Dr. Enrique Krumovich, who completed his doctorate at the Technion and went on to a post at Duke University without moving from CERN, tells about the excitement on the day of analyzing the data from the experiment in the hope that data indicating new particles will appear
In the previous articles in the series, we reported on the four senior Israeli scientists at CERN, but Israel is represented at the particle accelerator by dozens of doctoral students and post-doctoral students, each of whom provides a unique perspective in the vast complex that includes thousands of scientists, engineers and technicians from all over the world.
As fate would have it, and just a few days before this article was published, researchers from another experiment at CERN, known as LHCb, claimed that Discovered clues to new physics
More on the subject on the science website
- Cern CEO Rolf Hoyer: My dream is to find the first particle of dark matter. First article following a tour of the Cern facilities
- CERN tour notes Part II: The door leading to the Big Bang
- CERN tour notes, part XNUMX Will we sail only if we know there is an America across the ocean? Prof. Eliezer Rabinovitch from the Hebrew University on the importance of basic science (Gallery - LHC)
- CERN Tour Notes Part 21 - Prof. Elam Gross: The discovery of the Higgs is the beginning of the new science of the XNUMXst century
At the end of April, the National Academy of Sciences and Arts held a tour of journalists who (also) write about science at the CERN facilities in Geneva. The members of the delegation and the HM among them met with the CEO of CERN and with Israeli scientists working at the facility, and conducted tours of the various facilities. One of these scientists is Kromovitch, 33 years old, married, born in Mexico and came to Israel as part of a science project for high schools called SciTech in 1997. He fell in love with the Technion and returned to Israel immediately after graduating from high school - a year later. At the Technion he studied all three degrees in the Faculty of Physics, where in the higher degrees he specialized in particle physics, under the supervision of Prof. Yoram Rosen and Prof. Shlomit Terem. Today he is still at CERN as part of a possible post-doctorate at the American Duke University. He leads a team of 16 researchers from all over the world: the team includes researchers from all over the world - Japan, Venezuela, Italy, England and, of course, the USA."
"In the particle accelerator we are looking for new physics. We are highly motivated to search for the new physics even though the basic model of physics - the standard model - functions well. However, there are things that cannot be explained within its framework, such as dark matter, and the inability to include gravity within the description of particles, and in addition to these empirical issues, there is also a theoretical problem known as the "hierarchy problem".
To explain what the problem of hierarchy is, Dr. Krumovich starts from the recent discovery of the Higgs particle, which has a mass of about 125 GEV. According to quantum theory, the mass of the Higgs boson was supposed to be much greater, and there is some factor that cancels this effect. This may be one of the clues that there is another physics responsible for this phenomenon."
Additional dimensions and new powers
"We are looking for a very heavy particle that breaks up into particles of the standard model, when the properties of that particle cannot be predicted within the framework of the standard model." Dr. Krumovich explains.
There are several theories for predicting the properties of the particle - for example theories that include additional dimensions according to which the universe does not consist of only three dimensions of space and one dimension of time. According to the theory there are additional dimensions with other properties, and if these particles are discovered, this will be evidence for the theory. Another possibility is that there are new forces that we have not seen until now. It may be that the Higgs is not a unique particle but a complex particle, that is, it is several particles that look like one particle to us. Although there is quite strong evidence that the Higgs is not a complex particle this hypothesis is still being tested.
How is this done from a technical point of view?
Krumovich: "Because the particles are very heavy, we need a lot of energy to produce them. We cause the protons to collide in order to produce these heavy particles. Like everything in quantum physics there is a certain chance to produce such particles, but there is a risk that in most cases they will not be produced. Many collisions need to be made so that in a small part of the cases such particles will be produced. At the Atlas facility, we photograph every such collision, collect the data and analyze it in order to check whether particles of interest to us were formed. In addition, we must examine many cases of the creation of each type of particle so that we know for sure that it is not a statistical fluctuation. The accelerator produces 20 million collisions per second, but only a fraction of them may be of interest. We operate a mechanism that quickly checks the data from the collision and which makes sure to keep only a few hundred collisions per second in our computer system. Atlas can be thought of as a digital camera that provides us with points in space, and we need to link all these points to trajectories in order to recover the particles from them. The next step is an analysis of this data that ultimately allows us to locate rare phenomena among all this enormous amount - particles that are created with a frequency of less than one per trillion."
Are you not encountering the physical limitations of the accelerator's performance?
"We are trying to analyze everything that the experiment allows us to get at the moment. We have a limit on the energy of the accelerator and the statistical amount of data we can collect. We analyze the data and then we draw a conclusion that allows us to rule out alternative theories that, if they existed, should have been revealed at these energies, and thus we narrow the range. The point is that after a theory is rejected, the theoretician scientists who formulated it come and make changes to it that will allow it to still live, despite its dying state."
"In addition to my work as a physicist, I am also involved in planning the next upgrade of the accelerator, which includes the construction of a new detector, so I must be present there. What is special about this profession is that the space we deal in is very wide, there is always a wide range of things that everyone deals with and it is a privilege to be able to deal in all these fields. One day you're in the lab developing a detector prototype, another day you're collaborating with many people on their projects, another day you're connecting cables in an experiment, another day you're sitting down to write a data analysis."
Will upgrading the accelerator make it possible to find new physics?
Krumovich: "Nature does not have to give us new physics exactly in the next experiment. I'm not signing that we will spend anything. Higgs also had indirect evidence of mass in a certain range but until we found it we were not sure we would find it. The process of analyzing the data is a double-blind experiment. In order not to bribe ourselves, we plan the data in a simulation, after that we ask for the approval of the CERN partnership, and only then open the truth data. The lecture lasts several hours, during which we are anxious to know whether new physics has been discovered. Most of the time nothing is discovered, but occasionally a new phenomenon is discovered. It's an amazing feeling to be there at this point in time."
Do we have to be here or can the work be done from the Technion or Duke?
"Being there has a lot of meaning because a lot of physics happens in the cafeteria, you sit with someone and can come up with ideas. Spontaneous interaction is very significant for physics, with the whole internet age. Although we work in a very distributed team, but still with all this there is no substitute for the informal meetings that may give rise to interesting topics for research."
