Over the past two years, the Higgs Boson has seeped into the popular consciousness, and with the announcement of this year's Nobel Prize, it is in the limelight once again. Yet, many people are still not quite sure what this particle is, and what, if anything, it has to do with Pakistan's only Laureate, Abdus Salam.The 2013 Nobel Prize for Physics recognized a mechanism whereby the breaking of symmetry causes a field to pervade the vacuum. To get a sense of what that means, think of the vacuum as the blank canvas upon which our universe is painted, and the Higgs field as a color wash covering the canvas. Had the canvas been pure white, the 'true' colors of our painting would show up; instead, we experience colors after they have been tinted by the background - the Higgs field taints our perception. Just because the canvas is blank doesn't mean there's nothing on it!
Vast ideas have many sides, and often, a different metaphor is needed to explain each facet. One catch phrase regarding the Higgs Boson is that it explains the origin of mass. To understand the connection, consider how we experience mass. When asked to judge how heavy something is, an instinctive reaction is to try pushing the object in question. Intuition tells us that if the same force is exerted on two objects, the heavier one moves slower than the lighter. If two balls, pushed with equal force across a flat surface move with the same speed, we conclude their masses are equal.
But what if the balls carry electric charge, and we perform this experiment in the background of a constant electric field? We might find one ball moves slower than the other, and mistakenly conclude that it is heavier, whereas in truth the masses of both are the same. The discrepancy arises because first ball is pushed in a direction where its motion is resisted by the field, whereas the second ball is pushed in an unaffected direction, and so, proceeds at its natural speed.
In a symmetric universe no direction would be singled out, and regardless of its orientation, very ball would whizz around equally fast. If, however, we introduce a field that violates symmetry, we can pick out a 'special' direction, along which balls will move slower, and hence, appear more massive.
Just as an electric field can be oriented along any axis, the Higgs field too, is free to choose a direction. An illustrative example is that of a marble in a Mexican hat. Poised on the hump of the sombrero, the marble is surrounded with infinite possibilities, each as good as the next, but its position is precarious and almost impossible to maintain. Sooner or later, it will roll down into the circular rim, spontaneously breaking the symmetry. The direction in which the marble falls is completely random; the point on the rim where it lands is not distinguished in any way, until by virtue of the marble landing, it becomes the point of reference for everything that happens from then on.
Mass, which we had thought of as an intrinsic attribute, turns out to be a perceived quantity, a manifestation of the interaction between an object and the background. Particles which appear identical in the absence of a field can take on a variety of appearances in its presence.
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