PLato said,"Look to the perfection of the heavens for truth," while Aristotle said "look around you at what is, if you would know the truth" To Remember: Eskesthai
The movie presents the extraordinary figure of Abdus Salam of Pakistan, who not only was an outstanding scientist but also a generous humanitarian and a valuable person. His rich and busy life was an endless quest for symmetry, that he pursued in the universe of physical laws and in the world of human beings.See:Abdus Salam Movie – The Dream of Symmetry
John Ellis,theoretical physicist, answers the question "What is the Higgs boson?" in preparation for the press conference following the seminar on LHC 2012 results on the Higgs boson search, due on July 4 2012 at CERN. For more details: http://cern.ch/press/PressReleases/Releases2012/PR16.12E.html
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| webcast of seminar with ATLAS and CMS latest results from ICHEP |
"The soul is awestruck and shudders at the sight of the beautiful." Plato
The lessons of history are clear. The more exotic, the more abstract the knowledge, the more profound will be its consequences." Leon Lederman, from an address to the Franklin Institute, 1995
Centaurus A - one of the closest galaxies with an active galactic nucleus - although it is over 10 million light years away. If you are looking for a likely source of ultra-high-energy cosmic rays - you may not need to look further. Credit: ESO. |
Recent observations by the Pierre Auger Observatory have found a strong correlation between extragalactic cosmic rays patterns and the distribution of nearby galaxies with active galactic nuclei. Biermann and Souza have now come up with an evidence-based model for the origin of galactic and extragalactic cosmic rays – which has a number of testable predictions.
They propose that extragalactic cosmic rays are spun up in supermassive black hole accretion disks, which are the basis of active galactic nuclei. Furthermore, they estimate that nearly all extragalactic cosmic rays that reach Earth come from Centaurus A. So, no huge mystery – indeed a rich area for further research. Particles from an active supermassive black hole accretion disk in another galaxy are being delivered to our doorstep. See:Universe Today: Astronomy Without A Telescope – Oh-My-God Particles
On the evening of October 15, 1991, an ultra-high energy cosmic particle was observed over Salt Lake City, Utah. Dubbed the "Oh-My-God particle" (a play on the nickname "God particle" for the Higgs boson), it was estimated to have an energy of approximately 3 × 1020 electronvolts, equivalent to about 50 joules—in other words, it was a subatomic particle with macroscopic kinetic energy, comparable to that of a fastball, or to the mass-energy of a microbe. It was most likely a proton travelling with almost the speed of light (in the case that it was a proton its speed was approximately (1 - 4.9 × 10-24)c – after traveling one light year the particle would be only 46 nanometres behind a photon that left at the same time) and its observation was a shock to astrophysicists.
Since the first observation, by the University of Utah's Fly's Eye 2, at least fifteen similar events have been recorded, confirming the phenomenon. The source of such high energy particles remains a mystery, especially since interactions with blue-shifted cosmic microwave background radiation limit the distance that these particles can travel before losing energy (the Greisen-Zatsepin-Kuzmin limit).
Because of its mass the Oh-My-God particle would have experienced very little influence from cosmic electromagnetic and gravitational fields, and so its trajectory should be easily calculable. However, nothing of note was found in the estimated direction of its origin.
If some of physicists' favourite theories about extra dimensions are correct, it would also be possible for high-energy cosmic-ray particles from space to create black holes when they collide with molecules in the Earth's atmosphere. These black holes would be invisibly small, with a mass of only 10 micrograms or so. And they would be so unstable that they would explode in a burst of particles within around a billion-billion-billionth of a second.
One of the mysterious "Centauro" events seen by the Brazil Japan collaboration operating X-ray emulsion chambers at an altitude of 5200 m on Mt Chacaltaya in the Bolivian Andes. Given the number of hadrons seen in the lower chamber (left) physicists are intrigued by the relative lack of corresponding electromagnetic effects in the upper chamber (right).
