Columbia University - Panel Discussion on the Higgs Particle Research at CERN

Ask Brian Greene: Why Do We Think the Higgs Particle Exists?

http://worldsciencefestival.com/videos/ask_brian_greene_why_do_we_think_the_higgs_particle_exists

About This Video

Brian Greene explains why the theoretical Higgs Boson is so important to the

Standard Model of Physics, the backbone of how we understand the world around us.

Image courtesy of ATLAS; Recorded June 2011; Posted December 2011

Brian Greene is a professor of physics and mathematics at Columbia University,

and is recognized for a number of groundbreaking discoveries in his field of superstring theory.

Event Link -

http://www.worldleaders.columbia.edu/events/what-if-we-find-higgs-particle-and-what-if-we-don039t

Vid Link - A 10 min. Intro with pictures; then the panel discussion begins on a new vid screen (my unofficial transcript follows below so you can read along) - http://news.columbia.edu/higgs

If Broken go here - http://www.totalwebcasting.com/view/?id=columbia

Panel Members

MT - Michael Tuts, Columbia University Professor of Physics and U.S. ATLAS Operations Program Manager at the Large Hadron Collider at the CERN laboratory in Geneva.

BG - Brian Greene, Columbia University Professor of Physics and Mathematics.

DO - Dennis Overbye, The New York Times science reporter covering physics.

MDC - Mariette DiChristina, Editor-in-Chief of Scientific American.

[Unofficial Transcript]

MDC: What is the Higgs-Boson particle? (hbp/hb)

MT: In Geneva, Switzerland, is the CERN large Hadron collider which houses one of seven particle detectors. One is the ATLAS accelerator which is like a large sub-atomic microscope that can measures things like light (photons), plot particles trajectories when they smash, and take pictures of 100 billion protons  traveling towards another 100 billion in the opposite direction, where only some particles will smash into each other. When they smash new particles will be created. The Atlas is like a 100 million pixel camera taking 40 million pictures across a 100 million channels instantaneously.

We study things like quarks, leptons and electro-magnetic forces found in the world of the small. And have been studying these and many other particles and forces over the last 40 years trying to determine their relationships with one another, their undergirding structure, the antimatter twins, and have been relating these particles to non-particles called strings which seem to best describe the 124 basic particles which we have been able to determine. MT then discusses individual particles and forces and what they think they see with a Higgs particle decaying upon impact.

Summary of interactions between particles described by the Standard Model

Left-handed fermions in the Standard Model

Generation 1
Fermion (left-handed)	Symbol	Electric charge	Weak isospin	Weak hypercharge	Color charge [lhf 1]	Mass[lhf 2]
Electron						511 keV
Positron						511 keV
Electron neutrino						< 0.28 eV[lhf 3][lhf 4]
Electron antineutrino						< 0.28 eV[lhf 3][lhf 4]
Up quark						~ 3 MeV[lhf 5]
Up antiquark						~ 3 MeV[lhf 5]
Down quark						~ 6 MeV[lhf 5]
Down antiquark						~ 6 MeV[lhf 5]
Generation 2
Fermion (left-handed)	Symbol	Electric charge	Weak isospin	Weak hypercharge	Color charge [lhf 1]	Mass [lhf 2]
Muon						106 MeV
Antimuon						106 MeV
Muon neutrino						< 0.28 eV[lhf 3][lhf 4]
Muon antineutrino						< 0.28 eV[lhf 3][lhf 4]
Charm quark						~ 1.337 GeV
Charm antiquark						~ 1.3 GeV
Strange quark						~ 100 MeV
Strange antiquark						~ 100 MeV
Generation 3
Fermion (left-handed)	Symbol	Electric charge	Weak isospin	Weak hypercharge	Color charge[lhf 1]	Mass[lhf 2]
Tau						1.78 GeV
Antitau						1.78 GeV
Tau neutrino						< 0.28 eV[lhf 3][lhf 4]
Tau antineutrino						< 0.28 eV[lhf 3][lhf 4]
Top quark						171 GeV
Top antiquark						171 GeV
Bottom quark						~ 4.2 GeV
Bottom antiquark						~ 4.2 GeV
^ a b c These are not ordinary abelian charges, which can be added together, but are labels of group representations of Lie groups. ^ a b c Mass is really a coupling between a left-handed fermion and a right-handed fermion. For example, the mass of an electron is really a coupling between a left-handed electron and a right-handed electron, which is the antiparticle of a left-handed positron. Also neutrinos show large mixings in their mass coupling, so it's not accurate to talk about neutrino masses in the flavor basis or to suggest a left-handed electron antineutrino. ^ a b c d e f The Standard Model assumes that neutrinos are massless. However, several contemporary experiments prove that neutrinos oscillate between their flavour states, which could not happen if all were massless. It is straightforward to extend the model to fit these data but there are many possibilities, so the mass eigenstates are still open. See neutrino mass. ^ a b c d e f W.-M. Yao et al. (Particle Data Group) (2006). "Review of Particle Physics: Neutrino mass, mixing, and flavor change". Journal of Physics G 33: 1. arXiv:astro-ph/0601168. Bibcode 2006JPhG...33....1Y. doi:10.1088/0954-3899/33/1/001. http://pdg.lbl.gov/2007/reviews/numixrpp.pdf. ^ a b c d The masses of baryons and hadrons and various cross-sections are the experimentally measured quantities. Since quarks can't be isolated because of QCD confinement, the quantity here is supposed to be the mass of the quark at the renormalization scale of the QCD scale.

