CMS, ATLAS experiments report Higgs-like particle close to the 7 sigma level

Dec 17, 2012 by Harriet Dingle

(Phys.org)—The latest research findings from the Large Hadron Collider (LHC) at CERN show that the CMS and ATLAS experiments are now reporting that the significance of their observation of the Higgs-like particle is standing close to the 7 sigma level, well beyond the 5 required for a discovery, and that the new particle's properties appear to be consistent with those of a Standard Model Higgs boson.

This news comes in a week when the award for their '2012 Breakthrough of the Year' gone to the ATLAS and CMS collaborations at CERN, for their joint discovery of a Higgs-like particle at the LHC.

The CMS and ATLAS results were delivered when representatives of the Large Hadron Collider (LHC) and five of its experiments presented a round-up report on the first three years of activity to the CERN Council.

The CMS and ATLAS representatives went on to report that further analysis of the data, and a probable combination of both experiments' data next year, will be required before some key properties of the new particle, such as its spin, can be determined conclusively. The focus of the analysis has now moved from discovery to measurement of the new particle in its individual decay channels.

The measurements reported by both experiments show that the new Higgs-like particle is in good health with a mass of around 125 GeV, but much further analysis is needed to reveal the full details of its identity. The next update is scheduled for the spring 2013 conferences, but for the final word before the LHC resumes running in 2015, we'll probably have to wait some time longer.

Other highlights from CERN included the reporting on a measurement of one of the rarest processes so far observed in particle physics, the decay of a Bs (pronounced B-sub-s) meson into two muons. Measurements of rare decays provide important tests of the , and are good places to look for beyond the Standard Model. The highlights from the ALICE experiment's first three years are detailed studies of the quark-gluon plasma, QGP, the matter of the primordial universe. Measurements from the TOTEM experiment give insights on the structure of the proton and provide input to the analyses of the other LHC experiments.

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User comments : 28

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El_Nose
3.9 / 5 (7) Dec 17, 2012
FYI

99.9999998027% = 6 sigma

99.9999999997440% = 7 sigma 3 in a trillion chance of being wrong

Powerball odds are better
FrankHerbert
2 / 5 (8) Dec 17, 2012
"So you're telling me there's a chance?" - Lloyd Christmas
http://www.youtub...jNnDMfxA
ValeriaT
2.9 / 5 (15) Dec 17, 2012
Actually, it seems, they found more than single Higgs at the same moment. Which is something, which nobody really expected (including mine). For example the SUSY predicts multiple Higgs boson versions, but not so similar each other.
Dhanne
1.8 / 5 (10) Dec 17, 2012
They should now confirm that we aren't living in a story. Truth in Television is that 3 in a trillion chance happens every time.

http://tvtropes.o...neChance
Lurker2358
1 / 5 (10) Dec 17, 2012
The measurements reported by both experiments show that the new Higgs-like particle is in good health with a mass of around 125 GeV, but much further analysis is needed to reveal the full details of its identity. The next update is scheduled for the spring 2013 conferences, but for the final word before the LHC resumes running in 2015, we'll probably have to wait some time longer.


Rather long delay in a research cycle. Are they low on funding or something?

ValeriaT:
Interesting. I suspected there could be a "hidden particle within a hidden particle" problem, and this hints that such just might be the case.

The latest results from the ATLAS detector at the LHC suggest that when we look at its decay into two photons, we find that the new boson's mass is about 3 gigaelectronvolts greater than when calculated from its decay into particles called Z bosons.


That could be a discrepancy in the definition of kinetic energy, or maybe (a?) binding energy of the Z boson.
Lurker2358
1 / 5 (13) Dec 17, 2012
One of the things that has bothered me about particle physics is that most of the particles are never observed directly. In a certain sense, they are just as much "Dark Matter" as the substance of the same name "out there". We've never actually seen them. We've only seen side-effects and daughter particles, which is only slightly more than can be said for the stuff "out there".

On how and why there are so many particles and so many variations of particles, I suspect that there is something very simple and fundamental which is being overlooked.

If particles are "fundamental" then why do they each have multiple characteristics? Why would a "fundamental" Higgs Boson have both spin and mass? Why isn't there a massless "spin-up" and a "spin-down" particle?

