I had that somewhat rare experience two days ago, getting the message from Physical Review Letters that our paper had finally been published online. In our field it can take quite a long time to get a paper all the way to publication; this one took longer than usual…

The paper describes the results of our search for Higgs bosons predicted in supersymmetric theories, in the CDF experiment at Fermilab. Alas, we didn’t see any evidence for Higgs boson production, despite earlier hints that something might lurk in our sample, and so we were able to rule out some regions of supersymmetric parameter space. We first obtained a preliminary result from this analysis in late 2007. A group of us from Rutgers University, University of Valencia, and UC Davis all worked directly on it, within our several-hundred-member collaboration, using Tevatron data recorded up through mid-2007. Since then we’ve more than tripled our data sample, but this result stuck with the data sample on which it was based and has finally reached publication.

The analysis was the topic of the Ph.D. thesis of my student Cris Cuenca, who was formally a student of my former postdoc Juan Valls at University of Valencia. Cris was a visitor in our group at UC Davis, and I was effectively his thesis advisor. After we got the preliminary results, Cris focused on writing his thesis, eventually defending it in Valencia in April 2008. One nice effect of that was that I got to visit Valencia for the first time: what a fantastic city!

Once the thesis was done, it was clear we needed to publish the result formally. In fact, we should have been already writing the paper but as usual it’s hard to find time to get started on writing projects. Here is a place we could have saved some time, though…

Anyway, I wrote a draft after the birth of our son Ian in June 2008, while helping with baby care at home. In our collaboration there is a very formal review process before submitting a paper for publication. The spokespeople of the collaboration “godparents” who perform a full internal review of the analysis and the draft of the paper. Without naming names, we got some very knowledgeable godparents who asked us hard questions. Some of these questions took weeks to answer, because more data analysis had to be performed. And some of them led to even more questions. This review process is a good thing — it ensures that the quality of the final paper is very high, and that the result is correct to the best of our ability. In fact, in the course of the review process we found that there was a minor software bug, and we repeated the full end stage of the analysis. As it turned out, the bug had very little effect on the final result but we needed to be sure. (At present there are only unknown bugs in the analysis software!)

Whenever there is a change to an analysis like this, it needs to be re-approved in our physics analysis group meetings, with two presentations: a “pre-blessing”, and then a “blessing” two weeks later. (Hey, I’m not responsible for the pseudo-religious jargon used in this process…) This eventually happened in March 2008.

With the result final and the godparents happy with the paper draft, it was time for the general collaboration review. The collaboration gets two weeks to comment on each draft. Then the authors go through comment by comment and reply to the commenters, modifying the draft as needed. The godparents reviewed our replies and then we arrive at the next draft. This part of the process can take many weeks depending on how much time the authors have two devote to the paper. Once the final draft stage is reached, a “paper reading” is scheduled at the weekly general collaboration meeting. Following the presentation of the result, the collaboration has 48 hours before the paper is submitted to the journal. For us this happened, finally, in June of this year.

We heard back from PRL in late July, with blind referee comments to address. There then ensued a back-and-forth between us and the referees, answering questions, making changes to our submission, and eventually reaching agreement that the paper would be published in PRL. This happened a few weeks ago, and our paper has now appeared in what I think is still considered to be the most prestigious journal in our field, though Nature possibly tops it. (That might inspire a comment flame war but I hope not…)

Maybe this is an extreme example, and I certainly will endeavor to bring results to publication much more quickly in the future. (I always say that.) Certain results, if they are “hot”, can be published on a fast track in CDF, within weeks, but that is quite rare.

Many will, no doubt, argue that print media of almost every form is on the way out. Will this happen to print science journals? I do think there is a strong need for blindly refereed publication of scientific results, even though many scientists have reviewed these papers by the time they are submitted.

And clearly once the LHC experiments have physics results to publish, we will need a very rapid means of getting them into print. For any striking new discovery we’ll want to have a paper submitted for publication when we announce the result…this is in contrast to the case of not-very-striking results, where we announce the results at conferences first and publish later. The reason is that the experiments will try to establish scientific priority by publishing striking results before the other one does, but I have to wonder, in the modern age of electronic media and collaborations with thousands of members, whether simply announcing or presenting the the result in public doesn’t accomplish that anyway. If ATLAS says they see a resonance in muon pairs at 1.5 TeV mass and so does CMS, the same week, will we really say “ATLAS found it first” or “ATLAS was the one to discover it and CDF confirmed it?” I hope the science mainstream media don’t present such a thing that way…but more than that I just hope this is a problem we will actually face!