BG: How significant is the HB discovery? If found it will be huge. If not then that will be huge too.

HB says that space is filled with a glue like substance. This is all mathematical right now without verifiable objectification still undergoing for its discovery. If not there what other theories out there? Technicolor is another approach for generating mass from the super-microscopic realm… a deeper level of structure. However, the HB is more elegant in its structural hypotheses.

MT: Can the Technicolor be verified? We are already looking at this possibility along with looking for tiny black holes, etc.

MDC (Scientific American): What is the next particle to be found?

BG: “Where did the Higgs come from!?” J …in an endless stream of discovery and speculation.

MT: We are probing for everything out there that has been theorized.

DO (NYT): Nothing new has been discovered in the last 40 years… why is that?

BG: Isn’t that unfair to say? What about the discovery of the “top quark?”

MDC: However the particle/force table has been filled out…

DO: CERN and the Large Hadron Collider (LHC) is a massive, jointly national project that has been enormously expensive but now proving to be very helpful in detailing the birth of the universe and the energies that make it up. So then, my question is this… 125GeV energy level have shown the bumps in the detection. It’s this “bump” or nothing which can be massively awkward.

MDC: Whether true or not, this stream of discovery must be undertaken to rule out further errant theories. Super-symmetric particles were found to NOT be in a certain energy range which is a necessary discovery, not a meaningless discovery.

DO: Brian, please talk more about the Higgs field and how it affects the universe.

BG: The larger story beyond the Higgs will be the idea that a new form of matter will have been discovered for the first time with the difference being that the Higgs is uniquely different from all other particles found. Higgs is a particle of spin 0. No other particles have been found with no spin. This is therefore exciting to find. As example, the Big Bang theory leaves out the “Bang” in the theory… we get inflationary cosmology but no Higgs which we think is the compulsory “push” outwards cause the “bang” in the BB theory.

MDC: Everything looks promising but how will you know when you have verified the Higgs?

MT: The number of standard deviations driven by statistical results will tell us. Data is counted in inverse phantom bars? which we wish to quadruple our data at higher energy levels (from 7 trillion electron volts to 8 trillion electron volts). The higher energy levels have helped us in our research. Will it be enough? We don’t know.

Audience 1 (A1): How do we justify our massive expenditures to the public?

MT: By communicating our discoveries through the press. Through sharing our scientific discoveries and processes with the scientific community at large. By helping profit-based products be successful. By inspiring the next generation of global youth towards exploration.

BG: Not everybody has to be excited by CERN’s discoveries. Many want more practical objectives, services, and products.

MT: A particle physicist? Oh… discussion done. With the Higgs it can generate a bit more discussion.

A2: How long do you continue your search?

MT: This year should tell us through our data sets. But expect about the next 20 years to focus on this at CERN.

A3: Does the Higgs have mass?

BG: Yes. 125X more massive than a proton. Is it made up of more stuff? We don’t know just yet.

MT: Spin 0 particles need clarification. Is it the thing (a HBP) that we think it is. Does it decay into things that we thought it would decay into.

A4: The Standard Model of Particle Physics (SMPP)

BG: Physics is a field written generally in the language of mathematics. This field constantly critiques itself in a never-ending process of qualification and predictive discovery. From the math physicists go out and test those mathematic models. Gravity, super symmetry, Technicolor, string theory, are constantly proved and re-proved from a number of different angles.

A5: Strong and Weak nuclear forces.

BG: Energy levels are known at speculative force levels. Yes links are being examined from exotic theories. But the Higgs has a linkage that grab at our imaginations.

A6: Does the exact mass teach us anything? Does the Higgs exist anywhere in the world?

