Inspired by Regina Caputo’s excellent post on the CERN accelerator complex, I thought I should give you some fun facts about the LHC (in “human units”).
The LHC is designed to collide bunches of protons every 25 ns, i.e., at a 40 MHz rate (40 million/second). In each of these collisions, something happens. Since there is no way we can collect data at this rate, we try to pick only the interesting events, which occur very infrequently; however, this is easier said than done. Experiments like ATLAS employ a very sophisticated filtering system to keep only those events that we are interested in. This is called the trigger system, and it works because the interesting events have unique signatures that can be used to distinguish them from the uninteresting ones.
(I'm not skipping day 2, about heavy flavors and my own talk, but I think today's topic merits a reshuffling)
It is no secret that Moriond EW 2012 celebrates the year of the "Higgs". In December both CMS and ATLAS published preliminary results with the intention to present more complete analyses at this year's Moriond, now the time has come at last.
I work with crazy particles. Dark matter is pretty weird, so are neutrinos seemingly, but what I search for blows it all away. Tuesday was the day of my presentation. The format for these young scientist presentations are 5 minutes and time for a single question afterwards. Trying to present a full picture of any analysis in that short a time is impossible; instead the idea is more like handing out a business card telling the audience what you work on in the hope that some will be interested and contact you informally afterwards.
Not many trips take you to all ends of the world in one day, but that was nevertheless how it felt after the first talks at Moriond. Sunday and Monday have mainly featured presentations on neutrino and dark matter physics. Many of these experiments are placed in remote regions or deep under ground.
As a young physicist not many conferences have the same mystical status as Rencontres de Moriond. This gathering of physicists from all areas of particle physics is one of most anticipated events of the year. More a gathering than a conference, Moriond started in 1966 and has inspired many similar events. Presentations, time for discussion and recreation is combined to inspire and foster collaboration and new ideas. Another element is the meeting between young and more experienced scientists. Nearly half of the talks are given by young participants below 35 like myself. I was invited by the ATLAS collaboration to present our latest results on a search for a type of long-lived particles that has meant a lot to me for the last two years.
This is continuing from the previous post, where I discussed how we convert data collected by ATLAS into usable objects. Here I explain the steps to get a Physics result. I can now use our data sample to prove/disprove the predictions of Supersymmetry (SUSY), string theory or what have you. What steps do I follow?
OK, so I’ll try to give a flavour of how the data that we collect gets turned into a published result. As the title indicates, it takes a while! The post got very long, so I have split it in two parts. The first will talk about reconstructing data, and the second will explain the analysis stage.
A very happy new year to the readers of this blog. As we start 2012, hoping to finally find the elusive Higgs boson and other signatures of new physics, an important question needs to be answered first - are we going to have collisions at a center of mass energy of 7 or 8 TeV?
“If it’s just a fluctuation of background, it will take a lot of data to kill.” Dr. Fabiola Gianotti, spokesperson for the ATLAS collaboration, made this statement on Dec. 13, 2011 during a special seminar I attended at CERN. Within the minute that followed, I hurriedly concocted a tweet, tacked on #Higgs and #CERN hashtags, and sent Fabiola’s weighty comment out onto the WWW.