Prof S. M. Deen [University of Keele , UK
Introduction
Recently there has been great excitement about Higgs bosons, so much so that its sighting at the CERN LHC (Large Hadron Collider) made front-page news, an unheard of public interest in science. More recently, Higgs boson was celebrated at the opening ceremony of the 2012 Paralympic Games. Some people even revere it, calling it the God particle – a term detested by scientists, and hence is not used here. In this article I shall try to explain in simple terms with non-scientists in mind, what is a Higgs field, what are Higgs bosons and how they are thought to create the mass of fundamental particles. However, to understand Higgs, we first need to understand what is meant by mass in physics. So I shall start with mass, and then offer a simple view of the Higgs field and bosons, before delving into slightly more elaboration.
Mass
Mass is the amount of matter (or substance) in an object. The mass is meant to be an intrinsic property of an object, which does not change, unless the object is moving (as given by an Einstein’s equation), but here we shall generally assume all objects to be stationary (i.e. at rest), unless otherwise implied.
The mass of an object is most commonly defined as its weight at sea-level on earth, but this definition confuses mass with weight. Weight is a force that is given as Mg (where M is the mass of the object, and g is the gravity). Therefore in the mass definition, the earth’s gravity is taken to be 1 (i.e. g = 1). Since the gravity does not change much on the earth’s surface, mass and weight have roughly the same numerical value, unless we leave the earth. If you go to the sun where gravity is 28 times that of the earth, the weight of a 1Kg object would be 28Kg, and likewise due to the weaker gravity of the moon, the same 1Kg object from the earth would weigh 1/6 of a Kg, but mass in both cases will remain unchanged at 1Kg. So let us summarise: the difference between mass and weight on the surface of the earth is mainly conceptual, but on other places where gravity is very different, the weight will change, but the mass by definition will remain the same.
There are many alternative ways of defining mass, though they all yield equivalent mass contents. One convenient alternative definition for our purpose here is: the mass of a (stationary) object is measured by the resistance it offers in moving it from its stationary position [more strictly, by its resistance to acceleration]. Imagine two solid cubes of identical dimensions, one of aluminium and the other of gold, sitting (i.e. stationary) on a friction-free surface. The gold cube will be the heavier of the two, but neither of these two cubes will move unless they are pushed (i.e. force is applied to them); a stronger push (and hence a greater force) will be needed to move the gold cube. But why?
You can truthfully say that this is so because gold is heavier, or you can equally truthfully say that this is because gold has more mass. But a physicist, aware of the definition of mass given above, would look at this slightly differently and say that this is so because these objects encounter resistance to movement, the gold cube encountering greater resistance than the aluminium cube. Now from the resistance encountered by each (i.e. the push required to move each) you can calculate their respective masses. Remember that this definition will yield the equivalent mass values that you would get by weighing them on the earth’s surface.
Aside: the unit used in measuring the mass of a fundamental particle is not gram (gram is too large for it, given that the mass of an electron in grams is about 10 –27). The units used are: million electron volt (MeV), billion electron volt (GeV, not called BeV for some reason), etc. These units are the energy equivalent of mass in grams obtained by applying Einstein‘s Mass Energy Equivalence. An electron has a mass of ½ MeV, while a proton has roughly 1 GeV (2000 times of an electron). Strictly speaking the proton mass is 938.27 MeVs, but people often use the rough value of 1 GeV.
The Basic Idea: Higgs Field and Higgs Boson
I trust you are comfortable with the idea that the mass of an object is nothing but the effect of the resistance it encounters in moving from its position of rest. If it is not clear, then please do email me for further clarification.
Now I assume we agree that it is the resistance that causes mass. A photon (the light particle) encounters no resistance, and hence it has zero mass. If you are a clever theoretical physicist like Peter Higgs, you would now be thinking: “Hmm. Can I contemplate a field (force) in the early universe that creates resistance?” There you will have the starting idea. But first I shall offer two analogies:
(1). If you are walking in water, say 3 feet (1 metre) deep, you will find it hard, due to water resistance to your movement. So you will have to apply more force than you would do while walking on the ground at the same speed. In this case water is the equivalent of the Higgs field and the water molecules are the Higgs bosons, which are interacting with your body creating resistance to your movements.
