Tuesday, October 4, 2011

More faster-than-light neutrino speculation

Continuing perusal of the arxiv.org papers,

In http://arxiv.org/pdf/1109.5917v1, say that tachyonic neutrinos are positively ruled out because it would also require a violation of the conservation of energy, "a tachyonic interpretation is not only hardly reconciled with OPERA data on energy dependence, but that it clashes with neutrino production from pion and with neutrino oscillations."  They further explore some papers from the 90s by Coleman and Glashow that suggest test for the Lorentz equations in cosmic rays and accelerators.  Their basic suggestion is that neutrinos have their own limiting velocity that is different from (and possibly greater than) the speed of light.  This hypothesis is contradicted by neutrino oscillation experiments.  Oh well.

In http://arxiv.org/PS_cache/arxiv/pdf/1109/1109.6641v1.pdf, the authors work very hard to reconcile the SN1987a neutrino results with the OPERA results.  To review, the supernova neutrinos arrived 4 hours earlier than the light from the supernova (over 160,000 years--2 parts in a billion deviation).  Of course, the OPERA neutrinos are faster than light by 50 parts in a million.  Their main assertion is, obviously, neutrinos travel faster in Earth than in inter-galactic space.  OK.  Right.

In http://arxiv.org/PS_cache/arxiv/pdf/1109/1109.6282v1.pdf, the authors suggest, "the existence of light sterile neutrinos which can propagate in a higher dimensional bulk and achieve apparent superluminal velocities when measured by an observer confined to the 4D brane of the standard model."  That is, they find a shortcut in the extra dimensions (needed by many versions of String Theory) of space.  But only "sterile" neutrinos can do this, as "fertile" ("dirty"?) neutrinos are confined to be in our regular old four-dimensional space.  But OPERA measures muon neutrinos--they aren't sterile.

In "Superluminal Neutrinos without Revolution" by Susan Gardner of the University of Kentucky, she speculates that neutrinos are unique in that they do not interact with the "dark universe" like the rest of the particles.  Regular particles are slowed down by this interaction.

None of these are at all satisfying.

What are people speculating is the reason for the Faster-than-light neutrinos?

I have done a simple survey of papers from arxiv.org that match the search criteria "neutrino" and "opera".  At this moment, there are over 100 such papers.  Here is a summary.

In "New Constraints on Neutrino Velocities" by Andrew G. Cohen and Sheldon L. Glashow of Boston University (http://arxiv.org/pdf/1109.6562), they claim "that such superluminal neutrinos would lose energy rapidly via the bremsstrahlung of electron-positron pairs" and thus refute this discovery.

Walter Winter of Institut fur Theoretische Physik und Astrophysik, Universitat Wurzburg, suggests that maybe not all of the neutrinos are faster than light.  But he says that this does not particularly lead to any "reasonable" explanation.

Markus G. Kuhn of the Computer Laboratory at the University of Cambridge calculates that the Coriolis Effect of the south-eastward travelling neutrinos would only account for 2.2 nsec.  Oh well.

Shi-Yuan Li, School of Physics, Shandong University, Jinan, PRC says that all OPERA has done is "measured the phase speed of the neutrino wave function."  How boring.  He says, "velocity is too complex and case-dependent, generally can not be taken as basic observable related to some kind of space-time symmetry, but as a quantity defined by others, depending on the concrete cases."  Tell that to the police officer the next time you are pulled over for speeding.

E. Canessa, Science & Technology Collaborium, Italy, says "We pinpoint how a subatomic particle with non-zero mass may attain, in principle, velocities faster-than-light by travelling in helical motion in the limit of very large momentum."  He does a lot of hand-waving (and shows very little of his work) to conclude that the apparent velocity of a helically-moving neutrino is equal to the opening angle (in radians) of the helix, which can be greater than one.

Rafael S. Torrealba, Departamento de F´ısica.Universidad Centro Occidental ”Lisandro Alvarado”, suggest that "These puzzling result could be explained by stimulated emission of neutrinos in the decay tunnel, in close analogy with the amplification of a LASER pulse."  I don't get it.  I don't even know where this guy is (this seems to be Spanish, but maybe it is Italian).