Among the various extensions of the Standard Model to energies beyond 1 TeV, one of the most attractive alternatives to the (Supersymmetric?) Great Desert Scenario is the TeV-gravity hypothesis with large extra dimensions [1]. According to it, matter particles and vector gauge bosons are open-string excitations, attached to a 3-brane (our world), which is embedded into compactified D-dimensional bulk space, where the closed-string excitations, including gravity, can propagate. This is the simplest possibility. Specific realizations of this idea and alternative scenaria may be found in [2]. Apart from a certain philosophic and aesthetic attraction of such models, they lead to the exciting possibility of experimental discovery of unification of the Standard Model with Quantum Gravity within the next few years, in the forthcoming accelerator, neutrino and cosmic-ray experiments [3, 4, 5].
Moreover, one could even claim that Quantum Gravity phenomena are already present in existing cosmic-ray data [6]. In the present paper we shall argue that the long-known Centauro-like events (CLEs) may be due to the formation and subsequent evaporation of mini black holes (MBHs), predicted in TeV-gravity models.
"The soul is awestruck and shudders at the sight of the beautiful." Plato
The lessons of history are clear. The more exotic, the more abstract the knowledge, the more profound will be its consequences." Leon Lederman, from an address to the Franklin Institute, 1995
After the test (I felt only slightly better), I returned to the lab to find a janitor mopping the wire-strewn floor and singing an Italian operatic tune. As I entered, the guy shouted something in Italian and offered a handshake.
I said, "Okay, but be careful. The wires are carrying a high current and your wet mop may produce a short circuit." He stared cluelessly and, in total disgust, I walked out in the hall to wait for the guy to leave.
In the hall, there was the department chairman. "We have a new, dumb janitor, huh?" I said.
"New? No, wait! You mean the guy in your lab? "
"Yeah."
"That's no janitor, dummy, that's Professor Gilberto Bernardini, a world-famous Italian cosmic-ray expert whom I invited to spend a year here to help you in your research."
"Oh, my God!" I gasped and rushed in to repair my damage.
Over time, Bernardini and I learnt how to communicate and I began to watch Gilberto. There was his habit of entering a dark room, pushing the light switch: light. Pushing it again: off. On, off five or six times. Each time there would be a loud "fantastico!" Why? He seemed to have this remarkable sense of wonder about simple things.
Then the cloud chamber.
Gilberto: "Wat's dat wire in de middle?"
Leon: "That's carrying the radioactive source."
Gilberto: "Tayk id oud."
Leon: "It makes tracks."
Gilberto: "Tayk id oud."
After a few minutes, tracks appeared. My source had been far too radioactive for the chamber! Now we had a success. See:Life in physics and the crucial sense of wonder
"We all are of the citizens of the Sky" Camille Flammarion
The Flammarion woodcut. Flammarion's caption translates to "A medieval missionary tells that he has found the point where heaven and Earth meet..."The widely circulated woodcut of a man poking his head through the firmament of a flat Earth to view the mechanics of the spheres, executed in the style of the 16th century cannot be traced to an earlier source than Camille Flammarion's L'Atmosphère: Météorologie Populaire (Paris, 1888, p. 163) [38]. The woodcut illustrates the statement in the text that a medieval missionary claimed that "he reached the horizon where the Earth and the heavens met", an anecdote that may be traced back to Voltaire, but not to any known medieval source. In its original form, the woodcut included a decorative border that places it in the 19th century; in later publications, some claiming that the woodcut did, in fact, date to the 16th century, the border was removed. Flammarion, according to anecdotal evidence, had commissioned the woodcut himself. In any case, no source of the image earlier than Flammarion's book is known.
Peter Steinberg, when at Quantum diaries, lead us through this.
The creepy part of these kind of discussions is that one doesn't say that RHIC collisions "create" black holes, but that nucleus-nucleus collisions, and even proton-proton collisions, are in some sense black holes, albeit black holes in some sort of "dual" space which makes the theory easier.
