The Making of the Standard Theory

John Iliopoulos

1. Introduction
The construction of the Standard Model, which became gradually the Standard Theory of elementary particle physics, is, probably, the most remarkable achievement of modern theoretical physics. In this Chapter we shall deal mostly with the weak interactions. It may sound strange that a revolution in particle physics was initiated by the study of the weakest among them (the effects of the gravitational interactions are not measurable in high energy physics), but we shall see that the weak interactions triggered many such revolutions and we shall have the occasion to meditate on the fundamental significance of “tiny” effects. We shall outline the various steps, from the early days of the Fermi theory to the recent experimental discoveries, which confirmed all the fundamental predictions of the Theory. We shall follow a phenomenological approach, in which the introduction of every new concept is motivated by the search of a consistent theory which agrees with experiment. As we shall explain, this is only part of the story, the other part being the requirement of mathematical consistency… Read more at

What hadron collider is required to discover or falsify natural supersymmetry?

Howard Baer, Vernon Barger, James S. Gainer, Peisi Huang, Michael Savoy, Hasan Serce, Xerxes Tata
Weak scale supersymmetry (SUSY) remains a compelling extension of the Standard Model because it stabilizes the quantum corrections to the Higgs and W, Z boson masses. In natural SUSY models these corrections are, by definition, never much larger than the corresponding masses. Natural SUSY models all have an upper limit on the gluino mass, too high to lead to observable signals even at the high luminosity LHC. However, in models with gaugino mass unification, the wino is sufficiently light that supersymmetry discovery is possible in other channels over the entire natural SUSY parameter space with no worse than 3% fine-tuning. Here, we examine the SUSY reach in more general models with and without gaugino mass unification (specifically, natural generalized mirage mediation), and show that the high energy LHC (HE-LHC), a pp collider with \sqrt{s}=33 TeV, will be able to detect the gluino signal over the entire allowed mass range. Thus, HE-LHC would either discover or conclusively falsify natural SUSY.


Qbe: Quark Matter on Rubik’s Cube

Figure of Albert Einstein, the smile of Mona Lisa and Qbe: Quark Matter on Rubik’s 3x3 Cube, next to the Road to Reality: A Complete Guide to the Laws of the Universe. Photo courtesy of prof. T. Kodama, Rio de Janeiro, Brazil.

Figure of Albert Einstein, the smile of Mona Lisa and Qbe: Quark
Matter on Rubik’s 3×3 Cube, next to the Road to Reality: A Complete Guide to the
Laws of the Universe. Photo courtesy of prof. T. Kodama, Rio de Janeiro, Brazil.

T. Csörgő
Quarks can be represented on the faces of the 3×3 Rubik’s cube with the help of a symbolic representation of quarks and anti-quarks, that was
delevoped originally for a deck of elementary particle cards, called Quark Matter Card Game. Cubing the cards leads to a model of the nearly perfect
fluid of Quark Matter on Rubik’s cube, or Qbe, which can be utilized to provide hands-on experience with the high entropy density, overall color
neutrality and net baryon free, nearly perfect fluid nature of Quark Matter.


Universal Limit on Communication

Raphael Bousso
I derive a universal upper bound on the capacity of any communication channel between two distant systems. The Holevo quantity, and hence the mutual information, is at most of order EΔt/ℏ, where E the average energy of the signal, and Δt is the amount of time for which detectors operate. The bound does not depend on the size or mass of the emitting and receiving systems, nor on the nature of the signal. No restrictions on preparing and processing the signal are imposed.
As an example, I consider the encoding of information in the transverse or angular position of a signal emitted and received by systems of arbitrarily large cross-section. In the limit of a large message space, quantum effects become important even if individual signals are classical, and the bound is upheld.


What Happens When Energy Goes Missing?

Article: Performance of algorithms that reconstruct missing transverse momentum in √s = 8 TeV proton-proton collisions in the ATLAS detector
Authors: The ATLAS Collaboration
Reference: arXiv:1609.09324

The ATLAS experiment recently released a note detailing the nature and performance of algorithms designed to calculate what is perhaps the most difficult quantity in any LHC event: missing transverse energy. Missing transverse energy (MET) is so difficult because by its very nature, it is missing, thus making it unobservable in the detector. So where does this missing energy come from, and why do we even need to reconstruct it?