CERN physicists prove subatomic particles can switch into an antiparticle and back

Shane McGlaun - Jun 14, 2021, 4:42am CDT
CERN physicists prove subatomic particles can switch into an antiparticle and back

Physicists working with the LHCb experiment at CERN have proven that a subatomic particle can switch into its antiparticle and back again. The researchers were able to prove this using extremely precise measurements made using the LHCb experiment at CERN. During the experiment, the team gathered the first evidence that charm mesons can change into their antiparticle and back again.

Researchers on the project say that for more than a decade, scientists have known that charm mesons, which are subatomic particles containing quark and antiquark, can travel in a mixture of their particle and antiparticle states. That phenomenon is known as mixing. However, the recent experiment result shows that particles can oscillate between the two states for the first time.

Using the newly found evidence, researchers believe they can now tackle some of the bigger questions in physics around how particles behave outside the Standard Model. One question they intend to attempt to answer is if these transitions are caused by unknown particles not predicted by the guiding theory. The charm meson can be itself and its antiparticle simultaneously, a state known as quantum superposition.

Quantum superposition results in two particles, each with their mass presenting as a heavier and lighter version of the particle. The superposition allows the charm meson to oscillate between its antiparticle and back. Data was collected during the second run of the Large Hadron Collider, allowing scientists from the University of Oxford to measure a difference in mass between the two particles of 0.00000000000000000000000000000000000001 grams.

Such precision in measurement is only possible when the phenomena is observed many times. It’s also only possible due to the vast number of charm mesons being produced in LHC collisions. Professor Guy Wilkinson from the University of Oxford says what makes the discovery of oscillation in the charm meson particle so impressive is that unlike beauty mesons, which were observed oscillating in 2006, oscillation in this new case is very slow and extremely difficult to measure within the time it takes the meson to decay. Researchers are now attempting to gather more data to understand the oscillation process itself, which is seen as a significant step forward in solving matter-antimatter asymmetry.


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