Cosmic rays have been long been recognized as a background to the search for rare new physics processes in collider experiments. This was the case for the LEP detectors and it will certainly be the case for ATLAS and CMS. A thorough understanding of the development of cosmic rays in the overburden of ATLAS will be a useful tool in understanding the cosmic ray background and consequently how to minimize this background.
This page is aimed at those of us who wish to use the tools developed by the group working on simulating the development of cosmic rays (mostly muons) in ATLAS with a view to studying cosmic ray backgrounds to future searches.
An International Facility to Study the Highest Energy Cosmic Rays See:Pierre Auger Observatory
One day, some bright, enterprising physicist, perhaps inspired by this article, will complete the theory, open the doorway, and use the power of pure thought to determine if string theory is a theory of everything, anything, or nothing.See: Window On the Universe
Only time will tell if Einstein was correct when he said, "But the creative principle resides in mathematics. In a certain sense, therefore, I hold it true that pure thought can grasp reality, as the ancients dreamed."Michio Kaku
We observed muon components in the detected air showers and studied their characteristics. Generally speaking, more muons in a shower cascade favors heavier primary hadrons and measurement of muons is one of the methods used to infer the chemical composition of the energetic cosmic rays. Our recent measurement indicates no systematic change in the mass composition from a predominantly heavy to a light composition above 3 x 1017eV claimed by the Fly's Eye group.
MAGIC is an imaging atmospheric Cherenkov telescope or IACT that has started measuring since the commissioning ended in late 2004. The project is funded primarily by the funding agencies BMFB (Germany), MPG (Germany), INFN (Italy), and CICYT (Spain).
I’m sorry it just seems to get worse and worse as I find links have been changed or updated, some of the articles on cosmic particles, gone?
The Fly’s Eye and the Oh My God Particle?In recent years the main focus of fear has been the giant machines used by particle physicists. Could the violent collisions inside such a machine create something nasty? “Every time a new machine has been built at CERN,” says physicist Alvaro de Rujula, “the question has been posed and faced.”
Anyway here’s is a nice picture while too, any information on John Bachall, reveals another very interesting man.
Gamma-Ray Moon
The third point of the list is perhaps the most serious one. A theory which has in more than 30 years been unable to get its relation to physics straightened out is presented to physics students as a theory of everything which supersedes QFT before their critical faculties have been strengthened by learning about the concepts and open problems of the most successful theory of particle physics.
An equation means nothing to me unless it expresses a thought of God.-Srinivasa Ramanujan
Quantitative studies of future experiments to be carried out by LHC show that any signatures of missing energy can be used to probe the nature of gravity at small distances. The predicted effects could be accessible to the Tevatron Collider at Fermilab, but the higher energy LHC has the better chance.
These colliders are still under construction, but results also have consequences for "table-top" experiments, being carried out here at Stanford, as well as the University of Washington and the University of Colorado. Here’s the basic idea: imagine there are two extra dimensions on a scale of a millimeter. Next, take two massive particles separated by a meter, at which distance they obviously behave according to the well-known rules of 3-D space. But if you bring them very close, say closer than one millimeter, they become sensitive to the amount of extra space around. At close encounter the particles can exchange gravitons via the two extra dimensions, which changes the force law at very short distances. Instead of the Newtonian inverse square law you’ll have an inverse fourth power law. This signature is being looked for in the ongoing experiments.
Haines’ explanation theorizes that Z’s magnetic energies create microturbulences that increase the kinetic energies of ions caught in the field’s grip. Already hot, the extra jolt of kinetic energy then produces increased heat, as ions and their accompanying electrons release energy through friction-like viscous mixing even after they should have been exhausted.
Stanford's Savas Dimopoulos:
New Dimensions in Theoretical Physics
Our new picture is that the 3-D world is embedded in extra dimensions," says Savas Dimopoulos of Stanford University. "This gives us a totally new perspective for addressing theoretical and experimental problems.
