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41.
A. Lleres O. Bartalini V. Bellini J. P. Bocquet P. Calvat M. Capogni L. Casano M. Castoldi A. D'Angelo J. -P. Didelez R. Di Salvo A. Fantini C. Gaulard G. Gervino F. Ghio B. Girolami A. Giusa M. Guidal E. Hourany V. Kouznetsov R. Kunne A. Lapik P. Levi Sandri D. Moricciani A. N. Mushkarenkov V. Nedorezov L. Nicoletti C. Perrin C. Randieri D. Rebreyend F. Renard N. Rudnev T. Russew G. Russo C. Schaerf M. -L. Sperduto M. -C. Sutera A. Turinge 《The European Physical Journal A - Hadrons and Nuclei》2007,31(1):79-93
Beam asymmetries and hyperon recoil polarizations for the reactions γp → K
+Λ and γp → K
+Σ0 have been measured from the threshold production to 1500MeV with the GRAAL facility located at the ESRF in Grenoble. These
results complement the database for the beam asymmetry, covering for the first time the production threshold region. Recent
theoretical analyses are presented for which the beam asymmetry data bring interesting new information and allow to better
determine some resonance parameters. Most importantly, these results strengthen the need of a new D13 state around 1900MeV. 相似文献
42.
C. Curceanu M. Bazzi G. Beer L. Bombelli A. M. Bragadireanu M. Cargnelli M. Catitti C. Fiorini T. Frizzi F. Ghio B. Girolami C. Guaraldo M. Iliescu T. Ishiwatari P. Kienle P. Lechner P. Levi Sandri A. Longoni V. Lucherini J. Marton D. Pietreanu T. Ponta D. L. Sirghi F. Sirghi H. Soltau L. Struder E. Widmann J. Zmeskal 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):537-539
The DAΦNE electron-positron collider at the Frascati National Laboratories has made available a unique “beam" of negative kaons providing
unprecedented conditions for the study of the low-energy kaon-nucleon interaction, a field still largely unexplored. The DEAR
(DAΦNE Exotic Atom Research) experiment at DAΦNE and its successor SIDDHARTA (SIlicon Drift Detector for Hadronic Atom Research by Timing Application) aim at a precision
measurement of the strong-interaction shift and width of the fundamental 1s level, via the measurement of the X-ray transitions to this level, for kaonic hydrogen and kaonic deuterium. The aim is to
extract the isospin-dependent antikaon-nucleon scattering lengths and to contribute to the understanding of aspects of chiral
symmetry breaking in the strangeness sector. 相似文献
43.
C. Curceanu M. Bazzi G. Beer L. Bombelli A. M. Bragadireanu M. Cargnelli C. Fiorini T. Frizzi F. Ghio B. Girolami C. Guaraldo R. Hayano M. Iliescu T. Ishiwatari M. Iwasaki P. Kienle P. Lechner P. Levi Sandri A. Longoni V. Lucherini J. Marton S. Okada D. Pietreanu T. Ponta A. Romero Vidal A. Scordo H. -X. Shi D. L. Shirghi F. Sirghi H. Soltau L. Struder H. Tatsuno O. Vazquez Doce E. Widmann J. Zmeskal 《Hyperfine Interactions》2009,188(1-3):11-17
Radioactive 57Mn+(T 1/2?= 1.5 min) ions have been implanted at the ISOLDE facility at CERN with 60 keV energy to fluences <1012/cm2 into p-type Si1???x Ge x (x < 0.1) single crystals held at 300–600 K. The implantation and annealing processes result in the majority of the implanted Mn ions occupying substitutional lattice sites. In the subsequent 57Mn nuclear β ???-decay to the 14.4 keV Mössbauer state of 57Fe (T 1/2?= 100 ns), an average recoil energy of 40 eV is imparted to the 57Fe daughter atoms which results in a large fraction being expelled into tetrahedral interstitial sites and the creation of a vacancy. The remainder occupies substitutional sites. This technique of recoil production of 57m FeI thus allows for the study of the diffusion characteristics of interstitial Fe. From the temperature dependent line broadening, the activation energies have been determined and decrease with increasing Ge concentration which contributes significantly to the increase of the jump frequency. A similar result has been obtained in n-type SiGe but there the values for the activation energies were much higher. 相似文献
44.
SIDDHARTA Collaboration Bazzi M Beer G Bombelli L Bragadireanu AM Cargnelli M Curceanu Petrascu C Dʼuffizi A Fiorini C Frizzi T Ghio F Guaraldo C Hayano RS Iliescu M Ishiwatari T Iwasaki M Kienle P Levi Sandri P Longoni A Marton J Okada S Pietreanu D Ponta T Rizzo A Romero Vidal A Sbardella E Scordo A Shi H Sirghi DL Sirghi F Tatsuno H Tudorache A Tudorache V Vazquez Doce O Wünschek B Widmann E Zmeskal J 《Physics letters. [Part B]》2012,714(1):40-43
The kaonic (3)He and (4)He X-rays emitted in the [Formula: see text] transitions were measured in the SIDDHARTA experiment. The widths of the kaonic (3)He and (4)He 2p states were determined to be [Formula: see text], and [Formula: see text], respectively. Both results are consistent with the theoretical predictions. The width of kaonic (4)He is much smaller than the value of [Formula: see text] determined by the experiments performed in the 70's and 80's, while the width of kaonic (3)He was determined for the first time. 相似文献
45.
