SUNDAY April 4, 2021
ECONOMY & BUSINESS Page 3
The bulging supply of young low-skilled workers is likely to exceed demand — Sabina Dewan
Story by: Zeeshan Ahmad
97 % of sentences were either commuted to life imprisonment or decided otherwise in 2018
ENVIRONMENT
EDUCATION
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We are forcing the sea to boil over and surge out onto us —Tofiq Pasha Mooraj
In our patriarchal society girls’ education has never been a priority — Shad Begum
Design by: Umar Waqas
I
n the words of one researcher, science is not meant to cure us of mystery. Instead, he argues, it is supposed to reinvent and reinvigorate. For us lay people, science remains a mystery sans reinvention. For reasons mundane and existential, most of us shy away from asking the fundamental questions. Perhaps its due to our own shyness, even fear, that many of us hold such awe for those who dare go intellectually where the rest of us are unwilling or incapable of going. Speaking of awe and mysteries, there are a handful of places around the world that evoke both while capturing our collective imagination. If I mention the European Organisation for Nuclear Research, it may or may not mean anything to most of us. But, if I use the acronym CERN, many may find their thoughts transported to the world of Dan Brown, of scientific intrigue and where the impossible becomes possible. Speaking still of mysteries, and of CERN, there is the question of antimatter, a material many of us lay people may confuse with the similar sounding yet wildly different concepts of dark matter and dark energy. Beyond our own mysterious understanding of it, lie the antimatter mysteries that the scientists who study it continue to reinvent and reinvigorate in their attempts to understand it. As luck, or perhaps fate, would have it, one of them is Pakistani. Who better to demystify both what we know at the moment about antimatter and what working at CERN entails.
Demystifying antimatter For Muhammad Sameed, a life’s yearning for understanding has led to a dream come true. The 32-year-old Islamabad native is among a mere handful of Pakistanis who would think themselves lucky for a chance to work at CERN. What is more in Sameed’s case, he is physicist involved in studying antimatter particles at one of the world’s premier physics research organisations. At CERN, Sameed is part of the ALPHA experiment, an acronym that stands for the Antihydrogen Laser Physics Apparatus. Just recently, the ALPHA collaboration effort succeeded in cooling down antihydrogen particles – the simplest form of atomic antimatter – with laser light. Speaking with The Express Tribune, the young scientist began by admitting that the wider scientific com-
munity had perhaps contributed to some of the public misunderstandings about antimatter. “I think it is us physicists’ fault for giving such similar names to such different concepts,” he said when asked about the difference between antimatter, dark matter and dark energy. Taking his own crack at remedying that, he explained: “Before we explain antimatter, it is important remember what matter is, at the subatomic level.” Most of us learn about atoms and how they are made of electrons, protons and neutrons in school. “But that is where the general awareness ends,” said Sameed. “If you look deeper, while electrons are fundamental particles – they belong to a family of particles called leptons – protons and neutrons are not. Those two are made up of two more kinds of fundamental particles: the quarks and the gluons, which bind them.” He added that all matter that surrounds us and that we can interact with is made of particles from two families, namely quarks and leptons. Both families consist of six kinds of particles each.
Since the discovery of the antielectron in the US almost 90 years ago scientists have discovered an antimatter counterpart to each regular matter particle we know of According to Sameed, we have known all of this since the early part of the previous century, when quantum mechanics was developed. “Where does antimatter come in? It was first articulated in a theoretical study by physicist Paul Dirac,” he shared. Dirac, while solving a quantum mechanics equation, arrived at two solutions, one positive and the other negative. “The positive one corresponded to the electron. Dirac initially disregarded the negative solution, but later used it to hypothesise the existence of ‘antielectrons’,” Sameed explained. “He
made that prediction in 1928, and just four years later, an American experiment actually discovered it.” How was the discovery made, you wonder? “We have all these particles from outer space that pass through our planet,” said Sameed. “If we apply a magnetic field to them, we can determine which direction these particles turn in. If electrons turn to one side, particles with the opposite charge would turn in the other direction.” The physicist shared that since the discovery of the antielectron almost 90 years ago scientists have discovered an antimatter counterpart to each regular matter particle we know of. “The story we physicists should be telling people is that not only is antimatter real, but that these are particles are found in nature,” he said. “The real question is this: we know from equations and experiments that when matter is produced – in a lab or after the Big Bang – an equal amount of antimatter is produced. So how is it that ‘regular’ matter became so dominant in our universe and why is there so little antimatter occurring in nature?” According to Sameed, all research into antimatter at CERN and other organisations is focused on this question: “What happened? Where did all the antimatter go?” One proposed explanation, he shared, is that antimatter has some as yet unknown property that converts it into regular matter in unequal amounts. “So by producing and trapping antimatter in a lab, we test it for various properties and whether those can explain what happened to most antimatter in nature. This has been the focus of research for the last 30 to 40 years.”
Cooling with lasers Explaining the recent ALPHA experiment with laser cooling, Sameed began by explaining the choice of antihydrogen. “Hydrogen is the simplest atom we know of, with just one proton and one electron. Antihydrogen, similarly, is the simplest antiatom,” he said. “You take an antiproton, get an antielectron to orbit it, and you should have an antihydrogen atom. But this is easier said than done,” he explained. “The main challenge with producing antihydrogen or any other antimatter particle is that if an anti-matter particle comes in contact with a regular matter particle, both are annihilated. So in order to capture anti-matter particles, you need to create perfect vacuum to ensure
We know when matter is produced an equal amount of antimatter is produced. So how is it that ‘regular’ matter became so dominant in our universe? CERN physicist Muhammad Sameed they don’t come in contact with matter particles.” Sameed added that the challenge isn’t just limited to creating vacuum either. “You need to make sure that the container being used is designed in a way to ensure antimatter particles don’t come in contact with its walls. This is done using electromagnetic fields.” Explaining how scientists study antimatter, Sameed began by explaining how regular matter particles would be studied. “Take a regular hydrogen atom which is in what we call a ‘ground state’ or normal state. If we shine a laser with a specific energy level onto that simple atom, its electron can jump into an ‘excited’ state.” He said that scientists have known about the effects of lasers on hydrogen atoms for a long time. “We know what frequencies can excite it. For our experiment, we thought to test the same on anti-hydrogen atoms. We wondered if it would react differently to regular hydrogen due to differences in energy levels or other properties. Perhaps our findings could help unravel some of the mystery around why there is so little antimatter in the universe?” CONTINUED ON PAGE 2