CERN experiments observe particle consistent with long-sought Higgs boson

Geneva, 4 July 2012: At a seminar held at CERN1 today as a curtain raiser to the year’s major particle physics conference, ICHEP2012 in Melbourne, the ATLAS and CMS experiments presented their latest preliminary results in the search for the long sought Higgs particle. Both experiments observe a new particle in the mass region around 125-126 GeV.

“We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV. The outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage,” said ATLAS experiment spokesperson Fabiola Gianotti, “but a little more time is needed to prepare these results for publication.”

“The results are preliminary but the 5 sigma signal (a statistical near-certainty) at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks.”

“It’s hard not to get excited by these results,” said CERN Research Director Sergio Bertolucci. “ We stated last year that in 2012 we would either find a new Higgs-like particle or exclude the existence of the Standard Model Higgs. With all the necessary caution, it looks to me that we are at a branching point: the observation of this new particle indicates the path for the future towards a more detailed understanding of what we’re seeing in the data.”

The results presented today are labelled preliminary. They are based on data collected in 2011 and 2012, with the 2012 data still under analysis. Publication of the analyses shown today is expected around the end of July. A more complete picture of today’s observations will emerge later this year after the LHC provides the experiments with more data.

The next step will be to determine the precise nature of the particle and its significance for our understanding of the universe. Are its properties as expected for the long-sought Higgs boson, the final missing ingredient in the Standard Model of particle physics? Or is it something more exotic? The Standard Model describes the fundamental particles from which we, and every visible thing in the universe, are made, and the forces acting between them. All the matter that we can see, however, appears to be no more than about 4% of the total. A more exotic version of the Higgs particle could be a bridge to understanding the 96% of the universe that remains obscure.

“We have reached a milestone in our understanding of nature,” said CERN Director General Rolf Heuer. “The discovery of a particle consistent with the Higgs boson opens the way to more detailed studies, requiring larger statistics, which will pin down the new particle’s properties, and is likely to shed light on other mysteries of our universe.”

Positive identification of the new particle’s characteristics will take considerable time and data. But whatever form the Higgs particle takes, our knowledge of the fundamental structure of matter is about to take a major step forward.

Source: CERN press release


Star clears away birth clouds

Photo: Hubble Space Telescope image of star-forming region Sh 2-106, or S106 for short.
Image credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)

The Hubble Space Telescope’s Wide Field Camera-3 has captured this image of a giant cloud of hydrogen gas illuminated by a bright young star. The image shows how violent the end stages of the star-formation process can be, with the young object shaking up its stellar nursery. Click here for a much larger image!

Despite the celestial colors of this picture, there is nothing peaceful about star forming region Sh 2-106, or S106 for short. A devilish young star, named S106 IR, lies in it and ejects material at high speed, which disrupts the gas and dust around it. The star has a mass about 15 times that of the Sun and is in the final stages of its formation. It will soon quieten down by entering the main sequence, the adult stage of stellar life.

For now, S106 IR remains embedded in its parent cloud, but it is rebelling against it. The material spewing off the star not only gives the cloud its hourglass shape but also makes the hydrogen gas in it very hot and turbulent. The resulting intricate patterns are clearly visible in this Hubble image.

The young star also heats up the surrounding gas, making it reach temperatures of 10 000 degrees Celsius. The star’s radiation ionizes the hydrogen lobes, making them glow. The light from this glowing gas is colored blue in this image.

Separating these regions of glowing gas is a cooler, thick lane of dust, appearing red in the image. This dark material almost completely hides the ionizing star from view, but the young object can still be seen peeking through the widest part of the dust lane.

S106 was the 106th object to be cataloged by the astronomer Stewart Sharpless in the 1950s. It is a few thousand light-years distant in the direction of Cygnus (The Swan). The cloud itself is relatively small by the standards of star-forming regions, around 2 light-years along its longest axis. This is about half the distance between the Sun and Proxima Centauri, our nearest stellar neighbor.

This composite picture was obtained with the Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope. It results from the combination of two images taken in infrared light and one which is tuned to a specific wavelength of visible light emitted by excited hydrogen gas, known as H-alpha. This choice of wavelengths is ideal for targeting star-forming regions. The H-alpha filter isolates the light emitted from hydrogen in gas clouds while the infrared light can shine through the dust that often obscures these regions.