A shot from inside the LHCb.
Credit: CERN
This week, CERN announced that it has detected a new particle at the Large Hadron Collider (LHC) called the Xi-cc-plus. It’s a very heavy particle, with a mass four times that of a proton, and it’s believed to last only a sixth as long as similar, known particles.
That’s because its combination of two charm quarks and one down quark is inherently less stable than two charm quarks and one up quark. So, how did CERN manage to spy the particle if it’s so short-lived?
The Xi-cc-plus is the first new particle revealed by LHCb Upgrade 1, installed at the LHC in 2023. This fundamentally changed the LHCb experiment’s function. The simplest upgrade was to the luminosity, or the number of particles it can collide within a given timeframe. Put simply: More luminosity, more collisions, more data. And with more data comes more dice rolls, offering the potential to see brand new particles and physical interactions.
Behold, the Xi-cc-plus.
Credit: CERN
Another big upgrade is more nuanced, in the form of a world-first, all-software trigger. Rather than use a hardware trigger to capture data, which requires preselecting the event, the LHCb can now sift through data entirely in software and decide what to keep in real time.
That makes a useful collection of data much easier, as it lets even unexpected events enter the record while also giving scientists easy instant access to data for physics analysis.
Finally, the new detector greatly increased the “vertex resolution” of the detector, allowing it to pick up smaller perturbations in the particles it studies. This means that more subtle interactions can be discerned, yielding all-new insights.
The Xi-cc-plus isn’t a particularly important particle to the natural physics of the universe, it’s believed. Still, it can have important physical properties that make it useful to physicists. In particular, its decay as a two-charm particle can produce clearer data on fundamental quantum processes.
The LHCb upgrade is just one of several ongoing projects at the particle collider. The High Luminosity LHC upgrade is even larger and aims to increase the luminosity of the main experiment by a factor of 10, thereby increasing the cadence of insights it can produce. That upgrade is predicted to be operational by mid-2030.
