In the competition, a simulation of the output from an experiment to detect new particles in an accelerator that will open in 2007 was conducted. The participants had to find a needle in a haystack. All to think about strategies for mining the relevant information when the truth results come
Dikla Oren
Direct link to this page: https://www.hayadan.org.il/contsetlhc.html
Published for the first time on the knowledge site on 14/12/2003
Now the news also appeared in "Ideas", the journal of the Weizmann Institute that reports on innovations. We will also bring this report - after the original news.
Dikla Oren's original news
14/12/2003
A group of Israeli physicists from the Department of Particle Physics at the Weizmann Institute in Rehovot won an international competition for the visualization analysis of the information that will be obtained from the Atlas experiment at the LHC accelerator at CERN, which will be the largest accelerator in the world. The competition between the elementary particle physicists was an attempt to simulate dealing with the enormous flow of information that would come from the accelerator's detector. All the groups participating in the experiment hold three meetings a year. At the last meeting, held in Prague in September, the organizers of the competition announced the winning teams.
In 2007, the construction of the largest accelerator in the world, the LHC (Large Hadron Collider) at CERN Geneva, in Switzerland, which will reach higher energies than ever, should be completed. The new accelerator is a circular accelerator, with a radius of 4.3 km, in which two beams of protons will be accelerated and collide with each other. As a result of the collision, new and unfamiliar particles may be created, which, when disintegrated, will cause the creation of hundreds of particles. Each such collision is called an 'event'. The products of the collision will be able to be 'seen' using two sophisticated particle detectors that are being built at the same time as the accelerator and will be installed in it. In one of them, called ATLAS, three Israeli research groups are partners. Professor Ehud Duchovani from the Department of Elementary Particle Physics at the Weizmann Institute, a member of the winning team, makes the acceptance speech and says that recreating the process that occurred due to the collision by measuring the hundreds of particles emitted is similar to trying to reattach an object of unknown shape made of fine glass that was shattered into pieces.
If the complexity of each individual event is not enough, in the experiment about a billion events will occur per second. Only some of them are considered interesting. Therefore, one of the main problems will be dealing with the amounts of information and extracting the really interesting events. The need arose to find ways to filter out all the background noise on the one hand, and locate the spicy events, such as finding the elusive Higgs or signs of the existence of super symmetry, on the other hand.
To meet this need, Fabiola Gianotti, Atlas Physics Coordinator, and Ian Hinchliffe, Atlas Simulation Coordinator, organized the "Atlas Blind Analysis Test". The competition had two main goals. One is to test information analysis strategies, and the other is to have fun. Giannotti and Hinchliffe created samples of this type of output to be received from the detector at the start of the experiment. To do so, use the existing physical knowledge, that is, the standard model describing the elementary particles and their interactions, to create simulations of events. In addition, different models were used, which guess the physics beyond the standard model, to simulate events in which new physics may be discovered. After that, Gianotti and Hinchliffe sent the simulations to the physicists participating in the experiment, about 2000 physicists from 34 countries around the world, including Israel. The groups were asked to decipher the information, discover the new physics that was encrypted, and write a scientific article-like article about the discoveries.
The first problem that had to be dealt with was reading the information. This is no small thing. There were groups that fell at this stage. After solving that problem, the next hurdle was trying to identify the newly encoded physics. Once again, this is not a simple task, so holding the competition is a good preparation for the real experiment. For example, one of the groups tried to measure the spin of a new particle that they had 'discovered' and concluded that it had no spin, but in the end it turned out that it had a spin of one unit.
The winning Israeli team - Aryeh Melamed, Peter Rankel, Lydia Ziukovich, Michael Rivlin, Elam Gross and Ehud Duchovani from the Department of Elementary Particle Physics at the Weizmann Institute, Rehovot - came to the conclusion that two new particles are hidden in the information. The Cambridge University group in England also 'discovered' the same particles, but the Weizmann Institute added and claimed that there was another particle hidden in the information - which they did not manage to identify in the short time allocated, and indeed it was. None of the participants in the competition was able to identify the other particle. The group wrote an article of about thirteen pages. One of the paragraphs was dedicated to one of the more amusing things, showing how complicated and complex the information is: the group encountered two strange events that they could not explain. After the competition ended, it became clear that the organizers themselves did not know the meaning of these strange events.
