Category Astronomy/Space

Schematic of the measurement and the reservoir Penning traps. Credit http://dx.doi.org/10.1038/nature14861

In a stringent test of a fundamental property of the standard model of particle physics, known as CPT symmetry, researchers from the RIKEN-led BASE collaboration at CERN have made the most precise measurements so far of the charge-to-mass ratio of protons and their antimatter counterparts, antiprotons. The work was carried out using CERN’s Antiproton Decelerator, a device that provides low-energy antiprotons for antimatter studies.

All measured antiproton-to-H− cyclotron frequency ratios as a function of time Credit: http://dx.doi.org/10.1038/nature14861

CPT invariance – which the experiment was meant to test – means that a system remains unchanged if three fundamental properties a...

This image shows the first cosmic ray event recorded in the MicroBooNE TPC on Aug. 6. Credit: MicroBooNE

A school bus-sized detector packed with 170 tons of liquid argon has seen its first particle footprints. On Aug. 6, MicroBooNE, a liquid-argon time projection chamber recorded images of the tracks of cosmic muons, particles that shower down on Earth when cosmic rays collide with nuclei in our atmosphere.

“This is the first detector of this size and scale we’ve ever launched in the U.S. for use in a neutrino beam, so it’s a very important milestone for the future of neutrino physics,” said Sam Zeller, co-spokesperson for the MicroBooNE collaboration.

Picking up cosmic muons is just one brief stop during MicroBooNE’s expedition into particle physics...

Neutrinos are more abundant than any particle other than photons, yet they interact so weakly with other matter that every second, more than 100 billion stream — mainly unnoticed — through every square centimetre of Earth. Once thought to be massless, they in fact have a minuscule mass and can change type as they travel, a bizarre and entirely unexpected feature that physicists do not fully understand. Indeed, surprisingly little is known about the neutrino. “These are the most ubiquitous matter particles in the Universe that we know of, and probably the most mysterious,” says Nigel Lockyer, director of the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois.

4 unprecedented experiments look poised to change this...