- Published on Sunday, 21 October 2012 15:19
Deep Underground Science Laboratories and Projects Guest Editor: Alessandro Bettini
Physicists have developed a theoretical description of the elementary building blocks of matter and of the basic forces of Nature, called the Standard Model. It is the most comprehensive theory ever developed and has been tested with high precision up to energies of a few hundred times the proton mass. A new collider, the LHC, has started to work at still higher energies, discovering the last missing element of the SM, the so-called Higgs boson. However we know already that this, and any accelerator of the future, will not be sufficient.
The reason is that three of the four basic forces of Nature, namely strong, electromagnetic and weak, seem to become equal at high energies. Unfortunately the energy scale of the unification is extremely high, so high that we will never be able to reach it with an accelerator. Even higher is the Planck scale, the Big Bang energy, at which, presumably, also the fourth force, gravitation, becomes unified. We can exploit an indirect way, because phenomena characterised by a high-energy scale do, in fact, happen naturally even at the lower, every day, energies. However the higher their intrinsic energy scale is, the more rarely they happen.
The deep underground laboratories are dedicated to the search for these natural, but extremely rare nuclear and subnuclear phenomena, requiring a very low radioactive background environment. The background is due to cosmic rays and to decays of radioactive nuclei present, in traces, in all materials. Underground laboratories, shielded from cosmic and radioactive radiations, have been built in Europe, Japan and North America. More are planned in China, India and South America. They differ in size, depth and organisation, but their scientific programmes are similar and complementary. Other disciplines, like geodynamics and biology, can profit from the unique environment of the underground facilities.
The author of the paper of each laboratory or project is the Director of the given Lab or the PI of the given project.
To view this focus point and others already published, please click here.
- Published on Sunday, 21 October 2012 13:05
EPJ Plus – Determination of a time shift in the OPERA setup using high-energy horizontal muons in the LVD and OPERA detectors
- Published on Friday, 10 August 2012 15:15
The halls of the INFN Gran Sasso Laboratory (LNGS) were built in the 1980s based on the design of A. Zichichi and oriented towards CERN for experiments on neutrino beams. In 2006, the CERN Neutrinos to Gran Sasso (CNGS) beam was ready and the search could start for tau-neutrino appearances in the muon-neutrino beam produced at CERN. The OPERA detector was designed and built for this purpose.
- Published on Friday, 10 August 2012 15:13
What is the general relativistic version of the Navier-Stokes-Fourier dissipative hydrodynamics? Surprisingly, no satisfactory answer to this question is known today. Eckart's early solution [Eckart, Phys. Rev. 58, 919 (1940)], is considered outdated on many grounds: the instability of its equilibrium states, ill-posed initial-value formulation, inconsistency with linear irreversible thermodynamics, etc. Although alternative theories have been proposed recently, none appears to have won the consensus.
- Published on Friday, 10 August 2012 15:00
An interesting feature of black holes is the existence of quasi-normal modes, arising because the system has a peak in the wave potential (scalar, electromagnetic, or gravitational waves). The quasi-normal mode is excited when a disturbance is put in the field near but outside the black hole, (like a wave packet roughly in a circular orbit near the peak). The excitation then propagates outward and inward and decays.
- Published on Friday, 26 August 2011 12:00
The twin paradox has been a source of debate since it was discovered by Einstein. It can be analytically verified assuming the existence of global nonrotating inertial frames.The natural nonrotating frame and its identification with "fixed stars" is an aspect of Mach's Principle, which holds that the totality of matter in the universe determines the inertial frames.
- Published on Wednesday, 24 August 2011 18:30
At present there are no known elementary scalar fields. A possible candidate is the as yet undiscovered Higgs particle; however it could well be that this elusive particle is instead composite. This possibility is exhaustively examined in this article, which is both tutorial and extensive review, classifying the diverse technicolor models as extensions of the Standard Model of particle physics.
- Published on Wednesday, 17 August 2011 16:00
To date the most successful efforts to solve the irregular boundary Helmholtz equation with Neumann boundary conditions have been computational, but even this general method has its drawbacks. Panda et al. provide a new analytic approach which solves the irregular boundary problem via a perturbative series. As the authors show by working out several nontrivial examples, the benefits of this approach include a precise understanding of the behavior of the solution as the amplitude of the boundary distortion is increased, as well as the control over the analytic precision in the terms computed and its corresponding analytic error estimates. more
- Published on Wednesday, 10 August 2011 15:00
Oncological hadron therapy was first proposed 65 years ago by Robert R. Wilson, and it took more than 40 years to build the first dedicated facility, in Loma Linda in the nineties. The growth of new facilities since then has been exponential, and thousands of patients are now treated every year. Close collaboration between research institutes, clinical centers and industry is the basis and the future of this field. This EPJ Plus focus issue spotlights the status of hadron therapy in Europe, where different centers are already in operation, some are just now ready to start patient treatments, and new ones are being planned. more
- Published on Friday, 10 June 2011 14:30
While the hunt is on for the Higgs at the LHC, model building continues to explore also other scenarios. Here, an ultraviolet complete electroweak model is presented that assumes running coupling constants described by energy-dependent entire functions. Contrary to the conventional formulation the action contains no physical scalar fields and no Higgs particle, even if the foreseen masses for particles are compatible with known experimental values.