杏吧原创

FOR years, particle physicists at the powerful colliders of CERN and Fermilab have been searching for an unimaginably small and fleeting speck of matter called the Higgs boson 鈥� and failing to find it even though their calculations said they should. Should we care? Absolutely. The Higgs is predicted to give other particles their mass, and is therefore the keystone of particle physics 鈥� the so-called 鈥淕od particle鈥�. What is more, large sums of public money have been sunk into the hunt.

So why is it proving so elusive? It now seems that the calculations of where in the spectrum of mass the Higgs is likely to be found were off-beam, and that the particle is too heavy to be bagged by existing machines (see 鈥淗iggs hunt gets heavy鈥�). So, a sigh of relief. The experimenters can feel better about having missed the Higgs so far.

But also a small frown of unease. The mass estimate relies on other particle physics experiments, notably the measured mass of the top quark. What has changed now is the way those measurements are combined: instead of taking a simple average of the different top-quark masses, a group at Fermilab has decided to use a weighted average, giving more weight to results with smaller uncertainties. It鈥檚 a sensible idea 鈥� and with hindsight a rather obvious one. And yet the Fermilab group met resistance to its method. It took two-and-a-half years to be accepted.

Cynics may view that reluctance as suspiciously convenient. The Tevatron collider at Fermilab was recently upgraded at a cost of several million dollars. Much of the justification for this project was that it might detect the Higgs, but if the new mass estimate is correct it won鈥檛 stand a chance.

Does it matter? While it was sold to politicians and the public as a tool for finding the Higgs, the upgraded Tevatron will do a lot of other good physics as well. And sometime this decade, the Higgs 鈥� if it does exist 鈥� will probably be found in Europe by the much more powerful Large Hadron Collider at CERN.

Particle physicists consume huge quantities of public money. They should bend over backwards to be candid about their research and its prospects for success. If some simple statistics could have clarified the case for funding, it should have been done earlier 鈥� even if that might have raised politically awkward questions about the purpose of the Tevatron upgrade.