G. Henri, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG), Grenoble, France says, "it is enough that the beam composition varies during the leading and the trailing edges to explain an apparent time shift in the detected neutrinos."  I think the OPERA folks addressed this particular problem quite well.

Jerrold Franklin of the Department of Physics at Temple (Philadelphia, PA), says "The superluminal propagation of neutrinos observed by the OPERA collaboration is shown to be due to an imaginary ‘optical’ potential for the attenuation of the neutrino beam in passage through the Earth."  The heart of this one is the assumption that the mass of the neutrino has an imaginary component related to its attenuation.  He goes on to say that this accounts for the fact that the neutrinos in the SN1987a arrived in coincidence with the light from that event--there is no attenuation in space.  I don't buy it.

Thursday, September 29, 2011

How can OPERA's faster-than-light neutrino results make sense?

In my opinion, they can't make sense--I strongly favor the outcome that they made a mistake somewhere.  But for the sake of arguments, what *could* this result be saying?  There are a lot of loonies out there who are starting to stand up to say, "See, I told you so!  I've been saying Einstein was wrong for decades."  How long before we hear someone say, "This proves that you have to shut down the LHC!"  but I digress.

1. Neutrinos really do travel faster than light
Well, that would be something!  The Lorentz Transformations were derived towards the end of the 19th century in order to make sense of the Maxwell Equations of electricity and magnetism.  Our whole technological world is built on these equations, so anything that would allow the neutrino to go faster than light would have to be a small (very, very, very small) correction on these robust equations.  We would have seen this somewhere else by now, I think.

One way to keep everything in tact is to say that the neutrino has an imaginary mass.  (What is an imaginary mass?  How much would imaginary mass weigh in a gravity field?  Negative weight?  I have no idea.)  Then according to Lorentz, the faster the neutrino goes (beyond the speed of light), the lower its energy gets.  So infinitely fast neutrinos would have no energy.  But they would have infinite imaginary mass.  Is this dark energy?

2. Neutrinos fake going faster than light
This is the non-mistake outcome that I favor. Let's say that the momentum of the neutrino is very well known.  Then the Heisenberg Uncertainty Principle says that the position of the neutrino is uncertain.  What if there was some effect that enhanced the neutrino's position uncertainty in its direction of motion?  Then it would arrive slightly before it got there all along its direction of motion.  Maybe it has to do with the neutrinos' interesting spin signature.  We know that there is only one spin-type for the neutrino: left-handed spins for neutrinos and right-handed spin for antineutrinos.  Maybe the left-handed spin pushes the uncertainty forward a little bit, and the right-handed spin pushes it back.  This is easy (enough) to test at OPERA or here at MINOS.

This is, sort of, a combination of the Star Trek warp drive and the Hitchhiker's Guide infinite improbability drive.  I like it.

Friday, September 23, 2011

Neutrinos are weird, and wonderful

Actually, this astounding result is very good news for Fermilab! We have committed to studying neutrinos for the next 10-20 years. So when somebody asks, "Why should we care about neutrinos," the answer is easy!

If neutrinos can travel faster than light, this contradicts one of the very foundations of physics as we know it. Therefore, we need to understand how:
  • neutrinos can have this ability when no other matter in the universe does.
  • the equations of electricity and magnetism can include this result.
  • our understanding of Einstein's Relativity Theories ("Special" and "General") is affected, and neutrinos seem to be our way to do this.
And lastly, how come the Swiss are are so damn good at telling time? :-)

Observations of OPERA presentation

They have been sitting on this hyper-luminal neutrino for six months.

They initially did the analysis with intentionally inaccurate assumptions, while the various groups in OPERA made improvements on these aspects. For example, the biggest factors are
  • The distance between CERN and the experiment ("geodesy")
  • The measurement of the time the protons hit the target at CERN
  • The synchronization of the clocks between CERN and the experiment.
  • eight or ten other smaller effects
The thorough analysis with bad assumption led to neutrinos that were 1048 nanoseconds too fast. Then they "opened the box" on the more accurate systematic measurements. The corrections to the accurate results were 988 nanoseconds, leading to the 60 nanosecond too-fast result.

