22 October 2008

The LHC inaugration and the LHCFest

The official ceremony of inaugration of the Large Hadron Collider (LHC) took place on 21.10.2008 which was attended by quite a few important people, especially from the CERN member states. There were also delegations from other countries from all over the world, the delegations typically headed by education or science ministers of the respective countries. There were also the guests invited by the Director General (DG) of CERN, which were mainly physicists from CERN and all over the world, and heads of laboratories and funding agencies.
The ceremony took place in the SM18, which is the testing facility for the LHC magnets. In one of its halls, expositions from all the four major detectors were set up, along with posters and displays of parts of the LHC magnets. So the guests were to visit this hall, where, apart from the science, they were also served the "molecular cuisine", which was an assortment of chef Ettore Bocchia's creations including the famous ice creams cooled with liquid nitrogen to maintain a velvety texture. I had the good luck of being there as one of the presenters at the LHCb exposition, and given my sweet tooth, I had a ball. And you can find me stirring the ice cream while liquid nitrogen is being poured!
Going back to the ceremony, the guests were then taken to another hall called SMA18 where they were to be seated for the rest of the evening. There was also an exhibition titled "Accelerating Nobels", which is a series of photographs of Nobel laureates who were asked to make a drawing of their Nobel discovery and hold it while posing for the photograph. Another interesting thing about the exhibition was the photographer's comments for each of the photograph, and the ones for Anthony Leggett (nobel prize 2003) were
"It’s quite a twist when atoms form pairs to allow for superfluidity, but Tony Leggett wanted to show exactly how they do it – with his hands! “But Professor, how can you hold up your drawing to the camera when you need both of your hands for your presentation of paired atoms?”, I ask. “Just tape the drawing onto me!”, he replies."
This is ofcourse my favourite picture....

The ceremony began with a speech from the DG followed by speeches by the distinguished delegates.
Then there was a concert named "Origins: concert for a collider", a celebration of the wonder of the cosmos and the glory of life on Earth, as expressed through the imagery of a nature photographer Frans Lanting and the music by Philip Glass.
This was the end of the formal ceremony and the guests left by 1800.
The LHC Fest, which was open to all CERN users, included a buffet and a concert, was to start from 1830. Both the exposition hall and the ceremony hall were open so one could look at the displays by the four experiments and the Accelerating Nobels exhibition. There was a speech by the DG and also a performance of "Origins" for the fest. After which, the buffet was served at 2030 and a concert followed, which was in full swing even as I left around 2300. It was a very enjoyable evening overall and I am glad I was able to experience this unique day.

09 October 2008

Elephant in the room for the Nobel Prize in Physics!


On Tuesday it was announced that Makoto Kobayashi and Toshihide Maskawa have been awarded the Nobel Prize in Physics for 2008. The award is "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature." They share the prize with Yoichiro Nambu for his work on spontaneous symmetry breaking, a process vital to the derivation of the Higgs mechanism which gives particles mass in the standard model and which, as has been well publicised, is major part of the physics to be investigated with the LHC.

The work of Kobayashi and Maskawa concerns a slightly more obscure asymmetry in nature, so called CP violation. Essentially CP asymmetry reveals a subtle difference between the weak nuclear decays of some particles and their corresponding anti-particles and forms a cornerstone in the investigation of why the universe is made of matter and not anti-matter. It was first observed experimentally in the 1960s and at the time posed a theoretical conundrum. Kobayashi and Maskawa showed in the early 1970s that this effect could be incorporated into the standard model if there are at least 3 generations of quarks. This effectively predicted the yet to be discovered top and bottom quarks. Their work built on the flavour mixing formalism developed by the Italian Nicola Cabibbo and resulted in the so called CKM (Cabibbo-Kobayashi-Maskawa) matrix.


The ultimate test of the CKM matrix came this decade with the operation of the B Factories; BELLE in Japan and BaBar in the USA. These experiments produce pairs of B mesons (particle and anti-particle) and study their decays looking for the effects of CP violation predicted by Kobayashi and Maskawa. In 2001 both collaborations reported the first experimental observations of CP violation from B meson decays, completely in agreement with the CKM matrix formalism. They have since made scores of similar measurements all consistent with the model. Imperial College has been heavily involved with the BaBar experiment (named after the eponymous cartoon elephant who is also the experiment mascot) for the duration of it's running, which was completed earlier this year. We continue to work as part of the collaboration who are now analysing the final data set. Currently the Imperial group are looking at the effects of radiative penguin decays which can further constrain the elements of the CKM matrix.

It is the success of the CKM mechanism under intense experimental scrutiny which has made Kobayashi and Maskawa deserving winners of the 2008 Nobel Prize in physics.