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## Empirical aspects of a Mini-Helicon Plasma Thruster Experiment (mHTX@MIT); mHTX@MIT

Palaia, Joseph Eugene, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 137 leaves
ENG
Relevância na Pesquisa
46%
A helicon plasma source experiment has been developed and then constructed in the MIT Space Propulsion Laboratory (SPL) vacuum chamber. This experiment allows study of the intrinsic advantages of efficient helicon plasma production for use in space electric propulsion. Historical helicon experiment data have been applied to help size the experiment. The goal was to create a robust and flexible experimental system which would allow optimization of the source and system parameters for efficient thrust generation, and would permit for correlation between helicon theory and experiment. This effort may lead to the development of a new electric propulsion device, the Mini-Helicon Plasma Thruster. A design process was undertaken for the creation of this experimental setup, with the aid of a number of students and researchers at the MIT SPL. This thesis will focus on the author's specific contributions to this larger effort, which included the following elements. A survey of past helicon experiment parameters was completed, made possible largely due to the wealth of data provided by helicon plasma use in academia and for research and development. An analysis of the flow of propellant through the thruster was completed, utilizing low Mach number flow theory. A metallic structure was designed...

## A recipe for EFT uncertainty quantification in nuclear physics

Furnstahl, R. J.; Phillips, D. R.; Wesolowski, S.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.94%
The application of effective field theory (EFT) methods to nuclear systems provides the opportunity to rigorously estimate the uncertainties originating in the nuclear Hamiltonian. Yet this is just one source of uncertainty in the observables predicted by calculations based on nuclear EFTs. We discuss the goals of uncertainty quantification in such calculations and outline a recipe to obtain statistically meaningful error bars for their predictions. We argue that the different sources of theory error can be accounted for within a Bayesian framework, as we illustrate using a toy model.; Comment: Final version for JPhysG Focus issue "Enhancing the interaction between nuclear experiment and theory through information and statistics"

## Information and statistics: a new paradigm in theoretical nuclear physics

Piekarewicz, J.; Chen, Wei-Chia; Fattoyev, F. J.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.88%
Theoretical predictions of physical observables often involve extrapolations to regions that are poorly constrained by laboratory experiments and astrophysical observations. Without properly quantified theoretical errors, such model predictions are of very limited utility. In this contribution we use maximum-likelihood estimation to compute theoretical errors and assess correlations between physical observables. We illustrate the power and elegance of these methods using examples of both pedagogical and realistic interest. In particular, we implement a gaussian approximation to the likelihood function to develop a new relativistic effective interaction constrained by ground-state properties of finite nuclei, their monopole response, and masses of neutron stars.; Comment: 17 pages, 5 figures. Submitted to Journal of Physics G Focus issue "Enhancing the interaction between nuclear experiment and theory through information and statistics" (ISNET)

## KamLAND-experiment and Soliton-like Nuclear Georeactor. Part 1. Comparison of Theory with Experiment

Rusov, V. D.; Litvinov, D. A.; Mavrodiev, S. Cht.; Linnik, E. P.; Vaschenko, V. N.; Zelentsova, T. N.; Beglaryan, M. E.; Tarasov, V. A.; Chernegenko, S. A.; Smolyar, V. P.; Molchinikolov, P. O.; Merkotan, K. K.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.06%
We give an alternative description of the data produced in the KamLAND experiment, assuming the existence of a natural nuclear reactor on the boundary of the liquid and solid phases of the Earth's core. Analyzing the uncertainty of antineutrino spectrum of georeactor origin, we show that the theoretical (which takes into account the soliton-like nuclear georeactor) total reactor antineutrino spectra describe with good accuracy the experimental KamLAND-data over the years of 2002-2007 and 2002-2009, respectively. At the same time the parameters of mixing ({\Delta}(m21)^2=2.5\cdot 10^-5 eV^2, tan^2{\theta}12=0.437) calculated within the framework of georeactor hypothesis substantially differ from the parameters of mixing ({\Delta}(m21)^2=7.49\cdot 10^-5 eV^2, tan^2{\theta}12=0.436) obtained in KamLAND-experiment for total exposure over the period of 2002-2009. By traingulation of KamLAND and Borexino data we have constructed the coordinate location of soliton-like nuclear georeactors on the boundary of the liquid and solid phases of the Earth core. Based on the necessary condition of full synchronization of geological (magnetic) time scale and time evolution of heat power of nuclear georeactor, which plays the role of energy source of the Earth magnetic field...

## Quark fragmentation to $\pi^{\pm}$, $\pi^{0}$, $K^{\pm}$, $p$ and $\bar{p}$ in the nuclear environment

HERMES collaboration; Airapetian, A.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.98%
The influence of the nuclear medium on lepto-production of hadrons was studied in the HERMES experiment at DESY in semi-inclusive deep-inelastic scattering of 27.6 GeV positrons off deuterium, nitrogen and krypton targets. The differential multiplicity for krypton relative to that of deuterium has been measured for the first time for various identified hadrons ($\pi^+$, $\pi^-$, $\pi^0$, $K^+$, $K^-$, $p$ and $\bar{p}$) as a function of the virtual photon energy $\nu$, the fraction $z$ of this energy transferred to the hadron, and the hadron transverse momentum squared $p_t^2$. The multiplicity ratio is strongly reduced in the nuclear medium at low $\nu$ and high $z$, with significant differences among the various hadrons. The distribution of the hadron transverse momentum is broadened towards high $p_t^2$ in the nuclear medium, in a manner resembling the Cronin effect previously observed in collisions of heavy ions and protons with nuclei.; Comment: 8 pages, 5 figures

## Nuclear Transparency in 90 Degree c.m. Quasielastic A(p,2p) Reactions

Aclander, J.; Alster, J.; Asryan, G.; Averiche, Y.; Barton, D. S.; Baturin, V.; Buktoyarova, N.; Bunce, G.; Carroll, A. S.; Christensen, N.; Courant, H.; Durrant, S.; Fang, G.; Gabriel, K.; Gushue, S.; Heller, K. J.; Heppelmann, S.; Kosonovsky, I.; Leksan
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.04%
We summarize the results of two experimental programs at the Alternating Gradient Synchrotron of BNL to measure the nuclear transparency of nuclei measured in the A(p,2p) quasielastic scattering process near 90 Deg .in the pp center of mass. The incident momenta varied from 5.9 to 14.4 GeV/c, corresponding to 4.8 < Q^2 < 12.7 (GeV/c)^2. First, we describe the measurements with the newer experiment, E850, which had more complete kinematic definition of quasielastic events. In E850 the angular dependence of the nuclear transparency near 90 Deg. c.m., and the nuclear transparency for deuterons was studied. Second, we review the techniques used in an earlier experiment, E834, and show that the two experiments are consistent for the Carbon data. E834 also determines the nuclear transparencies for Li, Al, Cu, and Pb nuclei as well as for C. We find for both E850 and E834 that the A(p,2p) nuclear transparency, unlike that for A(e,e'p) nuclear transparency, is incompatible with a constant value versus energy as predicted by Glauber calculations. The A(p,2p) nuclear transparency for C and Al increases by a factor of two between 5.9 and 9.5 GeV/c incident proton momentum. At its peak the A(p,2p) nuclear transparency is about 80% of the constant A(e...

## KamLAND-Experiment and Soliton-Like Nuclear Georeactor

Rusov, V. D.; Litvinov, D. A.; Mavrodiev, S. Ch.; Linnik, E. P.; Vaschenko, V. N.; Zelentsova, T. N.; Tarasov, V. A.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.03%
We give an alternative description of the new data produced in the KamLAND experiment, assuming the existence of a natural nuclear reactor on the boundary of the liquid and solid phases of the Earth's core. Analyzing the uncertainty of antineutrino spectrum of georeactor origin, we show that the theoretical (which takes into account the soliton-like nuclear georeactor with power about 20 TW) reactor antineutrino spectrum describes with good accuracy the new experimental KamLAND-data. At the same time the parameters of mixing calculated within the framework of georeactor hypothesis are substantially closer to the data of solar flux SNO-experiment then the parameters of mixing obtained in KamLAND-experiment.; Comment: 11 pages, 4 figures

## Spin physics and TMD studies at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

Lansberg, J. P.; Anselmino, M.; Arnaldi, R.; Brodsky, S. J.; Chambert, V.; Dunnen, W. den; Didelez, J. P.; Genolini, B.; Ferreiro, E. G.; Fleuret, F.; Gao, Y.; Hadjidakis, C.; Hrvinacova, I.; Lorce, C.; Massacrier, L.; Mikkelsen, R.; Pisano, C.; Rakotozaf
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.98%
We report on the opportunities for spin physics and Transverse-Momentum Dependent distribution (TMD) studies at a future multi-purpose fixed-target experiment using the proton or lead ion LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic fixed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER@LHC using typical targets would surpass that of RHIC by more that 3 orders of magnitude in a similar energy region. In unpolarised proton-proton collisions, AFTER@LHC allows for measurements of TMDs such as the Boer-Mulders quark distributions, the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using the polarisation of hydrogen and nuclear targets, one can measure transverse single-spin asymmetries of quark and gluon sensitive probes, such as, respectively, Drell-Yan pair and quarkonium production. The fixed-target mode has the advantage to allow for measurements in the target-rapidity region, namely at large x^uparrow in the polarised nucleon. Overall, this allows for an ambitious spin program which we outline here.; Comment: 6 pages...

## Examination of uncertainties in nuclear data for cosmic ray physics with the AMS experiment

Tomassetti, Nicola
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46%
High-energy Li-Be-B nuclei in cosmic rays are being measured with unprecedent accuracy by the AMS experiment. These data bring valuable information to the cosmic ray propagation physics. In particular, combined measurements of B/C and Be/B ratios may allow to break the parameter degeneracy between the cosmic-ray diffusion coefficient and the size of the propagation region, which is crucial for dark matter searches. The parameter determination relies in the calculation of the Be and B production from collisions of heavier nuclei with the gas. Using the available cross-section data, I present for the first time an evaluation of the nuclear uncertainties and their impact in constraining the propagation models. I found that the AMS experiment can provide tight constraints on the transport parameters allowing to resolutely break the degeneracy, while nuclear uncertainties in the models are found to be a major limiting factor. Once these uncertainties are accounted, the degeneracy remains poorly resolved. In particular, the Be/B ratio at ~1 - 10 GeV/n is found not to bring valuable information for the parameter extraction. On the other hand, precise Be/B data at higher energy may be useful to test the nuclear physics inputs of the models.; Comment: 4 figures...

## Energy reconstruction in the Long-Baseline Neutrino Experiment

Mosel, Ulrich; Lalakulich, Olga; Gallmeister, Kai
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.98%
The Long-Baseline Neutrino Experiment aims at measuring fundamental physical parameters to high precision and exploring physics beyond the standard model. Nuclear targets introduce complications towards that aim. We investigate the uncertainties in the energy reconstruction, based on quasielastic scattering relations, due to nuclear effects. The reconstructed event distributions as a function of energy tend to be smeared out and shifted by several 100 MeV in their oscillatory structure if standard event selection is used. We show that a more restrictive experimental event selection offers the possibility to reach the accuracy needed for a determination of the mass ordering and the $CP$-violating phase. Quasielastic-based energy reconstruction could thus be a viable alternative to the calorimetric reconstruction also at higher energies.; Comment: Final version, as published in PRL

## Neutron skin of 208Pb, nuclear symmetry energy, and the parity radius experiment

Roca-Maza, X.; Centelles, M.; Viñas, X.; Warda, M.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.04%
A precise determination of the neutron skin thickness of a heavy nucleus sets a basic constraint on the nuclear symmetry energy (the neutron skin thickness is the difference of the neutron and proton rms radii of the nucleus). The parity radius experiment (PREX) may achieve it by electroweak parity-violating electron scattering (PVES) on 208Pb. We investigate PVES in nuclear mean field approach to allow the accurate extraction of the neutron skin thickness of 208Pb from the parity-violating asymmetry probed in the experiment. We demonstrate a high linear correlation between the parity-violating asymmetry and the neutron skin thickness in successful mean field forces as the best means to constrain the neutron skin of 208Pb from PREX, without assumptions on the neutron density shape. Continuation of the experiment with higher precision in the parity-violating asymmetry is motivated since the present method can support it to constrain the density slope of the nuclear symmetry energy to new accuracy.; Comment: 4 pages, 3 figures, some changes in text and references, version to appear in Phys. Rev. Lett

## Nuclear modification of J/psi production in Pb-Pb collisions at sqrt(s_NN)=2.76 TeV

Wiechula, Jens
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.98%
ALICE is the dedicated heavy-ion experiment at the LHC. Due to the unique particle identification capabilities of the central barrel detectors (|eta|<0.9), J/psi can be measured in the di-electron channel in the very demanding environment of central Pb-Pb collisions at the LHC. In addition J/psi are measured at forward rapidity (2.5

## Measurements of F_{2} and R=\sigma_{L}/\sigma_{T} on Nuclear Targets in the Nucleon Resonance Region

Mamyan, Vahe
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.06%
Jefferson Lab Experiment E04-001 used the Rosenbluth technique to measure R=\sigma_{L}/\sigma_{T} and F_{2} on nuclear targets. This experiment was part of a multilab effort to investigate quark-hadron duality and the electromagnetic and weak structure of the nuclei in the nucleon resonance region. In addition to the studies of quark-hadron duality in electron scattering on nuclear targets, these data will be used as input form factors in future analysis of neutrino data which investigate quark-hadron duality of the nucleon and nuclear axial structure functions. An important goal of this experiment is to provide precise data which to allow a reduction in uncertainties in neutrino oscillation parameters for neutrino oscillation experiments (K2K, MINOS). This inclusive experiment was completed in July 2007 at Jefferson Lab where the Hall C High Momentum Spectrometer detected the scattered electron. Measurements were done in the nuclear resonance region (1 < W^{2} < 4 GeV^{2}) spanning the four-momentum transfer range 0.5 < Q^{2} < 4.5 (GeV^{2}). Data was collected from four nuclear targets: C, Al, Fe and Cu.; Comment: arXiv admin note: text overlap with arXiv:hep-ph/0501217 and nucl-ex/0608013 by other authors

## Quarkonium Physics at a Fixed-Target Experiment using the LHC Beams

Lansberg, J. P.; Brodsky, S. J.; Fleuret, F.; Hadjidakis, C.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.98%
We outline the many quarkonium-physics opportunities offered by a multi-purpose fixed-target experiment using the p and Pb LHC beams extracted by a bent crystal. This provides an integrated luminosity of 0.5 fb-1 per year on a typical 1cm-long target. Such an extraction mode does not alter the performance of the collider experiments at the LHC. With such a high luminosity, one can analyse quarkonium production in great details in pp, pd and pA collisions at sqrt(sNN)~115 GeV and at sqrt(sNN)~72 GeV in PbA collisions. In a typical pp (pA) run, the obtained quarkonium yields per unit of rapidity are 2-3 orders of magnitude larger than those expected at RHIC and about respectively 10 (70) times larger than for ALICE. In PbA, they are comparable. By instrumenting the target-rapidity region, the large negative-xF domain can be accessed for the first time, greatly extending previous measurements by Hera-B and E866. Such analyses should help resolving the quarkonium-production controversies and clear the way for gluon PDF extraction via quarkonium studies. The nuclear target-species versatility provides a unique opportunity to study nuclear matter and the features of the hot and dense matter formed in PbA collisions. A polarised proton target allows the study of transverse-spin asymmetries in J/psi and Upsilon production...

## Automatic scanning of nuclear emulsions with wide-angle acceptance for nuclear fragment detection

Fukuda, T.; Fukunaga, S.; Ishida, H.; Kodama, K.; Matsuo, T.; Mikado, S.; Ogawa, S.; Shibuya, H.; Sudo, J.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.01%
Nuclear emulsion, a tracking detector with sub-micron position resolution, has played a successful role in the field of particle physics and the analysis speed has been substantially improved by the development of automated scanning systems. This paper describes a newly developed automated scanning system and its application to the analysis of nuclear fragments emitted almost isotropically in nuclear evaporation. This system is able to recognize tracks of nuclear fragments up to |tan{\theta}|< 3.0 (where {\theta} is the track angle with respect to the perpendicular to the emulsion film), while existing systems have an angular acceptance limited to |tan{\theta}|< 0.6. The automatic scanning for such a large angle track in nuclear emulsion is the first trial. Furthermore the track recognition algorithm is performed by a powerful Graphics Processing Unit (GPU) for the first time. This GPU has a sufficient computing power to process large area scanning data with a wide angular acceptance and enough flexibility to allow the tuning of the recognition algorithm. This new system will in particular be applied in the framework of the OPERA experiment : the background in the sample of tau decay candidates due to hadronic interactions will be reduced by a better detection of the emitted nuclear fragments.; Comment: 12 pages...

## Fluctuations of Conserved Quantities in High Energy Nuclear Collisions at RHIC

Luo, Xiaofeng
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.98%
Fluctuations of conserved quantities in heavy-ion collisions are used to probe the phase transition and the QCD critical point for the strongly interacting hot and dense nuclear matter. The STAR experiment has carried out moment analysis of net-proton (proxy for net-baryon (B)), net-kaon (proxy for net-strangeness (S)), and net-charge (Q). These measurements are important for understanding the quantum chromodynamics phase diagram. We present the analysis techniques used in the moment analysis by the STAR experiment and discuss the moments of net-proton and net-charge distributions from the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider.; Comment: 5 pages, 2 figures, Proceedings of Workshop for Young Scientists with Research Interests Focused on Physics at FAIR, Italy, Sept. 22-27, 2014 (FAIRNESS Workshop 2014)

## The Frontiers of Nuclear Science, A Long Range Plan

Committee, The DOE/NSF Nuclear Science Advisory
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.82%
This is a copy of the 2007 report prepared by the DOE/NSF Nuclear Science Advisory Committee in response to the charge from DOE and NSF to "conduct a study of the opportunities and priorities for U.S. nuclear physics research and recommend a long range plan that will provide a framework for coordinated advancement of the nation's nuclear science research programs over the next decade."

## Physics Opportunities of a Fixed-Target Experiment using the LHC Beams

Brodsky, S. J.; Fleuret, F.; Hadjidakis, C.; Lansberg, J. P.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.06%
We outline the many physics opportunities offered by a multi-purpose fixed-target experiment using the LHC proton and Pb beams extracted by a bent crystal. In a proton run with the LHC 7-TeV beam, one can analyze pp, pd and pA collisions at sqrt(s_NN)~115 GeV and even higher using the Fermi motion in a nuclear target. In a Pb run with a 2.76 TeV-per-nucleon beam, sqrt(s_NN) is as high as 72 GeV. Bent crystals can be used to extract about 5x10^8 protons/s; the integrated luminosity over a year reaches 0.5fb-1 on a typical 1 cm-long target without species limitation. Such an extraction mode does not alter the performance of the collider experiments at the LHC. By instrumenting the target-rapidity region, gluon and heavy-quark proton and neutron PDFs can be accessed at large x and even at x larger than 1 in the nuclear case. Single diffractive physics and, for the first time, the large negative-xF domain can be accessed. The nuclear target-species versatility provides a unique opportunity to study nuclear matter vs. the features of the hot and dense matter formed in heavy-ion collisions, which can be studied in PbA collisions over the full range of target-rapidity domain with a large variety of nuclei. The polarization of hydrogen and nuclear targets allows an ambitious spin program...

## Error analysis of nuclear forces and effective interactions

Perez, R. Navarro; Amaro, J. E.; Arriola, E. Ruiz
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.98%
The Nucleon-Nucleon interaction is the starting point for ab initio Nuclear Structure and Nuclear reactions calculations. Those are effectively carried out via effective interactions fitting scattering data up to a maximal center of mass momentum. However, NN interactions are subjected to statistical and systematic uncertainties which are expected to propagate and have some impact on the predictive power and accuracy of theoretical calculations, regardless on the numerical accuracy of the method used to solve the many body problem. We stress the necessary conditions required for a correct and self-consistent statistical interpretation of the discrepancies between theory and experiment which enable a subsequent statistical error propagation and correlation analysis. We comprehensively discuss an stringent and recently proposed tail-sensitive normality test and provide a simple recipe to implement it. As an application, we analyze the deduced uncertainties and correlations of effective interactions in terms of Moshinsky-Skyrme parameters and effective field theory counterterms as derived from the bare NN potential containing One-Pion-Exchange and Chiral Two-Pion-Exchange interactions inferred from scattering data.; Comment: 17 pages...

## A Fixed-Target ExpeRiment at the LHC (AFTER@LHC) : luminosities, target polarisation and a selection of physics studies

Lansberg, J. P.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Rosier, P.; Arnaldi, R.; Scomparin, E.; Brodsky, S. J.; Ferreiro, E. G.; Fleuret, F.; Rakotozafindrabe, A.; Uggerhøj, U. I.