Instead of the Newtonian inverse square law you’ll have an inverse fourth power law. "This signature" is being looked for in the ongoing experiments.
We are at a point where experiments must guide us, we cannot make progress without them," explains Jim Virdee, a particle physicist at Imperial College London
Unfortunately, all of this is overstated. At RHIC we don't make a "real" black hole, in the sense envisioned by Einstein's General Theory of Relativity. Rather, Nastase's point of view is that RHIC collisions can be described by a "dual" black hole. But what does "dual" mean in this context? It's not "two-ness" in any sense, but rather indicates that one can write down a theory which describes the collision as a black hole, but in a completely different world than that we see around us. To make his model work, he (and many other researchers who are exploring this direction) make a calculation of a black hole in 10 dimensions in order to describe difficult (but gravitationally benign) aspects of the strong interaction in 4 dimensions.
The Fly's Eye and the Oh My God Particle John Ellis was instrumental in opening up perspective here. What is happening outside of collision reductionist processes of the colliders
If conceived as a series of ever-wider experiential contexts, nested one within the other like a set of Chinese boxes, consciousness can be thought of as wrapping back around on itself in such a way that the outermost 'context' is indistinguishable from the innermost 'content' - a structure for which we coined the term 'liminocentric'.
There’s no other necessary connection to stringy physics except that it’s a KK theory (I guess the compactified dimensions can still be pretty big compared to the Planck length…perhaps they have to be?). It’s not obviously related to quantum gravity, anyway.
When you add a force that you want to treat perturbatively, which should be possible if the success of QED is reproduced by your quantum theory of gravity and electromagnetism, then you are expanding around "g=0" where "g" is the gauge coupling. In quantum gravity, there is a new ultraviolet cutoff "g.M_{Planck}" above which the effective theory breaks down. If "g" goes to zero, then this scale goes to zero, too. The theory therefore breaks down at all scales. You can't expand around the point where gravity is the strongest force because a quantum theory of gravity in which gravity is stronger than other forces is inconsistent.
The animation shows schematically the behavior of the gas molecules in the presence of a gravitational field. We can see in this figure that the concentration of molecules at the bottom of the vessel is higher than the one at the top of the vessel, and that the molecules being pushed upwards fall again under the action of the gravitational field.
Interactions between outgoing Hawking particles and ingoing matter are determined by gravitational forces and Standard Model interactions. In particular the gravitational interactions are responsible for the unitarity of the scattering against the horizon, as dictated by the holographic principle, but the Standard Model interactions also contribute, and understanding their effects is an important first step towards a complete understanding of the horizon’s dynamics. The relation between in- and outgoing states is described in terms of an operator algebra. In this paper, the first of a series, we describe the algebra induced on the horizon by U(1) vector fields and scalar fields, including the case of an Englert-Brout-Higgs mechanism, and a more careful consideration of the transverse vector field components.
On the evening of October 15, 1991, an ultra-high energy cosmic particle was observed over Salt Lake City, Utah. Dubbed the "Oh-My-God particle" (a play on the nickname "God particle" for the Higgs boson), it was estimated to have an energy of approximately 3 × 1020 electronvolts, equivalent to about 50 joules—in other words, it was a subatomic particle with macroscopic kinetic energy, comparable to that of a fastball, or to the mass-energy of a microbe. It was most likely a proton travelling with almost the speed of light (in the case that it was a proton its speed was approximately (1 - 4.9 × 10-24)c – after traveling one light year the particle would be only 46 nanometres behind a photon that left at the same time) and its observation was a shock to astrophysicists.
Since the first observation, by the University of Utah's Fly's Eye 2, at least fifteen similar events have been recorded, confirming the phenomenon. The source of such high energy particles remains a mystery, especially since interactions with blue-shifted cosmic microwave background radiation limit the distance that these particles can travel before losing energy (the Greisen-Zatsepin-Kuzmin limit).
