• A new Pope and a new particle – is it déjà vu?

    Habemus Papam et Deus Particular – We have a Pope and the God particle.
    The news bears an eerie likeness to Dan Brown’s plot in Angels and Demons.

    Last week two important events took place. In the Vatican, the College of Cardinals were guided by the Holy Spirit (or so the legend goes) to choose Jorge Mario Bergoglio as the new Pope of the Roman Catholic Church. As the world learned more about Pope Francis (who as it turns out is a chemistry graduate), not far from Rome, in La Thuile in Italy, physicists upped the ante. Guided by results from the Large Hadron Collider, the physicists announced they were now sure that they had found the God particle.

    So what? Well, in one meeting men dressed in red gowns chose a new direction for their institution. In the other meeting, men and women, some in suits, others in jeans, proclaimed it was time to move on to the next stage of understanding the universe we live in. As this is a science blog, let’s look at the latter news in more detail.

    Last July, CERN scientists announced that, they had found a new elementary particle weighing about 126 times the mass of the proton that was likely the long-sought Higgs boson. You can read more about the discovery in my earlier post. Unsure, what the Higgs boson is? The Higgs boson is what the Higgs field is made up of and it is the Higgs field which imparts mass to the simplest particles (e.g. electrons and quarks) that are the building blocks of all matter (you, me, everything we can touch and see). One analogy is to think about yourself swimming in a pool of water. As you (the particle) swim through the water (the Higgs field) you feel the friction of the water. The friction is analogous to the interaction that gives a particle in the Higgs field its mass. More interaction means implies a heavier particle. The Higgs bosons, which makes up the Higgs field are like the uncountably many water molecules that fill the swimming pool.

    Back in 2012, the two experiments, CMS and ATLAS, hadn’t collected enough data to say the particle was, for sure, the Higgs boson. Now, armed with more data from the LHC, they are reasonably certain that what they have found is a Higgs boson. When asked about the importance of the recent announcement, Andre David, a CMS Physicist, said, “We make progress slowly in trying to define things. We need to be very sure of what they are. We went from a Higgs-like object into a Higgs boson… it smells, quacks, walks exactly like a Higgs boson is supposed to.”

    Scientists like plots…and they love animated plots! In the video below, notice how as more data is collected, the signal for the detection at ~126 GeV rises above the background signal.

    Detecting a Higgs boson is rare, with just one observed for every 1 trillion proton-proton collisions but based on more than twice as much data as before, the results point firmly towards the particle first described in 1964 by Professor Peter Higgs. When a Higgs boson breaks down into lighter particles, two quantum properties of the boson, its spin and parity, affect the angles at which those lighter particles fly. Scientists from the ATLAS and CMS experiments studied decay pattern of the Higgs-like particle and found the Higgs-like boson is behaving the way the simplest type of Standard Model Higgs boson is supposed to behave. This discovery now eliminates some of the other competing theories for the Higgs boson and marks the end of a decades-long search for the particle, and the beginning of a new effort to understand its place in nature. It also paves way for the much anticipated Nobel Prize for Higgs et al. and perhaps the entire CERN team in the near future.

    What’s next? While many physicists will continue to study the properties of this Higgs boson, others hope that relatives of the Higgs particle await discovery. One theory, called supersymmetry, calls for five different varieties of Higgs boson, and could help us understand dark matter. But that will have to wait until 2015 when the collider is turned back on and it breaks its old record of colliding protons at an energy of 8 trillion electron volts and collides them at it is full potential of 13 trillion electron volts.

    The Higgs boson news last week coincided with not only with the papal appointment but also Einstein’s birthday and Pi Day… is the universe telling us something?

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