If the Higgs can have spin, it would seem to require at least 2 and possibly 3 flavors of higgs to explain all matter, because you'd need an up-higgs, a down-higgs, and zero-higgs to get all combinations of characteristics...
ShotmanMaslo
3.5 / 5 (8) Dec 17, 2012
Actually, it seems, they found more than http://www.newsci...sis.html at the same moment. Which is something, which nobody really expected (including mine). For example the SUSY predicts multiple Higgs boson versions, but not so similar each other.


It is very likely to be a systematic error present in Atlas ZZ channel, because CMS also measures Higgs mass in ZZ channel, and their value agrees with 126 GeV.
ValeriaT
1.5 / 5 (8) Dec 17, 2012
It's not the only anomaly observed there. IMO it could be a sign of fourth particle generation, which manifest itself with excess of events in diphoton channels too.
Q-Star
2.8 / 5 (11) Dec 17, 2012
It's not the only anomaly observed there. IMO it could be a sign of fourth particle generation, which manifest itself with excess of events in diphoton channels too.


But if the non moving electrons are longitudinally waving at the photons then wouldn't the third generation take precedence? It seems like a classic flat surface of the water wave to me.
ValeriaT
1.4 / 5 (9) Dec 17, 2012
During collisions of particles the lightweight fragments, i.e. photons are formed the more, the heavier and less stable the metastable products of collisions are. In this moment it's speculative idea only, but there is an possibility of new fourth generation of quarks and neutrinos - very unstable and only slightly differing from random quantum background. Because the vacuum is very slightly compressible already, only small difference in original mass of products of collisions can be detected.

It's like the detection of glass material with mutual collisions of Christmas glass spheres. The higher energy of collision we will use, the smaller shards we will observe without apparent spatial distribution, because the light is very slightly compressible. But when the energy of collision will really high, the compression of glass will create a tiny bump on the distribution curve of energies of products.
ValeriaT
1.8 / 5 (10) Dec 17, 2012
Errata: "because the light is very slightly compressible" should be "because the glass is very slightly compressible"

In AWT we should observe the very same effect with difference between spatial distribution of gamma ray and CMBR photon intensities on the sky, where the dark matter photons SURROUND the gamma ray photon sources, but they're not coinciding with them. So we could say: yes, we are prepared to explain this effect theoretically.
vacuum-mechanics
1.4 / 5 (9) Dec 17, 2012
(Phys.org)—The latest research findings from the Large Hadron Collider (LHC) at CERN show that the CMS and ATLAS experiments are now reporting that the significance of their observation of the Higgs-like particle is standing close to the 7 sigma level, well beyond the 5 required for a discovery, and that the new particle's properties appear to be consistent with those of a Standard Model Higgs boson.

It is interesting to note that Standard Model was born (from quantum mechanics + relativity) without aether! And then quantum field (with virtual particles) was introduced. Now LHC have showed that there is Higgs field/boson which is something like aether; what does this mean? May be the paper below could explain why it is something like that!
http://www.vacuum...=9〈=en
Torbjorn_Larsson_OM
5 / 5 (10) Dec 17, 2012
The bosun's boson - gliding into the history books.

@Valeria: "Actually, it seems, they found more than single Higgs at the same moment."

Actually, NS is sensationalist these days, and Strassler diagnosed it as measurements problem. Indeed, with these newer results "the new Higgs-like particle is in good health with a mass of around 125 GeV", rejecting the earlier result.

@Lurker: Long delay? They are analysing the fastest they can. They have analysed ~ 3*10^14 collisions, with many more particles in the jets! [ http://en.wikiped...ing_Grid ]

"most of the particles are never observed directly". Well then, define "directly" testably!

Observations are unambiguous, here defined as over 5 sigma within the observational constraints of a particle. (I.e. background deducted, peak width, et cetera, all giving the over 5 sigma result.) We never observe differently, and we certainly observe by proxy in all cases - that is what observations _do_, after all.
Torbjorn_Larsson_OM
4.8 / 5 (12) Dec 17, 2012
@vacuum-mechanics: "aether". Are you a sockpuppet of Valeria, the "aether" nut? "Aether", a hypothesized _medium_, was rejected by observations over a century ago, and relativity won't allow it.

Particle fields are old hat, the new thing with the Higgs field is that it is a scalar, like the earlier observed inflation field. (We have tested its inflation effect, its symmetry breaking leaving dark energy, its reheating of the vacuum leaving the primordial particles, and, in the CMB, its predicted quantum fluctuations.)

Particle fields are simply what quantum field theory gives you. A field is medium-less, i.e. the exact opposite to an "aether".
ValeriaT
1 / 5 (10) Dec 17, 2012
NS is sensationalist these days
The same story was published at Scientfic American, which is conservative journal.
Strassler diagnosed it as measurements problem
He just wrote, that CMS didn't observe 2nd Higgs, as ShotmanMaslo already noted. While level of expertise is required for "such diagnosis"?
A field is medium-less, i.e. the exact opposite to an "aether"
But it exhibits waves, so it must be elastic and it exhibits the virtual particles and Brownian noise - in similar way like every dense gas. This is somewhat suspicious similarity, don't you think? After all, the Higgs field is the scalar field of the same category.
ValeriaT
1 / 5 (11) Dec 17, 2012
Particle fields are simply what quantum field theory gives you
We have water surface models of Hawking radiation, double slit experiment, Zeeman effect, atom orbitals... Only very stupid people couldn't reconcile this similarity. The dense aether model of AWT handles the particle gas as the simplest geometric model of emergent behavior. It's just a model for modeling the hyperdimensional random Universe in physically relevant and least ad-hoced way. There are no actual particles, just nested density fluctuations of the emergent entropic field. But emergence and entropy are abstract, shapeless concept, we must attribute them to some real geometry. After all, at the water surface the waves aren't scattered with particles, rather with hyperbolic density fluctuations. The water molecules are so tiny, they're not observable with surface waves, so we can neglect them completely and consider the underwater as a continuum. What remains is the emergent dynamics of these fluctuations.
ValeriaT
1 / 5 (11) Dec 17, 2012
Whole the existence of Higgs field is somewhat suspicious in the field concept, because it introduces a virtual particles, which are of limited size. As Einstein already recognized in his study of Brownian motion, quantum field has no particles of fixed size: the smaller space-time distance scale we will use for observations, the higher energy density we get. Well known hierarchy problem implies, that quantum corrections can make the mass of the Higgs particle arbitrarily large, since virtual particles with arbitrary energies are allowed in quantum mechanics.

At the water surface it corresponds the principle: there are no particles. The shorter waves we will use for observations, the smaller virtual particles we will get. In dense aether model the particles of aether are simply always smaller, then you can observe. The finite mass of Higgs boson is just a consequence of the fact, we have no smaller particles for its detection
ValeriaT
1 / 5 (10) Dec 17, 2012
The concept of Higgs field is therefore a much wider, than it's presented right now. All massive particles are surrounded with field of virtual bosons (quarks, gluons, photons) - the average size of which is always smaller than these particles. These virtual bosons manifest with short-distance forces like the Yukawa forces at the nuclear scale, Cassimir force at the microscopic scale or like the dark matter at the cosmic scale. We should detect the Higgs boson-like effect with collision of whatever particles of defined size. The effective size of Higgs bosons at the human observer scale is the wavelength of CMBR (~ 3.2 cm). Such a generalized Higgs field gives the nonzero rest mass to all bosons, not just W/Z bosons and it scatters them, so they cannot mediate the forces of infinite distance.
ValeriaT
1 / 5 (9) Dec 17, 2012
The general understanding of physics is, the Higgs field applies to W/Z bosons only, which are therefore quite heavy. The lighter bosons (gluons and photons) are considered massless for the sake of consistency of formal theories, which are describing them (Standard Model and general relativity). But these are theories - how the reality appears? Well, we have a paradox here: the gluons are considered massless, but they cannot mediate forces at the distance longer than some 10E-15 meters. If they would be really massless, then they should be able to mediate the forces at infinite distance, isn't it true?

