Everything that has a beginning has an end.

The Oracle in The Matrix had a lot of little gems that she liked to deliver with an interesting combination of didactic aplomb and relative indifference. And so she said: “Everything that has a beginning has an end.” It seems logical enough, and to be frank, anyone who has entertained the hope that things might not ever end has certainly only found disappointment, disillusionment and inevitably disproof… at the end. It is with these thoughts in mind that I have been following with some interest the developments in Geneva with regard to the Large Hadron Collider.

The LHC is an amazing machine built with the intention of simulating the Big Bang conditions. All jokes aside, this is an interesting goal. Lot of heat, lots of energy, lots of dark matter… and then boom – erm, rather  – BANG. Are we sure this is what we want to do? Of course, the road to Big Banging has not been without it’s obstacles – like after eight years of construction bringing the machine to fruition, it kind of blew up when they flicked the “On” switch. £24 million later, they got it up and running again. Then this month: work on the machine was again interrupted when a short circuit took out an electrical substation. The incident was blamed on a piece of bread dropped by a passing bird. Let that be a warning to all of you who are serving birds toast. [Of course it does make me wonder what kind of bird we are talking about, you know, it always is 'a simple question of weight ratios!'] But now… Eureka! They have done it, ar at least sort of. They have “managed to smash proton beams together for the first time” causing “scientists [to] rejoice!” How nice; rejoicing just in time for the holidays.

The part I have been thinking about is the relationship of beginnings and ends. You see, if the aim of the project is to recreate the Big Bang – spilling out “energy and matter at vast speeds that eventually became stars – including our sun – planets and then life itself” it seems like there might be some stuff to clean up afterward. Especially as they endeavor to explore dark matter, antimatter and supersymmetry. So then a beginning = an ending. Not sure I am ready. Not that one ever really is… But it makes me consider the merits of the Steady State Theory. This is the antithesis of the Big Bang Theory. It has mostly been debunked, and as it was inspired by a 1945 Orson Welles film, Dead of Night, I am not sure this debunking is undeserved. I mean, scientist I am not, but I am sort of prejudiced towards slightly more sophisticated reasoning than film noir. In a (non-scientific) nutshell, the Big Bang is spontaneous, crazy, chaotic, combustible creation, while the Steady State is a nice, evenly paced, semi-static addition to the existing universe, like expanding sameness. The Steady State purports that with regard ot the universe, there is no beginning and no end. It is the universe’s version of the Tortoise and the Hare.

I think that science aside, one’s personal predilection for one of these theories over the other might say a lot about innate personality characteristics. Are you Big Bangin’ or a Steady State? Slow and steady or wild and crazy? Spontaneous or deliberate? Apocalyptic over never-ending?

If reason dictates that what has a beginning would logically have an ending, I suppose faith dictates that nothing ever really ends. In some ways both sentiments are supported by the recent discovery of Planet GJ1214b. If we wreck this planet (through inadvertant or intentional activities) we can simply go find another one and carry on. Just like the Watchmen’s Dr. Manhattan says after vaporizing Rorschach: “Nothing ever ends,” and then leaves Earth for a different galaxy.

Mickey: The whole world’s comin’ to an end, Mal!
Mallory: I see angels, Mickey. They’re comin’ down for us from heaven. And I see you ridin’ a big red horse, and you’re driving them horses, whippin’ ‘em, and they’re spitting and frothing all ‘long the mouth, and they’re coming right at us. And I see the future, and there’s no death, ’cause you and I, we’re angels…
Mickey: I love you, Mal.
Mallory: I know you do baby, and I’ve loved you since the day we met.

Geneva, 20 November 2009. Particle beams are once again circulating in the worlds most powerful particle accelerator, CERN’s Large Hadron Collider (LHC). This news comes after the machine was handed over for operation on Wednesday morning. A clockwise circulating beam was established at ten o’clock this evening. This is an important milestone on the road towards first physics at the LHC, expected in 2010.

Great article over at the New Scientist, giving a digest of the things that the LHC is looking for.

This time, it’s for real, folks!  The Large Hadron Collider (LHC) is up and running (again), and has started circulating a beam.

For those who may not know, the LHC is only the biggest, baddest, and most powerful particle accelerator the world has seen to date, boasting a 27km circumference which crosses the border between France and Switzerland. Once the LHC is eventually ramped up to full power sometime after 2010, it will smash beams of electrons into each other at near light-speed to extend the limits of our understanding of the universe’s physics. Researchers are hoping to gain more insight into the Big Bang, discover new particles associated with supersymmetry, and possibly even discover the theoretical Higgs boson, which names the origin of mass in the universe.  Some researchers even liken it to ‘The Force’ from Star Wars (nerds can dream too).  The LHC is a collaboration between over 100 countries.

Various groups have criticized the LHC  with claims that it will destroy the planet by creating microscopic black holes or theoretical particles known as ’strangelets’. Two CERN-sponsored safety reviews, endorsed by the American Physical Society, were conducted and state there is no cause for concern. I, for one, am flipping excited to see what the research uncovers.

