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Archive for December, 2009

From the Aquarium

Tuesday, December 22nd, 2009

Building HIT at ETH Hönggerberg

Building HIT at ETH Hönggerberg

Three weeks spent in hotel rooms are over. After one week in Munich, one in Geneva and one in Paris, we are in Zürich now. This is somewhat of an improvement, since we are staying at my mother’s place, where we have our own room and our stuff (smartly, we had left half of our clothes there when we left for Japan, mostly the ones for cold weather).
It doesn’t mean that traveling is over, though. For Christmas, we are heading South, to visit the Italian part of the family.
But for now, we are spending a few days at the Institute for Theoretical Physics of the Swiss Federal Institute of Technology (ETH). Which means that we are again treading old paths, since this is the place I got my degree from! Since I have very good memories from my undergrad years, I’m happy to be back. Having lunch at the canteen, then a coffee or tea at the Bistro, it’s like in the old days.
But some things are different from how I used to know them.

Sitting Space and glass office walls

Theoretical Physics has moved into a shiny new building last year. The outside walls are made of glass, and the inside ones, well, too. The ones towards the hallway, that is, not the ones separating the offices. It feels a bit like sitting inside an aquarium. The benefit of the outside walls being windows is the view.
Physics (along with other disciplines like Chemistry and Architecture) is located on a campus at the edge of town, up on a hill (the Hoenggerberg).
Balcony along HIT

Balcony along HIT

From the top floor of building HIT, where the theorists sit, the view is thus quite nice. The wall towards the inner part of the building being of glass, where there are the hallway and sitting and interaction areas, has the effect that everyone always knows who is in and whether they’re working…
On the whole, the new building is very impressive. The sitting areas are very nice, with leather armchairs. There’s also a tea kitchen and whiteboards are strewn around everywhere. A desk, a view, and a place to discuss with a whiteboard, what more does a theorist need?

The last two weeks, I had spent more or less in a state of emergency, preparing two completely different seminar talks. Now that these talks are over, I start to be more in a holiday mood. We’re even getting treated to a few days of snow here, something that rarely ever happens in Tokyo.


I have, in the last 48 hours, returned to the UK from my 18 month attachment at CERN. It feels great to be home again. My time there has been incredible and life-changing, but it also demonstrated that no matter how much you love a place and love your work, no matter how much you settle in, make friends, enjoy yourself, if it isn’t home then homesickness will still torment you. I missed those close to me so much it hurt. I would daydream wistfully about fish and chips. When it rained in Geneva I felt nostalgic for Birmingham. Sometimes, home is home is home and logic doesn’t come into it. I made the decision that in the long term, I want to be in the UK. Unfortunately, a consequence of this decision is that my career prospects now seem quite uncertain.

As Suzanne says, it really has been an incredible 2009, and especially so for ALICE. The year seems to be ending perfectly – early collisions brought about our first physics paper, and the data we have taken since is showing beautiful results. Our detectors are working well, and the physics we have been waiting so long for is finally happening. The year to come promises great things. This should be a happy time.

For the ALICE CTP group in Birmingham, as well as many other UK physics research groups, the mood has turned quite sour. Funding cuts to science this year have had disasterous impact on nuclear and particle physics. As a result, the Science and Technology Facilities Council have made the decision to cut completely the UK’s involvement with many international projects, including the ALICE experiment. Much of the UK’s research in nuclear and particle physics has been entirely dropped, which is highly damaging and makes long term prospects pretty grim. What I find hard to swallow is that many of these contributions were small, yet they were vital as investment for the future of the field in the UK.

The brutal way in which the cuts have been made seems to have left the worst possible dent in the field, which is unfortunately something I am not surprised by. During the funding crisis following STFC’s £80m shortfall, the UK’s part in the International Linear Collider was lost, and ALICE was already on dangerous ground (see my concerned letter to the Times). The Birmingham University group is the only one in the UK involved in ALICE, yet its impact is vital to the experiment. Not only are we working on important analysis areas (myself included!) but we are the group responsible for the Central Trigger Processor, without which the detector could not take data. We have been given until at least the next grant’s round in 2011 before the group will be dropped, and during that time we will be fighting the decision. Others were not so lucky and will be gone by Spring. The sheer scale of the loss for the particle and nuclear fields is hard to express.

I am very busy with work at the moment (there is quite alot to be done before the LHC restarts again next year) so I must stop here for now. I hope everyone is having a Merry Christmas. Those feeling the damage of the science cuts may be struggling to find festive cheer this year. I will be spending mine in Manchester with my boyfriend and family, so despite the terrible news I think I will find it hard not to be cheerful.