MT: The Higgs decays very, very quickly once it is seen. The SMPP teaches us a lot. But it is still being explored.

DO: If the Higgs is at 125 GeV what does that tell you?

BG: Yes, it proves the supporting math being it. If found to be at 142 GeV than we have the wrong math.

DO: This value is torture for theorist according to one physicist.

MDC: If not at 125, then what?

BG: It can affect super-symmetric theories, yes.

A7: null

A8: How can you deny conclusively the HB if you can’t prove it?

MT: We will find range-bound observations that will be conclusive relative to whether the Higgs exists at 125 or not.

BG: Other ideas would then arise that would be examined for helpfulness.

MT: Moreover, on the downside, the LHC will be found not be large enough to prove this theory by at least 3x.

A9: null

BG: We will go from mathematical theory to mathematical theory and in so doing better integrate our physical models.

Conclusion

MDC: Why should people care? “It’s always about where have we come from and where are we going.”

DO: null [Gawker.com]

BG: My mind is always open to discovery. Especially in linking the world of the small to the world of the large. Proving exotic ideas. Building big machines. Finding astronomical data that can be helpful to microscopic physics. Background radiation, [dark matter, and dark energy].

MT: Proving the Higgs theory is one goal. Improving precise measurements. Being open to the next frontier of discovery.

End

Wikipedia

http://en.wikipedia.org/wiki/Higgs_boson

"God particle" redirects here. For the book, see The God Particle (book).

For the "Oh-my-God particle," see Ultra-high-energy cosmic ray

The Higgs boson is a hypothetical elementary particle predicted by the Standard Model (SM) of particle physics. It belongs to a class of subatomic particles known as bosons, characterized by an integer value of their spin quantum number. The Higgs field is a quantum field with a non-zero value that fills all of space, and explains why fundamental particles such as quarks and electrons have mass. The Higgs boson is an excitation of the Higgs field above its ground state.

The existence of the Higgs boson is predicted by the Standard Model to explain how spontaneous breaking of electroweak symmetry (the Higgs mechanism) takes place in nature, which in turn explains why other elementary particles have mass.^{[Note 1]} Its discovery would further validate the Standard Model as essentially correct, as it is the only elementary particle predicted by the Standard Model that has not yet been observed in particle physics experiments.^[2] The Standard Model completely fixes the properties of the Higgs boson, except for its mass. It is expected to have no spin and no electric or color charge, and it interacts with other particles through weak interaction and Yukawa interactions. Alternative sources of the Higgs mechanism that do not need the Higgs boson are also possible and would be considered if the existence of the Higgs boson were ruled out. They are known as Higgsless models.

Experiments to determine whether the Higgs boson exists are currently being performed using the Large Hadron Collider (LHC) at CERN, and were performed at Fermilab's Tevatron until its closure in late 2011. Mathematical consistency of the Standard Model requires that any mechanism capable of generating the masses of elementary particles become visible at energies above 1.4 TeV;^[3] therefore, the LHC (designed to collide two 7-TeV proton beams) is expected to be able to answer the question of whether or not the Higgs boson actually exists.^[4] In December 2011, Fabiola Gianotti and Guido Tonelli, spokespersons of the two main experiments at the LHC (ATLAS and CMS) both reported independently that their data hints at a possibility the Higgs may exist with a mass around 125 GeV/c² (about 133 proton masses, on the order of 10⁻²⁵ kg). They also reported that the original range under investigation has been narrowed down considerably and that a mass outside approximately 115–130 GeV/c² is almost ruled out.^[5] No conclusive answer yet exists, although it is expected that the LHC will provide sufficient data by the end of 2012 for a definite answer.^[1][6][7][8]

In the popular media, the particle is sometimes referred to as the God particle, a title generally disliked by the scientific community as media hyperbole that misleads readers.^[9]

Wikipedia

http://en.wikipedia.org/wiki/Standard_Model

The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles. Developed throughout the mid to late 20th century, the current formulation was finalized in the mid 1970s upon experimental confirmation of the existence of quarks. Since then, discoveries of the bottom quark (1977), the top quark (1995) and the tau neutrino (2000) have given further credence to the Standard Model. Because of its success in explaining a wide variety of experimental results, the Standard Model is sometimes regarded as a theory of almost everything.

Still, the Standard Model falls short of being a complete theory of fundamental interactions because it does not incorporate the physics of dark energy nor of the full theory of gravitation as described by general relativity. The theory does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not correctly account for neutrino oscillations (and their non-zero masses). Although the Standard Model is believed to be theoretically self-consistent, it has several apparently unnatural properties giving rise to puzzles like the strong CP problem and the hierarchy problem.