(2). Imagine a large bowl (the early universe), in which many balls of different types are moving freely at the speed of light, in this otherwise empty bowl. Now fill the bowl with sand completely, thereby submerging all the balls. Sand, we assume, will react differently with different types of balls, creating different amounts of resistance to different balls as they try to move though that sand. We imagine some balls will not react with sand at all – they are the mass-less balls that will still be moving at the speed of light, the photon being one such ball. Of the other balls, each will have a different amount of resistance (and hence different mass) in this sand-filled bowl. The sand that filled the bowl is equivalent to the Higgs field, and the grains of sand reacting with those balls (dragging them if you prefer) and causing resistance are the Higgs bosons.
Now some caveats to the analogies given above. First you can get out of the water or the balls can be taken out of the sand. But you cannot get out of the Higgs field, it permeates the whole universe, it is everywhere, inside and outside everything including of course ourselves. Thus everything in the universe is submerged in a Higgs ocean, if you like. Secondly while water and sand are visible, the Higgs ocean is not, like the gravitational and electromagnetic fields, which are not visible.
Further Elaboration
Background
Physicists have defined over the years the properties of fundamental particles, such as electron, quarks, W and Z bosons, photon, etc. However, one very important property they were significantly unable to explain was why a particle has mass. Peter Higgs came out with the idea of a new field with a characteristic force particle in 1964 – an idea that subsequently induced several other physicists to join in. One might speculate that these theoretical physicists realised that the only way to create resistance was to have a new field in which its force particles would react with the fundamental particles, obstructing their movements. I imagine they also came to the conclusion that since the mass of a fundamental particle is constant everywhere, the resistance it encounters also has to be constant everywhere, and hence the number of force particles has to be sufficiently large and uniformly distributed to maintain that constant resistance everywhere, unlike the electromagnetic field (or the gravitational field), where the average number of its force particles is zero everywhere. This is indeed the case with that new force and its particle as explained below. Soon the field became known as the Higgs field, and the particle the Higgs boson.
First why it is called a boson? There are two classes of particles in physics, one class is called Fermions following the work of Enrico Fermi of Italy with Paul Dirac of England, Fermi later emigrating to the USA. Electron, neutron, proton, etc. are fermions. The other class of particles is called Bosons, following the work of Satyendra Nath Bose of Dhaka University (Bangladesh), with Einstein in 1927. Bose emigrated to India in 1947, some years before my entry to the Dhaka University as a Physics student. Photon, W and Z Bosons and the Higgs particle belong to the boson class. Some sub-nuclear particles, such as neutrons and protons are made up of other particles (such as quarks), but the fundamental (equivalently, elementary) particles, such as electrons and quarks, are not made up of other particles.
In the mid-1970s came what is called the Standard Model of Particle Physics, which explains the creation of the early universe and its contents, including of course the formation of fundamental particles. Prof Abdus Salam of Imperial College with two other physicists from the USA shared the 1979 Physics Nobel Prize for it. Salam (from Pakistan) was the first Muslim to receive a Nobel Prize, and as it happened he was my teacher at Imperial College during my Particle-Physics PhD study (apologies for bragging). The Standard Model uses the idea of Higgs boson to create mass. Many aspects of the Standard Model have been subsequently verified by experiments, including the existence of the Higgs boson, it would seem, if the results of the CERN LHC (Large Hadron Collider) are finally reconfirmed.
Universe at the beginning and the evolution of the Higgs Field
Before we proceed, note that the restriction that ‘nothing can go faster than the speed of light’ never applies to the expansion of the universe itself (how privileged can you get?). Now, when the universe was born, it was very, very hot. At time 10-43sec [this is: 1 divided by (1043), i.e., 1 divided by (1 followed by 43 zeros) sec], its temperature was about 1032 degrees [this is 1 followed by 32 zeros]. The universe then started expanding very fast at a huge rate, possibly 1060 [i.e. 1 followed by 60 zeros, which is a trillion trillion trillion trillion trillion] times faster than the speed of light, or perhaps even faster. This enormous expansion took place between 10-36 sec and 10-34 sec after the birth of the universe [Note 10-36 sec is one trillionth of a trillionth of a trillionth of one sec, while 10-34 sec is 100 times larger than 10-36 sec, which is thus 100 trillionths of a trillionth of a trillionth of one sec]. By 10-34 sec, the universe grew by a colossal factor of at least 10100 [that is 1 followed by 100 zeros] in volume, possibly to an infinite size.
In other words, in 100 trillionths of a trillionth of a trillionth of one sec, the universe attained a huge size (possibly an infinite size), cooling itself down as it expanded. This is called the inflationary expansion phase of the early universe, after which the universe still continued (and still continues) to grow, though not at that fast rate. Before I proceed further, let us consider an analogy of water transformation: hot steam cools down, first to condensation, then to water and finally to ice, as the temperature gradually goes below zero. All these various forms are really the different phases of water displayed as it cools. Similarly the universe has many phases that emerge as it cools down.
