A rare, fleeting 鈥渂eauty鈥� particle has been spotted in the first run of the Large Hadron Collider (LHC).
The LHC started work on 30聽March, and one of its four large detectors detected evidence of a beauty quark 鈥� also, less poetically, known as a 鈥� on 5聽April.
The find should be the first of many beauty decays that LHCb, the , will observe, and demonstrates the detector is working as planned.
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This first recorded particle is a meson composed of an anti-beauty quark 鈥� the beauty quark鈥檚 antiparticle 鈥� and an up quark 鈥� one of the two common quarks that make up protons and neutrons. While up quarks last for billions of years, the large beauty quarks swiftly decay into lower-energy particles in about 1.5聽x聽10-12 seconds.
After travelling only 2聽millimetres in the accelerator, the beauty quark decayed to a lighter quark 鈥� still paired with the original up quark 鈥� and the extra energy was carried off in the form of electron-like particles called .
Extremely rare
鈥淚t鈥檚 a very rare event 鈥� it鈥檚 like a needle in a haystack,鈥� says Andreas Schopper, a spokesperson for LHCb. 鈥淚n these 10聽million data or so we find this one event.鈥�
The particle was detected by LHCb鈥檚 automatic trigger system, which is designed to recognise unusual events or particles but to ignore the vast majority of proton collisions. Less than 1聽per cent of the collisions will be of interest to LHCb scientists.
Once an event is recorded, the details of detector signals are sent out to computing centres on five continents, where over a few days software reconstructs particle tracks. 鈥淚t is the teamwork of the collaboration,鈥� says Schopper. 鈥淭his is the first time we have really detected and reconstructed such a big particle.鈥�
Back to the big bang
LHCb will look at many such decays in order to shed light on that should have been created alongside the matter that makes up our universe.
The experiment is designed to examine what happens to beauty quarks, which form in high-energy explosions 鈥� not least the big bang. By comparing the decay products of beauty quarks, LHC researchers hope to find clues as to why our universe seems to favour matter over antimatter.
鈥淲hile precision measurements will need many millions of beauty particles, as with kisses, the first is always very special,鈥� says , spokesperson for the LHC鈥檚 ALICE experiment. 鈥淚t shows that the detector is up to its task, performing very well in identifying the complex decay pattern.鈥�
