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In this paper, it is shown that the experimental values of the nonextensive scattering entropies $S_L (p)$ and $S_theta (q)$ for the pion-nucleus ($pi^0 He, pi^0 C, pi^0 O, pi^0 Ca$) scatterings, in the energy region corresponding to $Delta (1236)$ r esonance in the elementary pion-nucleon interaction, are well described by the entropic optimal resonance predictions $S_L^o1 (p)$ and $S_theta^o1 (q)$ and when the nonextensivities indices are correlated by a Riesz-Thorin-like relation: 1/2p+1/2q=1.
We present results from a jet energy loss calculation using the Gyulassy-Levai-Vitev (GLV) formalism and bulk medium evolution from the covariant transport model MPC. At both RHIC and LHC energies we find that realistic transverse expansion strongly reduces elliptic flow at high pT compared to calculations with transversely frozen profiles. We argue that this is a generic feature of GLV energy loss. Transverse expansion also leads to stronger high-pT suppression, while fluctuations in energy loss with the location of scattering centers weaken the suppression. But, unlike the reduction of v2, these effects nearly disappear once alpha_s is adjusted to reproduce R_AA in central collisions.
In this Letter we comment on one particular aspect of Hypatias enigmatic biography by translating into English a short poem that appeared in a recent review of the third revised Polish edition of Maria Dzielskas book about Hypatia. It poses a simple and specifc question: did Hypatia know about the negative numbers?
46 - Muhammad Imran 2011
Electron transport through molecular bridge shows novel quantum features. Propogation of electronic wave function through molecular bridge is completely different than individual atomic bridge employed between two contacts. In case of molecular bridg e electronic wave propagators interfere and effect conduction through molecular bonding and anti-bonding states.In the present work i showed through simple calculation that interference of electronic wave propagators cause asymmetric propagation of electronic wave through bonding and anti-bonding state. While for hydrogenic molecule these propagators interfere completely destructively for bonding state and constructively for anti-bonding state, giving rise to only one peak in spectral function for anti- bonding state.
A new method is presented for finding Killing tensors in spacetimes with symmetries. The method is used to find all the Killing tensors of Melvins magnetic universe and the Schwarzschild vacuum. We show that they are all trivial. The method requires less computation than solving the full Killing tensor equations directly, and it can be used even when the spacetime is not algebraically special.
The lower limit for the mass of white dwarfs (WDs) with C-O core is commonly assumed to be roughly 0.5 Msun. As a consequence, WDs of lower masses are usually identified as He-core remnants. However, when the initial mass of the progenitor star is in between 1.8 and 3 Msun, which corresponds to the so called red giant (RGB) phase transition, the mass of the H-exhausted core at the tip of the RGB is 0.3 < M_H/Msun < 0.5. Prompted by this well known result of stellar evolution theory, we investigate the possibility to form C-O WDs with mass M < 0.5 Msun. The pre-WD evolution of stars with initial mass of about 2.3 Msun, undergoing anomalous mass-loss episodes during the RGB phase and leading to the formation of WDs with He-rich or CO-rich cores have been computed. The cooling sequences of the resulting WDs are also described. We show that the minimum mass for a C-O WD is about 0.33 Msun, so that both He and C-O core WDs can exist in the mass range 0.33-0.5 Msun. The models computed for the present paper provide the theoretical tools to indentify the observational counterpart of very low mass remnants with a C-O core among those commonly ascribed to the He-core WD population in the progressively growing sample of observed WDs of low mass. Moreover, we show that the central He-burning phase of the stripped progeny of the 2.3 Msun star lasts longer and longer as the total mass decreases. In particular, the M= 0.33 Msun model takes about 800 Myr to exhausts its central helium, which is more than three time longer than the value of the standard 2.3 Msun star: it is, by far, the longest core-He burning lifetime. Finally, we find the occurrence of gravonuclear instabilities during the He-burning shell phase.
The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current is examined considering the boron solar neutrinos. These neutrinos could potentially become a source of background in the future dark matter searches aiming at nucleon cross sections in the region well below the few events per ton per year.
The annihilation parameters of positrons with electrons in different shells of Argon, Iron and Copper atoms are calculated below the positronium (Ps) formation thresholds. Quite accurate ab initio calculations of the bound state wavefunctions of Argo n, Iron and Copper orbitals are obtained from Cowan computer code. A least-squares variational method (LSVM) is used for determining the wavefunction of the positrons. The program is employed for calculating the s-wave partial cross sections of positrons scattered by Iron and Copper atoms. Our results of the effective charge are compared with available experimental and theoretical ones. --
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