Physicists excited by hints of Higgs boson existence

Against the regular backdrop of results from known processes, proton-proton collisions have produced considerable fluctuations that have intrigued scientists working at the ATLAS project in CERN. 

The discovery of the Higgs boson could fill in a vital missing link in the ‘standard model’ which is the accepted theory of particle physics - it will tell scientists why everything in the universe has mass.

As a result of smashing high energy protons together about 100 trillion times the physicists have now been able to rule out the Higgs boson particle over an extensive mass range, in particular at large masses, where no previous studies have been possible.  This has given them a better, more precise clue as to where this elusive particle might be found.

Professor Paul Newman, particle physicist from the University of Birmingham and member of the ATLAS collaboration said: ‘We have a very successful theory that describes all of the known elementary particles and the forces that act between them. However, it doesn’t give the particles any mass, so we need to add one more ingredient to this theory which is where the Higgs boson comes in. 

‘No one has seen it and no one knows how heavy it is, so that is why we have been searching in such a wide mass range for it.  The new results have narrowed down this mass range quite considerably.  However the biggest excitement is for masses around 130 - 150 gigaelectron volts (about 150 times heavier than a proton) where we are seeing more events than would be expected from background sources alone.  We need more data before we can say for sure that this is the Higgs boson rather than a fluke.  For now we can only say that if there is a Higgs boson at around this mass, it would give this sort of signal.’

Birmingham physicists are part of a 3000 strong team of scientists from all over the world who have been working on the ATLAS experiment at the Large Hadron Collider.  Birmingham has made a significant contribution to this project by designing and building some of the sophisticated trigger electronics that are selecting the important particle collisions in the detector.  The collisions that are chosen by these triggers help scientists to concentrate on the data most likely to yield new discoveries.

Another experiment at the LHC, the CMS detector, has also seen similar results, which corroborate the findings at ATLAS.  Professor Dave Charlton, Birmingham physicist and deputy spokesperson for the international ATLAS collaboration, said: ‘The fact that both experiments see similar results makes it even more intriguing. We have some way to go and a lot more data to collect before we can confidently say if we have found the Higgs – or if it doesn’t exist.  But by the end of 2012 we expect to have the answer.  In the meantime this is some of the most exciting news to come from the LHC experiments.’

Provided by University of Birmingham