Nevertheless, the Standard Model is important to theoretical and experimental particle physicists alike. For theorists, the Standard Model is a paradigmatic example of a quantum field theory, which exhibits a wide range of physics including spontaneous symmetry breaking, anomalies, non-perturbative behavior, etc. It is used as a basis for building more exotic models which incorporate hypothetical particles, extra dimensions and elaborate symmetries (such as supersymmetry) in an attempt to explain experimental results at variance with the Standard Model, such as the existence of dark matter and neutrino oscillations. In turn, experimenters have incorporated the Standard Model into simulators to help search for new physics beyond the Standard Model.

Recently, the Standard Model has found applications in fields besides particle physics, such as astrophysics, cosmology, and nuclear physics.

Wikipedia

http://en.wikipedia.org/wiki/CERN

CERN

The European Organization for Nuclear Research (French: Organisation européenne pour la recherche nucléaire), known as CERN ( /ˈsɜrn/; French pronunciation: [sɛʁn]; see History), is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border. EWikiMiniEstablished in 1954, the organization has twenty European member states.

The term CERN is also used to refer to the laboratory itself, which employs just under 2400 full-time employees and hosts some 10000 visiting scientists and engineers representing 608 universities and research facilities and 113 nationalities.

CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research. Numerous experiments have been constructed at CERN by international collaborations to make use of them. It is also the birthplace of the World Wide Web. The main site at Meyrin also has a large computer centre containing very powerful data-processing facilities primarily for experimental data analysis and, because of the need to make them available to researchers elsewhere, has historically been a major wide area networking hub.

The CERN sites, as an international facility, are officially under neither Swiss nor French jurisdiction. Member states' contributions to CERN for the year 2008 totaled CHF 1 billion.

The Atlas Group

http://en.wikipedia.org/wiki/ATLAS_experiment

Computer generated cut-away view of ATLAS detector

showing its various components.

ATLAS (A Toroidal LHC Apparatus) is one of the seven particle detector experiments (ALICE, ATLAS, CMS, TOTEM, LHCb, LHCf and MoEDAL) constructed at the Large Hadron Collider (LHC), a new particle accelerator at the European Organization for Nuclear Research (CERN) in Switzerland. ATLAS is 44 metres long and 25 metres in diameter, weighing about 7,000 tonnes. The project is led by Fabiola Gianotti and involves roughly 2,000 scientists and engineers at 165 institutions in 35 countries.^[1][2] The construction was originally scheduled to be completed in June 2007, but was ready and detected its first beam events on 10 September 2008.^[3] The experiment is designed to observe phenomena that involve highly massive particles which were not observable using earlier lower-energy accelerators and might shed light on new theories of particle physics beyond the Standard Model.

The ATLAS collaboration, the group of physicists building the detector, was formed in 1992 when the proposed EAGLE (Experiment for Accurate Gamma, Lepton and Energy Measurements) and ASCOT (Apparatus with Super Conducting Toroids) collaborations merged their efforts into building a single, general-purpose particle detector for the Large Hadron Collider.^[4] The design was a combination of those two previous designs, as well as the detector research and development that had been done for the Superconducting Supercollider. The ATLAS experiment was proposed in its current form in 1994, and officially funded by the CERN member countries beginning in 1995. Additional countries, universities, and laboratories joined in subsequent years, and further institutions and physicists continue to join the collaboration even today. The work of construction began at individual institutions, with detector components shipped to CERN and assembled in the ATLAS experimental pit beginning in 2003.

ATLAS is designed as a general-purpose detector. When the proton beams produced by the Large Hadron Collider interact in the center of the detector, a variety of different particles with a broad range of energies may be produced. Rather than focusing on a particular physical process, ATLAS is designed to measure the broadest possible range of signals. This is intended to ensure that, whatever form any new physical processes or particles might take, ATLAS will be able to detect them and measure their properties. Experiments at earlier colliders, such as the Tevatron and Large Electron-Positron Collider, were designed based on a similar philosophy. However, the unique challenges of the Large Hadron Collider—its unprecedented energy and extremely high rate of collisions—require ATLAS to be larger and more complex than any detector ever built.

Large Hadron Collider

http://topics.nytimes.com/top/news/science/topics/large_hadron_collider/index.html

The Large Hadron Collider (LHC)

Valerio Mezzanotti for The New York Times

Updated: Dec. 13, 2011

Call it the Hubble Telescope of Inner Space

The Large Hadron Collider, located 300 feet underneath the French-Swiss border outside Geneva, is the world’s biggest and most expensive particle accelerator. It is designed to accelerate the subatomic particles known as protons to energies of 7 trillion electron volts apiece and then smash them together to create tiny fireballs, recreating conditions that last prevailed when the universe was less than a trillionth of a second old.