As the universe cooled down further, some of the forces such as the gravitational and the electromagnetic forces evolved. Some fundamental particles were also born, but they all had zero mass. As the universe cooled further, the Higgs field (with its Higgs bosons) came into existence, but with fluctuating field strengths, which settled to its final value at about 10-18sec [one billionth of a billionth of one sec] after the birth of the universe when the temperature cooled down to about 1015 degrees [1000 trillion degrees]. The universe had now reached the second billionth of a billionth of the first sec of its life, and many other amazing things would happen before it became one sec old. If you are wondering about the stars and galaxies, they were formed some 380,000 years later – beyond our scope here. I should mention here that these times and temperatures are rough and speculative. Another point is that the famous BigBang idea of the creation of the universe is not favoured by many physicists these days, and hence I do not use the term here.
The Higgs field reacts with itself, and a Higgs boson has a mass of about 125 GeVs (i.e. about 120 proton masses). Note that the Higgs field and the mass of fundamental particles would disappear if we could raise the temperature of the universe above 1015 degrees, which of course we cannot do. The current average temperature of the universe is about -270C (about 2.73 degrees above the Absolute zero).
As mentioned earlier the average value of the other fields (such as electromagnetic or gravitational) is zero everywhere in the universe, the average number of their respective characteristic force particles being zero. In contrast (again as hinted earlier) this is not so with the Higgs field, which has a large average value (i.e. strength) everywhere in the universe, implying a large number of Higgs bosons everywhere, which react with the fundamental particles endowing them with their mass. If you add up all the masses thus created and the values of the Higgs bosons (field) in the universe, they would cancel each other out making the total mass content of the universe zero. This would happen if you could raise the universal temperature above 1015 degrees as mentioned earlier. So everything in this universe of ours is magic – nothing really exists.
Some Remarks
The Higgs process discussed above is one of several possible ways in which Higgs field/bosons might work, the correct one is expected to be determined by further experiments at CERN and perhaps elsewhere. In fact there could be several types of Higgs field and several types of Higgs boson. Also the large strength of the Higgs field I mentioned above could be negative. Worse still, the strength of the Higgs field could be different in different regions of the universe, creating chaos – that is, the masses of fundamental particles (and hence the physical laws) could be different in different parts of the universe. In that case we do not need to invoke the theory of multiverses, even this one universe of ours could have different physical laws in its different regions, where there may not be any atoms and molecules, let alone stars and galaxies, as we know them.
Finally, do not forget that the mass content I have discussed here constitutes only 5 percents of the universe – we know nothing much about the other 95 percents, made up of Dark Matter and Dark Energy. The little that we do know fills us with so much wonder and amazement, that even Einstein exclaimed (and we concur): Allahu Akbar.
© S. M. Deen, 2012.
END
Your comments and observations would be welcome at the blogsite
www.scienceunderislam.blogspot.com
Note that comments are subject to editing as required by law
Prof Deen has clearly explained the concept of mass and its difference with weight. He goes on to name the subatomic particles which have mass and those which are mass less. Then he has used simple analogies to explain to ordinary readers the concept of Higgs boson and how it creates (or gives) to mass to matter.
ReplyDeleteLater the reader can also learn about the early stages of the universe, each of which is infinitesimal fraction of a second, before the Higgs boson field came into being and that the stars galaxies and planets were formed much later.
Then he mystified us by using the wizardry of mathematical physics and concludes that “So everything in this universe of ours is magic – nothing really exists.”
Finally we have been returned to ignorance by the introduction of ‘dark matter ‘and ‘dark energy’ and Einstein’s exclamation of Allahu Akbar
Md Soukat Ali
Dear Prof Deen
ReplyDeleteI read your article "MASS AND HIGGS BOSONS" and was very impressed by the way you explain very complex issues in particle physics in a very simple way that is understood even by a secondary school student. I used to know that Higgs Bosons contribute to the formation of new nuclei, e.g. Helium inside the sun. The mechanism of change is provided by the W^- boson, which changes one of the neutron down quark into an up quark then disintegrates into an electron and an electron-antineutrino, as follows.
Now I know much more; thank you.
I am sending your article to my son Kamal who teaches physics at a secondary school in Kuwait.
PS: Did Einstein really exclaim Allahu Akber?
