A Quantum Diaries Survivor

I receive and gladly paste here, given the interest this topic has aroused (and as some sort of reward, given the fact that it is comment number 100 to the post where it appeared):

The New York Times
Saturday 29 March 2008

Asking a Judge to Save the World, and Maybe a Whole Lot More

by Dennis Overbye

More fighting in Iraq. Somalia in chaos. People in this country can’t afford their mortgages and in some places now they can’t even afford rice.

None of this nor the rest of the grimness on the front page today will matter a bit, though, if two men pursuing a lawsuit in federal court in Hawaii turn out to be right. They think a giant particle accelerator that will begin smashing protons together outside Geneva this summer might produce a black hole or something else that will spell the end of the Earth — and maybe the universe.

Scientists say that is very unlikely — though they have done some checking just to make sure.

The world’s physicists have spent 14 years and $8 billion building the Large Hadron Collider, in which the colliding protons will recreate energies and conditions last seen a trillionth of a second after the Big Bang. Researchers will sift the debris from these primordial recreations for clues to the nature of mass and new forces and symmetries of nature.

But Walter L. Wagner and Luis Sancho contend that scientists at the European Center for Nuclear Research, or CERN, have played down the chances that the collider could produce, among other horrors, a tiny black hole, which, they say, could eat the Earth. Or it could spit out something called a “strangelet” that would convert our planet to a shrunken dense dead lump of something called “strange matter.” Their suit also says CERN has failed to provide an environmental impact statement as required under the National Environmental Policy Act.

Although it sounds bizarre, the case touches on a serious issue that has bothered scholars and scientists in recent years — namely how to estimate the risk of new groundbreaking experiments and who gets to decide whether or not to go ahead.

The lawsuit, filed March 21 in Federal District Court, in Honolulu, seeks a temporary restraining order prohibiting CERN from proceeding with the accelerator until it has produced a safety report and an environmental assessment. It names the federal Department of Energy, the Fermi National Accelerator Laboratory, the National Science Foundation and CERN as defendants.

According to a spokesman for the Justice Department, which is representing the Department of Energy, a scheduling meeting has been set for June 16.

Why should CERN, an organization of European nations based in Switzerland, even show up in a Hawaiian courtroom?

In an interview, Mr. Wagner said, “I don’t know if they’re going to show up.” CERN would have to voluntarily submit to the court’s jurisdiction, he said, adding that he and Mr. Sancho could have sued in France or Switzerland, but to save expenses they had added CERN to the docket here. He claimed that a restraining order on Fermilab and the Energy Department, which helps to supply and maintain the accelerator’s massive superconducting magnets, would shut down the project anyway.

James Gillies, head of communications at CERN, said the laboratory as of yet had no comment on the suit. “It’s hard to see how a district court in Hawaii has jurisdiction over an intergovernmental organization in Europe,” Mr. Gillies said.

“There is nothing new to suggest that the L.H.C. is unsafe,” he said, adding that its safety had been confirmed by two reports, with a third on the way, and would be the subject of a discussion during an open house at the lab on April 6.

“Scientifically, we’re not hiding away,” he said.

But Mr. Wagner is not mollified. “They’ve got a lot of propaganda saying it’s safe,” he said in an interview, “but basically it’s propaganda.”

In an e-mail message, Mr. Wagner called the CERN safety review “fundamentally flawed” and said it had been initiated too late. The review process violates the European Commission’s standards for adhering to the “Precautionary Principle,” he wrote, “and has not been done by ‘arms length’ scientists.”

Physicists in and out of CERN say a variety of studies, including an official CERN report in 2003, have concluded there is no problem. But just to be sure, last year the anonymous Safety Assessment Group was set up to do the review again.

“The possibility that a black hole eats up the Earth is too serious a threat to leave it as a matter of argument among crackpots,” said Michelangelo Mangano, a CERN theorist who said he was part of the group. The others prefer to remain anonymous, Mr. Mangano said, for various reasons. Their report was due in January.

This is not the first time around for Mr. Wagner. He filed similar suits in 1999 and 2000 to prevent the Brookhaven National Laboratory from operating the Relativistic Heavy Ion Collider. That suit was dismissed in 2001. The collider, which smashes together gold ions in the hopes of creating what is called a “quark-gluon plasma,” has been operating without incident since 2000.

