The Indian born particle physicist was awarded the CHIPP Prize 2016 on the occasion of the CHIPP annual meeting, which takes place between the 23rd and the 25th August in Lugano, Switzerland. ‘To get the CHIPP Prize makes me feel humbled and very happy’, says Mohamed Rameez, who commonly is referred to as just Rameez in the physics community. Rameez won the prize for his PhD thesis, which he completed this year at the University of Geneva in the field of neutrino research, supervised by his doctoral adviser Prof. Teresa Montaruli. Montaruli is one of the leading physicists in the IceCube Cooperation that searches for the tiny and yet obstinate elementary particles called neutrinos through a huge experiment in Antarctica. Rameez, like Montaruli is a part of the international collaboration, and he points out that he would not have been able to finish his doctoral thesis alone: ‘I have to emphasise that I work in a big collaboration of physicists, and everything I do is possible only because a lot of other people are doing their job exceptionally well.’
From engineering to physics
Rameez was born in Calicut, a coastal city in Kerala, the south western state of India. 'My given name is Mohamed Rameez and I have no surname; this is legally quite ok in India. I just prefer to be called Rameez because Mohamed is far too common and has religious connotations I don’t agree with', Rameez says. The sole son of a biologist and a businessman studied engineering on bachelor level at the Birla Institute of Technology and Science (BITS), one of India’s most recognized universities located in Rajasthan, the north of India. ‘Everyone who is good in maths in India does engineering because it's good for your career, and so did I‘, says Rameez. ‘But during the studies I realized that I was more interested in the abstract aspects by writing down and solving the physics problems than in the applied courses about how machines work.’ Subsequently after having earned a bachelor in engineering he switched to physics. In 2012 he completed his master degree in theoretical physics at BITS.
At the end of the master studies his interests switched to experimental particle physics (‘It sounds a little weird, I know.’). He then sought a research position in neutrino astronomy as he believed this discipline to be an emerging field in astronomy. So he came to Geneva in 2012 where Teresa Montaruli, one of the poineers of this field, offered him to do his PhD. ‘Teresa Montaruli accepted me even though I didn't have much of knowledge in the experimental particle physics field.’ The doctorate took him four years. For this scientific work Rameez has now been awarded with the CHIPP Prize 2016 – ‘for his leadership in the searches for dark matter annihilation in the sun with the IceCube Neutrino Observatory and his contribution to their theoretical interpretation’, emphasises the jury of the CHIPP Prize. Teresa Montaruli adds: ‘Rameez strikes everybody for his fast learning curve and his speed in achieving results. He is versatile, can go from measuring quantum efficiencies in laboratory to theoretical physics. He is also an amazing character, with an english-style sense of humor. He is independent and will achieve a brilliant academic and research career. He would cheer me and my group up cleverly every day!’
Dark matter in the sun
To come across a deeper understanding of the phenomena of dark matter – this is the general goal of the scientific work of Mohamed Rameez. Most of the physicists today are convinced that there is such a thing as dark matter which refers to a kind of matter which fills out the universe but could not be observed up to now because it is not interacting with the known matter. „We are reasonably certain that this up to now missed mass has the form of particles we have not yet detected’, Rameez explains, „we do not know the mass or the temperature or the velocity of this dark matter. We do not know where its particles are located exactly. Nevertheless there are a lot of hints that something like dark matter exists.’ In the preferred theory the particles composing dark matter are called WIMPs (weakly interacting massive particle).
To find evidence that supports the existence of dark matter is one of the main goals of current research in physics worldwide. For that purpose physicists have established a broad range of different theories and experiments to prove the existence both directly (e.g. by the XENON or the LUX experiment) or indirectly. One of the theories trying to prove the existence of dark matter indirectly postulates its existence in the interior of the sun: In this theory there exists in the interior of the sun both particles of dark matter and its antiparticles (means anti dark matter). When matter and anti matter get in contact they annihilate by emitting energy (radiation). In the mentioned theory, the annihilation of dark matter and anti dark matter in the interior of the sun would lead to the emission of neutrinos in the GeV energy scale (implying that they would be much more energetic than other, already known neutrinos with solar origin in the MeV scale). These neutrinos – after their journey through space arriving on earth – could be measured. In order to demonstrate this effect physicists have to build a neutrino measuring tool that can prove there are more neutrinos in the GeV energy range reaching the Earth from the direction of the Sun than from any other direction. „If you can show an excess of GeV neutrinos in the direction of the sun you have discovered dark matter’, Rameez says, ‘This is the smoking gun.’
IceCube has been looking for 'solar born' GeV neutrinos
The mentioned tool has been working since six years in the ancient ice of the South Pole. The experiment called IceCube measures neutrinos striking the earth from all directions of the universe (most of them created in the atmosphere by cosmic ray, some of them with cosmic origin). One of several purposes of the IceCube experiment is to measure if there are more neutrinos in the GeV energy range in the direction of the sun than in other directions – which could prove an excess of 'solar born' neutrinos (proving the aforementioned theory on the existence of dark matter in the interior of the sun). The measurement of high energetic 'solar born' neutrinos in the IceCube experiment – this is the main topic that Rameez has worked on in the last three years: ‘Thanks to my work we succeeded in improving the measurement sensitivity of 'solar born' neutrinos by a factor of almost 10 compared to previous analysis. We did this by employing new event reconstruction strategies and better data handling. If you want to see an excess of neutrino from the direction of the sun you have to bring your background signals as low as possible. I used new methods the reduce the background and to produce a very clean sample.’
That so far is the good news. The bad news is that – despite the improved sensitivity of neutrino detection – there is no proof for an excess in 'solar born' neutrinos up to now. Physicists in the IceCube experiment continue to collect information on incoming neutrinos. By collecting more data it could occur that they succeed to prove an excess within the next decade. ‘We have an upper limit, and it is possible that there is an excess lower than this limit.’ But Rameez is not convinced that this will really occur. ‘Till 2012 to 2013, or even last year, the belief was that all the dark matter was cold dark matter and all of the cold dark matter was WIMPs. People are starting to not believe this scenario anymore. That's the reason why I did a bit of model building for an alternate scenario of dark matter slightly different from WIMPs together with some theorists at the University of Geneva.’
A brief journey
In June 2016 Rameez took a further step in his career. After finishing his PhD thesis in Switzerland he moved as a post-doctoral fellow to the Niels Bohr International Academy (Niels Bohr Institute) in Copenhagen, Denmark. There he continues to work on neutrino astronomy, and he has started to work on cosmology too. For a scientist who is at home in the very cosmos a journey from India to Switzerland seems brief, and the journey from Geneva to Copenhagen even briefer.
Author: Benedikt Vogel