I’ve been meaning to write about this for, well, some time: how do we visualize time? What is the mental picture we have in our heads of this basic dimension of our existence? This is bound to be one the the stranger posts of mine you’ve read, but, so be it.

Looking online I find basically no research or anything written on this subject, but I am quite certain that just about everyone has some picture of time in their heads. For me, it’s quite a visual one, and past events and for that matter future ones are all attached to my mental picture of the time continuum. My notion of all history, from my own to that of the universe is inextricably linked with my internal mental images of time.

The thing is, as I have reflected on how I actually internally visualize time, I have found it to be somewhat bizarre. Or maybe not – I don’t really know because I haven’t really explored this in one-on-one conversation with others and haven’t learned from anything written out there just how different my picture is from others’. So here goes…I hope those of you out there who are intrigued or inspired by this will share their own images.

The main thing is that my mental picture of time changes depending on the time scale involved, from a microsecond to a minute to an hour, day, week, month, year, or many years. Starting at the largest time scales, those of the cosmos, when I am looking back in time over billions of years I imagine the classical, boring sort of “time as a line” progressing from left to right, straight across my mental image. As we zoom in to more recent cosmological time, though, millions of years, the line becomes more of a curve, and curving toward me. But then, very oddly (and this pattern will repeat itself) when we get to the much more recent past, say the last few thousand years, the curve is revealed to be more of a strip of sorts and moving from down and to the right (that’s the best way I can express it) toward the upper left.

It’s really strange: if I think of a time, say, 20 000 years ago, in my mental field of view it’s definitely off to the right, and as I refer to more recent times, the ribbon is such that more recent times are to the left of earlier times.

But this is not absolute: as we get to the last 2000 or so years, the earlier part is sort of coming straight at me, eventually becoming (you got it) a ribbon coming from the lower left to the upper right again. If I am considering the period from the Renaissance to the present, for example, I see a more distant past as actually more distant, off to the left, coming closer in more recent times an moving left to right. The future, on this time scale, goes off to my right sort of behind me (where I can’t see – duh!)

Okay I have probably lost at least 2/3 of the people who started reading this. Huh? Either this is so alien to how they think of time they don’t really see what I am seeing, or don’t care, or think that this is so off that wall it’s not worth reading further.

So, for the rest of you, the next part is where it gets kind of interesting. My mental timeline/ribbon, which has been snaking from left to right and back across my mental field of view, does a few more twists. As I think of the time scale of my life which began in the early 1960′s (okay, 1959), those early 60′s years are sort of again coming straight at me, becoming a left-to-right ribbon in the 70′s and then definitely right-to-left by the mid 80′s. The years from then to now flow from far away and to the right to nearby toward the left. But they don’t cross the center of my mental picture – that’s the present.

If we zoom in further, say to the past several years, the ribbon is a string of months going back. As I view earlier and earlier months they recede, up and to the right, and merge with the ribbon of the decades. Events, major and minor, are recallable by zooming into my past picture of then-present time. They are all there (the ones I remember, anyway), and freakily often I can remember the exact dates and times they occurred.

Last week to a few months ago is definitely on that ribbon, stretching up and to the right as we go further into the past. But then we get to yesterday, today, and tomorrow. Here the ribbon, which is segmented by lines marking the days, does a weird thing. For a given day, the ribbon starts out straight in front of me, going up, as if I had to climb it, the hours marked off by lines. The ribbon climbs up, into the darkness, reaching a peak and then, after midnight, descending down into the next day, week, month, and year, away from me, off into the distance in the left part of my mental view of time.

The future, the near future anyway (years) is definitely to the left in my mind’s eye. (And no, this whole post is not some sort of allegory of my personal political evolution…) The long term future is unpopulated by memories or images of expectations or hopes, and snakes off to the right.

All this changes when we are talking about smaller time scales. As I zoom into the present hour, to finer and finer scales it becomes more and more a straight line extending from left to right. I can zoom in from here to any micro-time scale and it stays the same. Somehow the left-right snaking curve is attached to particular memories, including my memories of historical events about which I have learned. Micro-time is so non-specific that it doesn’t trigger the snaky ribbon time view.