They "opened the box" six months ago, and they were clearly stunned. This collaboration of hundreds of scientists have considered possible mistakes in the analysis for this time.

An aside on the distance between the source and the experiment: They show a huge step function at the time of the Italian earthquake in 2009. This huge change in the distance was 7 centimeters!

This is an uncomfortably reasonable result--very precisely determined.

Neutrinos faster than light???

I've thought a lot about the CERN result that the neutrinos in the OPERA experiment travel slightly faster than the speed of light. This result is truly earth-shattering. A result is a result--first we have to see if there are any holes in it. The press reports say it is sound.

Here is what I know.

They see that the distance between CERN and the experiment in Italy is about 60 feet shorter, out of about 2.4 million feet (730 km) (or one part in 40,000), for neutrinos than what they measure it to be. (The result is that the neutrinos get there 60 nanoseconds early--I translated this into something more understandable). Their error-bars are 10 nanoseconds, which makes this a 6-sigma effect--quite believable.

The speed of light "speed limit" is not something to giggle at. A huge percentage of the understanding we have in the physical world would be toppled if this result is real.

Einstein came up with the "speed limit" after examining Lorentz's observation of the symmetries of the equations of electromagnetism (Maxwell's equations). Lorentz's work was in the 19th century. The constancy of the speed of light, and the inability of an object with mass to obtain the speed of light, is a consequence of the validity of the theories of electricity and magnetism. The fact that we are communicating by electronic computer is a pretty good testament to the validity of our understanding of E&M. Making Lortentz's equations invalid would mean that our understanding of E&M is wrong.

We measure the "speed limit" at Fermilab (and at CERN) every day. I could go on and on about this.

The normalized speed of a particle, beta, is equal to the square-root of (one minus the (the mass-squared over the energy-squared)). For beta to be greater than one would require an "imaginary" energy or mass (but not both). This is the definition of the hypothetical "tachion". An imaginary mass for the neutrino would be very interesting!

So, there are a few possible explanations for this results that I can think of, in order of plausibility (IMHO):
  1. The result is wrong, and there are several ways to satisfy this explanation.
  2. A neutrino has imaginary mass.
  3. There is some time/space/dimensional anomaly between CERN and the experiment, making the distance slightly shorter than it should be.
  4. Our understanding of physics is wrong
(Imaginary energy is what is required to create a stable wormhole, by the way.)

How could the result be wrong? We'll see what they have accounted for in their measurement.
  • Measuring the precise distance is very tricky. They are shooting the neutrinos through the earth, so this requires very precise knowledge of the shape of the Earth and the location of the source and the experiment.
  • Measuring the precise time is also very tricky. This, in particular, is what interests me. How do two places that are 730 km apart synchronize their clocks to this level of precision? Can GPS do that? (Of course, GPS technology RELIES on our understanding of E&M and the constancy of the speed of light. Ironic, eh?)
  • Exactly when and where are the neutrinos created? We think we understand the particle beam and its properties, but if this result is correct, then clearly we don't. (Another irony.)
In my lifetime, there have been two other times when there was a result of earth-shattering proportions:
I believe it is accurate to say that both of these were considered to be good experiments, but no one else has been able to verify the results. Thus, the community has considered these results to be flukes.

Friday, June 17, 2011

It is too hot to run!


I tried to run around the Fermilab Main Ring Road (3.7 miles). My goal was to run very slowly for 60 minutes--this should have been about 4.3 miles at a little over 13:00/mile--quite slow. (The Ring Road is split into 6 equal sectors, so that would be one full circuit, plus one extra sector.)

It was very sunny. The starting temperature was 78F--warm, but (I thought) not hot. The temperature at the end was about 83F.

Boy, was I wrong, and did I overestimate what I could do!

I got about half way around the ring (about 1.8 miles), running at the desired 13:00/mile pace, and I was exhausted! I then walked for exactly 3 minutes, thinking I could possible make it the rest of the way (or at least to the 5K/3.11 mile mark), but I could only muster a 3 minute jog at that slow pace. I finished the 5K in just over 40 minutes--I'd say I walked for 10 minutes. I pushed it a bit to end the 5K, and that was too much. I walked the rest of the way: total time--55 minutes.

