Direct test of time reversal invariance violation in B mesons

In this letter we reinterpret and reanalyze the available data of the B meson factories showing the existence of direct experimental evidence of time reversal invariance violation in B mesons. This reinterpretation consists of using the available observables to define a new observable which, in a model independent way and without assuming CPT invariance, compares a transition between a $B^0$ and a here-defined $B_\alpha$-state, with its time reversed transition. The observable then offers a direct way to probe time reversal invariance and it is therefore independent of any conclusion obtained from current experimental information on CP violation and CPT invariance. As far as the authors are concerned, this is the first direct evidence of time reversal invariance violation in B mesons and also the first one obtained from decaying particles whose mean life time difference is negligible.Comment: 9 pages, no figures. Refined version matching published article in Modern Physics Letters

Non-covalent interactions at electrochemical interfaces : one model fits all?

Acknowledgements Funding from the DGI (Spanish Ministry of Education and Science) through Project CTQ2009-07017 is gratefully acknowledged. E.P.M.L. wishes to thank the Universidad Nacional de Co´rdoba, Argentina, for a grant within the ‘‘Programa de Movilidad Internacional de Profesores Cuarto Centenario’’.Peer reviewedPublisher PD

The underpotential deposition that should not be : Cu(1x1) on Au(111)

Peer reviewedPostprin

Biomechanical analysis of bioresorbable maxillofacial plates

Bioresorbable devices are actually extensively applied for bone healing. These products are exposed to several physical, chemical and mechanical requirements. For this reason, mechanical performance under different loading conditions should be exhaustively analyzed in order to warrant the long term success. In this work, mechanical behavior of polylactic acid (PLA) maxillofacial miniplate implant was investigated by mechanical tests and numerical simulations. The obtained results showed, that thread profile and screws location, respect to the broken bone plane, represent key factors for stress distributions. On the other hand, experimental tests and simulations exhibited similar displacement values.Fil: Perez, Ezequiel M. Instituto Nacional de Tecnología Industrial. INTI-Plásticos; Argentin

Dynamic properties in a family of competitive growing models

The properties of a wide variety of growing models, generically called $X/RD$, are studied by means of numerical simulations and analytic developments. The study comprises the following $X$ models: Ballistic Deposition, Random Deposition with Surface Relaxation, Das Sarma-Tamboronea, Kim-Kosterlitz, Lai-Das Sarma, Wolf-Villain, Large Curvature, and three additional models that are variants of the Ballistic Deposition model. It is shown that after a growing regime, the interface width becomes saturated at a crossover time ($t_{x2}$) that, by fixing the sample size, scales with $p$ according to $t_{x2}(p)\propto p^{-y}, \qquad (p > 0)$, where $y$ is an exponent. Also, the interface width at saturation ($W_{sat}$) scales as $W_{sat}(p)\propto p^{-\delta}, \qquad (p > 0)$, where $\delta$ is another exponent. It is proved that, in any dimension, the exponents $\delta$ and $y$ obey the following relationship: $\delta = y \beta_{RD}$, where $\beta_{RD} = 1/2$ is the growing exponent for $RD$. Furthermore, both exponents exhibit universality in the $p \to 0$ limit. By mapping the behaviour of the average height difference of two neighbouring sites in discrete models of type $X/RD$ and two kinds of random walks, we have determined the exact value of the exponent $\delta$. Finally, by linking four well-established universality classes (namely Edwards-Wilkinson, Kardar-Parisi-Zhang, Linear-MBE and Non-linear-MBE) with the properties of both random walks, eight different stochastic equations for all the competitive models studied are derived.Comment: 23 pages, 6 figures, Submitted to Phys. Rev.

Short-Time Critical Dynamics of Damage Spreading in the Two-Dimensional Ising Model

The short-time critical dynamics of propagation of damage in the Ising ferromagnet in two dimensions is studied by means of Monte Carlo simulations. Starting with equilibrium configurations at $T= \infty$ and magnetization $M=0$, an initial damage is created by flipping a small amount of spins in one of the two replicas studied. In this way, the initial damage is proportional to the initial magnetization $M_0$ in one of the configurations upon quenching the system at $T_C$, the Onsager critical temperature of the ferromagnetic-paramagnetic transition. It is found that, at short times, the damage increases with an exponent $\theta_D=1.915(3)$, which is much larger than the exponent $\theta=0.197$ characteristic of the initial increase of the magnetization $M(t)$. Also, an epidemic study was performed. It is found that the average distance from the origin of the epidemic ($\langle R^2(t)\rangle$) grows with an exponent $z^* \approx \eta \approx 1.9$, which is the same, within error bars, as the exponent $\theta_D$. However, the survival probability of the epidemics reaches a plateau so that $\delta=0$. On the other hand, by quenching the system to lower temperatures one observes the critical spreading of the damage at $T_{D}\simeq 0.51 T_C$, where all the measured observables exhibit power laws with exponents $\theta_D = 1.026(3)$, $\delta = 0.133(1)$, and $z^*=1.74(3)$.Comment: 11 pages, 9 figures (included). Phys. Rev. E (2010), in press