Because of its mass the Oh-My-God particle would have experienced very little influence from cosmic electromagnetic and gravitational fields, and so its trajectory should be easily calculable. However, nothing of note was found in the estimated direction of its origin.
Quantum gravity is the field devoted to finding the microstructure of spacetime. Is space continuous? Does spacetime geometry make sense near the initial singularity? Deep inside a black hole? These are the sort of questions a theory of quantum gravity is expected to answer. The root of our search for the theory is a exploration of the quantum foundations of spacetime. At the very least, quantum gravity ought to describe physics on the smallest possible scales - expected to be 10-35 meters. (Easy to find with dimensional analysis: Build a quantity with the dimensions of length using the speed of light, Planck's constant, and Newton's constant.) Whether quantum gravity will yield a revolutionary shift in quantum theory, general relativity, or both remains to be seen
If conceived as a series of ever-wider experiential contexts, nested one within the other like a set of Chinese boxes, consciousness can be thought of as wrapping back around on itself in such a way that the outermost 'context' is indistinguishable from the innermost 'content' - a structure for which we coined the term 'liminocentric'.
The familiar extended dimensions, therefore, may very well also be in the shape of circles and hence subject to the R and 1/R physical identification of string theory. To put some rough numbers in, if the familiar dimensions are circular then their radii must be about as large as 15 billion light-years, which is about ten trillion trillion trillion trillion trillion (R= 1061) times the Planck length, and growing as the universe explands. If string theory is right, this is physically identical to the familiar dimensions being circular with incredibly tiny radii of about 1/R=1/1061=10-61 times the Planck length! There are our well-known familiar dimensions in an alternate description provided by string theory. [Greene's emphasis]. In fact, in the reciprocal language, these tiny circles are getting ever smaller as time goes by, since as R grows, 1/R shrinks. Now we seem to have really gone off the deep end. How can this possibly be true? How can a six-foot tall human being 'fit' inside such an unbelievably microscopic universe? How can a speck of a universe be physically identical to the great expanse we view in the heavens above? (Greene, The Elegant Universe, pages 248-249).
The calorimeter design for GLAST produces flashes of light that are used to determine how much energy is in each gamma-ray. A calorimeter ("calorie-meter") is a device that measures the energy (heat: calor) of a particle when it is totally absorbed.
While some people are looking for consistant means of determinations, others apply "conceptual situations" and bring forth comprehension of a kind. Now to this degree, that "gluonic perception is being adjusted" to see these values. The Smolins and others understood well the limitation of these views? Are there any?
All of the structures we observe in Saturn's radio spectrum are giving us clues about what might be going on in the source of the radio emissions above Saturn's auroras," said Dr. Bill Kurth, deputy principal investigator for the instrument. He is with the University of Iowa, Iowa City. Kurth made the discovery along with Principal Investigator Don Gurnett, a professor at the University. "We believe that the changing frequencies are related to tiny radio sources moving up and down along Saturn's magnetic field lines."
The auroral ionosphere is a natural emitter of radio waves, and many of these emissions are observable at ground level. Several types of radio emissions have been well documented using a variety of ground-based, stepped-frequency receivers (see reviews by LaBelle [1989] and LaBelle and Weatherwax, [1992]). In particular, auroral roar is a relatively narrowband emission at roughly 2 and 3 times the local electron cyclotron frequency ( ) [Kellogg and Monson, 1979; Kellogg and Monson, 1984; Weatherwax et al., 1993, 1995]. Much effort has been made in characterizing the seasonal, diurnal, and spectral characteristics of auroral roar to aid in determining its generation mechanism [e.g., Weatherwax et al., 1995.
If some of physicists' favourite theories about extra dimensions are correct, it would also be possible for high-energy cosmic-ray particles from space to create black holes when they collide with molecules in the Earth's atmosphere. These black holes would be invisibly small, with a mass of only 10 micrograms or so. And they would be so unstable that they would explode in a burst of particles within around a billion-billion-billionth of a second.
