The mass of the Higgs boson in the trinification subgroup of E6

The extension of the standard model to SU(3)_L x SU(3)_R x SU(3)_C is considered. Spontaneous symmetry breaking requires two Higgs field multiplets with a strong hierarchical structure of vacuum expectation values. These vacuum expectation values, some of them known from experiment, are used to construct invariant potentials in form of a sum of individual potentials relevant at the weak scale. As in a previous suggestion one may normalize the most important individual potentials such that their mass eigenvalues agree with their very large vacuum expectation values. In this case (for a wide class of parameters) the scalar field corresponding to the standard model Higgs turns out to have the precise mass value m_Higgs = v/sqrt(2) = 123 GeV at the weak scale. The physical mass (pole mass) is larger and found to be 125 +/- 1.4 GeV.Comment: 5 pages, version appearing in Phys. Rev.

Neurofisiologia i mesura del dolor

Què és el dolor? Com podem mesurar-lo? Un investigador de la Universitat de Nova York ens ho explic

The struggle between equity and efficiency: Do nordic countries have a free lunch?

Although there is a vast theoretical literature on the existence of a tradeoff between equity and efficiency, empirical investigations often fail to find evidence for this proposition. Furthermore there are hints that some social models in Europe can cope better with this trade-off and are actually able to provide what economists call a 'free lunch'. In this paper we use data from the Luxembourg Income Studies (LIS) to evaluate (a) whether there really exists something like a free lunch and (b) whether some social systems are actually better in coping with the trade-off between equity and efficiency.Obwohl in der theoretischen Literatur die Existenz eines Trade-Offs zwischen Effizienz und Gerechtigkeit deutlich bejaht wird, ist dieser in der Empirie nur schwierig zu finden. Darüber hinaus scheint der Trade-Off von den verschiedenen europäischen Sozialmodellen unterschiedlich gut bewältigt zu werden. In einigen Ländern scheint sogar kein Trade-Off zu bestehen, so dass die Vermutung besteht, dass ein 'free lunch' existiert. In diesem Paper nutzen wir Daten der Luxembourg Income Studies (LIS) um empirisch zu evaluieren, ob (a) tatsächlich ein 'free lunch' existiert und ob (b) eine strukturelle Überlegenheit des nordischen Sozialsystems vorliegt

Mutually unbiased bases for the rotor degree of freedom

We consider the existence of a continuous set of mutually unbiased bases for the continuous and periodic degree of freedom that describes motion on a circle (rotor degree of freedom). By a singular mapping of the circle to the line, we find a first, but somewhat unsatisfactory, continuous set which does not relate to an underlying Heisenberg pair of complementary observables. Then, by a nonsingular mapping of the discrete angular momentum basis of the rotor onto the Fock basis for linear motion, we construct such a Heisenberg pair for the rotor and use it to obtain a second, fully satisfactory, set of mutually unbiased bases.Comment: 9 pages, 4 figure

Mutually unbiased bases in dimension six: The four most distant bases

We consider the average distance between four bases in dimension six. The distance between two orthonormal bases vanishes when the bases are the same, and the distance reaches its maximal value of unity when the bases are unbiased. We perform a numerical search for the maximum average distance and find it to be strictly smaller than unity. This is strong evidence that no four mutually unbiased bases exist in dimension six. We also provide a two-parameter family of three bases which, together with the canonical basis, reach the numerically-found maximum of the average distance, and we conduct a detailed study of the structure of the extremal set of bases.Comment: 10 pages, 2 figures, 1 tabl

J004457+4123 (Sharov 21): not a remarkable nova in M31 but a background quasar with a spectacular UV flare

We announce the discovery of a quasar behind the disk of M31, which was previously classified as a remarkable nova in our neighbour galaxy. The paper is primarily aimed at the outburst of J004457+4123 (Sharov 21), with the first part focussed on the optical spectroscopy and the improvement in the photometric database. Both the optical spectrum and the broad band spectral energy distribution of Sharov 21 are shown to be very similar to that of normal, radio-quiet type 1 quasars. We present photometric data covering more than a century and resulting in a long-term light curve that is densely sampled over the past five decades. The variability of the quasar is characterized by a ground state with typical fluctuation amplitudes of ~0.2 mag around B~20.5, superimposed by a singular flare of ~2 yr duration (observer frame) with the maximum at 1992.81 where the UV flux has increased by a factor of ~20. The total energy in the flare is at least three orders of magnitudes higher than the radiated energy of the most luminous supernovae, provided that it comes from an intrinsic process and the energy is radiated isotropically. The profile of the flare light curve appears to be in agreement with the standard predictions for a stellar tidal disruption event where a ~10 M_sun giant star was shredded in the tidal field of a ~2...5 10^8 M_sun black hole. The short fallback time derived from the light curve requires an ultra-close encounter where the pericentre of the stellar orbit is deep within the tidal disruption radius. Gravitational microlensing provides an alternative explanation, though the probability of such a high amplification event is very low.Comment: Accepted for publication in Astronomy and Astrophysics, 14 pages, 11 figure

Проблема социальных коммуникаций в контексте современных международных отношений

Исследована роль технологического аспекта социальных коммуникаций в современных международных отношениях. Показано, что информационные технологии, устранив барьеры коммуникаций, как во внутренней, так и международной жизни, сделали внешнюю политику крупных государств более сдержанной и ответственной

Precision Measurement of the 29Si, 33S, and 36Cl Binding Energies

The binding energies of 29Si, 33S, and 36Cl have been measured with a relative uncertainty $< 0.59 \times 10^{-6}$ using a flat-crystal spectrometer. The unique features of these measurements are 1) nearly perfect crystals whose lattice spacing is known in meters, 2) a highly precise angle scale that is derived from first principles, and 3) a gamma-ray measurement facility that is coupled to a high flux reactor with near-core source capability. The binding energy is obtained by measuring all gamma-rays in a cascade scheme connecting the capture and ground states. The measurements require the extension of precision flat-crystal diffraction techniques to the 5 to 6 MeV energy region, a significant precision measurement challenge. The binding energies determined from these gamma-ray measurements are consistent with recent highly accurate atomic mass measurements within a relative uncertainty of $4.3 \times 10^{-7}$. The gamma-ray measurement uncertainties are the dominant contributors to the uncertainty of this consistency test. The measured gamma-ray energies are in agreement with earlier precision gamma-ray measurements.Comment: 13 pages, 4 figure