The fabric of the cosmos: Space, time, and the texture of reality
QB982 .G74
523.1

Google books

• Discrete non-commutative integrability: the proof of a conjecture by M. Kontsevich. (arXiv:0909.0615v1 [math-ph])
• Stochastic quantization and the role of time in quantum gravity. (arXiv:0908.4224v1 [hep-th])
• Division algebras and supersymmetry. (arXiv:0909.0551v1 [hep-th]) (Division Algebras and Supersymmetry)
• General relativity with small cosmological constant from spontaneous compactification of Lovelock theory in vacuum
• Quantization of Integrable Systems and Four Dimensional Gauge Theories. (arXiv:0908.4052v1 [hep-th])
• Introduction to Special Issue: Integrable Quantum Systems and Solvable Statistical Mechanics Models
• Entangled quantum states in a local deterministic theory. (arXiv:0908.3408v1 [quant-ph])
• Dequantization of the Dirac monopole
• The hidden mathematics of bathrooms
• Where Have All the Solitons Gone?
• This Week’s Finds in Mathematical Physics (Week 278)
• B-N-R Part 1: Twisted Endomorphisms, B-N-R Part 2: Moduli of Vector Bundles

• Institutions slap down those who speak up, argues campaigning scholar
• Can Science Be “Humanized?”
• Science Reporting and Evidence-Based Journalism
• They Might Be Giants Keeps Pop Kid-Friendly With Smart ‘Here Comes Science’
• An Update on C. P. Snow’s “Two Cultures”

Have quantum particles and gravity been reconciled?
Whatever will we do with all that string we’ve been collecting?

“… Matter is governed by the laws of quantum mechanics, but so far, Einstein’s theory has resisted all attempts to reconcile it with quantum mechanics. Our understanding of subatomic phenomena is encoded in the standard model of elementary particle physics (based on an extension of quantum electrodynamics called Yang-Mills theory) which, for all we know, correctly describes the interactions of known matter within relativistic quantum field theory. This is an elaborate mathematical framework, which took many decades to develop and still presents many difficulties. These are due in particular to the necessity of having to deal with infinite expressions appearing at intermediate stages of every calculation, and their removal by a procedure referred to as renormalization. Infinities generally arise because of the pointlike nature of elementary particles, implying short distance singularities in the formulas (or “ultraviolet infinities” in momentum space). To this day we are not sure whether quantum field theory makes sense as a mathematical theory, but we do know that it works exceedingly well in perturbation theory, yielding spectacular agreement between theory and experiment. However, applying the established rules of quantum field theory to Einstein gravity and its generalizations results in complete failure—with one possible exception: As Zvi Bern, John Carrasco, and Henrik Johanssen at UCLA, Lance Dixon at the Stanford Linear Accelerator Center, and Radu Roiban at Pennsylvania State University, all in the US, report in Physical Review Letters, N=8 supergravity, distinguished among all other field theories by its maximal supersymmetry, may evade this dilemma…”

Vanquishing Infinity: Ultraviolet Behavior of N=8 Supergravity at Four Loops – APS Viewpoint

Often in mathematics we work in an algebra with the property that the “degree” of an element has a multiplicative property. For example, in a polynomial ring in variables we can define the degree of a monomial to be the vector of its degrees with respect to each variable, and the product of monomials corresponds to the sum of vectors. More typically we can define the degree of a monomial to be its total degree (the sum of the components of the above vector); this degree is also multiplicative.

Algebras with this additional property are called graded algebras, and they show up surprisingly often in mathematics. As Alexandre Borovik notes, when schoolchildren work with units such as “apples” and “people” they are really working in a -graded algebra, and one could argue that the study of homogeneous elements (that is, elements of the same degree) in -graded algebras is the entire content of dimensional analysis.

At this point, I should give some definitions.

To define a graded algebra, we want to generalize the definition of a monomial. To say that a polynomial in one variable can be uniquely written as a sum of monomials is equivalent to giving a direct sum decomposition

where denotes the monomials of the form . Since the product of a monomial of degree with a monomial of degree is a monomial of degree , and ranges over the non-negative integers, we call this a -graded algebra.

In general, given a semigroup , a -graded algebra is an algebra with a direct sum decomposition

with the property that the multiplication sends the product of an element of and an element of to an element of . The elements of the factors are called the homogeneous elements, and the value of is called the degree. If you’re unfamiliar with direct sums, just remember that it means that any element of can be written uniquely as a sum of homogeneous elements. Because polynomial rings are the prototypical example, the case is referred to as “graded.”

Note that a “polynomial” (a sum of homogeneous elements of different degree) doesn’t necessarily have a well-defined degree; we aren’t requiring that have an ordering.

Graded algebras seem to appear whenever symmetry or homogeneity are important, although I don’t have much experience with their more sophisticated uses. Below are a few examples.

Fourier transforms

Every function can be uniquely written as the sum of an even function and an odd function. Generically, this takes the form

.

This gives the set of functions the structure of a -graded algebra; the direct sum decomposition is into the even and odd functions.

More generally, let be a primitive root of unity and say that a function has weight if . This gives the set of functions the structure of a -graded algebra; the direct sum decomposition is into the functions of weight . You might know this as the discrete Fourier transform or as the decomposition of a representation of into its irreducible one-dimensional representations. For example, for the decomposition into functions of weight takes the form

.