Whatever forms of matter and whatever laws and forces held sway Back Then — relics not seen in this part of space since the universe cooled 14 billion years ago — will spring fleetingly to life. If all goes well, they will leave their footprints in four mountains of hardware and computer memory that international armies of physicists have erected in the cavern.

After 16 years and $10 billion, on March 30, 2010, the collider finally began its work of smashing subatomic particles. The day was a milestone — delayed a year and a half by an assortment of technical problems — and brings closer a moment of truth for CERN and for the world’s physicists, who have staked their credibility and their careers, not to mention all those billions of dollars, on the conviction that they are within touching distance of fundamental discoveries about the universe. If they fail to see something new, experts agree, it could be a long time, if ever, before giant particle accelerators are built on Earth again, ringing down the curtain on at least one aspect of the age-old quest to understand what the world is made of and how it works.

“If you see nothing,” said John Ellis, a theoretical physicist at CERN, “in some sense then, we theorists have been talking rubbish for the last 35 years.”

Looking Back in Time

Machines like CERN’s new collider get their magic from Einstein‘s equation of mass and energy. The more energy that these machines can pack into their little fireballs, in effect the farther back in time they can go, closer and closer to the Big Bang, the smaller and smaller things they can see.

The new hadron collider, scientists say, will take physics into a realm of energy and time where the current reigning theories simply do not apply, corresponding to an era when cosmologists think that the universe was still differentiating itself, evolving from a primordial blandness and endless potential into the forces and particles that constitute modern reality.

One prime target is a mysterious particle called the Higgs that is thought to endow other particles with mass, according to the reigning theory of particle physics, known as the Standard Model.

In December 2011, two teams of scientists sifting debris from high-energy proton collisions in the LHC said that they had recorded “tantalizing hints” — but only hints — of the long-sought Higgs boson. It is likely to be another year, however, before they have enough data to say whether the elusive particle really exists, the scientists said.

The putative particle weighs in at about 125 billion electron volts, about 125 times heavier than a proton and 500,000 times heavier than an electron, according to one team of 3,000 physicists, known as Atlas, for the name of their particle detector.

The other equally large team, known as C.M.S. — for their detector, the Compact Muon Solenoid — found bumps in their data corresponding to a mass of about 126 billion electron volts.

Over the last 20 years, suspicious bumps that might have been the Higgs have come and gone, and scientists cautioned that the same thing could happen again, but the fact that two rival teams using two different mammoth particle detectors had recorded similar results was considered to be good news.

Read More...Cosmic Leapfrog

The advent of the CERN collider cements a shift in the balance of physics power away from American dominance that began in 1993, when Congress canceled the Superconducting Supercollider, a monster machine under construction in Waxahachie, Tex. The supercollider, the most powerful ever envisioned, would have sped protons around a 54-mile racetrack before slamming them together with 40 trillion electron volts.

For decades before that, physicists in the United States and Europe had leapfrogged one another with bigger, more expensive and, inevitably, fewer of these machines. The most powerful American accelerator now operating is the Tevatron, colliding protons and their antimatter opposites, antiprotons, with energies of a trillion electron volts apiece, at the Fermi National Accelerator Laboratory in Batavia, Ill. It is presently expected to run through 2010 or 2011.

Once upon a time, said Lyn Evans, who led the building of the CERN collider, “There was a nice equilibrium across the Atlantic. People used to come and go.”

Now, he said, “The center of gravity has moved to CERN.”

The Development of CERN

CERN was born amid vineyards and farmland in the countryside outside Geneva in 1954 out of the rubble of postwar Europe. It had a twofold mission of rebuilding European science and of having European countries work together.

Today, it has 20 countries as members. Yearly contributions are determined according to members’ domestic economies, and the result is a stable annual budget of about a billion Swiss francs. The vineyards and cows are still there, but so are strip malls and shopping centers.

It was here that the World Wide Web was born in the early 1990s, but the former director-general of CERN, Robert Aymar, joked recently that the lab’s greatest fame was as a locus of conspiracy in the novel “Angels and Demons,” by the author of “The DaVinci Code,” Dan Brown. The lab came into its own scientifically in the early ’80s, when Carlo Rubbia and Simon van der Meer won the Nobel Prize by colliding protons and antiprotons there to produce the particles known as the W and Z bosons, which are responsible for the so-called weak nuclear force that causes some radioactive decays.