My medium-green nylon shirt was too dark, as were my black shorts. The sun was unbearable. I wore a white, nylon baseball cap--I think that was OK, but it could have been better. I was very hungry by the end--a half-cup of Gatorade at the mid-way point would have been nice!

Overall, I did a workout, but not quite the one I planned. I was moving for 60 minutes, so I sort of met one of my goals. I did not over do it, which is a fundamental goal for a man my age, I think.

I sure hope that the 5K next Saturday (at 4PM) has cool and cloudy weather! I think I'll go buy a white nylon running shirt.

Addendum, Saturday June 18.

Based on suggestions from my coach/son (Marty), I adjusted my technique for the Heat-Of-The-Day run today.
  1. Arranged for lower temperatures (78F instead of 83F)--that was the hardest part.
  2. Drank a 20 oz Gatorade T-minus-100 minutes from the start of the workout
  3. Bought a white nylon shirt ($12 at MC Sports)
  4. Had my associate (that is, my wife Joanne) wait at the 2-mile mark with 2 liters of water--one to dump on my head and one to drink (I only had 4 sips).
It was MUCH better: Ran 3.25 miles and only walked for 3 minutes while taking the water from my associate. Then, when I arrived home, my associate was watering her garden, and she watered my head and neck some more. That felt goooooooooood!

Thursday, June 16, 2011

Quickly, is IS used too much?

A couple of pet peeves about the way people speak.

Is is

"What I want to say is, is that OK?"

In spoken English these days, running together two "is"'s happens all the time and it bugs me. You'd never write it that way. Everybody does it--I've even heard President Obama do it.


"Let's get a quick check of traffic."

I hear this on the radio and on TV all the time. Is it really any quicker than if you left out the word "quick?" I think it is just a signal that the speaker is making to himself (herself) that s/he is under time pressure.

I'm glad I don't have to speak publicly for a living--I'd make these mistakes, and a LOT more!

Thursday, May 19, 2011

Girls in Science?

I was walking down the Linac Gallery hallway, as I do many times every day, and there was a tour group of high school kids blocking the way. This also happens a lot. As I approached the group, I slowed down and said, with great cheer in my heart, "Excuse me." I love seeing these kids near my office. Actually, I love kids.

At the moment I spoke, the Grumpy Old Guy who was bringing up the rear of the group grumped,"Move it!" A split second later, he added, "Betsy, MOVE IT!" The poor girl did not have any time between my (hopefully) friendly greeting and Grumpy Old Guy's admonition.

Is this why there are no (few) women in science?


Thursday, April 7, 2011

From 2008: First LHC Circulating beam

I wrote this essay Sept 11, 2008: the day after first beam at the LHC.

Reflections on a great day

Wednesday [September 10, 2008] was a remarkable day for the accelerator-based physics programs of the world. Certainly, CERN is the primary beneficiary, but every other facility that has accelerators benefits enormously, too. Fermilab, Brookhaven, Thomas Jefferson Accelerator Facility (a.k.a.CEBAF) in the US; KEK in Japan, etcetra, etcetra.

CERN proved (and is continuing to prove) that big, complicated, new physics programs can work if you have the right mixture of engineers, physicists, politicians and support people, who are willing to work hard, and to work well, together. The complexity of the LHC is, by any measure, truly astounding. I would love to write many pages about some of these complexities, but I am having too much fun on my little bit of completxity right now. That they/we have begun to show that this is really possible is so much fun!

The feeling in the CCC at CERN is euphoric. No one was really sure that we could actually pull this off. The Director General of CERN had great khutspa to invite the media of the world to CERN to watch us succeed. It is not like we were launching a space ship, where its success or failure is obvious to anyone. He trusted us, and the fabulous media people at CERN and elsewhere (especially Fermilab) to get the message out in a way that people can understand.

