Physics
I present you my personal view on the hierarchy of objects that occur in nature. I only treat the lowest levels.
A-- The lowest level is space that is formed by the number system of the RATIONAL quaternions. However, better make it an affine space (a space without an origin). The real part of the quaternions defines progression. Progression conforms to proper time. As a consequence progression steps with a fixed step. Quaternionic numbers exist in 16 discrete symmetry sets
HYPOTHESIS: At its start nature used only one discrete symmetry set for its lowest level objects. This situation stays…
Maybe more interesting than the just reported result of searches for the Higgs boson into four-lepton final states (ee, eμ, μμ) are the result presented by CMS and ATLAS on the searches for the Higgs decay into tau-lepton pairs. The reason for the interest comes from the fact that last July the rather high rates of Higgs decays to photon pairs had suggested to some that this new particle might have reduced couplings to fermions, and could thus be a non-Standard Model particle after all.
[ Remember, though: if the Higgs boson is observed in direct production, it is very hard to assume it does…
Today new results of Higgs searches have first been shown in Kyoto, at the Hadron Collider Physics conference. Let us see the CMS and ATLAS updates of their measurements in the ZZ-> 4 leptons final state, which constitutes the best signal-to-noise channel to study Higgs properties cleanly and measure mass and spin-parity of the new found particle.
CMS first. CMS updated their ICHEP result by adding statistics from the 2012 run, for a total of 17.3 inverse femtobarns of proton-proton collisions at 7+8 TeV center-of-mass. The four-lepton invariant mass is shown on the right. As you can see,…
The Hadron Collider Physics symposium opened yesterday in Kyoto. I am not following the works very closely, but I did give a peek at today's talks, which were on the topic of top quark physics.
The top quark is the heaviest of the six known constituents of protons and neutrons. Discovered in 1995 by the CDF and DZERO experiments at the Tevatron 1.8 TeV proton-antiproton collider, the top quark is an excellent laboratory to study Standard Model physics. Due to its extremely short lifetime the top quark does not "dress up" in a colourless hadron, but lives as a free particle, and thus allows us…
It has taken a while, but the rare decay of B_s mesons (particles composed of a bottom and an anti-strange quark) to muon pairs has finally been seen. The authors of the find -we cannot yet call it an observation given the scarce statistical significance of the signal- are the members of the LHCb collaboration, one of the four experiments working with the proton-proton collisions delivered by the Large Hadron Collider at CERN.
The decay of the B mesons to muon pairs are quite rare -of the order of one in a billion- but very important, because they proceed via loop quantum diagrams within…
The CDF and DZERO collaborations at the Fermilab Tevatron collider just saw published on Physical Review D (PRD 86, 092003) their final combination of their most recent and precise measurements of the mass of the top quark.
This result, which is probably going to be the definitive one by the Tevatron experiments, reaches a precision in the top mass which is comparable to the precision of the scale you have in your bathroom, despite the fact that measuring your body weight is a quite simpler matter than determining the mass of an elementary particle, let alone one which exists for less than a…
A journalist I am following on twitter just posted the question in the title of this post. I felt bound to try and give an answer with as simple concepts as I found meaningful. So, what makes a unstable particle unstable ?
One answer is this: a particle is unstable if there is a way, not forbidden by any physical law, to convert its rest-mass into other forms of energy. One may understand this by thinking of entropy: any system left free to evolve will do so in the direction of maximum entropy. So since a single particle state is a very low-entropy system, while the decay products of its…
Researchers and academics below the full-professor level in Italy are currently busy with an idle exercise - putting together their applications to a selection for would-be assistant and full professors. By the way, this is happening to me as well, so you may understand why this blog has received little attention from me this past week: the occupation is extremely time-consuming.
Becoming university professors in Italy in the last few decades has been a rather complicated business, where the merit of candidates was often overshadowed by favouritisms and private interests.
In many institutes…
Today I feel as American as I've ever felt.
I've lived there for a while, and of course as a foreigner I have many things I love and many I hate about this remarkable country. But today, Americans electing Obama as President for four more years send a message. They say that the attempts at creating a more just society, one where some basic rights of citizens are not ran over by the interests of big corporations, are valued by the American people just as some of us living in another continent do.
Of course anybody can disagree about the way Obama has led the country in the past four…
vongehr |
Emergence, for example emergent gravity, implies a lower stratum from which something emerges. “Fundamental emergence” is the idea that all can or must be described as emergent, without however there being a full explanation of lower layers. A lowest fundamental layer may be inconsistent almost by definition (certainly if there is any "ontological commitment") and never more than what the emergence-description must assume. This is non-reductive, since the reduction into a lowest foundation, the resting on the bottom, works only because the bottom "hangs from the top", or better, the whole "…