![]() The LHCb experiment is taking more data during the second run right now. "We are planning a range of other measurements. "While these two results taken together are very promising, the observed phenomena won't be considered a true violation of the Standard Model without further experiments to verify our observations," said co-author Gregory Ciezarek, a physicist at the Dutch National Institute for Subatomic Physics (NIKHEF). This suggests that it's not just an instrumental effect-it's pointing to real physics." "The added weight of two experiments is the key here. ![]() This replication provides an important independent check on the observations," explained study co-author Brian Hamilton, a physics research associate at UMD. "The experiments were done in totally different environments, but they reflect the same physical model. (The UMD team has participated in the BaBar experiment since its inception in 1990's.) While both experiments involved the decay of B mesons, electron collisions drove the BaBar experiment and higher-energy proton collisions drove the LHC experiment. The LHCb result adds to a previous lepton decay finding, from the BaBar experiment at the Stanford Linear Accelerator Center, which suggested a similar deviation from Standard Model predictions. If this universality is broken, we can say that we've found evidence for non-standard physics." "Lepton universality is truly enshrined in the Standard Model. But there is no guarantee that this will hold true if we discover new particles or new forces," said study co-author and UMD team lead Hassan Jawahery, Distinguished University Professor of Physics and Gus T. "The Standard Model says the world interacts with all leptons in the same way. However, the team found a small, but notable, difference in the predicted rates of decay, suggesting that as-yet undiscovered forces or particles could be interfering in the process. Unlike their stable lepton cousin, the electron, tau leptons and muons are highly unstable and quickly decay within a fraction of a second.Īccording to a Standard Model concept called "lepton universality," which assumes that leptons are treated equally by all fundamental forces, the decay to the tau lepton and the muon should both happen at the same rate, once corrected for their mass difference. The researchers looked at B meson decays, processes that produce lighter particles, including two types of leptons: the tau lepton and the muon. ![]() The team, which includes physicists from the University of Maryland who made key contributions to the study, analyzed data collected by the LHCb detector during the first run of the LHC in 2011-12. The discovery, scheduled for publication in the Septemissue of the journal Physical Review Letters, could prove to be a significant lead in the search for non-standard phenomena. Now, a team of physicists working at CERN's Large Hadron Collider (LHC) has found new hints of particles-leptons, to be more precise-being treated in strange ways not predicted by the Standard Model.
0 Comments
Leave a Reply. |