Dr Muafaq Wafi
I have read extensively on Einstein's biography, and it is well-known that Einstein said God is Great following Muslims' AllahuAkber. I think he uttered the Arabic words, but it could have been in German.
DeleteMisbah Deen
I have read extensively on Eintein's life and it is well-known that Einstein said Allahu Akbar, following the Muslim tradition. I think he said the words in Arabic, but it could have been in German. Misbah Deen
DeleteProf. Deen melted a very complex topic wonderfully into layman's vernacular. Excellent article.
ReplyDeleteDear Professor Deen
ReplyDeleteThe Higgs particle in the Qur’an
Congratulations on an excellent article.
There are 2 types of fundamental particles, the Fermions (protons, electrons) and the Bosons (force particles, which include the Higgs particle). Atoms (Fermions) and its subatomic particles are referred to in chapter 10-61. This states atoms have weight (and therefore mass) and that there are particles that have a smaller weight (smaller mass) and these small mass particles can only refer to subatomic entities. What about the Bosons (Higgs Particle)? The Qur’an forecasts the modern notion of an expanding universe: “With power, skill and energy did We lay the foundation of the universe according to specified conditions and certainly We are steadily expanding it” (51-47). Since the Qur’an predicts a Big Crunch in the distant future, the expansion will one day grind to a halt, the universe will contract and pass through a mirror image of what happened during the period of expansion. Remember, initially the universe was formless and filled with hot gas only (41-11). Only later did the gaseous material organize its self into cosmic systems (41-12). Thus in the final stages of the contraction phase the highly structured universe will become gaseous once more and eventually atomize. This deduction is suggested by 44-10 and 56-5. Since the successive phases of cosmic evolution in the Big Crunch scenario will have been reversed in the beginning of creation, it follows from 56-5 that the creation of matter in the cosmic fireball must have begun as subatomic particles and atoms.
In 35-1 the creation of the forces of nature is appropriately mentioned with the origin of the universe since they played a crucial role in its beginning and is evolution. It describes the essential quantum features of the forces of nature. Since we are dealing with origins and since matter began in particle form, it is reasonable that the forces originated in a similar fashion. Regarding the origin of the forces of nature the Qur’an declares: “The hidden (or unseen) forces (of nature) We created (in the beginning, long) before (the creation of man), out of intense heat” (15-27). Unseen may describe the invisibility of the forces and its associated fields. Hidden may allude to the belief that a deeper unity underlies the forces of nature. Their symmetrical relationship is hidden but may be detected under extreme temperatures. This interpretation is suggested by the fact that they originated from the same source – heat.
Combining all these verses, it is inferred that the universe began as energy – energy is the ultimate building block of nature – the foundation of the universe as stated in 51-48. The energy transformed into particles (two types: atoms and bosons which include the Higgs particle); it is postulated that the Higgs particle existed a fraction of a second after the Big Bang; the force particles (and its associated fields) are “unseen”. The Higgs particle is a form of energy, a messenger ie it possesses information (endows other particles with their appropriate mass?) and has a tremendous velocity. Chapter 20-50 states: "Your Lord is He who gives unto everything that exists its true nature, then guides it towards its goal". It's reasonable to interpret this verse in the light of the Higgs particle in the following way. Particles were created mass less and received their mass subsequently, in this way "reaching their goal". All the above verses relate to the standard model and the Higgs particle is an outflow of this model. Note these interpretation are different from the conventional ones - you have to examine the Arabic roots and other relevant verses in the Qur'an to explain my understanding of the verses.
Referring to my comment above, Bosons which include The Higgs particle being a form of energy, a messenger that possesses information and moving at great speed, is expressed in chapter 35-1 of the Qur'an
ReplyDeleteResponse to Brother Joseph Noor From Prof S. M. Deen
DeleteThank you for your comment. However I am personally against using the Quranic verses to support scientific discoveries, since religious truth (i.e. divine truth) is eternal and scientific truth is transient. The use of eternal truth to endorse transient truth seems unsound to me. .
An eternal truth never changes, it can only be fully understood by an entity that is “All Knowing”, that is God. We humans can have only a partial understanding of an eternal truth, which will vary with our level of knowledge. Since our knowledge changes with time, we must reinterpret the divine truth for a deeper understanding. In contrast scientific truth is transient – it is valid only until the next discovery that contradicts it. For example, at one time Newton’s Gravitation was the scientific truth, now it is Einstein’s General Relativity, which I am sure will be replaced by something else in the future. Likewise, some 150 years ago, scientists believed in something called “ether” that they said pervaded the universe. Einstein demolished it. Now we have “Higgs’ ocean” pervading the universe. I do not know how long this theory will last. Observe that it is the job of scientists to disprove earlier theories, and replace them with more advanced ones – this is the way science progresses. There is no eternal truth in science.
