025
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Scientists trying to discover the elusive mass of neutrinos, tiny "ghost particles" that could solve some of the universe's biggest mysteries, announced a new limit on Thursday for how much they could weigh, halving the previous ...
General Physics
Apr 10, 2025
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On March 24, at the annual Rencontres de Moriond conference taking place in La Thuile, Italy, the LHCb collaboration at CERN reported a new milestone in our understanding of the subtle yet profound differences between matter ...
General Physics
Mar 26, 2025
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Quantum gravity is the missing link between general relativity and quantum mechanics, the yet-to-be-discovered key to a unified theory capable of explaining both the infinitely large and the infinitely small. The solution ...
General Physics
Mar 20, 2025
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Neutrinos have always been difficult to study because their small mass and neutral charge make them especially elusive. Scientists have made a lot of headway in the field and can now detect three flavors, or oscillation states, ...
General Physics
Feb 27, 2025
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An international team of physicists has successfully measured the size of a certain type of neutrino to a certain degree. In their paper published in the journal Nature, the group describes experiments they conducted that ...
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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