It’s that time of year again. This past Friday the CERN theory group had its annual Christmas party, featuring its unique brand of silliness: the CERN-TH Christmas play. I’ve not yet had the privilege to visit CERN, but one of my deepest physics desires is to one day be around during one of these parties. Recently the group started archiving their Christmas plays and making them available online. Here’s a summary of the 2008 play, courtesy of Jester at the Resonaances blog (curiously Jester wrote the year incorrectly).

The 2009 play can be found on the CERN Document Server. I wholeheartedly recommend it. It’s full of jokes about LHC media hype, pop culture, and yes, a lot of physics. The puns are packed in there rather densely, so those of you that can pick up most of the references in one viewing should consider trying out for Jeopardy. I prefer to make a game out of it so I eat a cookie for every time they mention a physicist whom I’ve met in person. Even if you don’t get any of the jokes, it’s still enjoyable to watch physicists having fun being silly.

My rough notes of the references in the play are below, after the break. (There are certainly a bunch that I’ve missed or misinterpreted.)




Friday, December 18th, 2009
Steve Myers, opening our workshop yesterday morning.

Steve Myers, opening our workshop yesterday morning.

For the last two and a half  days I’ve been at CERN, for a variety of meetings, including a two day workshop on the possibilities of a demonstration experiment for proton-driven plasma wakefield acceleration.  I’ve blogged about this idea a while back, now a group is coming together to work towards an experimental verification of those ideas. A really positive message from this meeting is that CERN is interested, crucial since such a project can not be undertaken without the support of a strong accelerator laboratory. Steve Myers, the director for accelerators and technology at CERN, opened the workshop yesterday morning. For the last two days, accelerator experts, plasma experts and detector people have been discussing possibilities for the construction and operation of long cells of plasma, for the creation of very short packets of highly energetic protons and the like. The goal of the experiment will be to demonstrate high acceleration gradients, way beyond what conventional accelerators can achieve nowadays. If that works, who knows where this could go? A brand new solution for future particle physics experiments at the energy frontier is something we are all hoping for…

A possible site for the experiment: A steep transfer tunnel from the SPS to the CERN West Area.

A possible site for the experiment: A steep transfer tunnel from the SPS to the CERN West Area.

We also managed to squeeze in a visit to a potential site for the experiment: A currently unused tunnel that connects the West Area (a huge experimental hall at CERN) with the SPS (the Super Proton Synchrotron, one of the accelerators here at CERN, and the final injector for the LHC). Since the SPS is something like 50 m underground, the tunnel has quite a steep slope. Here, a system for the compression of the proton packets from the accelerator could be set up, if we come up with a clever, cost efficient way to realize this. The plasma cell that will provide the acceleration would then probably be on flat ground at surface level in the experimental hall. On the picture you can see a few elements that are still left from the previous beam line in the tunnel. Now the details of the experiment have to be worked out, and a proposal to CERN has to be formulated. Exciting times are ahead, as a new project gets born.

Being at CERN at this very last day of the year that CERN is still open also gave me the opportunity to see the last LHC report of this year, where the accelerator and the experiments reported on their progress. Given the recent fantastic success of the LHC commissioning and first physics running, this event was a celebration of amazing first results achieved by incredibly well working detectors and by a smoothly running LHC. We were all sent off by Rolf Heuer, CERN’s director general, with best wishes for Christmas and for a happy new year, and the request to come back well rested for all the great things that lie ahead.

Today, it has started to snow here in Geneva, all of CERN is covered in a few white fluffy centimeters… And people are getting into a holiday mood. In a few minutes I’ll leave for the airport, my last flight (finally!) for this year…

Standing room only in the CERN Main Auditorium for the LHC Reports, as Fabiola Gianotti, the ATLAS Spokesperson, gives her report.

Standing room only in the CERN Main Auditorium for the LHC Reports, as Fabiola Gianotti, the ATLAS Spokesperson, gives her talk.


We’re currently in a period of 5 weeks away from home. While part of this period consists of family visits, most of it we have spent in hotel rooms.
At home I have regular eating habits and a regular exercise regime which includes running, going to the gym, and attending ballet and yoga classes. Obviously giving up all of this for 5 weeks is not a good idea.
While already last year, we have been bringing our running shoes along on trips (which during this trip, we’ve already put to use in the English Garden and the Jardin du Luxembourg), this time, I am making an effort to do better.
In Munich, I took three classes at my old dance school (well, that was easy, it’s walking distance from the physics building and I knew exactly how things work there). At CERN, I attended a class of the CERN Fitness Club (only one I have to admit, since most of the time I was in a state of emergency preparing my seminar talk). And in Paris, we attended a class of the Iyengar Yoga Center (which has given both of us a memorable 5 day whole body muscle soreness). For our next stop, Zürich, I am in the process of figuring out where to go.
Obviously I have not been as good as I am at home (partly also because I am less than excited to go running at temperatures below the freezing point), but I guess given the circumstances I have to go with “better than nothing”.
As for sanity during our hotel room evenings, I brought my guitar along and am trying to practice a bit on most evenings. Even though a bit inconvenient, this is possible since we are moving by train within Europe, and it’s worth it because both Domenico and I are using it. And it allows me to bring a bit of regularity into these hectic traveling weeks.



Friday, December 18th, 2009

On December 17 at 6PM the machine operators switched off the beam in the LHC


sending us greetings through our communication channel
(you can find here the status of the beam in real time http://op-webtools.web.cern.ch/op-webtools/vistar/vistars.php?usr=LHC1)

It has been an extraordinaty 2009. The LHC is back and it performed beyond expectations in the past couple of weeks (yes, it has been just a couple of weeks). The machine was able to provide stable beam (which means good quality beam with no risk of damaging the detectors) and the highest energy collisions in the World, breaking the Tevatron record with 2.36 TeV. ATLAS successfully collected hundred of thousands of candidate collisions. What you see in the beautiful visual representation of a reconstructed event is the production of “jets”.


Even though the LHC and the experiments have been built with the aim of discovering New Phenomena, standard “strong processes” are those happening more frequently, thus the ones produced and observed right from the beginning of data taking. What does “strong” stand for? The protons in the two circulating beams are made of quarks (the name “quark” was taken by Murray Gell-Mann from the book “Finnegan’s Wake” by James Joyce). all

Quarks are – based on today’s knowledge – elementary particles (they are not composed of other particles), and there are six of them coupled in pairs due to common properties. The lightest quarks are called “up” and “down”, slightly heavier ones are the “charm and strange” and finally the “bottom and top”.

The mass of the quarks ranges from small (0.001 times the mass of the proton) to the largest mass observed in particle physics so far (170 times the mass of the proton).

Each quark is accompanied by an antiquark with a different charge. What is  unusual is their fractional electric charge, for instance the top has charge +2/3 while the bottom has -1/3. The youngest quark is the top quark, discovered at the Tevatron in 1995. Quarks interact via quantum chromodynamics (QCD), the theory of the “strong interaction”. In the same way as the electrons interact via quantum electrodynamics (QED) thanks to their electric charge, quarks interact via their “color” charge. In fact, quarks carry colors (red, green and blue) which however has nothing to do with our daily concept of color. One important characteristic of QCD is called the “confinement”: the force between quarks does not decrease as the quarks separate.  This results in not being able to see quarks separately, but only bounded to form composite particles (the top is exceptional in this respect). While travelling through the detectors they generate showers of such particles called jets”.

Our collaborators in ATLAS scanned the data collected so far looking for signs of light particles, composed of quarks, being produced. In the first runs of data taking, we could already re-discover three of the quarks. We observed a bound state of light quarks, the u and d quarks, and once more data had been collected the strange quark – in form of resonance (a peak) – appeared on our screeens!

Finally, let me conclude this fantastic year with the words of the Director General at CERN “It has been a fantastic year for the LHC [….] I want to underline the fact that it has been made possible by the unique global collaboration that is particle physics. It has been truly heart-warming to see the community pulling together to achieve its goals”.

See you in 2010!


A Showcase for the Universe

Friday, December 18th, 2009

Last week on Tuesday night my wife and I were invited to the opening ceremony of a new exhibition in the Deutsches Museum, the biggest science and technology museum in Germany. The exhibition, called “The Evolution of the Universe”, was created by scientists from the Excellence Cluster ‘Universe’, to which I also belong. The exhibition shows the links between particle and nuclear physics, astrophysics and cosmology, and tells the story of the evolution of the universe from the big bang to today, and even looks at what lies ahead.

The story starts with theories about the very first instances after the big bang including inflation and then moves into the realms we are now probing with the LHC. There is a slice of an LHC main dipole magnet, and a real piece of the ATLAS silicon strip tracker SCT. It moves on through primordial nucleosynthesis to the formation of neutral hydrogen, the point where the universe became transparent. This is as far back as we can look today by studying the cosmic microwave background. From there it is on to star and galaxy formation, the role of dark matter and black holes in the structure formation in the universe, and the synthesis of heavy elements in supernova explosions. It ends with a look at the effects in an ever expanding universe. All these topics are also being studied by scientists within the Excellence Cluster.