"It's nice that teams from all over the Western world participated in the competition - all European countries, the USA, Canada and Japan," says Duchovni, "and the ones who succeeded were actually us from Israel." The contest organizers intend to repeat the contest and use more and more complex information.
One of the goals of the Atlas experiment is to search for new particles, which will prove the correctness of theories beyond the standard model. One of these theories is supersymmetry, a theory that predicts the existence of a partner for each particle in the Standard Model, a partner that differs from it in spin. The spin is an intrinsic property of particles. Particles with spin, which is an integer, are called bosons. In contrast, the particles that have half spin or odd multiples of it are called fermions. The super symmetry corresponds to every boson, having a whole spin, a particle with a half spin, and for every fermion, having a half spin, a particle with a whole spin. Apart from the difference in spin, the super symmetric particles differ from their counterparts in their net - the super symmetric particles are heavier. To discover a super symmetric particle, something that has not yet been done, an accelerator is needed, which will reach extremely high energies. Indeed, the LHC will reach energies of 7 TeV (eV are units of energy, one electron volt is equivalent to the energy, which will be added to the electron as a result of the acceleration by a potential difference of one volt) for each particle beam. This is an amount of energy equivalent to 10 billion batteries (!), says Professor Duchovny.
"The experiment we are going to do at the LHC is very special. Although we do not know what will be revealed in it, there is almost a certainty that something important will be revealed. We have every indication that we will find out important things. The significant increase in energy is very promising." Duchovny says and adds "the current theory is incomplete. The solution to the imperfection lies in the range of energies that the experiment will reach. This is a fun experience, and the feeling is that something good will come out of it."
The news on behalf of the Weizmann Institute as part of "Ideas" - January 2004
The Higgs show
Researchers and students at the Weizmann Institute came first in the competition
international for the discovery of a "fictitious matter particle"
"This will be the most complex machine ever built," says Prof. Ehud Duchovni from the Weizmann Institute of Science about the new particle accelerator now being built at the European Laboratory for Research in Particle Physics (CERN, on the France-Switzerland border). More than 2,000 physicists from about 50 countries are preparing to perform Using this accelerator - the construction of which will be completed in 2007 - a series of experiments is designed, among other things, to discover evidence for the existence of the "Higgs" particle, which according to the accepted physical theory ("the standard model") is responsible for the existence of all the mass in the universe.
In addition to building the accelerator, physicists all over the world, including at the Weizmann Institute of Science, are working on the construction of various components in the particle detector called ATLAS. This detector, which will identify and record the results of the particle collisions that will take place in the accelerator, will receive at any moment an amount of information greater than the amount of information flowing through all the telephone networks in the world combined. From this it is clear that the great challenge facing the scientists will be the need to process and decipher this enormous amount of information, and discover in it phenomena that have not yet been observed; For example, results indicating the presence of the "Higgs" particle.
The question is, how can one properly identify and interpret a phenomenon observed for the first time? In order to prepare for this confrontation, CERN decided to conduct a "dry" experiment: to create a fictitious information flow in the amount and nature of the information flow that will flow from the ATLAS detector in the real experiment, and to try to process and decode this fictitious information, and to detect in it phenomena that may indicate the presence of a particle ( fictitious) new. This fictitious information stream contained millions of events, and several clues to the existence of a new fictitious particle were hidden in it. The raw information was offered to dozens of groups of young researchers and students from universities and research institutes in different parts of the world, who competed among themselves in analyzing the information and "discovering" the fictitious new particle.
At the end of the international competition, a group of researchers from the Weizmann Institute of Science, under the guidance of Prof. Ehud Duchovni and Prof. Elam Gross, and with the participation of the post-doctoral researcher Dr. Michael Rivlin, and the research students Aryeh Melamed-Katz, Lydia Ziukowitz and Peter Rankel, came in first place. . Together with you, a group of researchers from the University of Cambridge, England, also came in first place. The first prize, a wooden thinking game, is currently displayed in the group's seminar room. The members of the group continue to prepare for the real thing, the flow of information that will come from the experiment in the new particle accelerator that will start operating in 2007.
An article about the competition in "New Scientist"
The home page of the competition
The home page of the Atlas experiment
Physics expert
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~710060735~~~95&SiteName=hayadan
