Friday, July 27, 2012


Boson Or Bust? Higgs And His Godless Particle

The recent announcement suggesting the discovery of the long awaited Higgs Boson, if confirmed, fills a gap in the theoretical description of elementary particles known as the Standard Model. It would still leave us far from the ultimate goal of combining gravity with the other major forces of nature.
Dr. NS Rajaram writes more on the latest ‘scientific discovery’

On July 4, 2012, scientists working at the Large Hadron Collider (LHC) at CERN in Geneva announced they had obtained data that suggested they had found evidence for the long sought after particle called the Higgs Boson. This was a search that had taken 5000 scientists more than ten years and cost over ten billion dollars making it the longest and most expensive particle hunt in history. (Two years ago when it was called the Big Bang experiment, the cost was said to be 14 billion dollars, but who is counting?)

Simulated Higgs Boson Signature
Simulated Higgs Boson Signature
Considering the scale and cost of the effort some hyperbole is probably to be expected. It was immediately hailed by the science community worldwide, with Stephen Hawkingcalling for a Nobel Prize for Peter Higgs after whom the Higgs Boson and its associated Higgs Mechanism are named. (This is passing strange as we shall see in due course.) Archana Sharma, an Indian member of the LHC immediately claimed that it was a discovery comparable to Newton’s discovery of gravity, Einstein’s relativity theory andquantum theory. (Correction: Newton did not discover gravity, he gave a mathematical description of it. Gravity was there all along)
This is a bit extreme to put it mildly. To begin with, there was no discovery but possible support for the existence of a hypothetical particle postulated by Peter Higgs and others way back, in 1964. It is not proper to compare something like this with major physical theories like relativity or quantum mechanics that changed our view of the world. The Higgs Boson, if proved to exist, at best fills a gap in what is known as the Standard Model used for describing the elementary particles (like proton, electron, etc) and the forces associated with them.
Bose to boson
The Higgs Boson is one of a class of elementary (or subatomic) particles called ‘bosons’ that are used to account for forces at the atomic level. They were named bosons by the Englishphysicist Paul Dirac after the Indian theoretical physicists Satyendra Nath Bose who first described the statistical behavior for the special but important case of photons or light particles. This was generalized and extended to other cases by Einstein. This is now called Bose-Einstein statistics. Along with the Fermi-Dirac statistics obtained a couple of years later, it marks the transition from the ‘old’ quantum theory of Planck and Einstein to particle physics. (The work of Pauli, Schrödinger and Heisenberg similarly led to ‘new’ quantum theory.)
To understand what this means we need to go back a hundred years and see where physics then stood. At that time the reality of atoms was accepted by most (but not all) scientists. They also knew that Einstein’s special relativity connected matter and energy via the equation E = mc2, the most famous if not the most important equation in physics. Max Planck in 1900 had introduced the idea of the quantum of energy as a mathematical tool to resolve a paradox in radiation. Einstein in 1905 had extended it to light claiming that light particles, now called photons were a physical reality and not just a mathematicaltrick. Since light waves were already known, this meant there was a duality in nature, with light being both wave and particle, just as matter and energy are different forms of the same thing.
In 1916, when Einstein completed his work on the general theory of relativity, Satyendra Nath Bose (born 1894) was a fresh graduate who had just been appointed a lecturer at the University of Calcutta. The excitement over the new physics, Einstein’s work in particular was so great that Bose taught himself both German and relativity theory which was not then part of the college science curriculum. Within a few years he had mastered both sufficiently to translate Einstein’s papers on special and general relativity from the original German into English, with some help from Meghnad Saha.
Peter Higgs
Peter Higgs
It was an exciting time in physics brimming with new ideas and results in relativity, quantum physics and atomic physics. In 1921, Bose had moved to the newly established Dakha University. He was already known as a talented young mathematician who had published several articles in the prestigious Journal of the Royal Society. So it is an error to describe him as a total unknown as many writers have tended to do. No matter, while going over Einstein’s work on quantum theory, Bose had a fundamental idea. He saw that photons tended to move to the same states that were occupied by other photons. He worked out the mathematics and sent his paper to the Royal Society for publication.
The Royal Society rejected his paper. These things happen all the time— there is no need to suppose any conspiracy. (In 1934, Nature had rejected Enrico Fermi’s paper on the neutrino later recognized as a landmark.) Undeterred, Bose sent the same paper to Einstein with a request to have it translated into German, for Germany was then the center of quantum physics. Einstein got it published with his own extensions. Bose (with Einstein) had described the statistical behavior of photons or light particles— the now famous Bose-Einstein statistics. It was only later, after the discovery of the Fermi-Dirac statistics that it was recognized that there are other particles with similar statistical properties (and spin) as the photon. Dirac coined the term ‘boson’ to describe them.
Sudarshan the tragic genius, greatest physicist after Feynman
Sudarshan the tragic genius, greatest physicist after Feynman
The Fermi-Dirac statistics describes the behavior of particles that can only occupy states that are not occupied by any other particle (unless they have opposite spin). They are called fermions (after Fermi). Fermions obey the Pauli Exclusion Principle while bosons do not. Also their spin values are different. Bosons have integer spins (0, 1, 2, …) while fermions have half integer spins (1/2, 3/2, 5/2, …). (The term ‘spin’ is unfortunate; it does not indicate rotation like a spinning top, but a dimension.)
Where does it leave physics?
With some oversimplification it may be said that the identification of bosons and fermions as basic elementary (subatomic) particles was the beginning of modern particle physics. All observed elementary particles are either fermions or bosons. At the present state of knowledge in quantum physics, the boundary between bosons and fermions is somewhat blurred, but it can be said that bosons are force carriers while fermions are responsible for mass (matter).
