Oscillations of neutral B mesons systems

The oscillation phenomenon in the neutral B mesons systems is now well established. The motivations and principles of the measurements are given; then the most recent results from the LEP experiments, the CDF collaboration at Fermilab and the SLD collaboration at SLAC are reviewed. The present world average of the \bd meson oscillation frequency is \dmd = 0.471 \pm 0.016 \ps and the lower limit on the \bs oscillation frequency is \dms > 12.4 \ps at 95% CL.Comment: 9 page

Strong gravitational field light deflection in binary systems containing a collapsed star

Large light deflection angles are produced in the strong gravitational field regions around neutron stars and black holes. In the case of binary systems, part of the photons emitted from the companion star towards the collapsed object are expected to be deflected in the direction of the earth. Based on a semi-classical approach we calculate the characteristic time delays and frequency shifts of these photons as a function of the binary orbital phase. The intensity of the strongly deflected light rays is reduced by many orders of magnitude, therefore making the observations of this phenomenon extremely difficult. Relativistic binary systems containing a radio pulsar and a collapsed object are the best available candidates for the detection of the strongly deflected photons. Based on the accurate knowledge of their orbital parameters, these systems allow to predict accurately the delays of the pulses along the highly deflected path, such that the sensitivity to very weak signals can be substantially improved through coherent summation over long time intervals. We discuss in detail the cases of PSR 1913+16 and PSR 1534+12 and find that the system geometry is far more promising for the latter. The observation of the highly deflected photons can provide a test of general relativity in an unprecedented strong field regime as well as a tight constraint on the radius of the collapsed object.Comment: 7 pages, uuencoded, gzip'ed, postscript file with figures included. Accepted for pubblication in MNRA

Constraints on the parameters of the CKM matrix by End 1998

A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix (CKM) is presented. This paper is an update of the results published in [1]. The experimental constraints imposed by the measurements of \epsilon_K, V_{ub}/V_{cb}, \Delta m_d and from the limit on \Delta m_d are used. Values of the constraints and of the parameters entering into the constraints, which restrict the range of the \bar{\rho} and \bar{\eta} parameters, include recent measurements presented at 1998 Summer Conferences and progress obtained by lattice QCD collaborations. The results are: \bar{\rho}=0.202 ^{+0.053}_{-0.059},\bar{\eta}=0.340 \pm 0.035, from which the angles \alpha, \beta and \gamma of the unitarity triangle are inferred : \sin 2 \alpha = -0.26 ^{+ 0.29}_{-0.28} ,\sin 2 \beta = 0.725 ^{+0.050}_{-0.060} ,\gamma= (59.5^{+8.5}_{-7.5})^{\circ}. Without using the constraint from \epsilon_K, \sin 2 \beta has been obtained: \sin 2 \beta = 0.72 ^{+0.07}_{-0.11}. Several external measurements or theoretical inputs have been removed, in turn, from the constraints and their respective probability density functions have been obtained. Central values and uncertainties on these quantities have been compared with actual measurements or theoretical evaluations. In this way it is possible to quantify the importance of the different measurements and the coherence of the Standard Model scenario for CP violation. An important result is that \Delta m_s is expected to be between [12.0-17.6] ps^{-1} with 68% C.L. and <20 ps^{-1} at 95% C.L. Finally relations between the CKM parameters and the quark masses are examined within a given model.Comment: 26 page

Customs Unions And Foreign Investment: Theory And Evidence From Mercosur’s Auto Industry

This paper demonstrates how regional trade agreements (RTAs) can lead to both foreign direct investment expansion and relocation effects. These two effects, in return, impact the endogenous formation of RTAs. The investment expansion effect results from foreign firms’ ability to serve a larger market from a single facility. The relocation effect occurs due to the firms’ desire to move their initial plants from high-cost member countries to low-cost ones. The relocation effect can overwhelm the expansion effect for the high-cost members and lead to the collapse of socially efficient RTAs. The auto industry in Mercosur is a great example to study these phenomena. Argentina was worried that low-cost Brazil would attract all of the foreign investment and dominate both markets. To convince Argentina to agree to free trade in automobiles (and to Mercosur), the auto sectoral agreement included the Compensated Trade Clause (CTC) which requires each firm to balance its trade between these countries. This mitigates the relocation problem by forcing firms to produce some models in Argentina and entices the governments to sign the RTA..

The rf control and detection system for PACO the parametric converter detector

In this technical note the rf control and detection system for a detector of small harmonic displacements based on two coupled microwave cavities (PACO) is presented. The basic idea underlying this detector is the principle of parametric power conversion between two resonant modes of the system, stimulated by the (small) harmonic modulation of one system parameter. In this experiment we change the cavity length applying an harmonic voltage to a piezo-electric crystal. The system can achieve a great sensitivity to small harmonic displacements and can be an interesting candidate for the detection of small, mechanically coupled, interactions (e.g. high frequency gravitational waves).Comment: 13 pages, 4 postscript figure

Do Caring Services Affect Off-Farm Work? Evidence from Italy

The article investigates the determinants of the off-farm work decision in Italian farm households, highlighting the role of caring services. Assuming that the household simultaneously decides over the optimal allocation of time of each of its members, a multivariate probit model is used to estimate the off-farm participation equations and to control for possible correlation among them. Evidence of correlation between spouse and descendant equations are found. Results suggest that policy actions geared at encouraging the off-farm participation of farm household members ought to enhance the availability and accessibility of caring services and increase the level of education of household members.Off-farm work participation, multivariate probit, household behavioural models, caring services, Agricultural and Food Policy, Consumer/Household Economics,

Pluriactivity Decisions by Farm Households in Italy

In this article we test whether in Italy the off-farm participation decisions of household members in working age are taken jointly and what are the variables that affect them. We find that the decisions of the operator, the spouse and the eldest child are not joint. Conversely, the participation decision of the operator and the spouse, that is of the two household's members belonging to the same generation, are found to be joint. The results suggest that policy actions for the purpose of encouraging off-farm participation rely on measures geared at improving the level of education and providing childcare services.off-farm work participation, multivariate probit, household models, Consumer/Household Economics, Labor and Human Capital, C35, J43, Q12,