Even more generally, let be a locally compact abelian group and let denote its Pontryagin dual, i.e. the continuous homomorphisms . Let be a space on which acts continuously, and given a character , say that a function has weight if for every . Subject to technical assumptions, this gives the space of functions the structure of a -graded algebra; the direct sum decomposition is into the functions of weight . (If isn’t discrete; the direct sum is replaced by an integral.) For more details, see Terence Tao’s notes on the Fourier transform. With (the circle group), (the circle), and we recover the usual gradation on the space of Fourier series of functions on the circle (equivalently, the space of Fourier series of periodic functions on the real line).

Commutative algebra

A polynomial ring is a graded algebra under total degree. This allows us to focus our attention on homogeneous polynomials, since those are the important ones in algebraic geometry. Given a graded algebra , define and define the Hilbert series

.

One can verify that when the Hilbert series is , and this should be familiar if you did the exercise about symmetric functions awhile back. Hilbert series behave well under the obvious operations: they are additive under direct sum and multiplicative under tensor product, provided the degree of a tensor product is defined appropriately. One can think of this as a “linearization” of the properties of combinatorial generating functions under disjoint union and Cartesian product. It is therefore reasonable to expect that the Hilbert series of a graded algebra encodes information about its structure.

Hilbert series can be used to study algebraic varieties, as follows: given a projective variety defined over , the ring of polynomial functions is a quotient of by the ideal of functions in vanishing on , hence inherits a gradation. The Hilbert series of a variety can be used to define its dimension, as follows.

Theorem: There exists a polynomial (the Hilbert polynomial) such that for all sufficiently large . The degree of this polynomial is the dimension of .

Intuitively, the degree of the Hilbert polynomial measures the number of “degrees of freedom” that polynomial functions on have. For the ring of functions is and the Hilbert polynomial is . For the Segre variety , the ring of functions is . Its Hilbert series begins

and we can compute its Hilbert polynomial as follows: after replacing the factor by in every monomial, the space of monomials of degree consists of

• Monomials in ; there are of these.
• Monomials in with a factor of ; there are of these.
• Monomials in with a factor of ; there are of these.

This gives the Hilbert polynomial , hence has dimension ; in fact, it’s a doubly ruled surface.

I haven’t checked, but I believe this generalizes: the Segre embedding might correspond to the Hadamard product of Hilbert series in general.

Supersymmetry

Now we enter the realm of things I don’t understand. A -graded algebra is called a superalgebra. Superalgebras have an even part and an odd part, as we have seen. A good example of a superalgebra is the ring of invariants of the alternating group acting on by permutation of the variables. The even part consists of the polynomials invariant under , the symmetric polynomials, and the odd part consists of the polynomials that gain the sign of a permutation under permutation, the alternating polynomials.

Supersymmetry is an idea from physics relating bosons to fermions. According to Masoud Khalkhali, if is the Hilbert space of states of a single boson, then the Hilbert space of states of bosons is the symmetric tensor power . If is instead the Hilbert space of states of a single fermion, then the Hilbert space of states of fermions is the exterior power ; this is the Pauli exclusion principle.

The exterior algebra of a -dimensional vector space has Hilbert series , since by Pauli exclusion a monomial of degree corresponds to a subset of size of basis vectors. In other words, fermion = subset. The symmetric algebra of can be identified with the space of polynomials in variables, so as we saw before it has Hilbert series . In other words, boson = multiset. The “supersymmetry” relating bosons and fermions is hinted at by the following:

.

The next GILA post will attempt to discuss these issues from a combinatorial perspective.

Springer Supersymmetry Structure and Phenomena Extensions of the Standard Model Oct 2001
Supersymmetry: Structure and Phenomena: Extensions of the Standard Model (Lecture Notes in Physics Monographs)
Springer | ISBN: 3540424423 | 2001-10-16 | PDF | 169 pages | 5 Mb

The book is a fairly non-technical introduction to modern supersymmetry phenomenology, approaching the subject in new and unique ways. It is suitable both for theorists and experimentalists, and emphasizes an intuitive grasp of the subject. Theoretical and experimental motivations, and the status and prospects of low-energy supersymmetry are discussed. It is shown by explicit construction that the stabilization of any perturbative theory which contains fundamental scalar bosons naturally leads to the notion of supersymmetry. The minimal supersymmetric extension of the standard model is then pedagogically defined and its experimental status is summarized. Renormalization of the models, including unification, is discussed and the linkage between high and low energies is demonstrated, providing a potential probe of Planck-scale physics such as unified theories. Besides a host of other phenomena, Higgs physics is discussed and the Higgs mass is shown to provide a crucial test of nearly all supersymmetric theories.

download Here

password tactools.org

http://vip-file.com/download/ac1193102237/3540424423.Springer.Supersymmetry.Structure.and.Phenomena.Extensions.of.the.Standard.Model.Oct.2001.pdf.html


Now you too can learn supersymmetry!

The other parts–this is part 1 of 8–are available on YouTube. YouTube offers great possibilities for distance learning for enrichment and differentiated instruction.

The last week of the semester was dedicated to Feynman rules in superspace. Before we go into that, it is good to review and set our conventions in superspace.

