Almost 14 billion years ago, the universe we inhabit burst into existence in an extraordinary event that initiated the Big Bang. In the first fleeting fraction of a second, the universe expanded exponentially, stretching far beyond the view of our best telescopes. All this, of course, was just theory.
Researchers from the BICEP2 collaboration today announced the first direct evidence for this cosmic inflation. Their data also represent the first images of gravitational waves, or ripples in space-time. These waves have been described as the "first tremors of the Big Bang." Finally, the data confirm a deep connection between quantum mechanics and general relativity.
The tau lepton is a particle of very complex phenomenology. Although point-like as its lighter counterparts - the electron and the muon - the tau has a quite respectable mass, 1.77 GeV, which makes all the difference from the other charged leptons.
The tau was discovered in 1975 by Martin Perl at the SPEAR electron-positron collider. The acceptance of that observation was quite slow: the events found by Perl and his team were complicated because of the peculiar properties of the newfound particle. Perl had found an excess of events featuring an electron and a muon and an energy imbalance, which were hard to explain unless hypothesizing the creation of a pair of short-lived, heavy leptons.
Fabrizio Tamburini, the Italian researcher who has discovered an innovative way to multiply the transmission of electromagnetic signals by exploiting the vorticity of photons, has received last Saturday the "San Valentino prize" at Palazzo Gazzolli in Terni, Italy.
The annual prize was founded in 1969 by Agostino Pensa and is meant to recognize the professional devotion of scientist and artists to their work. In the past years the prize has gone, among others, to several distinguished physicists: Ugo Amaldi, Carlo Rubbia, Emilio Segre', Tullio Regge.
It is nice to see that the Tevatron experiments are continuing to produce excellent scientific measurements well after the demise of the detectors. Of course the CDF and DZERO collaborations have shrunk in size and in available man-years for data analysis since the end of data taking, as most researchers have increased and gradually maxed their participations to
other experiments - typically the ones at the Large Hadro Collider; but a hard core of dedicated physicists remains actively involved in the analysis of the 10 inverse femtobarns of proton-antiproton collisions acquired in Run 2, in the conviction that the Tevatron data still provides a basis for scientific results that cannot be obtained elsewhere.
Did you know about that dyslectic guy with an impotence problem who once came to Fermilab ? He said he'd been advised to go there as he wanted to get a hadron.
The Super-CDMS dark-matter search has released two days ago the results from the analysis of nine months of data taking. The experiment has excellent sensitivity to weak interacting massive particles producing inelastic scattering with the Germanium in the detector.
The detector is composed of fifteen cylindrical 0.6 kg crystals stacked in groups of three, equipped with ionization and phonon detectors that are capable of measuring the energy of the signals. From that the recoil energy can be derived, and a rough estimate of WIMP candidates mass. The towers are kept at close to absolute zero temperature in the Soudan mine, where backgrounds from cosmic rays and other sources are very small.
Do you remember the CDF Dijet bump at 145 GeV
? In 2010, CDF published a paper that showed how the same data sample of W + jet events where they had previously isolated the "single-lepton" WW+WZ signal also presented an intriguing excess of events in the dijet mass distribution, in a region where the background -dominated by QCD radiation produced in association with a W- fell smoothly. That signal generated some controversy within the collaboration, and a lot of interest outside of it. It could be interpreted as some signal of a new technicolor resonance !
The Fermi National Accelerator Laboratory is still getting important particle work done, years after the closure of the Tevatron was announced.
Scientists on the CDF and DZero
experiments have announced that they have found the final predicted way of creating a top quark, completing a picture of this particle that has been nearly 20 years in the making.
The Y(4140) state, a resonance found in decays of the B meson to J/ψ φ K final states, is the protagonist of a long saga. Originally it was obseved by CDF in 4 inverse femtobarns of Run 2 data by Kai Yi, a very active "bump hunter" in the experiment - and I want to add, a successful one!
Kai had to withstand a very long review process within the collaboration before the evidence for the new particle could finally be published; and the addition of more data to the analysis, one year afterwards, left many in CDF with the suspect that the particle was maybe there only in the eye of the beholder: the new data did not seem to show a clear hint of the peak seen in the first part.
Microseconds after the big ban happened the universe was a superhot, superdense primordial soup of “quarks” and “gluons,” particles of matter and carriers of force.
The quark-gluon plasma cooled almost instantly but it set the stage for the universe we know today and to better understand how the universe evolved, a quark-gluon plasma is being reproduced in giant particle accelerators like the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), where the Solenoidal Tracker at RHIC ("STAR") experiment
has been collecting and analyzing data for the past decade.