O. Bartalini V. Bellini J. P. Bocquet P. Calvat A. D’Angelo J. -P. Didelez R. Di Salvo A. Fantini F. Ghio B. Girolami M. Guidal A. Giusa E. Hourany A. S. Ignatov R. Kunne A. M. Lapik P. Levi Sandri A. Lleres D. Moricciani A. N. Mushkarenkov V. G. Nedorezov C. Perrin D. Rebreyend F. Renard N. V. Rudnev T. Russew G. Russo C. Schaerf M. -L. Sperduto M. -C. Sutera A. A. Turinge 《Physics of Atomic Nuclei》2008,71(1):75-82
The total photoabsorption cross section on a free proton was measured at the GRAAL facility in the energy range E
γ = 600−1500 MeV. The large-aperture LAGRANγE detector and a liquid hydrogen target were used in the experiment performed with
a back-scattered Compton gamma beam. To improve the accuracy, two alternative methods were employed. First, a subtraction
method of using empty-target measurements allowed the cross section σ
tot to be evaluated directly because of a low level of the electromagnetic background. Second, an algorithm for evaluating σ
tot on the basis of summing the dominating partial cross sections was developed. Experimental results obtained for σ
tot by the two methods are compared with existing data.
The article was translated by the authors.
Published in Russian in Yadernaya Fizika, 2008, Vol. 71, No. 1, pp. 76–83. 相似文献
46.
Antonio Arcelli Gianni Porzi Samuele Rinaldi Monica Sandri 《Journal of Physical Organic Chemistry》2008,21(2):163-172
The aminolysis reaction of a series of β‐lactams in the presence of poly(ethyleneimine) (PEI) at 30°C and pH = 8.40 has been studied. The substrates investigated follow a pseudo first order rate, except two β‐lactams which show a two step consecutive reaction. Increasing the polyelectrolyte concentration, Michaelis–Menten type kinetics are been observed and for four substrates a more complex rate behaviour was verified owing to the polyelectrolyte inhibition effect. Both the binding constant K1 between polyelelectrolyte and β‐lactam and the first order rate constant of the reactive complex decomposition kcat were calculated. The substituent effect at C‐6′ or C‐7′ position of β‐lactam on the aminolysis rate does not correlate with the σI value (Taft plot). Most probably, steric and electronic effects are important, but the electrostatic ones are determining factors for the relevant acceleration attributable to both the binding phenomena and the increased reactivity of the substrate–polyelectrolyte complex. The comparison between poly(ethyleneimine) and Human Serum Albumin (HSA) is also discussed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
47.
Nikola Sandrić 《Journal of Theoretical Probability》2016,29(2):459-490
A stable-like Markov chain is a time-homogeneous Markov chain on the real line with the transition kernel \(p(x,\hbox {d}y)=f_x(y-x)\hbox {d}y\), where the density functions \(f_x(y)\), for large \(|y|\), have a power-law decay with exponent \(\alpha (x)+1\), where \(\alpha (x)\in (0,2)\). In this paper, under a certain uniformity condition on the density functions \(f_x(y)\) and additional mild drift conditions, we give sufficient conditions for recurrence in the case when \(0<\liminf _{|x|\longrightarrow \infty }\alpha (x)\), sufficient conditions for transience in the case when \(\limsup _{|x|\longrightarrow \infty }\alpha (x)<2\) and sufficient conditions for ergodicity in the case when \(0<\inf \{\alpha (x):x\in \mathbb {R}\}\). As a special case of these results, we give a new proof for the recurrence and transience property of a symmetric \(\alpha \)-stable random walk on \(\mathbb {R}\) with the index of stability \(\alpha \ne 1\). 相似文献
48.
O. Bartalini V. Bellini J. P. Bocquet M. Capogni L. Casano M. Castoldi P. Calvat A. D'Angelo R. Di Salvo A. Fantini C. Gaulard G. Gervino F. Ghio B. Girolami A. Giusa V. Kouznetsov A. Lapik P. Levi Sandri A. Lleres D. Moricciani A. N. Mushkarenkov V. Nedorezov L. Nicoletti C. Perrin D. Rebreyend F. Renard N. Rudnev T. Russew G. Russo C. Schaerf M. -L. Sperduto M. -C. Sutera A. Turinge 《The European Physical Journal A - Hadrons and Nuclei》2005,26(3):399-419
Neutral pion photoproduction has been measured from 550 to 1500 MeV with the GRAAL facility, located at the ESRF in Grenoble.
Differential cross-section and beam asymmetry have been measured over a wide angular range. These high-precision data improve
significantly the database for the beam asymmetry in the second and third resonance regions covering for the first time the
energy domain 1100-1500 MeV. New partial-wave analyses including these data are presented for which the beam asymmetry brings
crucial constraints. 相似文献
49.
S. Marchetti P. Sandri R. Simili 《International Journal of Infrared and Millimeter Waves》1997,18(11):2161-2175
In this work we report a complete theory of the metal-insulator-metal, antenna coupled, mm and sub-mm detectors. The voltage
-power responsivity is simply derived from the geometrical antenna proprieties and the electrical junction characteristics.
The calculated responsivity simply foresees our experimental results in the sub-mm — mm range and well fits all the previously
reported data 相似文献
50.
Richard C. Brower Robert G. Hohlfeld Raymond J. Nagem Guido v.H. Sandri 《Wave Motion》1993,18(4):383-400
The effect of spatial discretization on the isotropy of propagating waves is investigated. A general criterion is given for minimizing the numerical anisotropy and dispersion caused by spatial discretization, and specific discretizations in two and three space dimensions are derived which give, in a well-defined sense, optimally isotropic propagation. We establish the group-theoretic connection between the properties of the spatial discretization and the symmetries of the underlying computational grid. The discretization technique, described here in the context of the scalar wave equation, may also be applied to other partial differential equations containing the Laplacian or gradient operators. 相似文献