Another oddity about me in particular is that I actually find it hard to use a standard calendar to keep track of appointments, important meetings etc. I don’t see time on that seven-day table! But with a few anchor dates in the future, gotten from standard calendars, I can quickly calculate intervening dates and their days of the week. If I know I have an appointment on December 4, and an exam to give on December 7, I can see in my head what days they are and I do rather well remembering them. But at this moment, for example, I cannot tell you what day of the week Christmas is (though I know next January 18 is a Monday…)

I know there will be plenty of eye-rolling at this possibly boring description of my mental view of time, but, as I say, I hope it will trigger lots of you out there to share your own. If you really think about it (and I bet you probably have not) you so have *some* sort of picture in your head. What is it?

Mischievous baguette-dropping birds be damned! The LHC had another milestone this weekend, as the CMS experiment detected “splash” events.

They’re not quite to the promised land yet (even remembering that the beam energies are a lot lower than we eventually want them to be). A little while ago we had beam traveling through the accelerator, which is obviously a big step. These splash events happen when the beam collides into something “upstream,” creating a splash of particles that are then detected by the experiment. The big step will be when beams moving in opposite directions actually collide with each other inside the detector. I predict you’ll hear soon when that happens.

You can follow CMS at its Facebook fan page. 528 fans, I’m sure we can boost that number.

I already have a bet with Brian Schmidt that we will fine at least 3-sigma evidence for the Higgs within five years (either at Fermilab or the LHC). Feeling pretty optimistic right now.

The Institute for Complex Adaptive Matter has released a new online museum, The Emergent Universe. This is, I think a truly novel approach to communicating the central ideas of the new field of emergent phenomena and complexity, combining the underlying physical basis of a wide array of examples with art and music. The site itself presents an animated, non-directed interface to branching sets of topics and what I guess one would call exhibits (since it’s a museum after all). A lot of these are quite fun, and instructive. A visitor is left with the feeling that there is lots more to explore. The interface itself, I have to say, is very cool and a glimpse of what is to come on the internet. Today’s text- and photo-heavy web pages are bound to give way to sleek sophisticated designs like this one…

Have fun!

What do you call snail locomotion?

(Walking is obviously not right. Slithering is closer. Sliming?)

I enjoy teaching.

But I really hate blackboards.

I’m not sure what the results of Chad’s latest poll will be, but I’m betting that I’m in the minority of scientists. The scientific community contains many former social outcasts who grew up flaunting the social rules, and yet have completely bought into the idea that using blackboards makes you look like a Real Scientist.

Well screw that. Students in the back can’t see what you write. You get dust all over your clothes. The chalk dries out your finger tips. The dust gets all over the floor, making a mess for your overburdened cleaning staff. For a community that prides itself on moving forward, why are we stuck with a 200+ year old technology that doesn’t work all that well?

Now, white boards have their problems too. They’re easier to see, but the markers are always dried out (and expensive to replace as well). They also are somewhat dusty (though not nearly as bad as chalk). Progress, but not perfect.

The solution, however, currently lies in your toddler’s grasp.

The Magna Doodle.

The Magna Doodle works by having small chambers filled with a thick liquid and magnetic filings. You drag a magnetic pen across the surface, and the metal filings jump to the surface, making the small chamber dark. To erase, you pull a lever that drags a magnet along the back surface, pulling the metal filings away from the front, making the chamber appear white again. No mess, no fuss, no need to replace any parts

It also is substantially easier to write on than the Etch-a-sketch. At least for most of us.

The Laffer Curve is a simple idea: a government can’t raise taxes forever and expect to increase revenue along the way. Eventually you’re taking so much in taxes that people don’t have any reason to earn income. The argument is simple (and correct): if you have zero tax rate you get zero tax revenue. If you raise taxes just a bit, nobody will be discouraged from working, and you will collect some amount of revenue; therefore, the curve of revenue versus tax rate starts at zero and initially rises. But if the tax rate is 100%, nobody has any reason to work, and your total revenues will be back at zero. By the wonders of math, there must therefore be a maximum of the curve somewhere in between 0% and 100% tax rate.

An important question is, where are we on the curve? The notion of the Laffer curve has been used to justify all sorts of tax cuts, under the assumption/claim that we are to the right of the maximum, so that cutting taxes will actually increase revenues. Serious economists generally don’t believe this holds true in the U.S. right now, but the lure of the idea is undeniable: lose weight by eating more ice cream!

Via Marginal Revolution, here’s a study by Mathias Trabandt and Harald Uhlig that tries to get it right. Obviously they have models that make various assumptions, and I have no idea how realistic those assumptions are. They study the U.S. and several European countries, and find that Denmark and Sweden are just a bit on the wrong side of the curve for the specific case of capital income taxation. For the most part, however, tax rates lie to the left of the maximum. In the U.S., especially, we are significantly on the left. Here is the graph for labor taxes:

The vertical line is our average tax rate; the curves represent different model assumptions. They estimate the U.S. could increase revenues by about 36% by raising taxes. That obviously doesn’t necessarily imply that we should — but we could.