The whole trick is, the Standard Model is designed for description of particles INSIDE of atom nuclei, where these gluons propagate like the massless waves. But they're still pretty heavy - because their environment isn't massless. The environment of atom nuclei is actually a very dense stuff. Therefore the parameters of SM are fitted to this dense environment, not the vacuum.
ValeriaT
1 / 5 (9) Dec 17, 2012
Another missunderstanding - just more subtle one - exists regarding the mass of photons. If the Higgs field applies to all scales, then the photons should be massive at least a bit, right? How is it possible after then, that the photons can travel through the whole cosmic scale?
It's easy - these photons aren't the original photons, which were emanated with stars before billions of years. Due the decoherence the photons of visible light can travel just at few kilometer distance before they dissolve inside of vacuum fluctuation and another photon will emerge at their place. Therefore no photon can mediate the EM force at the infinite distances. General relativity solves the problem of alleged zero-mass of photon with arbitrary ad-hoced assumption, that the photon cannot transfer the mass, only the momentum. But does such an assumption holds truth from human observer perspective? Of course not, as we are observing the evaporation of matter from stars with radiation of photons routinely.
ValeriaT
1.2 / 5 (12) Dec 17, 2012
The problem of mainstream theories therefore isn't, they're wrong - they're just fitted to their particular validity scope. The general relativity applies to large scales, where the quantum fluctuations are negligible, so it considers the photons massless. It can describe the gravity, but it cannot describe the photons, because it cannot be quantized easily. The Standard model deals with interior of atom nuclei (the gluons cannot exist outside of it), so it assumes the gluons massless. But it cannot describe the gravity field instead. The general relativity considers the common quantum noise as a flat land, whereas the Standard Model describes even the extremely curved space-time inside of atom nuclei as a flatland. If we could live inside of it, then we would observe it relatively flat and the gluons would propagate quite freely there - the quantum noise would manifest only at short-distances (roughly one 1/10000 of the atom nuclei diameter), which are domains of W/Z bosons.
VendicarD
2.3 / 5 (3) Dec 17, 2012
"So you're telling me there's a chance?" - FrankHerbert quote

I prefer this Lauren Holly clip.

http://www.youtub...W-vXXDxA
Fleetfoot
5 / 5 (6) Dec 18, 2012
One of the things that has bothered me about particle physics is that most of the particles are never observed directly.


Their lifetimes are too short.

Why isn't there a massless "spin-up" and a "spin-down" particle?


That'll be the photon:

"The magnitude of its spin is ħ*sqrt(2) and the component measured along its direction of motion, its helicity, must be ±ħ. These two possible helicities, called right-handed and left-handed, correspond to the two possible circular polarization states of the photon."

http://en.wikiped...operties
FMM
4.6 / 5 (9) Dec 18, 2012
Please tolerate a remark about the repeated complaints that things are concluded to exist that aren't directly observed. We don't "directly" observe anything.

When I see my wife in the morning, I don't really "directly" "see" her. I observe light bounced off her that happens to enter my eye, and then gets interpreted by my brain. Its all inference -- I just don't notice that I am inferring my wife.

When the physicists infer the existence of the Higgs particle from the pattern of decay products, the principle is the same, except probably the certainty is better.
AmritSorli
1 / 5 (4) Dec 18, 2012
that all is fine.
But what is giving mass to the Higgs boson itself remains unanswered question, see article:
F. Wilczek, "Origins of Mass", http://arxiv.org/...7114.pdf (2012).
Kron
2.3 / 5 (9) Dec 18, 2012
When the physicists infer the existence of the Higgs particle from the pattern of decay products, the principle is the same, except probably the certainty is better [than]...when I see my wife in the morning.

LOL. Tendency to hallucinate? ;) jk.

The thing you must remember is that the decay channels are the tell tale signs of the Higgs boson. It is more like you wake up and see the covers on your wifes side of the bed a mess. You walk into the kitchen and find her coffee mug on the counter. You conclude at some level (sigma) that your wife slept in your bed got up had coffee, and left the house before you got up. The Higgs boson is not 'directly' 'inferred', like when you 'look' at your wife. Like the Higgs, your wife leaves clues behind that signify that she WAS there before you woke up. Your level of certainty that it is your wifes trail you're seeing is probably pretty high. But just because it appears that your wife was there does not mean she was.
Kron
2.1 / 5 (7) Dec 18, 2012
Just because it appears as if the Higgs boson was there, from the diphoton decay channel for example, does not mean that it actually was the Higgs boson. The decay seems to be what it is predicted for it to be, to a high level of precision (7 sigma at this point), but in science there is never certainty.

Maybe you had too much to drink the night before. The messy bed, and the coffee mug may have been left behind by a woman other than your wife. So even though you're 99.999999999744% sure that the trail left behind is your wifes, you still aren't certain.
Durgadas_Datta
1 / 5 (3) Dec 19, 2012
The possibility of two Higgs Boson,--One for gravity and another for anti gravity, we say dark energy ,and these are predicted in ether=gravity=dark energy theory of gravitoethertons by Durgadas Datta. Read balloon inside balloon theory of matter and antimatter producing gravitoethertons at common bounday by annihilation and injected into both the universe for further necessary action.