Mr. Wagner, who lives on the Big Island of Hawaii, studied physics and did cosmic ray research at the University of California, Berkeley, and received a doctorate in law from what is now known as the University of Northern California in Sacramento. He subsequently worked as a radiation safety officer for the Veterans Administration.

Mr. Sancho, who describes himself as an author and researcher on time theory, lives in Spain, probably in Barcelona, Mr. Wagner said.

Doomsday fears have a long, if not distinguished, pedigree in the history of physics. At Los Alamos before the first nuclear bomb was tested, Emil Konopinski was given the job of calculating whether or not the explosion would set the atmosphere on fire.

The Large Hadron Collider is designed to fire up protons to energies of seven trillion electron volts before banging them together. Nothing, indeed, will happen in the CERN collider that does not happen 100,000 times a day from cosmic rays in the atmosphere, said Nima Arkani-Hamed, a particle theorist at the Institute for Advanced Study in Princeton.

What is different, physicists admit, is that the fragments from cosmic rays will go shooting harmlessly through the Earth at nearly the speed of light, but anything created when the beams meet head-on in the collider will be born at rest relative to the laboratory and so will stick around and thus could create havoc.

The new worries are about black holes, which, according to some variants of string theory, could appear at the collider. That possibility, though a long shot, has been widely ballyhooed in many papers and popular articles in the last few years, but would they be dangerous?

According to a paper by the cosmologist Stephen Hawking in 1974, they would rapidly evaporate in a poof of radiation and elementary particles, and thus pose no threat. No one, though, has seen a black hole evaporate.

As a result, Mr. Wagner and Mr. Sancho contend in their complaint, black holes could really be stable, and a micro black hole created by the collider could grow, eventually swallowing the Earth.

But William Unruh, of the University of British Columbia, whose paper exploring the limits of Dr. Hawking’s radiation process was referenced on Mr. Wagner’s Web site, said they had missed his point. “Maybe physics really is so weird as to not have black holes evaporate,” he said. “But it would really, really have to be weird.”

Lisa Randall, a Harvard physicist whose work helped fuel the speculation about black holes at the collider, pointed out in a paper last year that black holes would probably not be produced at the collider after all, although other effects of so-called quantum gravity might appear.

As part of the safety assessment report, Dr. Mangano and Steve Giddings of the University of California, Santa Barbara, have been working intensely for the last few months on a paper exploring all the possibilities of these fearsome black holes. They think there are no problems but are reluctant to talk about their findings until they have been peer reviewed, Dr. Mangano said.

Dr. Arkani-Hamed said concerning worries about the death of the Earth or universe, “Neither has any merit.” He pointed out that because of the dice-throwing nature of quantum physics, there was some probability of almost anything happening. There is some minuscule probability, he said, “the Large Hadron Collider might make dragons that might eat us up.”

I met Mangano in Perugia at the end of January, and we indeed discussed the issue of black holes at the LHC in that occasion. I only remember Michelangelo mentioning that some evidence against the danger of LHC creating harmful effects came from the existence of neutron stars. I however respect his wish to wait for a review of his report…

Ever since the Tevatron Run II experiments have started to produce results of the search for a Standard Model Higgs boson, we have had a chance to compare observed and expected limits, and indulge in vacuous but entertaining speculations.

Now, however, the datasets amassed by CDF and D0 start to be large enough that a Higgs signal could -with a good dose of luck- start to cause observable effects. In other words, the game of limit-setting has been the default for seven years, but at some point one has to decide that rather than setting a limit one can start to quote a significance. When a significance is a number significantly smaller than two or three, the exercise is of dubious utility, but still, it gives some indication. If experiments are confident in their evaluation of systematic uncertainties, there really is nothing wrong in estimating the significance of a departure from background of the accumulated data in some Higgs-sensitive final state.

Of course, there is a boundary. Experimentalists in search for a new particle usually have to follow some kind of moral prescription. One usually starts trying to establish evidence for a particle, and if the data do not grant any, then one sets a limit. It is the case, for instance, of the search for a t’ quark which I described a few days ago.

In the case of Higgs searches, however, the fact that the expected signal is very, very small has changed that. Rather than first seeking evidence and then setting limits, experimentalists in CDF and D0 have so far relied on the expected reach -obtained through pseudo-experiments based on the analysis strategy and the dataset size- to decide what direction to take: determining a significance or quoting a limit. And the latter has always been the outcome.

