Electroweak precision measurements and collider probes of the Standard Model with large extra dimensions

The elementary particles of the Standard Model may live in more than 3+1 dimensions. We study the consequences of large compactified dimensions on scattering and decay observables at high-energy colliders. Our analysis includes global fits to electroweak precision data, indirect tests at high-energy electron-positron colliders (LEP2 and NLC), and direct probes of the Kaluza-Klein resonances at hadron colliders (Tevatron and LHC). The present limits depend sensitively on the Higgs sector, both the mass of the Higgs boson and how many dimensions it feels. If the Higgs boson is trapped on a 3+1 dimensional wall with the fermions, large Higgs masses (up to 500 GeV) and relatively light Kaluza-Klein mass scales (less than 4 TeV) can provide a good fit to precision data. That is, a light Higgs boson is not necessary to fit the electroweak precision data, as it is in the Standard Model. If the Higgs boson propagates in higher dimensions, precision data prefer a light Higgs boson (less than 260 GeV), and a higher compactification scale (greater than 3.8 TeV). Future colliders can probe much larger scales. For example, a 1.5 TeV electron-positron linear collider can indirectly discover Kaluza-Klein excitations up to 31 TeV if 500 fb^-1 integrated luminosity is obtained.Comment: 29 pages, LaTe

Atmospheric turbulence and superstatistics

Nonequilibrium systems with large-scale fluctuations of a suitable system parameter are often effectively described by a superposition of two statistics, a superstatistics. Here we illustrate this concept by analysing experimental data of fluctuations in atmospheric wind velocity differences at Florence airport.Comment: 9 pages, 4 figures. New version to appear in Europhysics News (2005

Possible Suppression of Resonant Signals for Split-UED by Mixing at the LHC?

The mixing of the imaginary parts of the transition amplitudes of nearby resonances via the breakdown of the Breit-Wigner approximation has been shown to lead to potentially large modifications in the signal rates for new physics at colliders. In the case of suppression, this effect may be significant enough to lead to some new physics signatures being initially missed in searches at, e.g., the LHC. Here we explore the influence of this `width mixing' on the production of the nearly degenerate, level-2 Kaluza-Klein (KK) neutral gauge bosons present in Split-UED. We demonstrate that in this particular case large cross section modifications in the resonance region are necessarily absent and explain why this is so based on the group theoretical structure of the SM.Comment: 10 pages, 2 figures; discussion and references adde

Optical spectroscopy of a microsized Rb vapour sample in magnetic fields up to 58 tesla

We use a magnetometer probe based on the Zeeman shift of the rubidium resonant optical transition to explore the atomic magnetic response for a wide range of field values. We record optical spectra for fields from few tesla up to 60 tesla, the limit of the coil producing the magnetic field. The atomic absorption is detected by the fluorescence emissions from a very small region with a submillimiter size. We investigate a wide range of magnetic interactions from the hyperfine Paschen-Back regime to the fine one, and the transitions between them. The magnetic field measurement is based on the rubidium absorption itself. The rubidium spectroscopic constants were previously measured with high precision, except the excited state Land\'e $g$-factor that we derive from the position of the absorption lines in the transition to the fine Paschen-Back regime. Our spectroscopic investigation, even if limited by the Doppler broadening of the absorption lines, measures the field with a 20 ppm uncertainty at the explored high magnetic fields. Its accuracy is limited to 75 ppm by the excited state Land\'e $g$-factor determination

Does the Lanham Act Lose Meaning for Companies That Operate Exclusively Over the Internet?

This Note will examine the differences between trademark registration and domain name registration, focusing specifically on the terms an applicant may register, the rights associated with those registrations, and the manner in which a registrant may lose, assign, and enforce those rights so that others my not use the same registered terms. This Note will also suggest that a company operating exclusively over the internet may obtain greater rights, and therefore protection, than a typical bricks and mortar company, simply by registering its domain name, and not trademark status

Single WRW_R Production in e−e−e^-e^- Collisions at the NLC

Single $W_R$ production in $e^-e^-$ collisions at the NLC can be used to probe the Majorana nature of the heavy neutrinos present in the Left-Right Symmetric Model below the kinematic threshold for their direct production. For colliders in the $\sqrt {s}=1-1.5$ TeV range, typical cross sections of order $1-10 fb$ are obtained, depending on the specific choice of model parameters. Backgrounds arising from Standard Model processes are shown to be small. This analysis greatly extends the kinematic range of previous studies wherein the production of an on-shell, like-sign pair of $W_R$'s at the NLC was considered.Comment: 13pp, 3 figures (available on request), LaTex, SLAC-PUB-647

Analytical investigation of the original painted canvas of Santa Irene, by Giuseppe Verrio (Church of Sant’Irene, Lecce, Italy)

The object of this study is unusual for both its material and technique. It is an oil painting on sheets of paper glued to a canvas made of linen fibres, thereby showing some execution peculiarities. It depicts the Virgin of Thessalonica in a hieratic attitude. The painting is attributed to the Salento-born artist Giuseppe Verrio (1639) for the church of the Theatine religious Order in Lecce, Italy, in which it is still placed, on the left altar of the transept. To truly understand and appreciate a work of art, it is important to have a basic knowledge of the materials and techniques used by the artist. For a better understanding of the execution techniques and to study the original materials and those that have been added over time, the painting was examined using the following analytical techniques: microscopic examination of cross-sections, μ-Raman spectroscopy and pyrolysis gas chromatography-mass spectrometry (Py-GC-MS). The data indicate that Verrio used different earthy, mineral and manufactured pigments, an organic dye used only on the paper, oil as a binder, and varnish as a protectant. The results demonstrate that the latter are both original and due to a subsequent restoration

The Dynamical Dipole Mode in Fusion Reactions with Exotic Nuclear Beams

We report the properties of the prompt dipole radiation, produced via a collective bremsstrahlung mechanism, in fusion reactions with exotic beams. We show that the gamma yield is sensitive to the density dependence of the symmetry energy below/around saturation. Moreover we find that the angular distribution of the emitted photons from such fast collective mode can represent a sensitive probe of its excitation mechanism and of fusion dynamics in the entrance channel.Comment: 5 pages, 3 figures, to appear in Phys.Rev.