For the very first time the CERN combines results of two experiments held at the LHC to detect an extremely rare particle decay as predicted by the Standard Model.
Scientists involved in the European Organization for Nuclear Research (CERN), Geneva, Switzerland have detected an extremely rare particle decay, by combining two experiments held at the Large Hadron Collider (LHC), which could further assist the researchers in understanding the Universe and Particle physics in some new light.
The Standard Model has been a major backbone of Particle physics since 1970s. With the help of Standard Model, physicists can not only classify the sub atomic particles but also make predictions about the particles that are not yet found or observed. Though Standard Model has had an upper hand in particle physics till date; however it fails to explain gravity, dark matter and the behavior of the particles during the initial developmental stages of the Universe. Scientists have been carrying out different experiments to check if the data predicted by the Standard Model deviates from the actual theory.
Different experiments have been carried out to check the decay of the sub atomic particles. When the results were compared with the Standard Model’s predictions, amazingly it always matched the predictions. This is the reason as to why Standard Model predictions have held up so far including the existence of Higg’s boson particle.
Higgs boson particle is an elementary particle that was already predicted by Standard Model which remained undetected; however with the help of LHC this particle was found in March 2013. Now, after almost 2 years, for the first time scientists have detected a rare particle decay which was “harder to find than the famous Higg’s particle”.
Scientists combined and analyzed the data collected by collider’s Compact Muon Solenoid (CMS) and Large Hadron Collider beauty (LHCb) experiments held during 2011 and 2012. With this scientists were able to detect the extremely rare decay of a particle called as the strange B (Bs) meson into two muons which was already predicted by the Standard Model of the particle physics. The major aim of both these experiments was to find the properties of particles and study their behavior in the Universe. The findings of these experiments have been published in Nature.
As per the predictions of Standard Model, Mesons are also sub atomic particles. The strange B (Bs) mesons are a particle flavor of the sub atomic particle which should decay at a rate of four out of every billion strange B mesons produced. On the other hand, the non strange B mesons at the rate of one in 10 billion. Strangely the results of the experiments supported the predictions of Standard Model with slight deviation.
As per a press release, Sheldon Stone from Syracuse University in the US, said “It’s amazing that this theoretical prediction is so accurate and even more amazing that we can actually observe it at all. This is a great triumph for the LHC and both experiments.”
Joel Butler, a physicist from the US’s Fermilab, who was a member of the CMS experiment said : “Many theories that propose to extend the Standard Model also predict an increase in this Bs decay rate. This new result allows us to discount or severely limit the parameters of most of these theories. Any viable theory must predict a change small enough to be accommodated by the remaining uncertainty.”
During the experiment scientists also detected another rarer type of B meson known as non strange B meson, into two muons. Now, the decay of non strange B meson was four times the Standard Model’s prediction which is a small deviation. Based on the results of the experiment the Bs meson results are much more closer to the Standard Model’s prediction and there is just slight deviation in the non strange B meson.
Hence Butler said: “It’s not way off the Standard Model prediction, but it’s low enough to keep us questioning. We’ve been taking more data this spring and hope to eventually nail down the value. When we have two to four times more data from the next run of the LHC, things will start to get really interesting.”
Stone said: “Bs mesons oscillate between their matter and their antimatter counterparts, a process first discovered at Fermilab in 2006. Studying the properties of B mesons will help us understand the imbalance of matter and antimatter in the Universe.”
For a long time scientists have been delving into various experiments just to poke the equations of the Standard Model’s predictions, so this deviation might prove to be beneficial. The data deviating from the Standard Model could help scientists to move towards a new theory and hence put more light on the dark energy or dark matter and also probably provide the reason as to why the universe is made up of matter instead of antimatter.
The Large Hadron Collider (LHC) was restarted after a gap of about 2 years, earlier in April 2015 and now scientists are eagerly looking forward to its new data which can definitely challenge the predictions of the Standard Model.
Resource : Science Alert.