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Bjoern Penning | Fermilab | USA

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Roaming Washington

Thursday, February 18th, 2010

The last days the annual meeting of the American Physical Society took place in Washington, D.C.

Although commonly perceived as sort of student conference due to the multitude of student talks given in parallel sessions, I think the APS offers an excellent variety of review talks and one can learn a great deal about neighboring fields. In addition there are sort of historical and prize sessions of great interest. Most notably this year maybe (at least for me as Higgs searcher), the Sakurai Prize. It is one of the most renowned prized in physics and was rewarded this year to Robert Brout, Francois Englert, Gerald Guralnik, C. R. Hagen, Peter Higgs, and Tom Kibble. E.g. the fathers of the spontaneous symmetry breaking in gauge theories and the masses of vector boson. Or to make it short, the Higgs Mechanism. Of course considering that there are six laureates I hesitate a bit using only the term ‘Higgs’ here. I think this was the case as well for other participants. E.g. Rob Rosser was referring only to  the ‘Brout-Englert-Higgs-Hagen-Guralnik-Kibble’ (BEHHGK) mechanism in this plenary talk some days later.

Anyway, it is important to note that this would have been the first time that all six of them (nicknamed ‘Gang of Six’) are under one roof. Unfortunately Peter Higgs couldn’t make it due to health concerns.  Even more surprising, Engler and (I think) Hagen mentioned that they never met Peter Higgs before! Wow, almost 50 years gone by since their famous papers and they’ve never met. Would haven been great to seem them altogether. But five of them was great as well.

Gang of Five
Gang of Five

The session itself was very interesting. Each of them gave a very nice review of their important papers back in ~1964, sprinkled with anecdotes setting things in the historical and scientific context. Very educating, very interesting.

Of course there were many more interesting talk, covering topics from the invention of the  laser via low energy experiment up to modern cosmology and dark energy searches. No to mention the general location of the APS in Washington, D.C. The capital of the US hosts some very impressive museums. Of course I had to pay a visit to the Smithsonian National Air and Space Museum. Wow! I think you don’t have to be a rocket scientist (or physicist) to be impressed. Right when entering one sees the original capsule of Friendship 7 and Apollo 11, hovering above them the X-15, Space Ship One, a Pioneer space probe and many many more unique exhibits.

Entrance of the Smithsonian National Air and Space Museum
Entrance of the Smithsonian National Air and Space Museum

The adjacent rooms host countless exhibits of man’s explorations. Just to mention a few, the original plane of the Brothers Wright, the space suits of Yuri Gagarin and Alan Shepard and the ones from the Apollo 11 crew, still dusty from the moon dust. There are countless more exhibits, originals and true to the original replicas of the space missions, probes, spacecrafts, moon lander and vehicle, civil, research and military air planes etc.

Apollo and Soyuz spacecraft docking
Apollo 11 Lunar Suit
Moon Lander

Really great. A tribute to the explatory spirit. Makes one consider, that since the moon landing and now almost as much time has passed as between the first flight of the Brother Wright and the moon landing. Somehow not really much has happened, unless of course someone considers the iPod or GSM phones or similar gadgets as a big leap in mankind’s development.


On board of the USS DZero

Wednesday, December 16th, 2009
USS DZero?

USS DZero?

I want to pick up a line coined by our spokesman Stefan at last week’s collaboration week. In his closing remarks he pointed out the fact that the collaboration is very lively and vibrant and compared the control room with the brigde of the USS Enterprise.

Dzero Control Room

DZero Control Room, quite a resemblance to the other bridge...

Just minutes after his overview talk I had a conversation with a well-known scientist who works at CDF and a Dark Matter experiment at Fermilab. He expressed his mild surprise that we managed to fill up the large meeting room entirely. Particularly right now shortly after the successful startup of the LHC (congrats!).

Indeed it is a bit surprising but as said by our Spokesman, the collaboration is very lively and vibrant and the collaboration week was great, both scientifically and as an opportunity of meeting many friends once again. Most meetings were so well attended that it was difficult to find a seat when arriving a bit late. But the exciting atmosphere goes beyond that. Our publication rate right now is one of the highest in the collaboration’s history and two new institutions are even joining the collaboration, bringing up the total number of institutions to 90 from 19 different countries. Moreover, although the detector is not the newest, it is in a very good shape, maybe better than ever.