As I mentioned above, despite the insufficient sensitivity, there is nothing wrong with estimating a significance. Even better than a significance, however, is a quantity cooked up by statisticians, which is the ratio between the likelihood that the data is signal+background-like and the likelihood that it is only background-like. Such a quantity has recently been computed by Wade Fisher - one of the experimentalists in D0 in charge of computing combined results of Higgs searches.

Below you can see what Fisher finds, in a very informative plot. The curves you should concentrate your attention on are the red and black hatched lines describing the relative likelihood of signal+background and background alone, plus the black line which represent the value assumed by the data, as a function of the Higgs mass (green and yellow areas represent the and range of variation of the background-alone hypothesis).

Three things to take home from this plot:

1. the signal+background and background alone curves already are quite separated at 160 GeV: a signal there would start to have an impact in CDF and D0 data - at about 1.5 standard deviations, as you can gather by observing that the red hatched line lies in the middle of the yellow band ( to ). That fact can be deduced also by the limit set by the Tevatron experiments at 95% CL limit on the 160 GeV Higgs cross section (<1.09 times the SM value): in practice, they have already “excluded” a 160 GeV Higgs at 85 to 90% CL (but these are my own guesstimates, so please do not trust them too much: they are not official). It was possible to reach the <1.09 point because of a negative fluctuation of backgrounds, as also shown by the full black line.
2. At lower masses, the two hatched curves are much closer together: there, the sensitivity is still wanting.
3. Between 115 and 130 GeV, however, the data is marginally more in line with the hypothesis that both signal and background are contributing. In other words, the 1.7-sigma significance obtained by LEP II experiments for a 115 GeV Higgs boson is starting to receive a small confirmation by the Tevatron data. Quite insufficient to get excited yet, but you know how these things work: discoveries may come in the matter of a night, or take months to consolidate.

It remains to say that despite having half a foot in CDF and a foot and a half in CMS, I am still rooting for CDF to discover the Higgs! As I mentioned in an interview three years ago (see video here), it would be fantastic if we found the Higgs in CDF. Go Tevatron!

The italian alpine club CAI has just released the results of a re-analysis of the history of the italian ascent to Mount Godwin-Austen, the 8611-meter peak in Karakorum called K-2, the second-highest peak in the world. And it is a wholesome rehabilitation of the role and testimony of Walter Bonatti (right), a member of the expedition and arguably the strongest climber of the time.

In the vigil of the final push to the summit of K2, at camp 8 on July 29th, 1954 Lacedelli and Compagnoni, together with Bonatti, had discussed the plan of assault and had decided where to place the tents of the ninth camp: just above 8000 meters. Despite his excellent physical form Bonatti had been given orders from base camp by Ardito Desio, the chief of the expedition, to leave the glory of the final ascent to his two colleagues, and he had accepted the agenda. Together with a sherpa he was to bring two air cylinders (19 kg each) to camp 9 for Lacedelli and Compagnoni, who would be waiting for them.

As he arrived to the agreed point on the evening of July 30th, Bonatti however found no camp, since Compagnoni had insisted with Lacedelli to place it higher - arguably because he feared Bonatti would join them in the ascent if given a chance. Bonatti and the sherpa Mahdi were thus prevented to reach camp 9 and they had to bivouac with no shelter at an altitude of over 8000 meters, risking their life (and Mahdi losing all the toes of his feet). They were the first men to ever survive such an ordeal.

On July 31st Compagnoni and Lacedelli retrieved the cylinders where Bonatti had left them, and ascended to the summit, conquering K2 for the first time. They later claimed they had found the air cylinders almost empty, and blamed Bonatti for using the air to survive during that night. This, along with other allegations moved to the unguilty Bonatti,  caused a huge controversy that lasted for decades. The official version for a long time favored the reconstruction of the events given by Compagnoni and Lacedelli. 

The committee appointed by CAI has re-examined the whole story and has concluded that Bonatti had not lied: he did not use the oxygen which Lacedelli and Compagnoni later breathed in their final, 12-hour climb: this is probably the last word in the long-standing issue. A picture taken at the summit, showing the two climbers still with their masks on, is probably the clearest evidence.