Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers from the University of Zurich discover new particle at CERN

27.04.2012
Physicists from the University of Zurich have discovered a previously unknown particle composed of three quarks in the Large Hadron Collider (LHC) particle accelerator. A new baryon could thus be detected for the first time at the LHC. The baryon known as Xi_b^* confirms fundamental assumptions of physics regarding the binding of quarks.

In particle physics, the baryon family refers to particles that are made up of three quarks. Quarks form a group of six particles that differ in their masses and charges. The two lightest quarks, the so-called “up” and “down” quarks, form the two atomic components, protons and neutrons.

All baryons that are composed of the three lightest quarks (“up”, “down” and “strange” quarks) are known. Only very few baryons with heavy quarks have been observed to date. They can only be generated artificially in particle accelerators as they are heavy and very unstable.

In the course of proton collisions in the LHC at CERN, physicists Claude Amsler, Vincenzo Chiochia and Ernest Aguiló from the University of Zurich’s Physics Institute managed to detect a baryon with one light and two heavy quarks. The particle Xi_b^* comprises one “up”, one “strange” and one “bottom” quark (usb), is electrically neutral and has a spin of 3/2 (1.5). Its mass is comparable to that of a lithium atom. The new discovery means that two of the three baryons predicted in the usb composition by theory have now been observed.

The discovery was based on data gathered in the CMS detector, which the University of Zurich was involved in developing. The new particle cannot be detected directly as it is too unstable to be registered by the detector. However, Xi_b^* breaks up in a known cascade of decay products. Ernest Aguiló, a postdoctoral student from Professor Amsler’s group, identified traces of the respective decay products in the measurement data and was able to reconstruct the decay cascades starting from Xi_b^* decays.

The calculations are based on data from proton-proton collisions at an energy of seven Tera electron volts (TeV) collected by the CMS detector between April and November 2011. A total of 21 Xi_b^* baryon decays were discovered – statistically sufficient to rule out a statistical fluctuation.

The discovery of the new particle confirms the theory of how quarks bind and therefore helps to understand the strong interaction, one of the four basic forces of physics which determines the structure of matter.

UZH and the LHC

The University of Zurich is involved in the LHC at CERN with three research groups. Professor Amsler’s and Professor Chiochia’s groups are working on the CMS experiment; Professor Straumann’s group is involved in the LHCb experiment.

CMS detector

The CMS detector is designed to measure the energy and momentum of photons, electrons, muons and other charged particles with a high degree of accuracy. Various measuring instruments are arranged in layers in the 12,500-ton detector, with which traces of the particles resulting from the collisions can be recorded. 179 institutions worldwide were involved in developing CMS. In Switzerland, these are the University of Zurich, ETH Zurich and the Paul Scherrer Institute.

Contacts

Prof. Claude Amsler
Physik-Institut
University of Zurich
Tel.: +41 22 767 29 14
E-Mail: claude.amsler@cern.ch
Website: http://www.mnf.uzh.ch/index.php?id=500

Prof. Vincenzo Chiochia
Physik-Institut
University of Zurich
Tel.: +41 22 767 60 41
E-Mail: vincenzo.chiochia@cern.ch
Website: http://unizh.web.cern.ch/unizh/People/Vincenzo_Chiochia.htm

Beat Müller | Universität Zürich
Further information:
http://www.mnf.uzh.ch/index.php?id=500
http://unizh.web.cern.ch/unizh/People/Vincenzo_Chiochia.htm

Further reports about: CERN CMS LHC Xi_b^* atomic components lightest quarks neutrons proton collisions protons

More articles from Physics and Astronomy:

nachricht Writing and deleting magnets with lasers
19.04.2018 | Helmholtz-Zentrum Dresden-Rossendorf

nachricht Ultrafast electron oscillation and dephasing monitored by attosecond light source
19.04.2018 | Yokohama National University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Diamond-like carbon is formed differently to what was believed -- machine learning enables development of new model

19.04.2018 | Materials Sciences

Electromagnetic wizardry: Wireless power transfer enhanced by backward signal

19.04.2018 | Physics and Astronomy

Ultrafast electron oscillation and dephasing monitored by attosecond light source

19.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>