CERN De-Bugs Hadron Collider With Static Analysis


CERN has been rooting out defects in its Large Hadron Collider, as physicists discover faster-than-light particles

Particle physics lab CERN has announed it may have discovered faster-than-light neutrino particles today. The result could rewrite the laws of physics – but scientists must first work hard to eliminate all possible sources of error from the experiment.

While that effort goes on, CERN’s high-profile Large Hadron Collider (LHC) experiment continues, with the reassurance that 40,000 software errors have been eliminated from the source code of the software used to analyse its results.

CERN (European Organisation for Nuclear Research) is using static analysis software from testing company Coverity to eliminate software defects from ROOT – the C++ framework that is used to store, analyse and visualise data about the LHC.

Eliminating code defects

ROOT contains a core of 3.5 million lines of code, and CERN physicists have written a further 50 million lines in their search for a theoretical particle called Higgs boson, which could answer fundamental questions about how the universe works – even while the possible super-fast neutrinos raise new ones.

The experiments conducted using the LHC generate approximately 15 petabytes of data per year, equivalent to 15,000 standard disk drives.

“ROOT is used by all 10,000 physicists, so software integrity is a major issue,” said Axel Naumann, a member of CERN’s ROOT Development Team. “A bug in ROOT can have a significant negative impact on the results of the LHC experiments and physicists’ data analyses.”

Coverity’s static analysis solution checks the code for defects as it is being written, so they can be eliminated at an early stage, when they are the easiest and least expensive to find and fix.

Coverity’s software has also been used in the past to root out bugs in Google Android Froyo’s open source kernel.

Within the first week of testing ROOT, Static Analysis reportedly uncovered buffer overflows and memory leaks, with very few false positives. CERN’s ROOT Development team were able to resolve these issues in six weeks. The organisation continues to use the solution to prevent further software defects from occurring.

The news comes as CERN scientists working on the so-called Opera (Oscillation Project with Emulsion-tRacking Apparatus) experiment claim to have recorded neutrinos travelling faster than light, producing a finding that could overturn Einstein’s long-accepted special relativity theory, currently treated as  one of the fundamental laws of physics.

Scientists at CERN’s Gran Sasso facility in Italy said that a neutrino beam fired from a particle accelerator near Geneva to a lab 730km away travelled 60 nanoseconds faster than the speed of light. They calculated the margin of error at just ten nanoseconds, making the difference statistically significant.

‘We are buggered’

“This result comes as a complete surprise,” said Opera spokesperson Antonio Ereditato of the University of Bern. “After many months of studies and cross checks we have not found any instrumental effect that could explain the result of the measurement.”

The results will be discussed at a special seminar at CERN today, timed to coincide with the publication of a research paper describing the experiment. Researchers are inviting the scientific community to scrutinise the results and try to identify potential causes for the strange results.

“Cause cannot come after effect and that is absolutely fundamental to our construction of the physical universe,” Subir Sarkar, head of particle theory at Oxford University, told the Guardian. “If we do not have causality, we are buggered.”