Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Evidence found for the Higgs boson direct decay into fermions

23.06.2014

For the first time, researchers at CERN have found evidence for the direct decay of the Higgs boson into fermions – another strong indication that the particle discovered in 2012 behaves in the way the standard model of particle physics predicts. Researchers from the University of Zurich made a significant contribution to the study published in Nature Physics.

For the first time, scientists from the CMS experiment on the Large Hadron Collider (LHC) at CERN have succeeded in finding evidence for the direct decay of the Higgs boson into fermions. Previously, the Higgs particle could only be detected through its decay into bosons.

“This is a major step forwards,” explains Professor Vincenzo Chiochia from the University of Zurich’s Physics Institute, whose group was involved in analyzing the data. “We now know that the Higgs particle can decay into both bosons and fermions, which means we can exclude certain theories predicting that the Higgs particle does not couple to fermions.” As a group of elementary particles, fermions form the matter while bosons act as force carriers between fermions.

According to the standard model of particle physics, the interaction strength between the fermions and the Higgs field must be proportional to their mass. “This prediction was confirmed,” says Chiochia; “a strong indication that the particle discovered in 2012 actually behaves like the Higgs particle proposed in the theory.”

... more about:
»CERN »CMS »Collider »GeV »Hadron »Higgs »LHC »Vincenzo »detector »fermions »mass »physics

Combined data analysis
The researchers analyzed the data gathered at the LHC between 2011 and 2012, combining the Higgs decays into bottom quarks and tau leptons, both of which belong to the fermion particle group. The results reveal that an accumulation of these decays comes about at a Higgs particle mass near 125 gigaelectron volts (GeV) and with a significance of 3.8 sigma. This means that the probability of the background alone fluctuating up by this amount or more is about one in 14,000. In particle physics, a discovery is deemed confirmed from a significance of five sigma.

Measuring the Higgs decay modes
Three different processes were studied, whereby the UZH researchers analyzed the Higgs decay into taus. Because the Higgs particle is extremely short-lived, it cannot be detected directly, but rather only via its decay products. The bottom quarks and taus, however, have a long enough lifetime to be measured directly in the CMS experiment’s pixel detector.


The University of Zurich and the Large Hadron Collider
The University of Zurich is actively involved in the LHC at CERN with five experimental research groups: The groups headed by professors Florencia Canelli, Vincenzo Chiochia and Ben Kilminster conduct research with the CMS detector, Professors Ulrich Straumann’s and Nicola Serra’s groups with the LHCb detector. For the analysis and interpretation of the data, they are supported by the groups under professors Thomas Gehrmann, Stefano Pozzorini, Gino Isidori and PD Dr. Massimiliano Grazzini.

The CMS detector at CERN
The CMS detector measures the energy and impulse of photons, electrons, muons and other charged particles with high precision. Different measuring instruments are arranged in tiers inside the 12,500-ton detector. 179 institutions worldwide are involved in the construction and operation of the CMS detector. The Swiss institutions are the University of Zurich, ETH Zurich and the Paul Scherrer Institute, which jointly developed and constructed the CMS pixel detector. 


Literature:
The CMS Collaboration. «Evidence for the direct decay of the 125 GeV Higgs boson to fermions», Nature Physics Online. DOI: 10.1038/nphys3005

Contact:
Prof. Vincenzo Chiochia
Physics Institute of the University of Zurich
Tel. + 41 22 767 60 41
Mobile: +41 76 487 57 50
E-Mail: vincenzo.chiochia@cern.ch

Bettina Jakob
Media Relations
University of Zurich
Tel. +41 44 634 44 39
E-Mail: bettina.jakob@kommunikation.uzh.ch

Weitere Informationen:

http://www.mediadesk.uzh.ch

Bettina Jakob | Universität Zürich

Further reports about: CERN CMS Collider GeV Hadron Higgs LHC Vincenzo detector fermions mass physics

More articles from Physics and Astronomy:

nachricht Witnessing turbulent motion in the atmosphere of a distant star
23.08.2017 | Max-Planck-Institut für Radioastronomie

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Scientists discover species of dolphin that existed along South Carolina coast

24.08.2017 | Life Sciences

The science of fluoride flipping

24.08.2017 | Life Sciences

Optimizing therapy planning for cancers of the liver

24.08.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>