Bosons are bits of energy, or quanta, that, according to the weird house rules of the subatomic world, transmit forces as they are tossed back and forth in a sort of game of catch between matter particles. The W’s and Z’s are closely related to photons, which transmit electromagnetic forces, or light.

The lab followed up that triumph by building a 17-mile-long ring, the Large Electron-Positron collider, or LEP, to manufacture W and Z particles for further study. The United States started and then abandoned its plans for an accelerator, which would have been named Isabelle, but in the meantime, CERN physicists had been mulling building their own giant proton collider in the LEP tunnel.

The Collider’s Cost Problems

In 1994 CERN’s governing council gave its approval. The United States eventually agreed to chip in $531 million for the project. CERN also arranged to borrow about $400 million from the European Investment Bank. Even so, there was a crisis in 2001 when the project was found to be 18 percent over budget, necessitating cutting other programs at the lab. The collider’s name comes from the word hadron, which denotes subatomic particles like protons and neutrons that feel the “strong” nuclear force that binds atomic nuclei.

Whether the Europeans would have gone ahead if the United States had still been in the game depends on whom you ask. Dr. Aymar, the former director, who was not there in the ’90s, said there was no guarantee then that the United States would have succeeded even if it had proceeded.

“Certainly in Europe the situation of CERN is such that we appreciate competition,” he said. “But we assume we are the leader and we have all intention [in the world] to remain the leader. And we’ll do everything which is needed to remain the leader.”

Sunken Cathedrals

The guts of the collider are some 1,232 electromagnets, thick as tree trunks, long as boxcars, weighing in at 35 tons apiece, strung together like an endless train stretching around the gentle curve of the CERN tunnel.

In order to bend 7-trillion-electron-volt protons around in such a tight circle these magnets, known as dipoles, have to produce magnetic fields of 8.36 Tesla, more than 100,000 times the Earth’s field, requiring in turn a current of 13,000 amperes through the magnet’s coils. To make this possible the entire ring is bathed in 128 tons of liquid helium to keep it cooled to 1.9 degrees Kelvin, at which temperature the niobium-titanium cables are superconducting and pass the current without resistance.

Running through the core of this train, surrounded by magnets and cold, are two vacuum pipes, one for protons going clockwise, the other counterclockwise. Traveling in tight bunches along the twin beams, the protons will cross each other at four points around the ring, 30 million times a second. During each of these violent crossings, physicists expect that about 20 protons, or the parts thereof — quarks or gluons — will actually collide and spit fire. It is in vast caverns at those intersection points that the detectors, or “sunken cathedrals” in the words of a CERN theorist, Alvaro de Rujula, are placed to capture the holy fire.

Detectors And Their Quarry

Two of the detectors are specialized. One, called Alice, is designed to study a sort of primordial fluid, called a quark-gluon plasma, that is created when the collider smashes together lead nuclei.

The other, LHCb, will hunt for subtle differences in matter and antimatter that could help explain how the universe, which was presumably born with equal amounts of both, came to be dominated by matter.

The other two, known as Atlas and the Compact Muon Solenoid, or C.M.S. for short, are the designated rival workhorses of the collider, designed expressly to capture and measure every last spray of particle and spark of energy from the proton collisions.

Or as Katie McAlpine, who writes about science for the Atlas group, put it in “The L.H.C. Rap,”

“LHCb sees where the antimatter’s gone.

Alice looks at collisions of lead ions.

CMS and Atlas are two of a kind,

They’re looking for whatever new particles they can find.”

The last two, Atlas and C.M.S., represent complementary strategies for hunting one of the prime targets of the collider, a particle known as the Higgs boson, which is expected to disintegrate into a spray of lesser particles. Exactly which particles are produced depends on how massive the Higgs really is.

One telltale signature of the Higgs and other subatomic cataclysms is a negatively charged particle known as a muon, a sort of heavy electron that comes flying out at nearly the speed of light. Physicists measure muon momentum by seeing how much their paths bend in a magnetic field.

It is the need to have magnets strong enough and large enough to produce measurable bending, physicists say, that determines the gigantic size of the detectors.

The Compact Muon Solenoid weighs 12,000 tons, the heaviest scientific instrument ever made. It takes its name from a massive superconducting electromagnet that produces a powerful field running along the path of the protons.

Conversely, the magnetic field on Atlas wraps like tape around the proton beam. At 150 feet long and 80 feet high, Atlas is bigger than its rival, but it is much lighter, about 7,000 tons, about as much as the Eiffel Tower.