A remark: as in any quantum field theory analysis, here we will see the need for regularization. Now we need to to preserve the supersymmetry of the theory and the task of finding a regulator that obeys this criteria is non-trivial. Nevertheless, there exist such regularization schemes, namely dimensional reduction.

In any case, as action we will take the Wess-Zumino model coupled to super Yang-Mills. Of course this theory only has simple supersymmetry, but actually this is one of the only cases where superspace methods are useful. I do not want to rule out superspace methods for extended supersymmetry since one never knows what one might end up doing for his/her Ph.D. thesis. The action has the form:

.

The prepotential is

.

In four-dimensional Minkowski spacetime the Lorentz group is doubly covered by . We will label spinors with a Weyl index . The supercovariant derivatives, (giving objects that are covariant under supersymmetric transformations) are defined as follows:

Now we set the convention for raising and lowering Weyl indices (which actually we do not follow in the definition of the supercovariant derivatives): Weyl indices are raised with the two-dimensional antisymmetric symbol in the ¨from north-west to south-east¨ fashion. Namely,

The bars on spinors with dotted indices will be omited in what follows (they are redundant anyway). For example, we have the anticommutators for the supercovariant derivatives:

Now we move on to integration. We start with

Similarly for the dotted coordinates:

This expression follows from the single integration:

The integral of anticommuting variables can be written in terms of the derivative.

This will be useful later. Total supercovariant derivatives integrate to zero:

Here we have ignore boundary terms. Integration over all superspace can be expressed as

Now we turn to chiral superfields. A superfield is a function that is defined on superspace (i.e. it has dependence on the spacetime coordinates and the supercoordinates also). A chiral superfield satisfies the constraint:

Either      or      but not both.

With chiral superfields one can do wonders. For example, sticking to the first choice for constraint defining a chiral superfield,  we have the property

This is useful when re-writing chiral integrals as integrals over the whole supercoordinates:

We have forgotten about Dirac delta functions for supercoordinates! For a single supercoordinate we define:

In particular, for the case of the identity function we get

This result can be generalized to the full superspace integral:

(Writing the integral as derivatives as discussed above.) The solution to this equation is

We can mention some properties related to this delta function:

the higgs boson and the Large Hadron Collider

“Parsing the God Particle, the Ultimate Metaphor”

Large Hadron Collider @ CERN

Yesterday Sven Heinemeyer kindly provided me with an updated version of a plot which best describes the experimental constraints on the Higgs boson mass, coming from electroweak observables measured at LEP and SLD, and from the most recent measurements of W boson and top quark masses. It is shown on the right (click to get the full-sized version).

The graph is a quite busy one, but I will try below to explain everything one bit at a time, hoping I keep things simple enough that a non-physicist can understand it.

The axes show suitable ranges of values of the top quark mass (varying on the horizontal axis) and of the W boson masses (on the vertical axis). The value of these quantities is functionally dependent (because of quantum effects connected to the propagation of the particles and their interaction with the Higgs field) on the Higgs boson mass.

The dependence, however, is really “soft”: if you were to double the Higgs mass by a factor of two from its true value, the effect on top and W masses would be only of the order of 1% or less. Because of that, only recently have the determinations of top quark and W boson masses started to provide meaningful inputs for a guess of the mass of the Higgs.

Top mass and W mass measurements are plotted in the graphs in the form of ellipses encompassing the most likely values: their size is such that the true masses should lie within their boundaries, 68% of the time. The red ellipse shows CDF results, and the blue one shows DZERO results.

There is a third measurement of the W mass shown in the plot: it is displayed as a horizontal band limited by two black lines, and it comes from the LEP II measurements. The band also encompasses the 68% most likely W masses, as ellipses do.

In addition to W and top masses, other experimental results constrain the mass of top, W, and Higgs boson. The most stringent of these results are those coming from the LEP experiment at CERN, from detailed analysis of electroweak interactions studied in the production of Z bosons. A wide band crossing the graph from left to right, with a small tilt, encompasses the most likely region for top and W masses.

So far we have described measurements. Then, there are two different physical models one should consider in order to link those measurements to the Higgs mass. The first one is the Standard Model: it dictates precisely the inter-dependence of all the parameters mentioned above. Because of the precise SM predictions, for any choice of the Higgs boson mass one can draw a curve in the top mass versus W mass plane. However, in the graph a full band is hatched instead. This correspond to allowing the Higgs boson mass to vary from a minimum of 114 GeV to 400 GeV. 114 GeV is the lower limit on the Higgs boson mass found by the LEP II experiments in their direct searches, using electron-positron collisions; while 400 GeV is just a reference value.

The boundaries of the red region show the functional dependence of Higgs mass on top and W masses: an increase of top mass, for fixed W mass, results in an increase of the Higgs mass, as is clear by starting from the 114 GeV upper boundary of the red region, since one then would move into the region, to higher Higgs masses. On the contrary, for a fixed top mass, an increase in W boson mass results in a decrease of the Higgs mass predicted by the Standard Model. Also note that the red region includes a narrow band which has been left white: it is the region corresponding to Higgs masses varying between 160 and 170 GeV, the masses that direct searches at the Tevatron have excluded at 95% confidence level.

