I read ArXiv regularly. It's not easy because most of the latest publications of physics go there before print. Apart from pedagogical articles (for teaching purposes), all the articles are aimed at other scientists working at the state of art in the subject. I try read the principles at the beginnings of the paper, skim the maths, and see if the conclusion match the rest of physics. So apologies to the authors if I accidentally misquote them.
Today there were enough fascinating articles that I wanted to write about them. This might become an occasional series so let me know if you find this useful.
Recently, a lot of experiment papers came out form CERN and the Tevatron. The Dijet at 150 and Top anti-top asymmetry are still controversial, and lots of phenomenology papers have come out recently on what simple extension to the standard model might produce this result. Still no signals of Supersymmetry, or low energy extra dimensions.
BaBars active as well, regularly finding new resonances and decays of Bottom quark mesons.
Light Higgsino from Axion Dark Radiation.
This paper is actually my foe, I've a pet theory that clashes with an axion, and I've never really believed supersymmetry. But so what of my prejudices, supersymmetry is the most popular extension of the standard model, and the PQ axion is the standard way to prevent QCD breaking parity, (left right symmetry). If both are true, then you get a saxion and a axino, which decay down to the axion making warm dark matter. This paper begins by quote three results that seem to show a extra low mass, unknown particle present in the universe at time of the formation of helium in the big bang, nucleosynithesis, this might be an axion. The Authors see, how many axions, decaying saxions and Higgsino would make.
Could a light Higgs Boson illuminate the dark sector
If there are other particles in nature, the Higgs boson might decay into them. This might happen even if the unknown particles get there mass some other way, (because their version of the Higgs might mix with ours). The Authors find that because the Higgs at 126 GeV is so light and decays slowly in the standard model, that detailed study of its decay might find many types of new unknown particles.
Technidilation at 125 GeV
Could the Higgs boson be a composite particle. The recent Higgs Signal at CERN produces two photons much more often than the standard model predicted. The authors look to see if a fermions bound under some force like the color force in QCD might match the diphoton signal. And find that a 6 color technicolor model might fit.
Spontaneous generation of Geometry in four dimensions
Making 4d space from just fermions! The authors start with fermion fields and vector spin connection, and build spacetime out of it. Is that, covariant fermions and contravariant fermion (spinor) indices i see? Bind them together and build curved spacetime.
The Conformal universe III: Basic Mechanisms of Matter Generation
The conformal symmetry, is the set of symmetries that preserve the cause and effect structure of space and time. Lorentz Symmetry, Translations in space and time, Dilations expanding space time and Othrochronous Inversions turning space and time inside out at a particular event in spacetime.
I learned a lot of Conformal Symmetry from Renato Nobili part II. In the third part, he works through inflation and create matter antimatter asymmetry, baryogensis, from the decay of an SU(5) Higgs field during the early universe. I'd recommend the whole series of articles.
Super Higgs in Superspace
Quantum Gravity needs Symmetry
Not going to pretend these ones aren't totally above me. Gravitinos forming a Higgs mechanism in superspace. And how N=8 supergravity may be ultraviolet finite. But I wanted to comment that in the last few years, since the books by Peter Woit and Lee Smolin, I've seen a lot less papers on string theory and supergravity. So good to see that some research is still going on. Remember Peter and Lee weren't saying string theory shouldn't go on, but that too much of the physics output was string theory, and maybe we're missing other better theories.
Beyond QCD: A composite universe
QCD Theorist, find the QCD isn't limited to describing hadron and mesons, it might build a Higgs bosons from a similar theory, technicolor. This articles describes why technicolor might explain not just the Higgs, but inflation and dark matter as well.
Introduction to loop quantum gravity
One of the founds of LQG, Abhay Asktekar, describes LQG, and how far its progress as been for students and current researchers. LQC describe spacetime and general relavity from networks of vertices and lines carrying a spin.
I thought today's ArXiv output was particularly good at showing what current research in physics is like, but there's always interesting papers there, once you're at the level where you can (partially) follow them.
Favorite ArXiv Articles Of The Day