Okay, it’s time to come clean – I am a ham. That is, I am an FCC-licensed amateur radio operator, call sign KI6GDQ. I got into it a few years ago because my wife’s parents and sister and brother in law are hams, and we all go camping in northern California every summer. Obviously a little hand held ham transceiver is not a bad way to communicate when there’s no cell phone coverage, though the range is limited to a few miles in the mountains up there.

And, living here in California, which a friend of mine notes is a beautiful land with a decidedly savage side, it’s not bad to have a means of communication that doesn’t depend on the grid, be it the electric grid or the Internet/phone grid. My in-laws live in Pacifica, south of San Francisco, which is hemmed in on all sides: the ocean to the west, mountains to the north and south, and the San Andreas fault to the east. A big earthquake could easily isolate them from the rest of the peninsula. So my father in law (N6FG) helps run a 2-meter repeater on a nearby mountaintop; he and and my mother-in-law (K6IIP) participate in local emergency response groups.

A friend of mine joked that amateur radio is the original social networking tool. (Well, unless you count the postal service.) Early in the last century, when radio was young, the advent of high-power vacuum tubes made it possible for amateurs to build transmitters that allowed them to talk to other hams all over the country, and around the world, ionospheric conditions permitting. At night, when the lower layers generated by solar radiation dissipate, a vast electromagnetic mirror called the F layer forms several hundred miles up. Signals from the surface can bounce off this mirror essentially all the way around the planet. Hard-core DXers still go to great lengths with antennas and legal-limit (1500 watt) transmitters to make contacts with Morse code. (And then there are the truly crazy ones who go on expeditions to remote islands off Antarctica solely for the purpose of making nearly 100,000 ham radio contacts all over the world.)

(more…)

Flip through a random magazine, and you are likely to be confronted by one of the great mysteries of modern times: an ad for a mechanical watch. For the past 30 years it has been possible to acquire a watch with a quartz movement for a minimal investment. These watches are small and light, and do an extraordinary job of keeping time (i.e, drifting by roughly one minute a year). Nonetheless, there is a flourishing market for watches with mechanical movements. These watches are generally large and heavy, are significantly more expensive, and most importantly, are far inferior as time pieces: easily a factor of ten worse than their quartz counterparts. How could there still exist a market for these obviously inferior watches? The answer lies somewhere in the unfathomable realm of fashion and marketing.

Last week’s New Yorker has an article [pay per view] by Patricia Marx about Baselworld 2009, the annual watch fair. Although I find the article annoyingly cutesy, it has some interesting tidbits. I guess there’s little reason to buy these watches besides the ineffable associations with the brand. So watchmakers go to extraordinary lengths to craft and define their brands:

Among the countless blowouts at Baselword, Breitling’s is considered to be the most lavish. A few years back, guests were taken in buses to a quarry that had been transformed into a mythical Persian landscape, appointed with sandpits and palm trees. Camels and white stallions roamed the premises, as did chickens. Guests were given flowing robes and head scarves to wear, and sat on cushions, where they were entertained by belly dancers while being served a Middle Eastern banquet and forbidden hooch. Hookahs were passed around. “Just when you thought it was over,” Roberta Naas, a watch-industry writer, told me, “one of the walls disappeared, revealing Siberian tigers and tiger tamers in cages.” After the animal act, the cages vanished in a puff of smoke, and, lo, another wall lifted and the pseudo oasis turned into a pseudo disco. Another year, at what the Breitling people call their “terrorist party,” the buses were pulled over at an abandoned warehouse by men in full military garb with machine guns, who subjected the passengers to interrogations. Afterward, there was dinner and dancing.

This was all in the middle of Switzerland. For a Swiss watch company. To what end exactly? You obviously can’t sell your watches on the basis of their time-keeping ability, so you craft a completely arbitrary image. And, amazingly, it actually works. Fortunes are being made selling bulky, antiquated, unreliable time pieces. The last paragraph of the article pays homage to the fact that time belongs to physicists:

It turns out that memories may be a thing of the future, if as some physicists believe, time runs backward (backward wristwatch, houseofrave.com, $28.95). More bad news: time may be running out of time. Other physicists speculate that our universe could mutate from space-time to just plain space. Time itself would cease to exist. Even your platinum Sotirio Bulgari with a perpetual calendar will be no good then ($212,000).