The second area, hatched in green, is not showing a single model predictions, but rather a range of values allowed by varying arbitrarily many of the parameters describing the supersymmetric extension of the SM called “MSSM”, its “minimal” extension. Even in the minimal extension there are about a hundred additional parameters introduced in the theory, and the values of a few of those modify the interconnection between top mass and W mass in a way that makes direct functional dependencies in the graph impossible to draw. Still, the hatched green region shows a “possible range of values” of the top quark and W boson masses. The arrow pointing down only describes what is expected for W and top masses if the mass of supersymmetric particles is increased from values barely above present exclusion limits to very high values.

So, to summarize, what to get from the plot ? I think the graph describes many things in one single package, and it is not easy to get the right message from it alone. Here is a short commentary, in bits.

• All experimental results are consistent with each other (but here, I should add, a result from NuTeV which finds indirectly the W mass from the measured ratio of neutral current and charged current neutrino interactions is not shown);
• Results point to a small patch of the plane, consistent with a light Higgs boson if the Standard Model holds
• The lower part of the MSSM allowed region is favored, pointing to heavy supersymmetric particles if that theory holds
• Among experimental determinations, the most constraining are those of the top mass; but once the top mass is known to within a few GeV, it is the W mass the one which tells us more about the unknown mass of the Higgs boson
• One point to note when comparing measurements from LEP II and the Tevatron experiments: when one draws a 2-D ellipse of 68% contour, this compares unfavourably to a band, which encompasses the same probability in a 1-D distribution. This is clear if one compares the actual measurements: CDF (with 200/pb of data), DZERO (with five times more statistics), LEP II (average of four experiments). The ellipses look like they are half as precise as the black band, while they are actually only 30-40% worse. If the above is obscure to you, a simple graphical explanation is provided here.
• When averaged, CDF and DZERO will actually beat the LEP II precision measurement -and they are sitting on 25 times more data (CDF) or 5 times more (DZERO).

I have no idea if The Manga Guide to Databases will be any good (the publisher sez, “In The Manga Guide to Databases, Tico the fairy teaches the Princess how to simplify her data management. We follow along as they design a relational database, understand the entity-relationship model, perform basic database operations, and delve into more advanced topics. Once the Princess is familiar with transactions and basic SQL statements, she can keep her data timely and accurate for the entire kingdom. Finally, Tico explains ways to make the database more efficient and secure, and they discuss methods for concurrency and replication.”) but I sure hope it’s the start of a trend. I want a manga guide to supersymmetry, the surplus labor theory of value, tensor calculus and many other elusive concepts.

Manga guide to databases – Boing Boing

The LHC has been in construction for some 13 years

Scientists have hailed a successful switch-on for an enormous experiment which will recreate the conditions a few moments after the Big Bang.

They have now fired two beams of particles called protons around the 27km-long tunnel which houses the Large Hadron Collider (LHC).

The £5bn machine on the Swiss-French border is designed to smash protons together with cataclysmic force.

Scientists hope it will shed light on fundamental questions in physics.

The first – clockwise – beam completed its first circuit of the underground tunnel at just before 0930 BST. The second – anti-clockwise – beam successfully circled the ring after 1400 BST.

We will be looking at what the Universe was made of billionths of a second after the Big Bang  Dr Tara Shears, University of Liverpool What is the Large Hadron Collider?

So far, all the beams have been stopped, or “dumped”, after just a few circuits.On Thursday, engineers hoped to inject clockwise and anti-clockwise protons again, but this time they plan to “close the orbit”, letting the beams run continuously for a few seconds each.

The BBC understands that low-energy collisions could happen in the next few days. This will allow engineers to calibrate instruments, but will not produce data of scientific interest.

“There it is,” project leader Lyn Evans said when the beam completed its lap. There were cheers in the control room when engineers heard of the successful test.

He added later: “We had a very smooth start-up.”The LHC is arguably the most complicated and ambitious experiment ever built; the project has been hit by cost overruns, equipment trouble and construction problems. The switch-on itself is two years late.

The collider is operated by the European Organization for Nuclear Research – better known by its French acronym Cern.

The vast circular tunnel – or “ring” – which runs under the French-Swiss border contains more than 1,000 cylindrical magnets arranged end-to-end.

The magnets are there to steer the beam around this vast circuit.

Eventually, two proton beams will be steered in opposite directions around the LHC at close to the speed of light, completing about 11,000 laps each second.

At allotted points around the tunnel, the beams will cross paths, smashing together near four massive “detectors” that monitor the collisions for interesting events.

Scientists are hoping that new sub-atomic particles will emerge, revealing fundamental insights into the nature of the cosmos.

Major effort

“We will be able to see deeper into matter than ever before,” said Dr Tara Shears, a particle physicist at the University of Liverpool.

“We will be looking at what the Universe was made of billionths of a second after the Big Bang. That is amazing, that really is fantastic.”

The LHC should answer one very simple question: What is mass?

LHC DETECTORS ATLAS - one of two so-called general purpose detectors. Atlas will be used to look for signs of new physics, including the origins of mass and extra dimensions CMS - the second general purpose detector will, like ATLAS, hunt for the Higgs boson and look for clues to the nature of dark matter ALICE - will study a “liquid” form of matter called quark-gluon plasma that existed shortly after the Big Bang LHCb - Equal amounts of matter and anti-matter were created in the Big Bang. LHCb will try to investigate what happened to the “missing” anti-matter

“We know the answer will be found at the LHC,” said Jim Virdee, a particle physicist at Imperial College London.