As an example, when I got to my Swiss apartment on Wednesday evening, there was a report on the Swiss/German station on the LHC success. One of the German-speaking physicists I know gave the interview. I couldn't understand any of it (aside from the occasional word or two), but it was clear that it was a glowing report! Then we changed the station to the Swiss/French station and saw a different group of reporters and a different group of (French-speaking) physicists extoling the achievements of the day. (I understood a bit more of that one.) Then we changed to the Swiss/Italian station--same thing/different folks! Wow! When we sat down to supper, #3 son suggested we turn on the TV to see if other coverage was on,and there on CNN was the American report!

And the hits just keep on coming. The achievements of Wednesday were well documented. But the progress made yesterday and today were (to the experienced observer) equally (if not more) significant. They went from having the protons go around three times to "100+" times to having them stay in with essentially no losses for 10 minutes (early this (Friday) morning). No losses!! This is amazing! The number of pieces that have had to work to make this happen is huge--some people estimate that there are around 100,000 components that all have to work for the system to work. For example, we were all worried about the RF systems, but they stepped up to the plate and connected--they captured the beam in the RF today, a critical part of the 10-minute proton storage.

By the time I got in for the scheduling meeting this morning, they had even tried to scan the wires (my little bit of complexity). Fortunately, it didn't work, since I was not there. :-) We got the wire scanning in short order.

At this meeting, one of the scientists pointed out that they could not measure the lifetime of the stored beam since it didn't last long enough to let the beam diminish enough to get that measurement. That brought a euphoric chuckle from the other folks in the meeting!

The international nature of this effort is wonderful, and it is the only way any sort of big science can be done from now on. Germans, Italians, French, Spanish, British, Polish, Russian, Austrian, American, Canadian, Indian and Belgian scientist and engineers working together, usually in (not quite) perfect harmony. Our fathers and grandfathers were killing each other, damnit!! Now we sharing a coffee or a beer, and joking about our national character (Americans are cowboys, Germans are engineering geeks, French demand that we have 2-hour lunches every day, the Brits can't stand talking about football any more, and the Swiss are gun-toting, organizing, clean-freaks).

Fermilab Director, Pier Oddone, spoke elequently about this international cooperation in his remarks during the Fermilab "Pajama Party" Wednesday morning. Oddone pushed for the LHC@FNAL Operations Center to be a centerpiece of this philosophy. They tell me that 400 people were at that party--wow!

Saturday, March 19, 2011

Silent Armageddon

There a many lessons to learn from the nuclear catastrophe in Japan: Everything breaks; people are only human; heroes exist; radiation is analogous to poop; and reactors need active attention to stay safe. I think we knew the last one, but it is worth some further reflection.

How long will our technically-competent society last? Maybe thousands of years? If our technical society fails in the next, oh, ten thousand years, hundreds (thousands?) of nuclear power plants can turn into Japan’s Fukushima Daiichi. Without a constant flow of cooling water, even the spent fuel rods can explode and spread their radiation into the surrounding regions.

I believe that this society needs nuclear power. But we also need to come up with a solution for storing nuclear waste in a way that does not require active systems to maintain its quiesence

Saturday, March 12, 2011

Distribution of wealth in the US

How many people hold half of the wealth in the US?

This is a little difficult to extract from a simple Google search. But I found out these interesting things:

  • From this, I calculate that half of the total wealth in the US is held by approximately the top 5% of the people in 2007, and approximately the top 6% in 1992.

  • Other interesting findings: The Gini Coefficient, which is a measure of the statistical dispersion of the population distribution of a system: a value of 0 means a completely equal distribution; a value of 1 means the maximally unequal distribution. The US (according to this Wikipedia article) has a Gini of 46.8 in 2009 (up from 36.8 in 1968). Some have estimated the Gini coefficient in the US to be as high as 0.82.

  • Another fine article, with more charts and graphs, can be found here. I need to study this detailed article!
It is worth repeating:

Half of the wealth in the United States is held by the richest 5% of the people.

In other words,
15.6 million people have half the wealth of the US, and
292.6 million people hold the other half of the wealth.

And, as I expected, the relative wealth of the richest people in the US is increasing.

Engineering Open House at University of Illinois, March 11, 2011

I offer my thoughts on the EOH at UIUC yesterday. Overall, it was a great day!