The two detectors have much in common, including “onion layers” of instruments to measure different particles and the ability to cope with harsh radiation and vast amounts of data. The central C.M.S. detector is made of strips of silicon that record the passage of charged particles. It is in effect a 60-megapixel digital camera taking 40 million pictures a second.

To manage this onslaught the teams’ computers have to perform triage, and winnow those events to a couple of hundred per second. Even so, the collider will produce the equivalent of 3 million DVDs worth of data every year, and a grid computing system of more than 100,000 processors from over 170 sites in 34 countries has been constructed to cope with it.

*The competition between Atlas and the C.M.S. is in keeping with a long tradition of having rival teams and rival detectors at big experiments to keep each other honest and to cover all the bets.

At the Fermilab Tevatron, the teams, several hundred strong, are called CDF and D0. In the glory years 20 years ago at CERN, they were called UA1 and UA2. Over the years, as the machines have grown, so have the groups that built them, from teams to armies, 1,800 people from 34 countries for Atlas and 2,520 from 37 countries for the C.M.S. The other two experiments — Alice with 1,000 scientists, and LHCb with 663 — are only slightly smaller.

Cocktail Party Physics

The payoff for this investment, physicists say, could be a new understanding of one of the most fundamental of aspects of reality, namely the nature of mass.

This is where the shadowy particle known as the Higgs boson, a.k.a. the God particle, comes in.

In the Standard Model, a suite of equations describing all the forces but gravity, which has held sway as the law of the cosmos for the last 35 years, elementary particles are born in the Big Bang without mass, sort of like Adam and Eve being born without sin.

Some of them (the particles, that is) acquire their heft, so the story goes, by wading through a sort of molasses that pervades all of space. The Higgs process, named after Peter Higgs, a Scottish physicist who first showed how this could work in 1964, has been compared to a cocktail party where particles gather their masses by interaction. The more they interact, the more mass they gain.

The Higgs idea is crucial to a theory that electromagnetism and the weak force are separate manifestations of a single so-called electroweak force. It shows how the massless bits of light called photons could be long-lost brothers to the heavy W and Z bosons, which would gain large masses from such cocktail party interactions as the universe cooled.

The confirmation of the theory by the Nobel-winning work at CERN 20 years ago ignited hopes among physicists that they could eventually unite the rest of the forces of nature [known as the Theory of Everything, or TOE].

Moreover, Higgs-like fields have been proposed as the source of an enormous burst of expansion, known as inflation, early in the universe [the Higgs particle is what gives the push to the Bang - res]; and possibly, as the secret of the dark energy that now seems to be speeding up the expansion of the universe. So it is important to know whether the theory works and, if not, to find out what does endow the universe with mass.

But nobody has ever seen a Higgs boson, the particle that personifies this molasses. It should be producible in particle accelerators, but nature has given confusing clues about where to look for it. Measurements of other exotic particles suggest that the Higgs’s mass should be around 90 billion electron volts, the unit of choice in particle physics. But other results, from the LEP collider before it shut down in 2000, indicate that the Higgs must weigh more than 114 billion electron volts. By comparison, an electron is half a million electron volts, and a proton is about 2,000 times heavier.

The new collider was specifically designed to hunt for the Higgs particle, which is key to the Standard Model and to any greater theory that would supersede it. The Tevatron [near Chicago] is also searching for the Higgs.

Theorists say the Higgs or something like it has to show up simply because the Standard Model breaks down and calculations using it go kerflooey at energies exceeding one trillion electron volts. If you try to predict what happens when two particles collide, it gives nonsense, explained Dr. Ellis. 

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Cosmic Dreams

If the CERN experimenters find the Higgs, Nobel Prizes will flow like water. But just finding the elusive particle will not be enough to satisfy the theorists, who profess to be haunted by a much deeper problem, namely why the putative particle is not millions of times heavier than it appears to be.

When they try to calculate the mass of the Higgs particle using the Standard Model and quantum mechanics, they get what Dr. Ellis called “a very infinite answer.”

Rather than a trillion electron volts or so, quantum effects push the mass all the way up to 10 quadrillion trillion electron volts, known as the Planck energy, where gravity and the other particle forces are equal.

The culprit is quantum weirdness, one principle of which is that anything that is not forbidden will happen. That means the Higgs calculation must include the effects of its interactions with all other known particles, including so-called virtual particles that can wink in and out of existence, which shift its mass off the scale.

As a result, if the Standard Model is valid for all energies, physicists say, they are at a loss to explain why the Higgs mass isn’t a quadrillion times bigger than it is. Another way to put it is to ask why gravity is so much weaker than the other forces — the theory wants them all to be equal.

