Damn, this has been a decent week for the sciences:

Members of the CMS collaboration announced the experiment’s first discovery of a new particle today.

In a paper submitted to Physical Review Letters, the CMS collaboration described the first observation of an excited, neutral Xi_b baryon, a particle made up of three quarks, including one beauty quark.

The new baryon is one of many particles made up of quarks predicted by the theory of quantum chromodynamics.

(from CMS collaboration discovers its first new particle)

quantumaniac:

Neutrino evidence against “faster-than-light” claim

Neutrinos do not go faster than light, according to new measurements made by an experiment called ICARUS at the Gran Sasso Laboratory using a new measuring technique, called a liquid argon time projection chamber and working independently from the OPERA scientists who had made the tentative but extremely controversial claim about “faster-than-light” particles. Particles that travel faster than light would unravel Albert Einstein’s 1905 theory of special relativity, a cornerstone of modern physics.

Their findings “indicate the neutrinos do not exceed the speed of light,” the European Centre for Nuclear Research (CERN) said, ading that there may have been technical hitches that had skewed the initial measurements, something that skeptics of the findings said they had always suspected.

The controversy began last September, when CERN’s so-called OPERA team cautiously announced that sub-atomic particles called neutrinos had travelled some six kilometres (nearly four ) per second faster than the velocity of light, described by Einstein as the maximum speed in the cosmos.

The neutrinos were timed at their departure from CERN’s giant underground lab near Geneva and again, after travelling 732 km (454 miles) through the Earth’s crust, at their arrival at the Gran Sasso Laboratory in Italy.

To complete the trip, the neutrinos should have taken 0.0024 seconds. Instead, the particles were recorded as hitting the detectors in Italy 0.00000006 seconds sooner than expected.Knowing their findings would create a global controversy, the OPERA team urged other physicists to carry out their own checks to corroborate or refute what had been seen.

“ICARUS measures the neutrino’s velocity to be no faster than the speed of light,” said Carlo Rubbia, a Nobel winner and spokesperson for the ICARUS project..”Whatever the result, the OPERA experiment has behaved with perfect scientific integrity in opening their measurement to broad scrutiny and inviting independent measurements. This is how science works,” said CERN Research Director Sergio Bertolucci, who added that further verifications were being made, including new experiments with particle beams in May, “to give us the final verdict.”

In February, CERN said that the OPERA team were verifying a cable connection and a timing instrument called an oscillator that may have flawed measurements of the neutrinos’ flight time.Strengthening this scenario, Bertolucci said on Friday “the evidence is beginning to point towards the OPERA result being an artifact of the measurement.”

It has been a busy week in the world of particle physics, with attention focused on the home of the LHC: CERN. This year, the LHC generated five inverse femtobarns worth of data—nearly half the amount generated during the entire lifetime of the Tevatron—before shutting down the proton program a few weeks ago. From now until its scheduled winter shutdown, the LHC will be doing lead ion collisions to examine the quark-gluon interactions that dominated the Universe immediately after the Big Bang.

In the mean time, analysis of the data has continued, and some significant news has come out this week. A further dissection of last year’s data has placed tighter limits on where the Higgs boson, which provides mass to other particles, might be hiding (assuming it exists). Meanwhile, the LHCb detector, which studies particles that contain heavy quarks, has found an anomalous behavior that might hint at physics beyond the Standard Model. And the LHC accelerator chain has sent some more neutrinos to detectors at Italy’s Gran Sasso, which has helped them eliminate some potential sources of error in their faster-than-light findings.

(via Fast neutrinos, C-P violations, and the shrinking space for the Higgs)

Oh, yeah. Moving faster than the speed of light has been the hot topic in the news and OPERA has been the key player. In case you didn’t know, the experiment unleashed some particles at CERN, close to Geneva. It wasn’t the production that caused the buzz, it was the revelation they arrived at the Gran Sasso Laboratory in Italy around 60 nanoseconds sooner than they should have. Sooner than the speed of light allows!

Since the announcement, the physics world has been on fire, producing more than 80 papers – each with their own opinion. While some tried to explain the effect, others discredited it. The overpowering concensus was the OPERA team simply must have forgotten one critical element. On October 14, 2011, Ronald van Elburg at the University of Groningen in the Netherlands put forth his own statement – one that provides a persuasive point that he may have found the error in the calculations.