The exhibition was professionally designed with the help of the agency “Die Werft”, and is definitely a pleasure to look at and to explore. There are interactive models that show the effect of dark energy and dark matter on the structure sizes, the role of black holes in galaxy formation and the origin of different chemical elements, to just name a few.

If you happen to pass through Munich, the Deutsches Museum  is always worth a visit, and this new exhibition in the astronomy section makes it even more attractive.

Picture Credits: KB Media

The first second of the universe, with an illustration of CP violation, and a slice of an LHC dipole and a piece of the ATLAS SCT.

The first second of the universe, with an illustration of CP violation, and a slice of an LHC dipole and a piece of the ATLAS SCT.

The microwave background: As far as we can look back in time.

The microwave background: As far as we can look back in time.

A place to rest and to admire the wonders of the universe.

A place to rest and to admire the wonders of the universe.

For more information on the exhibition (in German), and more pictures, go to



End of 2009 Run

Thursday, December 17th, 2009

Yesterday, the LHC collided its last particles for 2009. It has been an exciting end to the year, and the beginning of a new era in particle physics. The collider and all the experiments have proven that they work very well, and are ready for the first physics run.
This is also my last blog entry for the US LHC web site. It has been fun, and I appreciate all the interesting comments and questions to my posts over the last year and a half.
A few new bloggers are starting up, and I’ll be among the readers for an exciting 2010. Happy New Year!


A Very Exciting Week

Wednesday, December 16th, 2009

Without a good way to tie three disparate topics together, I will go through the excitement chronologically:

SLAC public tours have started up again! On Tuesday the first public tour (in about 2 years) took place. I was not guiding the tour, but tagged along to prepare for future tours. There were about 10 people on the tour, a nice group (in both size and temperament) for the first run. The tour seemed quite successful and we all learned lessons for future tours. I was really impressed by the questions that were asked, and how well the tour guide, Keith Bechtol, was able to answer them. I have a lot of studying to do in order to know the cross section of the electron bunches, the expected radiation doses at a variety of locations around the lab, the use schedule for LCLS, and all of the dates of construction and discoveries! While I anticipate lots of WIPP travel in the next few months, I hope that I can lead a few tours in between trips. I’m certainly happy to see tours running again.

I’m blogging from an airplane right now– how futuristic is that? My understanding is that those of you in Europe have had wireless (and cell phones?) on planes for a while, but this is the first flight I’ve used wireless on. Right now it is a free trial, and I’m not yet convinced that I’d pay $13 for this for a flight, unless it was a very long flight.

Of course, the reason I’m on the airplane is more exciting: holiday travel! I’m traveling to Ohio to spend almost two weeks with family and I could really use the break. I saw snow last year there, so I’m eager to see if I can actually have a white Christmas this year. Certainly the mountains we are flying over right now are snow covered, but it isn’t quite the same thing.

The future is always the most exciting, right? Tomorrow (in exactly 25 hours) the new CDMS results will be announced. Thanks to many rumours, there has been some speculation that CDMS may have seen something. Since CDMS is an incredibly sensitive experiment that has a very tiny background, something is actually saying a lot. Their past results have been that they saw zero events. No background events, no signal. So seeing anything would be a change, and it wouldn’t take too many events (like 6) for it to not be consistent with background – ie, EVIDENCE FOR DARK MATTER!

I haven’t been this excited since the MiniBooNE results were announced when I was an undergrad at MIT. That experiment was testing the (unexpected) results of a previous experiment, LSND. If MiniBooNE confirmed the LSND results, it would imply there was something strange in the neutrino sector (like a sterile neutrino). The MiniBooNE results were consistent with the “standard” neutrino model – the audience was palpably disappointed. Of course, the structure of these talks are that the first 45 minutes or so describe the experiment, analysis methods, and possible backgrounds without announcing the actual results. At the end of the talk the “box is opened” and everyone either starts discussing it with their neighbours or runs out of the room to go and write a theory to match the new data. I think those are 45 of the most excruciatingly exciting minutes possible in science.

But since my present status is flying away from SLAC at 582 mph, I won’t be at SLAC for the talk tomorrow given by Prof. Cooley of Southern Methodist University. There are simultaneous announcements occurring at Fermilab and SLAC, both being webcasted. I will be tuning in from three timezones away, hoping for a birthday present of dark matter. I can’t imagine anything I would rather receive for my 25th birthday than a breakthrough in our understanding of the universe.


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…