The favoured model involves a particle called the Higgs boson – dubbed the “God Particle”. According to the theory, particles acquire their mass through interactions with an all-pervading field carried by the Higgs.

The latest astronomical observations suggest ordinary matter – such as the galaxies, gas, stars and planets – makes up just 4% of the Universe.

The rest is dark matter (23%) and dark energy (73%). Physicists think the LHC could provide clues about the nature of this mysterious “stuff”.

But Professor Virdee told BBC News: “Nature can surprise us… we have to be ready to detect anything it throws at us.”

Full beam ahead

Engineers injected the first low-intensity proton beams into the LHC in August. But they did not go all the way around the ring.

Technicians had to be on the lookout for potential problems.

Steve Myers, head of the accelerator and beam department, said: “There are on the order of 2,000 magnetic circuits in the machine. This means there are 2,000 power supplies which generate the current which flows in the coils of the magnets.”

If there was a fault with any of these, he said, it would have stopped the beams. They were also wary of obstacles in the beam pipe which could prevent the protons from completing their first circuit.

Superconducting magnets are cooled down using liquid helium

Mr Myers has experience of the latter problem. While working on the LHC’s predecessor, a machine called the Large-Electron Positron Collider, engineers found two beer bottles wedged into the beam pipe – a deliberate, one-off act of sabotage.

The culprits – who were drinking a particular brand that advertising once claimed would “refresh the parts other beers cannot reach” – were never found.

In order to get both beams to circulate continuously, engineers will “close the orbit”. The beams themselves are made up of several “packets” – each about a metre long – containing billions of protons.

The protons would disperse if left to their own devices, so engineers use electrical forces to “grab” them, keeping the particles tightly huddled in packets.

Once the beams are captured, the same system of electrical forces is used to give the particles an energetic kick, accelerating them to greater and greater speeds.

Long haul

The idea of the Large Hadron Collider emerged in the early 1980s. The project was eventually approved in 1996 at a cost of 2.6bn Swiss Francs, which amounts to about £1.3bn at present exchange rates.

However, CERN underestimated equipment and engineering costs when it set out its original budget, plunging the lab into a cash crisis.

CERN had to borrow hundreds of millions of euros in bank loans to get the LHC completed. The current price is nearly four times that originally envisaged.

During winter, the LHC will be shut down, allowing equipment to be fine-tuned for collisions at full energy.

“What’s so exciting is that we haven’t had a large new facility starting up for years,” explained Dr Shears.

“Our experiments are so huge, so complex and so expensive that they don’t come along very often. When they do, we get all the physics out of them that we can.”

Engineers celebrated the success with champagne, but a certain brand of beer was not on the menu.

Source:

“‘Big Bang’ experiments starts well”, BBC News Online, Science/Nature, Paul Rincon, 10th Sept 2008

Source: http://cdsweb.cern.ch/record/840316?ln=en

“As a project, it’s magnificent,” says Prof Frank Wilczek of MIT, who has received death threats from some of the cranks who fear the start of the machine could mark the end of the world. “I like to say it’s our civilization’s answer to the Pyramids of Egypt.”

Early on this morning I was jolted and put in awe at CERN’s (the European nuclear research centre outside Geneva) large hadron collider is to be eventually (around 9.30this AM) fired up in two opposite directions to recreate conditions a split second after the big bang, which everyone knows to be the beginning of this universe.

This is a sweeping movement forward in the field of science, and I only hope that this experiment, which has been deemed the most costly ever to be taken upon, will reinforce or discover more and other theories to the origin of our universe. To think if this experiment were to under mind all previous understand of the big bang? Outrageous! But intriguing at the same time. To look at the microcosm to learn of the macrocosm! Science has known this for eons! I cannot wait to see where this will lead our species, further into the realm of knowledge and universal understanding…

As for all the crazy village people who would go with their torches and pitchforks to destroy the machine with fear in their eyes and hearts…I have but one thing to say. Instead of getting in the way of science and truth, simply go to your bunkers because all you have to think to yourself is that Armageddon is (“finally?”) here, so you should be happy to go where ever it is you are going. Right? Ha!

In any case, this is outstanding and could be the best scientific discovery ever. We may beable to find the things that have been perplexing my mind since Dan Brown’s Angels&Demons. Here, from the UK’s Guardian is a list of what the LHC could discover for us:

When the Large Hadron Collider is up to full power, it will be crashing protons together 600 million times per second. After each impact, giant detectors will scour the subatomic wreckage looking for evidence of new physics.

Scientists have some pretty good hunches about what the machine might find, from creating never-seen-before particles to discovering hidden dimensions and dark matter, the mysterious substance that makes up 25% of the universe.

Supersymmetry

Many physicists believe that deep down, all the forces of nature are linked, including gravity, electromagnetism, the strong force – which binds the constituents of atomic nuclei together – and the weak force – which governs radioactive decay in stars.