To get a clearer picture, the distance the neutrinos traveled is straightforward. They began in CERN and were measured via global positioning systems. However, the Gran Sasso Laboratory is located beneath the Earth under a kilometre-high mountain. Regardless, the OPERA team took this into account and provided an accurate distance measurement of 730 km to within tolerances of 20 cm. The neutrino flight time is then measured by using clocks at the opposing ends, with the team knowing exactly when the particles left and when they landed.

But were the clocks perfectly synchronized?

Keeping time is again the domain of the GPS satellites which each broadcasting a highly accurate time signal from orbit some 20,000km overhead. But is it possible the team overlooked the amount of time it took for the satellite signals to return to Earth? In his statement, van Elburg says there is one effect that the OPERA team seems to have overlooked: the relativistic motion of the GPS clocks.

(via Special relativity may answer faster-than-light neutrino mystery)

Physicists Weigh Antimatter with Amazing Accuracy

A new measurement provides the most accurate weight yet of antimatter, revealing the mass of the antiproton (the proton’s antiparticle) down to one part in a billion, researchers announced today (July 28).

To give a sense of just how accurate their measurement was, researcher Masaki Hori said: “Imagine measuring the weight of the Eiffel Tower. The accuracy we’ve achieved here is roughly equivalent to making that measurement to within less than the weight of a sparrow perched on top. Next time it will be a feather.”

The result, detailed this week in the journal Nature, may help scientists investigate the mystery of why the universe is made of regular matter even though they suspect roughly equal parts of matter and antimatter were around just after the universe formed. When a particle, such as a proton, meets with its antimatter partner, the antiproton, the two annihilate each other in a powerful explosion.

(via LiveScience)

For the good of all of us: CERN launches open source hardware effort

Open source software is used extensively by CERN, the particle physics lab behind the Large Hadron Collider (LHC) experiments. In fact, the organization even maintains its very own Linux distribution—based on Red Hat Enterprise Linux—called Scientific Linux CERN. Inspired by the productivity of Linux development, a group of CERN engineers have decided to bring the advantages of the open source software development model to the world of hardware.

CERN has launched a new community-centric effort called the Open Hardware Repository (OHR) with the aim of encouraging collaborative electronics design. CERN has also developed a new license, called the Open Hardware License (OHL), to govern the distribution of open hardware designs.

(via Ars Technica )

CERN Scientists Trap Antimatter for Almost 17 Minutes

What happened to antimatter? That’s the grand riddle that scientists are attempting to piece together, but it takes quite a bit of work to conduct experiments on the elusive mirror image of matter (remember, matter is anything that has a volume and occupies mass).

But CERN scientists have now been able to isolate unstable antimatter for a grand total of nearly 17 minutes. That’s a far cry from experiments performed last fall, when scientists were only able to record the presence of antimatter for fractions of seconds. The increased longevity should now give researchers the time they need to perform studies on antiatoms related to change-parity-time reversal (CPT) symmetry.

So just how difficult is it to trap antimatter for study? Just like in Star Trek, the combination of matter and antimatter particles leads to the annihilation of both and the production of a small flash of energy. Thus, to successfully trap antimatter, researchers use magnetic fields to contain antiatoms. When they turn off the field, the resulting annihilation events–recorded by a special detector–clue the scientists into just how many antiatoms are left after a set period of containment time.

CERN’s full study was published in the journal Nature Physics: “Confinement of antihydrogen for 1,000 seconds.”

(via PCMag.com)

scienceisbeauty:

Electron Positron Physics for the Layman by Dr Claus Grupen (Siegen University, Department of Physics)

(IMHO something is doing wrong the interpreter)

Rumor: LHC Sees Hint of the Higgs Boson

A leaked internal memo from physicists working at the Large Hadron Collider near Geneva reports a whiff of the Higgs boson, the long-sought theoretical particle that could make or break the standard model of particle physics.

The preliminary note, which is still under review, was posted April 21 in an anonymous comment on physicist Peter Woit’s blog, “Not Even Wrong.” Four physicists claim that ATLAS, one of the LHC’s all-purpose particle hunting experiments, caught a Higgs particle decaying into two high-energy photons — but at a much higher rate than the standard model predicts.