First off, the bus service from lot E-14 (at the basketball arena) was poorly executed. We waited 20 minutes for the coach that was supposed to come at most every 10 minutes. That was not so bad except (a) the people were getting pretty grumpy, and (b) when the bus arrived, the driver was a real prick. He kept whining about how there could only be one person per seat, "Federal law! I'm the one who goes to jail!" Sheese! By the end of the day, there were two coaches running, which I'm sure solved the problem. Also, the promised "tour guide" during the short trip to the engineering area had very little to say.

That's essentially all the bad news.

They couldn't have asked for nicer weather! There were several no-so-smart girls in sockless sandals. One poor girl had toes about the color of her toenail polish. But that's what kids do when Mom (or Dad) is not there to dress them.

The exhibits were awesome. In hindsight, the most impressive part may have been that there was not a faculty member to be seen anywhere! Get too close to a display and a student would ask, "Do you want to hear about my project?" Love it!

Our two favorite displays were the UIUC Formula car entry, outside of the Mechanical Engineering building (picture here)

And the Ford corporate display, featuring a 1998 ME graduate who is now an engineer at Ford in Dearborn, MI. What a nice fellow!

There was a great session with one of the Deans of the Engineering College, Michael C. Hirschi. He answered all kinds of questions with insight and patience. Of course, he was a bit distracted at first when Northwestern was about to beat Ohio State. (But, unfortunately for the State of Illinois sports enthusiast and Buckeye haters, Ohio State pulled it out in OT.) I was particularly impressed with the questions Sterling asked about the student-run clubs and the answers he gave.

Another high point was the demo staged by the UIUC fire department (or was it the Fire Protection Department at UIUC?) They had set up some boxes in the quad about the size of a small dorm room (8x8x8), furnished with dorm-like furnishings. One end of the box, facing the crowd, was open. They lit a small fire in a trash can in the mocked-up room and started a timer. Within 5 seconds, the smoke alarm started beeping--"This is your warning to get out!" said the emcee. Within a few more seconds, the fire was visible, and smoke was starting to fill the "room". At about the one minute mark, they stated that the ceiling temperature was 180F and the floor temp was still the ambient 50F--still clear to crawl out safely. One minute later, the room was actually engulfed in flames! Somewhere in that minute, the smoke detector melted and stopped beeping. They always say that you don't have much time to react to a fire in your home. This was incredibly vivid proof of that.

Finally, let me say that I love driving to Champaign/Urbana! The country road are so peaceful and pretty. I especially like the sunsets!

Saturday, January 8, 2011

Utilizing the Focus Micro-adjust of the Canon 7D

I have attempted to utilize the micro-adjust on my Canon 7D for the four lenses I own. I was not quite sure how do do this, so I just made it up.

My technique was to stretch a tape measure along the dining room table, and put a high-contrast card vertical to the table next to a specific mark on the tape measure (e.g., the 16-inch mark, which is red on my tape).

Then I put the camera on a tripod, set it to ASA 100, and set the camera to "A" mode with the widest aperture possible. Finally, I set it up to do a mirror lockup and a 10 second delay.

Examining each picture, I look for the shot with the card in focus, along with the "16" mark on the tape. And also the "15" and the "17" on the tape needs to be the same amount of out of focus. (For the 11-16 Tokina, the widest aperture kept at least four inch marks in color. The Canon 50 was the most dramatic, of course.)

I have created a Picasa web album of the final set of photos, and you can find it here.

Canon7D Micro Focus Adjust

Here are some typical pictures from this process.

The final setting for the 55-250mm lens (+10)

My 50mm f1.8 set to +20

My 50mm f1.8 set to +15

My 50mm f1.8 set to +10

The final result I record here, as much for my own benefit as anything else.

Canon EF-S 18-55 -- +8
Canon EF-S 55-250 -- +10
Canon EF 50mm f1.8 -- +19 (!!!)
Tokina 11-16 f2.8 -- +10

So, every lens is off in the same direction. These numbers mean that the camera will make the focus point too close to the camera. Moving the adjustment positive moves the focus point towards infinity (away from the camera).

I really do not know if this is a function of the lens or to camera or both. But I am astounded that all of my lenses are so far off from what I presumed (being "Canon quality" (whatever)) they would be: a value of zero.