One of the most compelling theories that achieves this unification is called supersymmetry, which predicts that every fundamental particle in the universe has an invisible, overweight twin. The theory has spawned a plethora of bizarre names, such as the squark, the twin of the quark, and the photino, the twin of the photon, the stuff of light.

If supersymmetry is real, it could be one of the first discoveries to emerge from Cern.

Dark matter

Astronomers can only see 5% of the matter that makes up the universe, including all of the planets, stars and dust clouds. Of the rest, around 25% is believed to be “dark matter”, so called because it does not emit light or any other kind of radiation. Dark matter is thought to stretch throughout the universe like a cosmic skeleton, clustering around galaxies and influencing their movement by exerting a powerful gravitational pull on them.

Scientists are not sure what dark matter is made of, but a leading candidate is called a neutralino, a supersymmetrical particle. So finding neutralinos would not only prove supersymmetry, but could well explain what dark matter is too. These particles could be produced in the first collisions at the LHC.

The Higgs boson (aka the God particle)

Named after Peter Higgs, an Edinburgh University physicist, the Higgs boson is crucial to understanding the origin of mass. Shortly after the big bang, it is thought that many particles weighed nothing, but became heavy later on, thanks to the Higgs field. Cern has hunted for the Higgs particle before and thought they caught a glimpse of it in 2000 with their previous particle collider.

Most physicists believe the LHC will almost certainly find the Higgs boson, but it is likely to take a year or so.

Extra dimensions

Scientists will be astounded if the LHC discovers extra dimensions, but it is a possibility. Theories predict different types of extra dimension, with some coiled up and microscopic, and others stretched over just one millimetre.

Extra dimensions might explain why we feel gravity very weakly. In another dimension, it could be extremely powerful.

Black holes

Some scientists believe that gravity will turn out to be very strong when measured over incredibly small distances. It is possible that the LHC will unleash a burst of strong gravity, and that this could create a ball of incredibly dense matter, a black hole. According to Stephen Hawking, small black holes would evaporate and vanish harmlessly.

Antimatter

The LHC is guaranteed to create antimatter. But more importantly, it will try to explain why almost everything in the universe is made of normal matter and not antimatter. At the beginning of the universe, matter and antimatter were created in equal quantities, but somehow matter got the upper hand.

 

On a less serious note here is the Large Hadron Rap. Enjoy! Perhaps you physics teachers out there could find some use for this?

 Reference: Telegraph.Co.Uk

I’ve blogged quite a  bit about the Large Hadron Collider, most of it centered on covering the facts – not the fear — of what’s going to happen once the first proton hits the accelerator. And speaking of hitting, you can hit this link for all my LHC blogging.

This link covers the more exciting aspects of the LHC. Namely the mission profile for the collider and some general facts about this awesome piece of machinery.

From the link:

World’s biggest atom-smasher: Mission profile

Following is a mission profile of the Large Hadron Collider (LHC), the world’s biggest atom-smasher, which is due to start operations on Wednesday:

- Hunt for the HIGGS BOSON, a theorised particle that would explain why other particles have mass. Confirming the Higgs would fill a huge gap in the so-called Standard Model, the theory that summarises our present knowledge of particles. Over the years, scientists have whittled down the ranges of mass that the Higgs is likely to have. But they have lacked a machine capable of generating collisions powerful enough to to confirm whether this so-called God particle really does exist.

- Explore SUPERSYMMETRY, the notion that a whole bestiary of related but more massive particles exists beyond those in the Standard Model. Supersymmetry could explain one of the weirdest discoveries of recent years — that visible matter only accounts for some four percent of the cosmos. Dark matter (23 percent) and dark energy (73 percent) account for the rest. A popular theory is that dark matter comprises supersymmetric particles called neutralinos.

- Investigate the mystery of MATTER AND ANTI-MATTER. When energy transforms into matter, it produces a particle and its mirror image — called an anti-particle — which holds the opposite electrical charge. When particles and anti-particles collide, they annihilate each other in a small flash of energy. According to conventional theories of the cosmos, matter and anti-matter should exist in equal amounts, but the puzzle is that anti-matter is rare.

- Replicate the earliest moments after the BIG BANG that created the Universe. At its primal stage, matter existed as a sort of hot, dense soup called quark-gluon plasma. As it cooled, sub-atomic particles called quarks clumped together to form protons and neutrons and other composite particles. The LHC will smash heavy ions together, briefly generating temperatures 100,000 times hotter than the centre of the Sun and freeing quarks from their confinent. The researchers can then see how the liberated quarks aggregate to form ordinary matter.

Come Wednesday and the Swiss-French border is the epicenter of all action. At 0730 GMT protons will be injected into a 27- kilometre tunnel in an effort to study the underlying secret of the cosmos and which eventually would lead us to an even bigger challenge of proving to ourselves of the existence of parallel dimensions. This is being made possible via the LHC, which will accelerate the sub-atomic particles to the speeds of light and smash them together which could generate temperatures even hotter than the center of the Sun in a microscopic space. The LHC has the power to smash the sub-atomic particles at a mind boggling 14 TeV which is seven times more than the Tevatron.

The experiment would largely be zeroin’ in on finding the Higgs Boson dubbed the “God like Particle” by the Nobel laureate Leon M Lederman. It is so called as it is just thought to be existing but has no exact proof of its exisence, though thought to have existed when the age of our universe was one trillionth a second. Physicists are mighty sure that the LHC ‘d be providing them with the break through.