One of the mysterious "Centauro" events seen by the Brazil Japan collaboration operating X-ray emulsion chambers at an altitude of 5200 m on Mt Chacaltaya in the Bolivian Andes. Given the number of hadrons seen in the lower chamber (left) physicists are intrigued by the relative lack of corresponding electromagnetic effects in the upper chamber (right).
Among the various extensions of the Standard Model to energies beyond 1 TeV, one of the most attractive alternatives to the (Supersymmetric?) Great Desert Scenario is the TeV-gravity hypothesis with large extra dimensions [1]. According to it, matter particles and vector gauge bosons are open-string excitations, attached to a 3-brane (our world), which is embedded into compactified D-dimensional bulk space, where the closed-string excitations, including gravity, can propagate. This is the simplest possibility. Specific realizations of this idea and alternative scenaria may be found in [2]. Apart from a certain philosophic and aesthetic attraction of such models, they lead to the exciting possibility of experimental discovery of unification of the Standard Model with Quantum Gravity within the next few years, in the forthcoming accelerator, neutrino and cosmic-ray experiments [3, 4, 5].
Moreover, one could even claim that Quantum Gravity phenomena are already present in existing cosmic-ray data [6]. In the present paper we shall argue that the long-known Centauro-like events (CLEs) may be due to the formation and subsequent evaporation of mini black holes (MBHs), predicted in TeV-gravity models.
Describing the strong, weak and electromagnetic interactions in terms of gauge theories, the Standard Model (SM) of fundamental particles and their interactions has successfully explained and predicted many aspects of high-energy particle interactions. However, despite its tremendous successes, it remains theoretically unsatisfactory. The SM cannot answer what is the origin of particle masses, contains a large number of arbitrary parameters, and does not explain why there are so many types of quarks and leptons, among other questions. Perhaps as much as theoretical breakthroughs are needed in order to improve the SM, so are experimental observations on phenomena which can further constrain the SM or may reveal physics beyond it.
In this paper we elaborate on the idea of an emergent spacetime which arises due to the dynamical breaking of diffeomorphism invariance in the early universe. In preparation for an explicit symmetry breaking scenario, we consider nonlinear realizations of the group of analytical diffeomorphisms which provide a unified description of spacetime structures. We find that gravitational fields, such as the affine connection, metric and coordinates, can all be interpreted as Goldstone fields of the diffeomorphism group. We then construct a Higgs mechanism for gravity in which an affine spacetime evolves into a Riemannian one by the condensation of a metric. The symmetry breaking potential is identical to that of hybrid inflation but with the non-inflaton scalar extended to a symmetric second rank tensor. This tensor is required for the realization of the metric as a Higgs field. We finally comment on the role of Goldstone coordinates as a dynamical fluid of reference.
Clementine was a joint project between the Strategic Defense Initiative Organization and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon and the near-Earth asteroid 1620 Geographos. The observations included imaging at various wavelengths including ultraviolet and infrared, laser ranging altimetry, and charged particle measurements. These observations were originally for the purposes of assessing the surface mineralogy of the Moon and Geographos, obtaining lunar altimetry from 60N to 60S latitude, and determining the size, shape, rotational characteristics, surface properties, and cratering statistics of Geographos.
The Clementine gravity experiment used measurements of perturbations in the motion of the spacecraft to infer the lunar gravity fieldGravity is "flavor blind," so when a microscopic blackhole evaporates it produces all the Standard Model particles with equal probability. Once one accounts for spin and color, it turns out that particles produced when a blackhole decays are about 72 percent quarks and Gluons, 18 percent leptons, and the rest are bosons. Such a distinctive shower of particles would be hard to miss. So there is the possibility that the Pierre Auger Observatory will detect blackholes.Page 262, Out of this World, by Stephen Webb