Image of a display of events reconstructing the way we see the sigma-> P Mu Mu disintegration in the LHCB detector, zooming very close to the interaction of the particles. We see tracks manifest from the front, and they are folded by the LHCB magnet. Credits: LHCB collaboration.
The bars, the composite particles composed of three quarks linked together via the so-called strong force, constitute the most visible question and have therefore been at the center of numerous physics studies. The study of rare processes via the decomposition of unstable baritum in other particles could potentially contribute to the discovery of physical new ones which cannot be explained by the standard model of particle physics.
The LHCB experience is a large-scale research effort involving scientists working in universities around the world, aimed at studying particle physics containing so-called B quarks and looking for a new physics beyond the standard model, based on a large and specialized detector located in CERN. In an article recently published in Physical examination lettersThe LHCB collaboration has reported the observation of an ultra-rare process via which a type of baryon known as Sigma-Plus (σ⁺) is disintegrated in a proton and two muons with opposite loads.
“The motivation of our study came at the origin of the measurement of the Hypercp experience in Fermilab, who had evidence of this disintegration with 3 disintegrations seen in 2005,” professor at the University of Cagliari and member of the LHCB collaboration, at Phys.org, told Francesco Dettori.
“The interest in their measure is that, looking at the pair of Moon of the three candidates, he showed that they had the same combined mass, instead of a distribution as planned.
The results recently collected in Fermilab 20 years ago drew the attention of many particle physicists around the world+→ P𝜇+𝜇–), which are rooted in theories beyond the standard model. Other experiences focused on Dimuon pairs have not been able to observe this ultra-rare disintegration process, but due to its scope and scale, the LHCB experience had all the tools necessary to seek this ultra-rare disintegration.
“We analyzed the data collected in 2016-2018 in the Proton-Proton collisions to the great collision of Hadron,” said Gabriele Martelli, associate researcher with the INFN, Pérugie section. “The σ+ Baryon is just slightly heavier than the proton, therefore in these high energy collisions, almost all collisions also produce one of these particles. In particular, we estimated that 1014 (one hundred billions) σ baritists were produced in the experience during this period. “”
The very rare disintegration that the team sought has a distinctive signature which differs from other disintegrations, because the baron σ is relatively long. As part of their study, LHCB collaboration has sought the peak of disintegration up to tens of centimeters from the Proton-Protton interaction.
“At the same time, the two muons and the proton, loaded, are seen by our detectors and identified through different stages of particle identification,” said Martelli. “Although the signature is easy to rebuild, we must fight with a large quantity of random combinations that could imitate this disintegration, and we used automatic learning methods to reject them.”
In the end, the researchers were able to observe the σ+→ P𝜇+𝜇– Decay, which is the rarest of all the disintegrates bray studied to date. It is a remarkable scientific realization that highlights the sensitivity of the LHCB detector to CERN.
“Having observed hundreds of these disintegrations gave us the opportunity to precisely measure its probability and other properties, and compare them to the predictions of the standard model,” said Dettori. “Historically, the rare disintegrics were the place where the particles were discovered through their quantum effects, long before the accelerators have energy to produce them directly. The most notable case being the` `charm of charm ” discovered to explain a decadence which has been measured to be more rare than expected.”
The LHCB experience has already contributed to improving understanding of the various phenomena of particles explained by the standard model. However, the precision and sensitivity of the detector still improve, the researchers involved in experience could access disintegration processes which are increasingly rare, which could in turn lead to the observation of new particles and physical interactions.
“Using data collected from 2023, with the LHCB improved detector, we should be able to measure thousands of these disintegrations and not only probe their probability but also other characteristics,” added Martelli.
“The next property we want to study is the difference between matter and antimatter (known as the symmetry of charges of load) in this disintegration, by comparing disintegrations σ with the anti -σ. The measurement of this CP symmetry in many disintegrations is fundamental to finding indices on the desire for matter / antimatter of the universe.”
Written for you by our author Ingrid Fadelli, edited by Gaby Clark, and verified and examined by Robert Egan – This article is the result of meticulous human work. We are counting on readers like you to keep independent scientific journalism alive. If this report matters to you, please consider a donation (especially monthly). You will get a without advertising count as a thank you.
More information:
R. Aaij et al, observation of the very rare σ+→ Pμ+μ– Rot, Physical examination letters (2025). DOI: 10.1103 / R3V2-KMMP.
© 2025 Science X Network
Quote: LHCB collaboration observes the disintegration of ultra-rare baron (2025, August 19) recovered on August 20, 2025 from
This document is subject to copyright. In addition to any fair program for private or research purposes, no part can be reproduced without written authorization. The content is provided only for information purposes.