Tomorrow’s experiment would also be implying to solve many other mysteries of that of the Matter- Anti-matter, the Super Symmetry, and also ‘d give picture of the Universe just moments( and that is just one-trillionth of a second) after the Big Bang, which was some 13.7 billion years ago. Even the mysterious relationship of the dark matter and the dark energy which almost amount up to some 96% of the universe is also to be revealed. So, much depends on this experiment that at the end of it all who knows some glaring secrets are to be revealed.  The LHC is implied to open up many more vistas if the 10-hour gargantuan experiment is successful which ‘d naturally be.

After two decades of intense scientific labour this experiment is finally into its final stages and going to be carried tomorrow which could even be instrumental in answering some theories like the Super symmetry and also on the question of how the particles acquire mass that was predicted by Peter Higgs.

On the eve of the experiment the experimenters have also to douse the various dooms day prophecies that are doing their rounds such as that of the creation of some particle called Strangelet that ‘d turn the earth into goo.

What ever may be the outcome the whole idea of all the scientists from around the world working as one unit forgetting the geographical or political boundaries perse is really fantastic and as far as the creation of the Black holes is concerned I’d be happy if the were to exist any thing more than an atto of a second.

As for me I’m eagerly awaiting the results of this most ambitious experiment ever in the human history which ‘d break up even more vistas and who knows might even change the whole out look of the Universe. But the results ‘d be out only after a few weeks and guess this new year ‘d ‘nt be the same again!

Ben Allanach is a reader in theoretical physics at the University of Cambridge. Before that he was a post-doc at LAPP (Annecy, France), CERN (Geneva, Switzerland), Cambridge (UK) and the Rutherford Appleton Laboratory (UK). He likes drawing and playing guitar in dodgy rock bands. He is currently interested in beyond the standard model collider phenomenology, and is the author of SOFTSUSY, a computer program that calculates the SUSY particle spectrum. He also tries to do a bit of outreach from time to time. I invited him to discuss the results of his studies here after I discussed the paper by Buchmuller et al. two days ago, since I was interested in understanding the subtle differences between today’s different SUSY forecasts.

In a paper last year “Natural Priors, CMSSM Fits and LHC Weather Forecasts “, we (Kyle Cranmer, Chris Lester, Arne Weber and myself) performed a global fit to a simple supersymmetric model (the CMSSM). Data included were:

• relic density of dark matter
• Top mass, strong coupling constant, bottom mass and fine structure
  constant data
• Electroweak data: W mass and the weak mixing angle
• Anomalous magnetic moment of the muon
• B physics: branching ratio,
  branching ratio, and
  isospin asymmetry
• All direct search limits, including higgs limits from LEP2

and used to make predictions for supersymmetric particle masses and cross sections. We showed two characterisations of the data: Bayesian (with various prior probability measures) and the more familiar frequentist one, which I’ll discuss here.

We vary all parameters in order to produce a profile likelihood plot of the LHC cross-sections for producing either strongly interacting SUSY particles, weak gaugino SUSY particles or sleptons directly. This is equivalently a plot of $latex e^{-\chi^2)/2}$:

The good news is that the LHC has great prospects for producing SUSY particles in large numbers assuming the CMSSM: for 1 of data, we expect the production of over 2000 of them to 95% confidence level (shown by the downward facing arrows). Of these, some fraction will escape detection, but the message is very positive. The CMSSM prefers a light higgs, as shown by this plot:

The different curves correspond to different assumptions about the priors (the green one labelled profile shows the usual interpretation), but as the figure shows, these aren’t so important. Arrows show the 95% confidence level upper bounds: 118 GeV for the lightest neutral higgs .

Comparison of results from two papers

The results are quite similar to the recent ones of the Buchmueller et al crowd (who use recent updated data and more observables) lightish SUSY is preferred, primarily because the anomalous magnetic moment of the muon prefers a non-zero SUSY contribution. Also, the W boson mass and weak mixing angle show a slight preference for light SUSY. Because the LHC has enough energy to produce these particles, detection should be quite easy.

The central results of each paper can be expressed in the parameter plane vs (scalar supersymmetric particle masses vs gaugino supersymmetric particle mass). Here, I show the result of our fit on the left and theirs on the right:

To compare the two figures, you must convert their axes of the right-hand figure to the one on the left (note the different scales, although I tried to re-size them to make the scales comparable – apologies to Buchmueller et al for flipping their axes to aid comparison). The comparison should be between the solid line of the right-hand diagram, and the outer solid line on the left (both 95% confidence level contours), but the Buchmueller et al gang get lighter scalars than us, by a factor
of about 2 or so.

Why should the two results differ?

The top mass has changed in the last year from GeV to GeV. Also, Buchmueller et al include additional observables: other electroweak, B and K-physics ones. My understanding is that none of these is very sensitive to the SUSY particle masses, given the constraints from direct searches though. Perhaps most of these extra observables very slightly prefer light SUSY, so that they disfavour GeV range? Buchmueller et al should be able to tell us by examining their data.

Thanks to Tommaso for inviting this guest post.