Resonance-continuum interference in the di-photon Higgs signal at the LHC

A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg -> H -> gamma gamma, with the continuum QCD background, gg -> gamma gamma induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg -> gamma gamma scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.Comment: 10 pages, 2 figure

The parentage of 'Sangiovese', the most important Italian wine grape

A previous microsatellite study pointed out a possible parent-offspring relationship between 'Sangiovese', the most widespread red grape cultivar in Italy, and 'Ciliegiolo', an ancient Tuscan variety. Testing 'Sangiovese' as a parent of 'Ciliegiolo', we searched for the putative other parent in our extensive, private and standardized database, but we did not find any candidate. Testing 'Ciliegiolo' as a parent of 'Sangiovese', we found four candidate cultivars. After the analysis of 50 microsatellites, only one stood the paternity test and we established with a strong statistical support that 'Sangiovese' is a progeny of 'Ciliegiolo' and 'Calabrese di Montenuovo', an obscure grapevine from Campania, Italy. This cultivar does not have a registered name and is supposed to have been introduced from Calabria. Among 180 additional local grape cultivars from Calabria, Campania or Tuscany, we did not find any matching variety. As a consequence, we propose to adopt the name 'Calabrese di Montenuovo' for this grape cultivar. In addition, we found relatives of 'Sangiovese' and 'Calabrese di Montenuovo' in Calabria, thus strongly suggesting a Calabrian origin for 'Calabrese di Montenuovo' and indicating that 'Sangiovese' has ancestors and/or progenies in Tuscany and in Southern Italy.

Non-equilibrium phase transition in a sheared granular mixture

The dynamics of an impurity (or tracer particle) immersed in a dilute granular gas under uniform shear flow is investigated. A non-equilibrium phase transition is identified from an exact solution of the inelastic Boltzmann equation for a granular binary mixture in the tracer limit, where the impurity carries either a vanishing (disordered phase) or a finite (ordered phase) fraction of the total kinetic energy of the system. In the disordered phase, the granular temperature ratio (impurity "temperature" over that of the host fluid) is finite, while it diverges in the ordered phase. To correctly capture this extreme violation of energy equipartition, we show that the picture of an impurity enslaved to the host fluid is insufficient

Evaluación de la capacidad de rebrote en avena con distinta intensidad de defoliación y dos frecuencias de corte

La finalidad del presente trabajo fue estudiar el efecto de la frecuencia de corte y la intensidad de defoliación de la avena (Avena sativa), sobre la producción de materia seca y la persistencia. El ensayo se llevó a cabo en la Facultad de Agronomía de la UNLPam, durante el ciclo de cultivo en el año 1989. El diseño experimental empleado fue el de bloques completos al azar involucrando un arreglo de tratamiento factorial con cuatro repeticiones. En la experiencia se determinó producción de materia seca y stand de plantas. La comparación de las distintas frecuencias de corte dentro de una misma intensidad de defoliación, mostró diferencias altamente significativas en producción de materia seca en favor del intervalo entre cortes más prolongados y a su vez al comparar distintas intensidades de defoliación dentro de una misma frecuencia, se encontraron diferencias altamente significativas siendo mayor la producción de materia seca a mayor I.A.F. (índice de área foliar) remanente. En lo que respecta a stand de plantas se observó una pérdida muy importante en el corte más intenso, donde las pérdidas fueron del ochenta y cinco por ciento. Para lograr una alta producción de materia seca y buena persistencia se deben combinar una baja frecuencia con un elevado LA.F. remanente.Director: Ing. Agr. Oscar Hernández. Profesor Titular Cátedra de Forrajicultura y Manejó de pasturas

Diffusion Process in a Flow

We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, $\vec{F}=\vec{\nabla }V$ with $V(\vec{x},t)$ bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes. We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, $\vec{F}=\vec{\nabla }V$ with $V(\vec{x},t)$ bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes.Comment: 10 pages, Late

Numerical Schemes for Multivalued Backward Stochastic Differential Systems

We define some approximation schemes for different kinds of generalized backward stochastic differential systems, considered in the Markovian framework. We propose a mixed approximation scheme for a decoupled system of forward reflected SDE and backward stochastic variational inequality. We use an Euler scheme type, combined with Yosida approximation techniques.Comment: 13 page

Los Alisos, a new fossiliferous locality for Guanaco Formation (late Miocene) in Jujuy (Argentina), and a first approach of its paleoecological and biochronology implications

Very scarce information is available about the extinct Neogene communities of the Subandean valleys of Jujuy province, Northwestern Argentina. A new vertebrate fossiliferous locality (Los Alisos), and the first mammalian assemblage from Guanaco Formation, is described. The taxa recorded include mainly caviomorph rodents (Hystricognathi)represented by Orthomyctera sp., Lagostomus sp., and an Octodontoidea and cingulates (Xenarthra)represented by the armadillos aff. Stenotatus, Dasypus sp. nov., two Euphractinae, and a Glyptodontidae. A single remain of a turtle (Testudines)is also described. The composition of the faunistic record has similitude with Andalhuala, Chiquimil and Salicas formations, but some taxa differ from all other late Miocene Northwestern Argentina localities. The most outstanding feature of Los Alisos paleocommunity is the presence of Dasypus, which confirms the existence of the genus in times as old as the late Miocene. The presence of a tuff with known age (5.9–6.4 Ma)immediately below to the fossiliferous level gives a lower temporal constraint for the association, and this absolute age as well as the biochrons of the identified taxa are compatible with an Huayquerian stage. The integrative analysis of the mammals of Los Alisos allowed preliminary paleoecological and paleoenvironmental inferences for Guanaco Formation, indicating a landscape composed by open areas, whether extensive or arranged in patches, including grasslands, under warm and seasonal climatic conditions.Fil: Ercoli, Marcos Darío. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Alvarez, Alicia. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Santamans, Carla Daniela. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: González Patagua, Sonia A.. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Villalba Ulberich, Juan Pablo. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; ArgentinaFil: Constantini, Ornela Estefania. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Geología Minera; Argentin

Broken symmetries and directed collective energy transport

We study the appearance of directed energy current in homogeneous spatially extended systems coupled to a heat bath in the presence of an external ac field E(t). The systems are described by nonlinear field equations. By making use of a symmetry analysis we predict the right choice of E(t) and obtain directed energy transport for systems with a nonzero topological charge Q. We demonstrate that the symmetry properties of motion of topological solitons (kinks and antikinks) are equivalent to the ones for the energy current. Numerical simulations confirm the predictions of the symmetry analysis and, moreover, show that the directed energy current drastically increases as the dissipation parameter $\alpha$ reduces. Our results generalize recent rigorous theories of currents generated by broken time-space symmetries to the case of interacting many-particle systems.Comment: 4 pages, 2 figure