Some years ago when the Big Bang” theory of creation was the accepted scientific truth, I was present in a discussion of some well-known Quran translators who wanted to support the “Big Bang” theory by a Quranic verse. I argued against that idea, but unsuccessfully, since they had greater faith in scientific truth than I had. Today the “Big Bang” theory is no longer the flavour of the month [You might have seen the recent of repeat of the “Horizon” on the BBC4].
For more information on the difference between the religious and scientific truths, please see my book “Science Under Islam”, which also includes the observation of Al-Kindi, who died around 870CE.
I agree with Prof. Deen’s comment. Brother Joseph Noor’s explains in a very articulated manner how the scientific theories were already predicted in Quran. Though his explanation will be attractive to many Muslims, I am afraid, I cannot agree with him on the grounds given by Prof. Deen. As he states, and later explains with examples, “religious truth (i.e. divine truth) is eternal and scientific truth (theory or discovery) is transient. “
DeleteI wonder how many scientists of the heyday of Muslim civilization quoted verses from Quran each time they came up with a new scientific theory or proved a scientific law. I feel rather disappointed by seeing so many Muslim scholars referring to Quran like this.
Md. Soukat Ali
Dear Prof. Deen
ReplyDeleteI humbly disagree with some of your views. There are several hundred verses on science in the Qur’an; what is their purpose? The Book appeals to its readers: “Will they then not reflect on this Qur’an” 4-82? The Qur’an invites examination, it is provable and testable i.e. it adopts the scientific approach. The Book’s superior knowledge of the universe is to convince man of its divine origin. Scrutiny of its scientific verses is an effective way of testing its accuracy. I agree, the scientific verses can only be fully comprehended by the creator and man can only have partial understanding of such truths. But the Qur’an is guidance on all facets of the human condition including science. There is a dizzying array of eternal scientific truths in the Qur’an: the motion of celestial bodies in their respective orbits, the oval shape of the earth, the immutability of the laws of nature and so on. No future theory will ever predict a flat stationary earth. Sure, these phenomena maybe described more accurately in the future, but their foundation will remain unchanged.
The Qur’an often links moral and scientific statements to give the former more appealing power. For example, it compares a sinner to someone surrounded by darkness that prevails in the depth of the ocean, or to a person ascending into the sky constricting his chest. The darkness at the bottom of the sea and the thinning of air as one ascends, are relatively recent finds. Rejecting the moral message of the Qur’an would be tantamount to a rejection of its closely associated impeccable scientific message which is problematic. Poor vision in the depth of the ocean and a decrease oxygen pressure with increase altitude are phenomena valid for all time.
The Qur’an describes a creative process which is evolutionary in nature. There is an armour of text relating the principle of evolution. If modern man is the product of numerous transformations over geological time from humble chemicals in the earth, does death imply final extinction? In this evolutionary view the Hereafter is a logical if not a necessary step in man’s continuous evolutionary journey towards a higher life. Evolution according to the Qur’an is God’s way of implementing his majestic creation, and eternal organising principle.
Verse 77-25 gives insight into the nature of gravity – its universal and attractive features. It is a pulling force exerted by matter (earth). Another meaning is to grip (think of gravitational grip – everything is subject to its “grip”). The Arabic language is crucial to my argument – see below. Although Newton’s law of gravity is inadequate under certain conditions, its features as described in 77-25 have not changed. It is just that Newton’s mathematical description of gravity (which is still based on 77-25) is a partial truth. Einstein’s concept of gravity is also discussed in the Qur’an. If Newton had read these verses, he might have deduced this radical new vision of gravity and saved science a few centuries.
The Arabic language is a key component in proving the divinity of the Qur’an. No wonder the Qur’an exclaims in several verses, “This is an Arabic Qur’an!” If a new important theory is developed, the relevant scientific principles in the Qur’an will provide guidance as to whether it is in conformity with reality. If the particular theory is refined at a later stage, the rich Arabic meaning will accommodate the updated version. The Qur’an will never support a concept that will subsequently be shown to be incorrect, provided the basic rules of interpretation are strictly adhered to (especially 3-7). The same principle applies to all other scientific concepts. Since the Book argues its moral message, concept of justice, esoteric realities etc. on the basis of its scientific verses, it follows that such verses must be eternal.
Salaam
Joseph Noor