Entangled particles revive a 35-year-old test of the Standard Model
Physicists at the BESIII Collaboration have breathed new life into a decades-old test of one of the Standard Model's most important ideas, using a technique that had gone almost untouched by experimenters for 35 years.
Physicists at the BESIII Collaboration have reignited a 35-year-old test of the Standard Model using a technique that had been neglected for decades. This test focuses on the CKM matrix, a table of numbers that governs how one type of fundamental particle can transform into another. The researchers examined pairs of unstable particles called lambda hyperons, which are linked through quantum entanglement.
By tracking these entangled pairs, the team obtained an independent measurement of VUS, a parameter describing how likely a strange quark is to turn into an up quark. This measurement aligns with the predictions of the Standard Model, which states that all probabilities in the CKM matrix must sum to exactly one. The BESIII Collaboration's precise measurement supports the theory, although it still shows a minor discrepancy with previous kaon-based results.
The researchers are optimistic that further data and calculations could ultimately reveal if the Standard Model contains any hidden inconsistencies, potentially paving the way for new theories to explain these discrepancies.
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