“The present result is the first definitive observation of physics beyond the standard model,” the note says. “Exciting new physics, including new particles, may be expected to be found in the very near future.”

The word from CERN, which operates the LHC, is that the leaked note is not an official result, and hasn’t been backed up by the cast of thousands that makes up the rest of the ATLAS collaboration.

(via Wired Science | Wired.com)

unknownskywalker:

Study finds there may be five versions of the Higgs boson

The Higgs Boson is extremely important to the accepted theory of physics, known as the “Standard Model”, which incorporate everything known at the time about interactions between sub-atomic particles. The Higgs boson is thought to be the sub-atomic particle that mediates the force through which all other sub-atomic particles acquire their mass.

Scientists have been trying for five decades to detect the Higgs boson, but have so far failed. Now theoretical physicist Adam Martin and colleagues at the Fermilab’s Tevatron particle accelerator have analyzed results from the DZero experiment and suggest there may be multiple versions of the Higgs boson.

The DZero experiment set up and observed collisions protons and anti-protons and was designed to examine the reason why the world is composed of normal matter rather than its opposite: anti-matter. They found the collisions resulted in pairs of muons one percent more often than anti-muon particles. The asymmetry could explain why matter has come to dominate over anti-matter, rather than the two annihilating each other.

This effect, called CP violation, had been seen before but not to the same degree as seen in DZero, and the degree of asymmetry found in the latest results is greater than can be accounted for by the Standard Model. The results could be explained by the existence of five Higgs boson particles with similar masses, with one having a negative electric charge, one negative and three neutral. The theory is called the two-Higgs doublet model.

The two-Higgs doublet model is not the only possible explanation for the results, but fitting a new effect in the Standard Model without disrupting its fit with other tests is difficult. The Standard Model accommodates only one Higgs doublet, and while the Higgs is considered a single particle, it actually comes in a package of four. Only one is seen because the other three are seen as W and Z bosons. Adding another Higgs doublet adds four more particles.

Many physicists have come to regard the Standard Model as incomplete since it does not explain gravity or describe dark matter. An extension to the Standard Model, known as “supersymmetry,” proposes that each particle has a more massive “shadow” partner particle, effectively doubling the number of known particles. Such a scheme could accommodate the two-Higgs doublet model. So far no experimental evidence has been found for the existence of the “shadow” particles.

The search for the Higgs boson is one of the main aims of the Large Hadron Collider (LHC) near Geneva in Switzerland. The facility, the world’s largest particle accelerator, could also find experimental evidence for supersymmetry.

Image: CDF II detector at the Tevatron, a 2 TeV proton-antiproton collider located at Fermilab in Batavia IL, USA. [+]

Source: Provided by Cornell University. | via: PhysOrg.com | Other: 80beats

CERN Press Release: Particle Chameleon Caught in the act of Changing

“Researchers on the OPERA experiment at the INFN¹’s Gran Sasso laboratory in Italy today announced the first direct observation of a tau particle in a muon neutrino beam sent through the Earth from CERN², 730km away. This is a significant result, providing the final missing piece of a puzzle that has been challenging science since the 1960s, and giving tantalizing hints of new physics to come.

The neutrino puzzle began with a pioneering and ultimately Nobel Prize winning experiment conducted by US scientist Ray Davis beginning in the 1960s. He observed far fewer neutrinos arriving at the Earth from the Sun than solar models predicted: either solar models were wrong, or something was happening to the neutrinos on their way. A possible solution to the puzzle was provided in 1969 by the theorists Bruno Pontecorvo and Vladimir Gribov, who first suggested that chameleon-like oscillatory changes between different types of neutrinos could be responsible for the apparent neutrino deficit.

Several experiments since have observed the disappearance of muon-neutrinos, confirming the oscillation hypothesis, but until now no observations of the appearance of a tau-neutrino in a pure muon-neutrino beam have been observed: this is the first time that the neutrino chameleon has been caught in the act of changing from muon-type to tau-type.”

(via fuckyeahmath)

“An eary bid for the “geek-of-the-week” prize from my son, who is modelling the t-shirt he bought from the gift shop at CERN.

This t-shirt encapsulates the standard model of particle physics; line 1 describes the 4 forces, line 2 the particles, line 3 how the particles gain their mass from the Higgs boson, & line 4 the Higgs field. But then you knew that.” They sell t-shirts at CERN? Awesome.