I was wondering why no one else besides them was making a big deal out of this discovery. Now it makes sense; it's not a huge deal in general (according to you).mfb said:The B hadrons were expected to exist. Nice to see them and some theorists will learn something from their mass, but nothing unexpected.
The ##Z_c^-(4100)## hint is interesting. It is based on about half the recorded data, so we will probably get an update with more statistics soon.
It is interesting to see how LHCb announces the discoveries of these particles. They quote a significance of 12.6σ based on 3/fb integrated luminosity from Run 1 (2011/2012). The selection is nothing fancy and similar to many other analyses. A peak that prominent is really easy to find, a bachelor student could have found the particles in 2013 - and there is a good chance someone did see them that early. LHCb could have made a quick conference note about them, but they decided to directly write a full paper about them, which takes much more time. There are no other experiments that could find these particles, so they were not in a hurry. The long delay still indicates that there are not so many people working on it.
This is not the first time new particles pop up with huge significances - and not necessarily the last. How many more hadrons did LHCb find where the analysis is still ongoing?
mfb said:A peak that prominent is really easy to find, a bachelor student could have found the particles in 2013 - and there is a good chance someone did see them that early. LHCb could have made a quick conference note about them, but they decided to directly write a full paper about them, which takes much more time. There are no other experiments that could find these particles, so they were not in a hurry. The long delay still indicates that there are not so many people working on it.
It would have been a big deal if they had discovered particles not already predicted by current theory so that physicists would have a new clue in how to modify the Standard Model. But these detections essentially say, "yup, the theory still works."Amrator said:I was wondering why no one else besides them was making a big deal out of this discovery. Now it makes sense; it's not a huge deal in general (according to you).
What they're really saying is "yup, our accelerator is still useful." And it is.vela said:It would have been a big deal if they had discovered particles not already predicted by current theory so that physicists would have a new clue in how to modify the Standard Model. But these detections essentially say, "yup, the theory still works."
Amrator said:https://home.cern/about/updates/2018/09/lhcb-experiment-discovers-two-perhaps-three-new-particles
http://lhcb-public.web.cern.ch/lhcb-public/Welcome.html#LHCCCKM
This is very exciting news! What exactly does it say about the strong interaction?
The LHCb experiment at CERN has discovered two new particles, named X(6900) and X(6975). These particles are excited states of a type of subatomic particle called a baryon, which is made up of three quarks.
The LHCb experiment is a particle detector that is part of the Large Hadron Collider (LHC) at CERN. The LHCb experiment collides protons at high energies and then records the particles produced by these collisions. By analyzing these particles, scientists can identify new particles and study their properties.
These new particles are significant because they are the first excited states of a baryon containing a bottom quark to be observed. This is a type of particle that is predicted by the Standard Model of particle physics, but has never been seen before. The discovery of these particles can provide valuable insights into the nature of matter and the fundamental forces that govern the universe.
The two new particles have similar masses, but their different decay patterns suggest that they have different internal structures. The X(6900) is more likely to decay into a D0 meson and a J/ψ meson, while the X(6975) is more likely to decay into a D0 meson and a η' meson. This indicates that the two particles have different combinations of quarks and anti-quarks.
The discovery of these new particles can help scientists better understand the strong force which binds quarks together, as well as the structure of hadrons (particles made of quarks). It can also provide new insights into the nature of matter and the fundamental forces of the universe, and may open up new avenues for exploring the frontiers of particle physics and expanding our understanding of the universe.