Theorists can rig their calculations to have the numbers come out right, but it feels like cheating, and they would like to have a theory in which the numbers emerge naturally.

One solution that has been proposed is a new principle of nature called supersymmetry that, if true, would be a bonanza for the CERN collider.

It posits a relation between the particles of matter like electrons and quarks and particles that transmit forces like photons and the W boson. For each particle in one category, there is an as-yet-undiscovered superpartner in the other category.

These superpartners cancel out all the quantum effects that make the Higgs mass skyrocket. Supersymmetry also fixes a glitch in the age-old dream of explaining all the forces of nature as manifestations of one primordial force. It predicts that at a high enough energy, all the forces — electromagnetic, strong and weak — have identical strengths.

For several years, supersymmetry has been a sort of best bet to be the next step beyond the Standard Model, which is undefeated in experiments but has enormous gaps. The Standard Model does not include gravity or explain why, for example, the universe is matter instead of antimatter or even why particles have the masses they do, and so few physicists think it is the end of the story of the universe.

But so far there is no direct evidence for any of the thousands of versions of supersymmetry that have been proposed. Indeed, many theorists are troubled that its effects have not already shown up in precision measurements at accelerators.

Physicists say the best indirect evidence for supersymmetry comes from the skies, where the galaxies have been found to be swaddled by clouds of invisible dark matter, presumably unknown particles left over from the Big Bang. Astrophysical and cosmological calculations suggest that this dark matter makes up 25 [23% - wikipedia] percent of the universe by mass. By comparison the atoms of which people and stars are made comprise only 4 percent of nature [the remaining 73% is dark energy, as yet undetected - res].

The Higgs is expected to occur once in every trillion events, and it is expected that it will take a couple of years of running in order to get enough data to say if it exists. But some supersymmetric particles, if they exist, should be produced abundantly and could thus pop out of the data much sooner.

The prospect of discovering the identity of a quarter of the universe, or even something more surprising and fundamental has sustained physicists over the decades it has taken to build the collider and its detectors. Without these experiments, said Jim Virdee, of Imperial College, London, and spokesperson for the C.M.S. team, “this field which began with Newton just stops.”

“When we started, we did not know how to do this experiment and did not know if it would work,” he said. “Twenty-five hundred scientists can work together. Our judge is not God or governments, but nature. If we make a mistake, nature will not hesitate to punish us.”

The Collider in Operation

The first experiments with the collider were delayed by over a year when an explosion vaporized an electrical connection and spewed tons of helium underneath the Swiss-French countryside in the fall of 2008. The explosion took place only nine days after the physicists celebrated threading the first protons around the 17-mile underground racetrack by drinking Champagne. The incident exposed a weakness in the connections between the collider’s thousands of magnets that will mean a longer wait until it is ready to operate at peak power.

On Nov. 23, 2009, the first collision was produced in a test of the collider systems’ ability to synchronize the beams, in which bunches of protons travel along at nearly the speed of light, and make them collide at the right points. The protons were at their so-called injection energies of 450 billion electron volts, a far cry from the energies the machine will eventually achieve.

Four months later, the collider went into full operation for the first time, whipping protons to 99 percent of the speed of light and to energy levels of 3.5 trillion electron volts apiece. That was cause for great celebration, but the machine is still operating at half of peak power.

Because of the defective joints and some mysteriously underperforming magnets, the collider will not run at or near full strength until at least 2012. According to theoretical models, that would stretch out the time it should take to achieve the collider’s main goals, including producing a particle known as the Higgs boson, which is thought to be responsible for imbuing other elementary particles with mass.

The results from two collider teams announced in December 2011, giving hints that the Higgs boson existed, led to predictions that scientists there would be able to answer the question one way or another by the end of 2012.

 For more Information go to:

Biologos: Particle Physics of the Universe & Multiverse, Parts 1-4

http://relevancy22.blogspot.com/2012/04/biologos-universe-multiverse.html

The Higgs-Boson God Particle Found

http://relevancy22.blogspot.com/2011/12/cern-physicists-find-hint-of-higgs.html

CERN physicists find hint of Higgs boson

http://relevancy22.blogspot.com/2011/12/cern-physicists-find-hint-of-higgs.html

Brian Greene Hosts "The Fabric of the Universe" on NOVA

http://relevancy22.blogspot.com/2011/11/brian-greene-hosts-fabric-of-universe.html

Alan Guth on Inflationary Cosmology

http://relevancy22.blogspot.com/2011/12/alan-guth-on-inflationary-cosmology.html