I have no idea what she’s talking about. Maybe our local expert on the arrow of time will chime in?

Modern humans have a fascination with time: how quickly it passes, what happened yesterday, what will happen tomorrow. I like to believe that physics has a role to play in this. On the one hand, Einstein was so kind as to show that time is a fairly complicated, observer-dependent quantity. And thus the only time that is really meaningful is, in some sense, the time we measure on our own watches. So we had better keep track! On the other hand, we have now firmly established that the Universe has not been around forever. It is only 14 billion years old. There is a huge psychological difference between living in an eternal Universe and one that has a finite history. It’s now incumbent upon us to keep track of the Universe’s age. Unfortunately, we’re still a little unclear as to the Universe’s life expectancy. Current indications are that the dark energy will continue to accelerate the Universe’s expansion, and therefore the Universe will last forever (instead of ending in a Big Crunch). However, given how little we understand about dark energy, this is at best an educated guess—nobody would be all that surprised if it turned out to be a much more complicated scenario. And so, in this framework of a Universe with a finite age, and an uncertain future, it makes sense to keep careful track of the passage of time. It is now 3:10:12 PM Mountain Standard Time on Friday, June 5. I need to get back to work.

Back in 1996, after the initially very mysterious explosion and crash of Flight 800 from JFK to Rome, there were numerous eyewitness accounts of a “streak in the sky” just before the crash. This led to the “missile theory” of the crash, which was eventually attributed to the explosion of the center fuel tank by the NTSB. But, also at the time, it was suggested that a meteor of sufficient size could have struck the plane, bringing it down.

Could a meteor have brought down Air France 447? Today we are starting to see reports that there actually may have been a meteor:

However, both pilots of an Air Comet flight from Lima to Lisbon sent a written report on the bright flash they said they saw to Air France, Airbus and the Spanish civil aviation authority, the airline told CNN.

“Suddenly, we saw in the distance a strong and intense flash of white light, which followed a descending and vertical trajectory and which broke up in six seconds,” the captain wrote.

Obviously for any given flight the chances are very, very small that a meteor will bring down an airliner, but as Hailey and Helfand pointed out in a letter to the NYT in 1996, the correct question to ask is this: “What is the probability that, for all flights in history, one or more could have been downed by a meteor?” They concluded that there was a 1-in-10 chance that this could happen…let’s use their logic, brought up to date somewhat, for 2009, for Flight 447.

Helfand, an astronomer, is presumably the one who estimated that “approximately 3,000 meteors a day with the requisite mass strike Earth”. This is a difficult number to get. How much mass? How fast does it need to be moving? But let’s assume that this number is correct; it translates to 125 meteors per hour.

Next we need to know the total number of flight hours at altitude for all commercial planes. In 2000 there were about 18 million flights per year. Clearly in the past 20 years (which we’ll take as our reference, since it spans 1989-2009, with both flights 800 and 447) it was not always so…but let’s take a guess that the 18 million figure is roughly correct for that 20 year period. That would yield 360 million commercial airline flights from 1989-2000. Hailey and Helfand assumed that each flight was two hours in duration. Again, a tough number to find on line, so we’ll take it at face value, giving us 720 million flight hours in our reference period.

They also claim that if there were 3500 planes in the air at any time, this would correspond to covering two-billionths of Earth’s surface. Now the earth’s surface area is 5×10¹⁴ m². Using my trusty HP-15c, I get that this would imply an average target area for a commercial airliner of 291 m², which is reasonable. Each plane, that is, covers 5.7×10^-13 of Earth’s surface. If a meteor hits the earth it has that probability of hitting a given plane on average.

So, in our reference 20-year period we have 720 million hours of flight time, times 125 meteors per hour, times 5.7×10^-13 = 0.051, which we can take as the average number of airliners struck by meteors in the period 1989-2009. That’s a one-in-twenty chance of some plane going down for this reason in that 20 year period. Extrapolating to all flights ever would require a better estimate of total flight hours, but it’s not twenty times the number in the past 20 years, for sure – that is, it’s not yet close to one.

Obviously there are a lot of uncertainties in this estimate; perhaps a factor of two from the number of meteors of sufficient mass per day, the average flight duration and number of flights?

Anyway the meteor idea is not crazy, though not likely. The weather seems more likely to be at the root of the tragedy…but we may never know. One thing, though, is clear: if we keep flying big planes at high altitude, eventually one will get hit by a meteor.