Thursday, 16 February 2012

Chasing Ghosts - those elusive neutrinos

T2K (Tokai to Kamioka) Experiment, Japan. Image courtesy of

Particle Decelerator attended a fascinating talk on 15 February by Ben Still, a particle physicist working on the Tokai to Kamioka (T2K) neutrino experiment in Japan, alongside another 500 scientists and engineers.
Held in Lewes in Sussex, Still's talk, entitled "Chasing Ghosts and the Creation of the Universe" attempted to shine a light on the current state of play in neutrino research.

As the abstract noted:
Neutrinos are all around us in every nook and cranny. Trillions upon trillions inside and out of every planet, star, galaxy and the space in between. Billions pass through you every single second, night and day. But despite the phenomenal numbers it was not until 1953 that conclusive evidence of the existence of the neutrino, the most abundant thing in nature, was discovered. Since then scientists have devoted their lives to chasing these ghosts of nature. Despite its meagre size the tiny neutrino has had a profound effect upon our Universe and may hold the answer to one of the greatest questions of all time: the creation of the universe.

Still began by giving an introductory background to the history of this field of science, noting the key contributions by Wolfgang Pauli, Enrico Fermi, Clyde Cowan and Frederick Reines.He then analysed the famous faster-than-light neutrino results, which the OPERA experiment yielded in 2011. He concluded by providing insight into why this field of study is beginning to yield results that may help us answer fundamental questions such as where all the matter in the universe came from. Preliminary results from T2K in 2011 are discussed in further detail here.

"We are going to work as hard as we can to confirm or refute it"
Ben Still on T2K's commitment to cross-check OPERA's neutrino result.

During his talk, Still confirmed that checking the OPERA results is a key priority for both T2K in Japan, and their sister experiment MINOS in the States. T2K was taken offline due to the logistical impact of the earthquake in Japan in 2011, and the subsequent Fukushima disaster, and is only just now coming back online. Upgrades of both MIINOS and T2K are underway, and it is expected that MINOS will start yielding research that may refute or confirm the OPERA result within a year, with things taking a bit longer at T2K - perhaps up to 2 - 3 years.

In many ways, the Q&A was the most fascinating part of the evening, with Still clearly identifying himself as an experimentalist first. He spoke articulately and passionately about the importance of evidence based science, declaring,"we should be lead by experiment, not theory."

"Until theorists can come up with ways we can test their theories, they are just dealing with works of fiction."

Whilst clearly respectful of the elegance of mathematics and theory, Still advocated an experiment-lead approach to science, stating that experiments such as the LHC were correcting a "bias toward theory that has defined physics since the 1970s".

He quipped, "mathematicians and theorists are going to love super-luminal neutrinos, because they enable them write grant applications that will allow them to indulge in the realm of fiction".

Deliberately provocative stuff, and a fantastically stimulating insight into the current lay of the land in neutrino research.

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