Mar 26, 2025 06:48 PM
(This post was last modified: Mar 26, 2025 06:57 PM by C C.)
https://www.symmetrymagazine.org/article...entity=und
EXCERPTS: Yesterday, at the annual Rencontres de Moriond conference taking place in La Thuile, Italy, the LHCb collaboration at CERN reported a new milestone in our understanding of the subtle yet profound differences between matter and antimatter...
[...] Particles are known to have identical mass and opposite charges with respect to their antimatter partners. However, when particles transform or decay into other particles, for example as occurs when an atomic nucleus undergoes radioactive decay, CP violation causes a crack in this mirror-like symmetry. The effect can manifest itself in a difference between the rates at which particles and their antimatter counterparts decay into lighter particles, which physicists can log using highly sophisticated detectors and data analysis techniques.
The LHCb collaboration observed CP violation in a heavier, short-lived cousin of protons and neutrons called the beauty-lambda baryon Λb, which is composed of an up quark, a down quark and a beauty quark...
[...] The analysis showed that the difference between the numbers of Λb and anti-Λb decays, divided by the sum of the two, differs by 2.45% from zero with an uncertainty of about 0.47%. Statistically speaking, the result differs from zero by 5.2 standard deviations, which is above the threshold required to claim an observation of the existence of CP violation in this baryon decay.
While it has long been expected that CP violation exists among baryons, the complex predictions of the Standard Model of particle physics are not yet precise enough to enable a thorough comparison between theory and the LHCb’s measurement.
Perplexingly, the amount of CP violation predicted by the Standard Model is many orders of magnitude too small to account for the matter-antimatter asymmetry observed in the universe. This suggests the existence of new sources of CP violation beyond those predicted by the Standard Model, the search for which is an important part of the LHC physics program and will continue at future colliders that may succeed it... (MORE - details)
EXCERPTS: Yesterday, at the annual Rencontres de Moriond conference taking place in La Thuile, Italy, the LHCb collaboration at CERN reported a new milestone in our understanding of the subtle yet profound differences between matter and antimatter...
[...] Particles are known to have identical mass and opposite charges with respect to their antimatter partners. However, when particles transform or decay into other particles, for example as occurs when an atomic nucleus undergoes radioactive decay, CP violation causes a crack in this mirror-like symmetry. The effect can manifest itself in a difference between the rates at which particles and their antimatter counterparts decay into lighter particles, which physicists can log using highly sophisticated detectors and data analysis techniques.
The LHCb collaboration observed CP violation in a heavier, short-lived cousin of protons and neutrons called the beauty-lambda baryon Λb, which is composed of an up quark, a down quark and a beauty quark...
[...] The analysis showed that the difference between the numbers of Λb and anti-Λb decays, divided by the sum of the two, differs by 2.45% from zero with an uncertainty of about 0.47%. Statistically speaking, the result differs from zero by 5.2 standard deviations, which is above the threshold required to claim an observation of the existence of CP violation in this baryon decay.
While it has long been expected that CP violation exists among baryons, the complex predictions of the Standard Model of particle physics are not yet precise enough to enable a thorough comparison between theory and the LHCb’s measurement.
Perplexingly, the amount of CP violation predicted by the Standard Model is many orders of magnitude too small to account for the matter-antimatter asymmetry observed in the universe. This suggests the existence of new sources of CP violation beyond those predicted by the Standard Model, the search for which is an important part of the LHC physics program and will continue at future colliders that may succeed it... (MORE - details)