Back to the Star Trek comparison. Our “Scotties” in Operations keep us going at a more than 93% efficiency rate and during this summer’s shutdown we managed to fix more than we were able to break in 8 years of running: The amount of dead channels in the tracker is at a record low, entire sub-detectors have been re-commissioned or included for the first time and the calorimeter calibration is doing well and shows a high stability and very good resolution. But most of all – just as the Enterprise –  we’re running on the real deal, Antimatter! And the Tevatron crew supplies us with a fair amount of that, currently 7fb-1 and steadily increasing. The Tevatron will remain being the highest energy matter-antimatter collider.

Recorded and Delivered Luminosity at DZero

Recorded and Delivered Luminosity at DZero

But no doubts shall be raised though. I am also looking forward to exciting discoveries – hopefully soon – at the LHC.  But the LHC energies must exceed the Tevatron’s by a factor of three or more before it starts to be competitive in many Standard Model measurements, including low mass SM Higgs boson searches. Unless background free discoveries (like. t’ or Z’) happen to reveal themselves easily, it will be crucial to understand the detectors very well and the path to discovery won’t be a short one. The very same challenges the Tevatron experiments have faced in the past.

So, the Tevatron fleet along with the USS DZero and its sister ship USS CDF were intended to be de-commissioned years ago. But the structural integrity is very good, the shields and engines are up and our Dilithium crystals (or whatever is responsible for our antimatter) are fully charged. The new ships of the line are ready to push far beyond our reach but we’re already out there since a while.
Anticipating their coming, Captain Stefan, Captain Dmitri and their crew continue to explore new worlds, new particles and to boldly go where no man has gone before…

So, the Tevatron fleet along with the USS DZero and its sister
ship USS CDF were intended to be de-commissioned years ago.
But the structural integrity is very good, the shields and engines are up and
our Dilithium crystals (or whatever is responsible for our antimatter)
fully charged. The new ships of the line are ready to push far beyond our
reach but we’re already out there since a while.
Anticipating their coming, Captain Stefan, Captain Dimitri and their crew
continue to explore new worlds, new particles, and to boldly go where no man
has gone before…

Interesting times..

Monday, October 5th, 2009

The last month has been a very interesting one. On this day four weeks ago I defended my thesis in Germany. Followed by some days of packing, sorting and finally flying to Chicago. The following Monday, one week after my defense, I started my new job. I am now Research Assistant at Fermilab and this already since three weeks. Astonishing how fast things develop sometimes.

Of course after moving to the US it took some days to get settled both, new job and new living. Although I was familiar with both, Chicago and Fermilab, there are subtle but important difference. But to make things short… it is great and I enjoy it. Maybe the following two pictures give an impression why.

First about private things, this is a view from the backporch of my new place:

Sears tower from backporch

Sears tower from backporch

Of course it is not just the nice view making my day, this is merely a symbol for the advantages being back in Chicago. Meeting dear friends, the amenities and culture of a big city and seeing again a wonderful person very close to me.

And there is work (not really the best term for our type of business right) better work and life at Fermilab. The very same week I arrived beam was put again into the Tevatron, leading to a challenging time for the CDF and D0 collaboration to resume operations. The effort made by the Tevatron machine people and both collaborations was truly impressive. I happened to be on shift already twice and we had very stable data taking at quite high luminosities. You see here a plot of the data taking efficiencies at D0:

Data takine efficiency of D0, Oct. 2009.

Data taking efficiency of D0, Oct. 2009.

The blue, red and green markers give the daily, ten-days average and monthly data taking efficiency. The plot shows the entire time since start of RunII, the gaps indicate the shutdowns of the Tevatron during the last years. The last few blue dots represent the performance of the D0 shift crew directly after the shutdown. As one sees, within literally a day or two the efficiency reached again levels higher than 90%. Very nice. Parallel to starting the Tevatron we happened to have a collaboration meeting last week and I think it is fair to say that the plot above is as well just a symbol for the atmosphere dominating the experiment. Busy, challenging but it is fun and I see many impressive results coming out of it.

A friend of mine, an experienced scientist, used to say “never graduate, it just gets worse”. Well, so far I can’t agree. Sure, work ramps up pretty quickly, the responsibilities even faster and I of course the whole process of graduating has it’s purpose. But once over it feels very good and being able to focus on research again is great. In the end  our work is our hobby as well, right?