It has taken a while, but the rare decay of B_s mesons (particles composed of a bottom and an anti-strange quark) to muon pairs has finally been seen. The authors of the find -we cannot yet call it an observation given the scarce statistical significance of the signal- are the members of the LHCb collaboration, one of the four experiments working with the proton-proton collisions delivered by the Large Hadron Collider at CERN.
The decay of the B mesons to muon pairs are quite rare -of the order of one in a billion- but very important, because they proceed via loop quantum diagrams within which existing particles may circulate. And since these loops are virtual, even very massive particles, even ones we do not know yet about, would produce a significant contribution. So measuring the rate of the rare decays allow us to gauge whether there is new physics in store for us, or whether there is just a desert of Standard Model physics awaiting us at the high-energy frontier.
The CDF and DZERO collaborations at the Tevatron collider have sought for these rare decays for two decades, and now the CERN experiments have taken over. The LHCb detector is quite well suited to spot these decays, since it looks at very forward-going proton-proton collisions, ones which produce B quarks in large amounts. Eventually CMS and ATLAS will take over (they have collected a larger integrated luminosity), so now is the time for LHCb to show their stuff. And they do.
The figure below, hot off the press, shows the LHCb data in a reconstructed dimuon mass distribution. A B_s signal seems to be there (the red component; the blue line is the total fit, which includes backgrounds), although the statistical significance is still in the range where fluctuations might be the real source of the bump. LHCb estimates it as a 3.5 standard deviations effect.
For more information on the analysis, see here. Tomorrow a seminar at CERN will provide all the details on this new search. What can be noted already, despite the fact that the decay has not been "observed" as canonically required with five standard deviations of more, is the fact that many new physics theories receive a hard blow by the very good match between Standard Model prediction and observed rate.
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Global 'Roadmap' Shows Where To Put Roads Without Costing The Earth
- Neil Tyson On The Politics Of Science Denial
- Synaptic Plasticity And Memory In Silent Neurons
- Low Carb Vs. Low Fat Diets: Which Is Better?
- Wockhardt Is First Indian Pharmaceutical Company To Get FDA QIDP Status
- How The Higgs Became The Target Of Run 2 At The Tevatron
- Brain Size Matters When It Comes To Remembering
- "That's why I deleted the comment Robert! I had just read an article about people beheading and..."
- "So ignore the data that shows the Antarctic breaking ice extent records. Ignore the water displacement..."
- "You don't think science media is a lot better about calling out anti-science on both political..."
- "From what I have seen over the years on Science 2.0 I regard LagrangiansForBreakfast and Ed brown..."
- "Edison's superior lamp filament was made of carbon, not tungsten. In 1906, the General Electric..."
- NYU study compares consequences of teen alcohol and marijuana use
- Discovery hints at why stress is more devastating for some
- Simple awareness campaign in general practice identifies new cases of AF
- ROCKET AF trial suggests that digoxin increases risk of death in AF patients
- Health structures explain nearly 20 percent of non-adherence to heart failure guidelines