The next stage in the development of particle physics was the unification of three basic forces of nature— electromagnetism, weak force (radioactive decay) and strong force (nuclear force). Each is identified with a class of bosons. It is known that photons are the carriers of the electromagnetic field. W and Z bosons are the carriers of the weak force, while gluons are bosons that carry the strong force.
Where does the Higgs Boson—the so-called God Particle—fit into this picture? Uncomfortably between bosons and fermions; it is a boson but is also the medium that causes fermions to acquire mass from the Higgs Field through something called the Higgs Mechanism. This scenario was postulated by Peter Higgs along with six others in 1964. Higgs never claimed to be its sole originator. So where does Peter Higgs fit into the picture if a Nobel Prize is given as suggested by Hawking? Again uncomfortably with six others.
So, if the Hadron data is confirmed to be from the Higgs Boson, it may suggest that the basics of the Higgs Mechanism are valid— that fermions acquire their mass from the Higgs Field mediated by the Higgs Boson. Paradoxically the Higgs Boson is very heavy but being a boson it has no mass. What does this mean? Nobody is sure. All measurements are indirect and there are many variables and other possible explanations. The Higgs Mechanism is probably the simplest, or as physicists like to say, the most parsimonious. But nature may not be so kind, God Particle notwithstanding.
This, even if confirmed, does not complete the picture. We looked at only three forces leaving out the fourth and the most important— gravity. Gravity is the weakest and also the most important force in nature. Einstein showed that gravity is really the geometry of space (or space-time), while the quantum world seems to have no geometry, even though quantum physics is essentially a geometric theory based on concepts like Hilbert spaces and operators. Several workers (including this writer) believe that the many paradoxes that plague quantum physics like particles flying through double slits and non-locality and the like are the result of this mismatch— of imposing geometry on a space that has no geometry.
To get back, we are far away from having a theory that includes gravity. Einstein labored on such a theory for over forty years but failed.  An elementary particle called the graviton (a boson if it exists) has been postulated for the purpose, but it is so small (or weak) that its discovery is beyond the capability of existing or currently foreseeable technology.
The Nobel tragedy
In the aftermath of the Higgs Boson announcement, there was much hand-wringing in India that S.N. Bose who “discovered the boson” (which he didn’t) has been forgotten and his contribution ignored in the West. One prominent news channel screamed: “The God Particle’s neglected namesake.” The absurdity of this will be clear to anyone who takes the trouble to look through a textbook on modern physics. Most of them probably learnt of him for the first time when the press reported the discovery of the Higgs Boson. Bose’s contribution was widely recognized in his time both in India and the West. It was the English physicist Paul Dirac who coined the term ‘boson’. The fact that Einstein himself took the trouble to translate and publish Bose’s article should lay to rest the charge that Bose was ignored.
Bose did not get the Nobel Prize for his work. Should he have? It is hard to say. He lived and worked during a period when physics was in state of ferment with many spectacular discoveries that overshadowed his work. Not only Bose, but also George Gamow, Pascual Jordan and Samuel Goudsmidt who all made important contributions failed to get it. Neither did J. Robert Oppenheimer or David Bohm later. Although politics probably played a part in the denial of the Prize to Jordan and Bohm, this could not have been the case with Bose. He was simply unlucky to be working when physics was making extraordinary progress with many stalwarts in action. In a leaner period (like the present) he would have stood a better chance.
So it cannot be said that Bose was unjustly treated either in his own time or later. It is a different story, however, with another Indian scientist, E.C.G. Sudarshan, who, it can be argued is the world’s greatest theoretical physicist after Richard Feynman. He was cheated out of the Nobel Prize not once but twice— not just passed over but with others being rewarded for what was demonstrably his work.
If there is a tragic figure in modern physics it has to be George Sudarshan (born 1931) from Kerala. Sudarshan has been passed over for the Physics Nobel Prize on more than one occasion, leading tocontroversy in 2005 when several physicists wrote to the Swedish Academy, protesting that Sudarshan should have been awarded a share of the Prize for the Sudarshan diagonal representation (also known asSudarshan-Glauber representation) in quantum optics, for which Roy J. Glauber won his share of the prize. Worse, Glauber is credited with the Glauber-Sudarshan P-representation, even though it wasGeorge Sudarshan who developed it first, with Glauber only adopting it later.
A similar thing had happened before. In 2007, Sudarshan himself observed: “The 2005 Nobel Prize for Physics was awarded for my work, but I wasn’t the one to get it. Each one of the discoveries that this Nobel was given for work based on my research.” Sudarshan also commented on not being selected for the 1979 Nobel: “Steven Weinberg, Sheldon Glashow and Abdus Salam built on work I had done as a 26-year-old student.”
All this is a matter of record that not disputed by any scientist. Sudarshan is 81 now and one hopes that the Nobel Committee will recognize its error and award him the long overdue Prize. At one time even his name was excluded from the famous representation now known as the Sudarshan-Glauber representation. This at least has been corrected, but it is small consolation for such a great injustice. My appeal to Indian fans is, instead of lamenting over Bose, let us do all we can to see that George Sudarshan gets his due— the Nobel. Such activism led to recognizing J.C. Bose as the true discoverer of the radio rather than Marconi.
Finally, how about the Higgs Boson being the ‘God Particle’? Forget it. If God (or gods) does (or do) exist, and as omnipotent as believers hold, he should do better than stake his existence on such a messy and unstable particle as the Higgs Boson whose own existence is still in doubt.