JON CARTWRIGHT

Published in Physics World, 10 Feb 2009

Maximum-energy collisions will take place at the Large Hadron Collider (LHC) only after 2010.

Following the recommendations of LHC staff given at a workshop last week in Chamonix, France, CERN management has decided upon a restart schedule that will see the accelerator collide protons at record energies of 10 TeV towards the end of this year. However, collisions at the maximum collision energy of 14 TeV will have to wait until at least 2011.

CERN says that it has made the decision to ensure that there is enough data produced next year for theorists to search for new physics. […]

The rest of this article is available here.

Published in Physics World, 2 Feb 2009

Evidence for axions is once again mounting as researchers claim the hypothetical particles can explain how very high-energy photons travel unimpeded through the cosmos.

Such photons and other neutral cosmic rays (aside from neutrinos) should be unable to travel inter-galactic distances because they are absorbed by the universe’s opaque background of microwaves — yet they are still detected on Earth.

Now a group led by Malcolm Fairbairn of King’s College, London, has found a correlation between where detected cosmic rays originate and where photons and axions are more likely to “mix”. The result implies that cosmic-ray photons could reach Earth from distant galaxies by temporarily converting into axions, which can bypass the microwave background without absorption. […]

The rest of this article is available here.

Published in Physics World, 23 Jan 2009

Scientists interested in the upper atmosphere should turn their attention to measurements made deep underground — says an international team of physicists who have noticed that the number of cosmic-ray remnants hitting Earth is linked to freak warming events in the upper atmosphere. The link implies that measurements of cosmic rays — both future and past — could help scientists improve climate and weather forecast models.

Cosmic rays are mostly high-energy protons and are constantly bombarding atoms in Earth’s atmosphere to create pions. These pions either decay into lighter muons or continue to interact with nearby atoms and avoid decaying into muons. If the atmosphere is cool and thick then the chance of continued interactions is much higher, and the number of muons generated is therefore far fewer than when the atmosphere is warmer. […]

The rest of this article is available here.