Energy threshold in multiple ionization by electron or positron impact

The energy threshold for the formation of highly charged ions is experimentally well-known and measured. For single ionization, it is the binding energy of the outermost electrons. For multiple ionization, the ionization begins at impact energies %experimental measurements show that the minimum impact energy is much larger than the theoretically expected ones. In this contribution we present a simple expression for the energy threshold for multiple ionization by electron or positron impact. It was obtained as the mean value of the energy transferred to each ionized electron by using Thompson classical approximation. Present results reproduce quite well the experimental thresholds. Moreover, the inclusion of these values in the theoretical multiple ionization cross sections allows describing rather well the experimental data for single up to sextuple ionization of rare gases.Fil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Miraglia, Jorge Esteban. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Dielectric approaches for interactions of protons, positrons, and electrons in cold matter and plasmas

This work investigates the projectile and temperature dependence of the energy loss of charged particles in matter. To this end, we analyze two dielectric approaches which consider the presence of bound and free electrons and the effects of the ionization process. With these approaches, we calculate the energy-loss moments of protons, positrons, and electrons traversing Si, Fe, and Al targets, both in the cold solid phase and in the plasma state. We compare the results from the unified-wave-packet model (UWPM) and the shellwise local plasma approximation (SLPA) on an extensive range of parameters, including low, intermediate, and high projectile energies and target temperatures going from cold solid-state densities to hot plasma with temperatures up to 1000 eV. We reformulate the SLPA to include light-particle restrictions. We give special consideration to the case of positrons and electrons, where the inner-shell effects have not been analyzed in our previous works. Comparisons with experimental results for cold solid targets are presented, and stopping enhancement effects for heated targets are described, showing the physical origin of these effects.Fil: Archubi, Claudio Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Arista, N. R.. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; Argentin

Significance of the high charge state of projectile ions inside the target and its role in electron capture leading to target-ionization phenomena

The K x-ray spectra of different targets (Cu, Zn, and Ge) induced by 3-5 MeV/u Si projectile ions have been measured to determine the K-shell ionization cross section. A significant difference is observed between the measurements and theoretical estimates, with the latter being about 50% below the experimental results. This underestimation is attributed to the charge exchange from the target K shell to projectile K and L shells. Such an observation can only be possible if the projectile ions attain up to H- and He-like charge states. Corresponding projectile charge state fractions have been evaluated from the Lorentzian charge state distribution, where the mean charge state is taken from the Fermi gas model [W. Brandt, Phys. Rev. Lett. 30, 358 (1973)PRLTAO0031-900710.1103/PhysRevLett.30.358] and the width from the Novikov and Teplova approach [Phys. Lett. A 378, 1286 (2014)10.1016/j.physleta.2014.03.004]. The sum of the direct ionization cross section and K-K+K-L capture cross sections gives a good agreement with the measured cross sections. Furthermore, we have validated this methodology with available data for a Si ion on Ti target. Such results may be useful in many solid target-based applications.Fil: Chatterjee, Soumya. University Of Kalyani; IndiaFil: Sharma, Prashant. Weizmann Institute Of Science Israel; IsraelFil: Singh, Shashank. Panjab University; IndiaFil: Oswal, Mumtaz. No especifíca;Fil: Kumar, Sunil. No especifíca;Fil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitra, D.. University Of Kalyani; IndiaFil: Nandi, T.. No especifíca

Experimental and theoretical L-shell ionization cross sections of heavy atoms by impact of Si ions

We present a theoretical and experimental study of the subshell resolved L-shell ionization of relativistic targets such as 73Ta, 78Pt,90Th, and 92U. The measurements of x-ray production cross sections by (84?140 MeV) Si+q ions (q = 8; 12), were held at the Inter-University Accelerator Centre of New Delhi. Multiple-hole fluorescence and Coster-Kronig yields were used to obtain the Li(i = 1?3)ionization cross sections from the measured x-ray production cross sections of Lℓ, Lα, and Lβ, Lη, and Lγ lines. The experimental results are compared with ab initio theoretical calculations by means of the shell-wise local plasma approximation (SLPA). This model uses the quantum dielectric formalism to obtain the total ionization cross sections from an initial ground state. The wave functions and binding energies of the different targets were obtained by solving the fully-relativistic Dirac equation using the HULLAC code package. These calculations are based on first-order perturbation theory with a central field, including Breit interaction and quantum electrodynamics corrections. The present SLPA ionization cross sections of the L-shell are found to be independent of the charge state of the Si ions. The experimental observations display also quite similar character if the correct mean projectile charge state inside the target is used for including the multiple ionization effect during ion-solid collisions. A general good agreement between the experimental measurements and full theoretical calculations supports the reliability of present results. The comparison also includes the well-known ECPSSR and ECUSAR semi empirical approximations. We noted that the ECUSAR results agree well with the SLPA, while the ECPSSR cross sections are rather low.Fil: Oswal, M.. Dev Samaj College; India. Panjab University; IndiaFil: Kumar, Sunil. Panjab University; India. Degree college; IndiaFil: Singh, Udai. Jagiellonian University; PoloniaFil: Singh, G.. Panjab University; IndiaFil: Singh, K.P.. Panjab University; IndiaFil: Mehta, D.. Panjab University; IndiaFil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitra, D.. Kalyani University; IndiaFil: Nandi, T.. Inter-University Accelerator Centre; Indi

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass