Articles de revues : « MHV scattering amplitudes »

1

Wu, Jun-Bao, and Chuan-Jie Zhu. "MHV Vertices and Scattering Amplitudes in Gauge Theory." Journal of High Energy Physics 2004, no. 07 (2004): 032. http://dx.doi.org/10.1088/1126-6708/2004/07/032.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

2

ANTONIADIS, IGNATIOS, and GEORGE SAVVIDY. "CONFORMAL INVARIANCE OF TENSOR BOSON TREE AMPLITUDES." Modern Physics Letters A 27, no. 18 (2012): 1250103. http://dx.doi.org/10.1142/s0217732312501039.

Texte intégral

Résumé :

The BCFW recursion relation allows to find out the tree-level scattering amplitudes for gluons and tensor gauge bosons in generalized Yang–Mills theory. We demonstrate that the corresponding MHV amplitudes for the tensor gauge bosons of spin-s and n gluons are invariant under conformal group of transformations. This is highly unexpected result for the higher-spin particles, in particular this is not true for the scattering amplitudes of gravitons. We discuss and compare the tree-level scattering amplitudes for the charged tensor bosons with the corresponding scattering amplitudes for gravitons, stressing their differences and similarities.

Styles APA, Harvard, Vancouver, ISO, etc.

3

GEORGIOU, GEORGE, and GEORGE SAVVIDY. "PRODUCTION OF NON-ABELIAN TENSOR GAUGE BOSONS TREE AMPLITUDES AND BCFW RECURSION RELATION." International Journal of Modern Physics A 26, no. 15 (2011): 2537–55. http://dx.doi.org/10.1142/s0217751x1105350x.

Texte intégral

Résumé :

The BCFW recursion relation is used to calculate tree-level scattering amplitudes in generalized Yang–Mills theory and, in particular, four-particle amplitudes for the production rate of non-Abelian tensor gauge bosons of arbitrary high spin in the fusion of two gluons. The consistency of the calculations in different kinematical channels is fulfilled when all dimensionless cubic coupling constants between vector bosons and high spin non-Abelian tensor gauge bosons are equal to the Yang–Mills coupling constant. We derive a generalization of the Parke–Taylor formula in the case of production of two tensor gauge bosons of spin-s and N gluons (jets). The expression is holomorphic in the spinor variables of the scattered particles, exactly as the MHV gluon amplitude is, and reduces to the gluonic MHV amplitude when s = 1.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Wu, Jun-Bao, and Chuan-Jie Zhu. "MHV Vertices and Fermionic Scattering Amplitudes in Gauge Theory with Quarks and Gluinos." Journal of High Energy Physics 2004, no. 09 (2004): 063. http://dx.doi.org/10.1088/1126-6708/2004/09/063.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

5

KIM, YONG JOO, and MOON HOE CHA. "COULOMB-MODIFIED EIKONAL MODEL ANALYSIS OF REFRACTIVE12C+12CELASTIC SCATTERING AT Elab= 240 AND 360MeV." International Journal of Modern Physics E 11, no. 03 (2002): 211–19. http://dx.doi.org/10.1142/s0218301302000764.

Texte intégral

Résumé :

We present the Coulomb-modified eikonal model by using a tangential velocity at the distance of closest approach. The Fraunhöfer oscillations observed in the elastic angular distributions of the12C +12C system at Elab= 240 and 360 MeV can be explained due to the strong interference between the near- and far-side scattering amplitudes. We have found that the strongly real and weakly imaginary potentials are required to describe the refractive12C +12C elastic scatterings at Elab= 240 and 360 MeV. The refractive pattern, dominated by the far-side component of the scattering amplitude, can be shown to be sensitive to the real part of optical potential at small radius. Introducing the tangential velocity, it is shown that the Coulomb-modified eikonal model satisfactorily reproduces experimental data concerning the refractive pattern in the angular distributions of the12C +12C system at Elab= 240 and 360 MeV.

Styles APA, Harvard, Vancouver, ISO, etc.

6

YAHYA, G. A. "DEFORMED OPTICAL POTENTIAL ANALYSES FOR P+12C." International Journal of Modern Physics E 13, no. 04 (2004): 851–66. http://dx.doi.org/10.1142/s0218301304002508.

Texte intégral

Résumé :

The high energy single folding optical potential approximation is studied to calculate the differential cross-section for proton elastic scattering of 12 C at 156 MeV and 1440 MeV and 12 C for state 2+ (4.44 MeV) at 1440 MeV. A Gaussian nuclear density distribution was used for the proton and Gaussian and Brink nuclear density distributions for the 12 C target. We used the following three effects to derive twelve different methods for the central optical potential: (i) Love and Franey and the Gaussian amplitudes, with the Brink and one-term Gaussian nuclear density distributions, (ii) Pauli correlation in the Gaussian amplitude with these densities, (iii) coupling channels on the differential cross-sections in proton elastic scattering of 12 C at 1440 MeV with single channel calculations using these amplitudes, nuclear density distributions and Pauli correlation in the Gaussian amplitude. A new numerical technique was performed to solve the deformed optical potential equations using computational programs.

Styles APA, Harvard, Vancouver, ISO, etc.

7

KHAN, Z. A., DEEKSHA CHAUHAN, and MINITA SINGH. "ANALYSIS OF p-4, 6, 8He AND p-6, 9, 11Li SCATTERING." International Journal of Modern Physics E 22, no. 11 (2013): 1350082. http://dx.doi.org/10.1142/s0218301313500821.

Texte intégral

Résumé :

Using the Coulomb modified Glauber model, we analyze the elastic scattering of protons from He and Li isotopes at 60 MeV and 72 MeV. The calculations require two inputs; the nucleon–nucleon (NN) amplitude and the nucleon density distributions in target nuclei. The central part of the NN amplitude is taken from the available NN scattering observables. To find the spin-dependent part, we employ p-4 He scattering data to fix its parameter values. For target nuclei, we use nucleon density distributions available in the literature. The NN amplitude, as obtained in this work, is then used to study the sensitivity of the calculated differential cross-section and polarization for p-6, 8 He scattering on the density distributions used. It is found that both the differential cross-section and polarization could provide a test to know which is the better choice of nucleon (especially neutron) density distributions. We also present the differential cross-sections for p-6, 9, 11 Li scattering at 60 MeV and 72 MeV in order to assess the suitability of the obtained NN amplitude. It is found that the results are in reasonable agreement with the experiment up to only moderate scattering angles, leaving significant discrepancy at large scattering angles. Our calculations suggest the need of medium modifications in the NN amplitude, arising due to Pauli blocking.

Styles APA, Harvard, Vancouver, ISO, etc.

8

Niskanen, J. A. "THE FORWARD AMPLITUDE IN LOW ENERGY $P\bar P$ SCATTERING." Modern Physics Letters A 03, no. 01 (1988): 57–64. http://dx.doi.org/10.1142/s021773238800009x.

Texte intégral

Résumé :

It is shown that the abrupt rise of around 200 MeV/c in the real-to-imaginary ratio ρ of the forward scattering amplitude in low energy [Formula: see text] scattering is not due to the [Formula: see text] threshold or approximations in the treatment of the coulomb nuclear interference. The latter breaks down below Plab≈100 MeV/c. The possibility of a potential resonance is discussed.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Bartels, J., L. N. Lipatov, and A. Prygarin. "MHV amplitude for 3→3 gluon scattering in Regge limit." Physics Letters B 705, no. 5 (2011): 507–12. http://dx.doi.org/10.1016/j.physletb.2011.09.061.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

10

KIM, YONG JOO, and MOON HOE CHA. "COULOMB-MODIFIED EIKONAL PHASE SHIFT ANALYSIS BASED ON HYPERBOLIC TRAJECTORY FOR 12C + 12C ELASTIC SCATTERINGS." International Journal of Modern Physics E 13, no. 02 (2004): 439–50. http://dx.doi.org/10.1142/s0218301304002296.

Texte intégral

Résumé :

We present a Coulomb-modified eikonal model formalism based on hyperbolic trajectory for heavy-ion elastic scattering. This formalism has been applied satisfactorily to elastic scatterings of the 12 C + 12 C system at E lab =240, 360 and 1016 MeV. The presence of a nuclear rainbow in this system is evidenced through a classical deflection function. The Fraunhöfer oscillations observed in the elastic angular distributions can be explained due to interference between the near- and far-side amplitudes. We have found that the hyperbolic trajectory effect on the eikonal model is important when the absorptive potential is weak and the real potential is strong.

Styles APA, Harvard, Vancouver, ISO, etc.

11

BEREZHNOY, YU A., and V. P. MIKHAILYUK. "ELASTIC 12C–12C SCATTERING AT INTERMEDIATE ENERGIES." International Journal of Modern Physics E 11, no. 04 (2002): 281–87. http://dx.doi.org/10.1142/s0218301302000880.

Texte intégral

Résumé :

The differential cross-sections for elastic 12C–12C scattering at 2400 and 1449 MeV are calculated on the basis of the multiple diffraction scattering theory and α-cluster model with dispersion. At the energy 2400 MeV the calculations were performed by means of "effective" and "free" α–α amplitudes. It is shown that the results obtained differ significantly.

Styles APA, Harvard, Vancouver, ISO, etc.

12

ROCA, L., та E. OSET. "EXTRACTION OF THE Λ(1405) POLES FROM π0Σ0 PHOTOPRODUCTION DATA". International Journal of Modern Physics: Conference Series 26 (січень 2014): 1460086. http://dx.doi.org/10.1142/s2010194514600866.

Texte intégral

Résumé :

In this contribution we review a work where we showed how to extract the position of the two Λ(1405) poles from experimental photoproduction data which have been measured recently in the γp → K+π0Σ0 reaction at Jefferson Lab. Using a potential motivated by chiral dynamics but with free parameters, we solve the Bethe Salpeter equation in the coupled channels [Formula: see text] and πΣ in isospin I=0 and parameterize the amplitude for the photonuclear reaction in terms of a linear combination of the πΣ → πΣ and [Formula: see text] scattering amplitudes in I=0, with a different linear combination for each energy. Good fits to the data are obtained which lead to two poles at 1385 - 68i MeV and 1419 - 22i MeV, similar to those found in the chiral unitary approach.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Tag El-Din, Ibrahim M. A., M. M. Taha, and Samia S. A. Hassan. "Study of p-4Hetotal reaction cross-section using Glauber and Coulomb-modified Glauber models." International Journal of Modern Physics E 23, no. 03 (2014): 1450010. http://dx.doi.org/10.1142/s0218301314500104.

Texte intégral

Résumé :

The total nuclear reaction cross-section σRfor p-4He in the energy range from 25 MeV to 1000 MeV is calculated within Glauber and Coulomb-modified Glauber models. The Coulomb-modified Glauber model (CMGM) is introduced via modification of the Coulomb trajectory of the projectile from a straight line, and calculation of the effective radius of interaction. The effects of in-medium nucleon–nucleon (NN) total cross-section, phase variation, high order momentum transfer component of nucleon–nucleon elastic scattering amplitude and Pauli blocking are studied. It is pointed out that the phase variation of the nucleon–nucleon amplitude plays a significant role in describing σRwith γ = -1.6 fm2at in-medium nuclear density ϱ = 0 and γ = -2 fm2at ϱ = 0.17 fm-3in the whole energy range. A remarkable fit to the available experimental data is obtained by invoking Pauli blocking and high order momentum transfer of nucleon–nucleon (NN) elastic scattering amplitude for Ep< 100 MeV.

Styles APA, Harvard, Vancouver, ISO, etc.

14

LADYGINA, NADEZHDA B. "RESCATTERING EFFECTS IN DEUTERON-PROTON ELASTIC SCATTERING AT INTERMEDIATE ENERGIES." International Journal of Modern Physics A 26, no. 03n04 (2011): 728–30. http://dx.doi.org/10.1142/s0217751x11052669.

Texte intégral

Résumé :

The deuteron-proton elastic scattering is considered at the deuteron energies from 500 up to 2000 MeV. The multiple-scattering-expansion technique is applied to evaluate the reaction amplitude. The one-nucleon-exchange, single scattering and double scattering contributions are taken into account. Also, some relativistic effects are included into consideration. The obtained results are compared with the experimental data both for the differential cross section and polarization observables.

Styles APA, Harvard, Vancouver, ISO, etc.

15

KIM, YONG JOO, and MOON HOE CHA. "SECOND-ORDER EIKONAL MODEL ANALYSIS OF16O+16OELASTIC SCATTERING." International Journal of Modern Physics E 10, no. 04n05 (2001): 373–86. http://dx.doi.org/10.1142/s0218301301000563.

Texte intégral

Résumé :

We analyze the elastic scattering angular distributions of the16O +16O system at Elab=480 MeV and 704 MeV within the framework of the second-order eikonal model based on Coulomb trajectories of colliding nuclei. The diffractive oscillatory structure observed in the elastic angular distribution could be explained due to the interference between the near- and far-side scattering amplitudes. The presence of a nuclear rainbow in this system is evidenced through a classical deflection function. The effective optical potential is developed from the second-order non-eikonal phase shifts.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Miller, Sean B. S., Andreas Ekström, and Christian Forssén. "Wave-packet continuum discretisation for nucleon–nucleon scattering predictions." Journal of Physics G: Nuclear and Particle Physics 49, no. 2 (2021): 024001. http://dx.doi.org/10.1088/1361-6471/ac3cfd.

Texte intégral

Résumé :

Abstract In this paper we analyse the efficiency, precision, and accuracy of computing elastic nucleon–nucleon (NN) scattering amplitudes with the wave-packet continuum discretisation method (WPCD). This method provides approximate scattering solutions at multiple scattering energies simultaneously. We therefore utilise a graphics processing unit to explore the benefits of this inherent parallelism. From a theoretical perspective, the WPCD method promises a speedup compared to a standard matrix-inversion method. We use the chiral NNLOopt interaction to demonstrate that WPCD enables efficient computation of NN scattering amplitudes provided one can tolerate an averaged method error of 1–5 mb in the total cross section at scattering energies 0–350 MeV in the laboratory frame of reference. Considering only scattering energies ∼40–350 MeV, we find a smaller method error of ≲ 1–2 mb. By increasing the number of wave-packets we can further reduce the overall method error. However, the parallel leverage of the WPCD method will be offset by the increased size of the resulting discretisation mesh. In practice, a GPU-implementation is mainly advantageous for matrices that fit in the fast on-chip shared memory. We find that WPCD is a promising method for computationally efficient, statistical analyses of nuclear interactions from effective field theory, where we can utilise Bayesian inference methods to incorporate relevant uncertainties.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Pilipenko, V. V., and V. I. Kuprikov. "Model of multiple Dirac eikonal scattering of protons by nuclei." International Journal of Modern Physics E 27, no. 10 (2018): 1850088. http://dx.doi.org/10.1142/s021830131850088x.

Texte intégral

Résumé :

The model of multiple Dirac eikonal scattering (MDES) of incident proton by target-nucleus nucleons is developed, in which new expressions for the elastic [Formula: see text]-scattering amplitudes are obtained from the multiple scattering Watson series with employing the eikonal approximation for the Dirac propagators of the free proton motion between successive scattering acts on nucleons. Based on this model, calculations for the complete set of observables of the elastic [Formula: see text] and [Formula: see text]Pb at 800[Formula: see text]MeV have been performed, using proton–nucleon amplitudes determined from the phase analysis and the nucleon densities obtained from describing the target-nucleus structure in the relativistic mean-field approximation. A comparison has been made of the results of these calculations with analogous calculations on the basis of the Glauber multiple diffraction theory.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Babak, O. V., Yu A. Berezhnoy, and V. P. Mikhailyuk. "Born Approximation for Polarization Observables at the Scattering of Protons by 40Ca Nuclei." Ukrainian Journal of Physics 65, no. 5 (2020): 369. http://dx.doi.org/10.15407/ujpe65.5.369.

Texte intégral

Résumé :

A development of the optical model for the description of the hadron-nucleus scattering is proposed. When describing the behavior of polarization observables for the elastic proton scattering on 40Ca nuclei in the energy interval from 200 to 800 MeV, the Born approximation is used. Analytical expressions for the scattering amplitudes, as well as for the differential cross-sections and polarization observables, are obtained. The comparison of the scattering observables calculated in the 1st and 2nd Born approximations is made. It is shown that the observables calculated in this approach are in a reasonable agreement with the available experimental data.

Styles APA, Harvard, Vancouver, ISO, etc.

19

AHMAD, I., M. A. ABDULMOMEN, and M. A. ALVI. "EIKONAL DESCRIPTION OF 12C–12C ELASTIC SCATTERING IN TERMS OF PHENOMENOLOGICAL EFFECTIVE NN POTENTIAL." International Journal of Modern Physics E 11, no. 06 (2002): 519–29. http://dx.doi.org/10.1142/s0218301302001022.

Texte intégral

Résumé :

A phenomenological method of analysis for heavy-ion elastic scattering data at intermediate energies is proposed within the framework of the optical limit approximation of the Glauber multiple scattering theory. The essential point of our method is to evaluate the NN scattering amplitude in terms of a phenomenological effective NN potential the parameters of which are varied to fit the experimental data. It is applied to analyze 12C–12C elastic scattering data in the energy range of 25–200 MeV/nucleon with a good degree of success.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Lukyanov, V. K., E. V. Zemlyanaya, K. V. Lukyanov, A. Y. Ellithi, and I. A. M. Abdul-Magead. "Study of elastic and inelastic pion-nucleus scattering using the microscopic model of optical potential." International Journal of Modern Physics E 24, no. 05 (2015): 1550035. http://dx.doi.org/10.1142/s0218301315500354.

Texte intégral

Résumé :

The pion-nucleus microscopic optical potential (OP), defined by the pion-nucleon scattering amplitude and by the generalized density distribution of a target nucleus that incudes internal degrees of freedom, is applied to construct the pion-nucleus differential cross-sections of elastic and inelastic scattering on the nuclei 28 Si , 58 Ni , 208 Pb at T lab = 291 MeV. Calculations are based on the relativistic wave equation and thus relativistic effects and distortions on the relative motion wave functions are taken into account. The respective experimental data are analyzed and the in-medium parameters of the elementary πN-amplitude are established and compared with those from the pion scattering on free nucleons.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Badran, R. I., A. I. Istaiti, W. N. Mashaqbeh та I. H. Al-Lehyani. "Regge pole analysis of elastic scattering of α particles by even isotopes of Ni target nuclei at incident energies above Coulomb barrier". International Journal of Modern Physics E 24, № 11 (2015): 1550082. http://dx.doi.org/10.1142/s0218301315500822.

Texte intégral

Résumé :

Regge pole model is adopted to account for the angular distribution at backward angles for a set of elastic scattering processes of incident [Formula: see text]-particles by different isotopes of nickel ions, [Formula: see text]Ni, at different laboratory energies above Coulomb barrier. The reproduction of cross-sections at backward angles is preceded by an attempt to fit the experimental data at forward angles of the scattering. Three-parameter McIntyre model which is based on concept of strong absorption parametrization of the scattering matrix elements, has been employed to analyze and reproduce the experimental data of angular distribution of different elastic scattering reactions at forward angles. The three parameters extracted from McIntyre model analysis are employed as fixed entries in the fitting process of the full angle-range of angular distribution where another four free parameters are employed using the Regge pole model. Diffractive features observed in the angular distributions are studied. The Fresnel-type diffraction pattern is found dominant for all investigated elastic scatterings where Coulomb interaction is strong. The interaction radius of elastic scattering is found decreasing and the total cross-section increasing when the incident projectile energy increases. Moreover, the interaction radius and total reaction cross-section are found increasing with the increase in the size of target ion. Such diffractive behavior is consistent with the prescriptions of strong absorption model (SAM). Furthermore, the explanation of the diffractive features of studied elastic scattering reactions is model-independent. The Regge pole analysis reveals the existence of a pole which has its location, width, amplitude and phase angle exhibiting a common peak at energy of 24.1[Formula: see text]MeV with oscillatory behaviour at energies around this peak energy, for all elastic scattering of alpha particle on isotopes of Ni targets except that of [Formula: see text]Ni target which exhibits extra peaks for energy larger than 24.1[Formula: see text]MeV. We believe that the presence of poles is responsible for the oscillatory structure of the backward cross-sections. The variation of Regge pole parameters with both incident energy and size of target nucleus is illustrated.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Ghahramany, N., and H. Falinejad. "Formation of the interaction matrix in pion–nucleon scattering in optimal conditions and amplitude determination at 471, 547, and 625 MeV c−1." Canadian Journal of Physics 73, no. 9-10 (1995): 638–41. http://dx.doi.org/10.1139/p95-093.

Texte intégral

Résumé :

The most recent measurements of the polarization parameters were used to determine the magnitudes and relative phase of spin amplitudes in charged pion – proton scattering at 471, 547, and 625 MeV c−1. In addition to optimal conditions, invariance laws were imposed to reduce the number of independent amplitudes to two. In the transverse frame we obtained two amplitudes both being nonflip. In the helicity frame also we obtained two amplitudes, one spin flip and the other being spin nonflip. The magnitudes of the transverse amplitudes were also determined at 2.39 GeV c−1 in terms of square momentum transfer. In all the calculations, the differential cross section is normalized to unity.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Mahalanabis, Jayanti. "Determination of scattering amplitude from glauber model analysis of elastic scattering at 179.3 MeV." Nuclear Physics B - Proceedings Supplements 8 (June 1989): 268–70. http://dx.doi.org/10.1016/0920-5632(89)90237-5.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

24

MIKHAILYUK, V. P. "ELASTIC SCATTERING OF DEUTERONS ON α-CLUSTER NUCLEI". Modern Physics Letters A 10, № 38 (1995): 2915–21. http://dx.doi.org/10.1142/s0217732395003045.

Texte intégral

Résumé :

The differential cross-sections for elastic scattering of deuterons on 12 C and 16 O nuclei at 700 MeV are calculated on the basis of multiple diffraction scattering theory and the α-cluster model with dispersion. For d−12 C scattering it was shown that the results of the calculations by the model, when the effects related with the deuteron structure included via deuteron-α amplitude are in better agreement with the experimental data than those by the model, in which incident deuteron is considered as composed of neutron and proton.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Hausammann, R., E. Heer, R. Hess, et al. "Direct experimental reconstruction of theppelastic scattering amplitudes between 447 and 579 MeV." Physical Review D 40, no. 1 (1989): 22–34. http://dx.doi.org/10.1103/physrevd.40.22.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

26

CHAUHAN, DEEKSHA, and Z. A. KHAN. "16O-NUCLEUS ELASTIC SCATTERING IN THE ENERGY RANGE 300 MeV–1.503 GeV." International Journal of Modern Physics E 18, no. 09 (2009): 1887–902. http://dx.doi.org/10.1142/s0218301309013944.

Texte intégral

Résumé :

In this work we analyze the elastic angular distribution for the scattering of 16 O from 12 C , 16 O , 28 Si , 40 Ca , 90 Zr , and 208 Pb in the energy range 300 MeV–1.503 GeV within the framework of the Coulomb modified correlation expansion for the Glauber amplitude. Our calculations involve (i) up to the two-body density term in the correlation expansion, (ii) the realistic nuclear form factors, and (iii) the high q-components of the basic (input) NN amplitude. The results are found to provide a satisfactory explanation of the data in all the cases. Moreover, we could assess the energy dependence of the NN amplitude, and the trend of its slope strengthens the need of nondiffractive behavior of the NN amplitude in the energy range under consideration. We also show that the c.m. correlations play an important role in nucleus–nucleus collision.

Styles APA, Harvard, Vancouver, ISO, etc.

27

KIM, YONG JOO, and MOON HOE CHA. "NON-EIKONAL PHASE SHIFT ANALYSIS FOR 12C + 12C ELASTIC SCATTERING." International Journal of Modern Physics E 09, no. 01 (2000): 67–76. http://dx.doi.org/10.1142/s0218301300000052.

Texte intégral

Résumé :

We present first-order non-eikonal correction to the eikonal phase shifts for heavy ion elastic scattering based on Coulomb trajectories of colliding nuclei. It has been applied satisfactorily to elastic angular distributions of the 12 C + 12 C system at E lab = 240, 360 and 1016 MeV. The refractive oscillations observed in the elastic scattering angular distributions could be explained due to interference between the near- and far-side amplitudes. The presence of a nuclear rainbow is evidenced through classical deflection function. We have found that the first-order non-eikonal effect on the imaginary potential is important when the absorptive potential is weak and the real potential is strong.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Spangler, S. R. "Interstellar Magnetohydrodynamic Waves as Revealed by Radio Astronomy." Symposium - International Astronomical Union 140 (1990): 176. http://dx.doi.org/10.1017/s0074180900189880.

Texte intégral

Résumé :

The plasma density fluctuations responsible for interstellar scintillations occur on the same scales as interstellar magnetohydrodynamic waves (Alfvén waves), which are responsible for many important processes such as the acceleration of the cosmic rays. This suggests that these density fluctuations represent a compressive component of MHD waves, and raises the exciting possibility that radioastronomical observations can provide more or less direct measurements of interstellar microphysical processes. Extraction of MHD wave properties from the radio scattering measurements requires a sound theoretical understanding of the relationship between the magnetic field in an MHD wave and the corresponding plasma density perturbation. We present a plasma kinetic theory treatment of the density compression associated with an MHD wave field. The density perturbation may be expressed as the sum of three terms. These terms are proportional to the wave amplitude, wave intensity, and sine transform of the wave intensity, respectively. The coefficients of these three terms are functions of the plasma β, the electron-to-ion temperature ratio, and the angle of wave propagation with respect to the large scale magnetic field. This relation can serve as the basis for inferring the MHD wave field given a radio scattering measurement of the density fluctuation statistics. In an attempt to apply these ideas to the interstellar plasma turbulence, we have made VLBI angular broadening measurements of sources whose lines of sight pass close to supernova remnants. The intensity of MHD waves is expected to be high in the vicinity of the shock waves associated with supernova remnants. We do not yet have unambiguous evidence of enhanced radio wave scattering due to shock-associated MHD waves. However, we have found anomalously high scattering for the source CL4, whose line of sight passes through the Cygnus Loop.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Gou, B. "Initial Research of np Scattering with Polarized Deuterium Target at ANKE/COSY." International Journal of Modern Physics: Conference Series 40 (January 2016): 1660058. http://dx.doi.org/10.1142/s2010194516600582.

Texte intégral

Résumé :

The quasi-free np charge-exchange reaction [Formula: see text] has to be employed to extend the investigations of np scattering at ANKE to the highest energy available at COSY. As the proof-of-principle experiment, the initial research has been conducted at proton energy [Formula: see text] MeV using a polarized Deuterium target. The vector and tensor analyzing powers [Formula: see text] and [Formula: see text] were measured for momentum transfers [Formula: see text] MeV/c. These data connect smoothly with the previous measurements at [Formula: see text] MeV/c performed using a polarized deuteron beam. The reported data are well reproduced by the impulse approximation using the SAID np amplitudes. The results therefore proves that it is possible to continue the np programme at higher energies at ANKE.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Lukyanov, Valery, Elena Zemlyanaya, and Konstantin Lukyanov. "Microscopic model of optical potential for testing the 12,14Be+p elastic scattering at 700 Mev." EPJ Web of Conferences 204 (2019): 09003. http://dx.doi.org/10.1051/epjconf/201920409003.

Texte intégral

Résumé :

The data on the 12,14Be + p elastic scattering cross sections at 700 Mev are compared with those obtained by solving the relativistic wave equation with the microscopic optical potentials calculated as folding of the NN amplitude of scattering with densities of these nuclei in the form of the symmetrized Fermi function with the fitted radius and diffuseness parameters, and also with the densities obtained in two microscopic models, based on the Generator Coordinate Method (GCM) and the other one – on the Variational Method of Calculations (VMC). For 12Be, above models turn out to be in a small disagreement with the data at "large" angles of scattering θ ≥ 9°, while for the 14Be one sees some inconsistence at smaller angles, too.

Styles APA, Harvard, Vancouver, ISO, etc.

31

ARASH, FIROOZ, MICHEAL J. MORAVCSIK, and GARY R. GOLDSTEIN. "SIMPLE REACTION STRUCTURES IN A "COMPLICATED" KINEMATIC RANGE." International Journal of Modern Physics A 02, no. 03 (1987): 739–51. http://dx.doi.org/10.1142/s0217751x87000284.

Texte intégral

Résumé :

The energy range between 500 and 1000 MeV is usually considered a "complicated" one for elastic proton-proton scattering in which there is no simple description. It is shown that in that energy range, for much of the angular range, two simple features of the magnitudes and relative phases of the invariant amplitudes in the planar transverse frame give a good approximation of the observed data on unpolarized cross section as well as all the various polarization measurements. The features appear to be particularly pronounced at the larger scattering angles and higher energies, thus suggesting a connection with the small distance part of the internucleon force which thus may shed light on the validity of various quark models. Similar regularities also appear in a similar energy and angular range for pion-nucleon scattering. A simple way is presented on a quark level to summarize these regularities.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Wenying, Ruan, and Liu Youyan. "Phase variation in the NN amplitude and proton-nucleus scattering at 800 MeV." Journal of Physics G: Nuclear and Particle Physics 21, no. 4 (1995): 537–44. http://dx.doi.org/10.1088/0954-3899/21/4/005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

33

Dabylova, S. B., Yu N. Kopach, S. K. Sakhiyev, D. N. Grozdanov, and N. A. Fedorov. "Determination of the response function of the NaI detector for g-quanta with an energy of 4.43 MeV, formed during inelastic scattering of neutrons with an energy of 14.1 MeV on carbon nuclei." Eurasian Journal of Physics and Functional Materials 4, no. 4 (2020): 281–90. http://dx.doi.org/10.29317/ejpfm.2020040402.

Texte intégral

Résumé :

The work is devoted to determining the response function of the detector NaI(Tl) for g -quanta with energy of 4.43 MeV, formed during inelastic scattering of neutrons with energy of 14.1 MeV on the nuclei 12C. In gamma spectrometry, output pulses are recorded, the amplitudes of which are proportional to the energy lost in the detection medium by incident photons. One of the main tasks of radiation detection is to restore radiation characteristics from signals measured at the outputs of detectors. For this, it is necessary to know, first of all, the general characteristics of detectors as converters of radiation into signals. The main characteristic of the detector is its response function, which can be defined as the probability that a particle with given properties generates a certain signal in the detector that will be registered by the device. The article presents the results of modeling the response function of a scintillation detector based on a NaI(Tl) crystal for gamma radiation from inelastic fast neutron scattering in order to study the mechanism of its formation.

Styles APA, Harvard, Vancouver, ISO, etc.

34

URBÁN, J., A. BUDZANOWSKI, A. CHATTERJEE та ін. "SEARCH FOR BOUND η-NUCLEUS STATES". International Journal of Modern Physics A 24, № 02n03 (2009): 206–13. http://dx.doi.org/10.1142/s0217751x09043493.

Texte intégral

Résumé :

The extracted s-wave scattering amplitude from both the polarized and unpolarized d + d → 4He + η reaction at 2385.5 MeV/c allowed to determine the scattering length which fulfills the requirements for bound η. In the p + 27Al → 3He + p + π- + X reaction studied at recoil free kinematics the η meson is produced almost at rest and so it can be bound with enhanced probability. This state proceeds via N*(1535) resonance and the decay products proton and pion emitted into opposite direction are detected in concidence with 3He produced at zero degree. Under these conditions some hints for bound state can be observed with an upper limit of the cross section of ≈ 0.5 nb.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Islam, M. Sujan, Ragib Absar Ramon, M. Mizanur Rahman, et al. "Primary rainbow and Airy minima in ¹²C + ¹²C elastic scattering with families of non-monotonic potentials*." Journal of Physics G: Nuclear and Particle Physics 48, no. 12 (2021): 125108. http://dx.doi.org/10.1088/1361-6471/ac2fb0.

Texte intégral

Résumé :

Abstract The experimental differential cross section of the 12C + 12C elastic scattering over a wide laboratory energy scale 25 ⩽ E lab ⩽ 360 MeV are analyzed within the framework of the optical model (OM) using non-monotonic (NM) nucleus–nucleus potential. The real parts of the NM potentials are derived from the energy density functional (EDF) formalism with the sudden approximation embodying the Pauli exclusion principle and the imaginary parts are taken as phenomenology. The diffractive and the refractive scattering with Airy structures in the whole angular region of the 12C + 12C elastic scattering in the above mentioned energy range are found profoundly successful in OM with the NM nucleus–nucleus potentials in five of different potential families. All the families at lower energies converge at 240 MeV to the unique potential family starting with the EDF potential. This, in conjunction with our recent findings for the 16O + 16O system in Islam et al (2021 J. Phys. G 48 075109), not only verifies the Goldberg criterion for elimination of discrete potential ambiguities for NM potentials, but also establishes that this leads uniquely to the EDF family. The 90° excitation function is also successfully reproduced with extension using NM potentials. The near- and far-side (N/F) decomposition of total elastic scattering amplitude has also been studied using our NM potentials.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Gasparyan, A. M., M. F. M. Lutz, and B. Pasquini. "Spin Observables in Pion Photoproduction and Nucleon Compton Scattering from the Chiral Lagrangian and Dispersion Relations." International Journal of Modern Physics: Conference Series 40 (January 2016): 1660066. http://dx.doi.org/10.1142/s2010194516600661.

Texte intégral

Résumé :

A scheme based on the chiral Lagrangian, analyticity and unitarity is applied to spin observables in pion photoproduction and nucleon Compton scattering. Subthreshold partial-wave amplitudes are calculated in chiral perturbation theory and extrapolated beyond the threshold region imposing the micro-causality and the unitarity constraint. A reasonable description of various spin observables up to energies [Formula: see text] MeV is obtained in terms of the parameters relevant at order [Formula: see text] in the chiral Lagrangian. Nucleon spin-polarizabilities predicted in our scheme are consistent with recent measurements of double polarization asymmetries at MAMI.

Styles APA, Harvard, Vancouver, ISO, etc.

37

Nessi-Tedaldi, F., and M. Simonius. "Calculation of parity non-conserving pp-scattering amplitudes and analysis of a 45 MeV measurement." Physics Letters B 215, no. 1 (1988): 159–65. http://dx.doi.org/10.1016/0370-2693(88)91090-8.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

38

Rudchik, A. T., A. A. Rudchik, O. E. Kutsyk та ін. "12С(15N,14N)13C reaction mechanisms at energy 81 MeV". Nuclear Physics and Atomic Energy 21, № 4 (2020): 295–301. http://dx.doi.org/10.15407/jnpae2020.04.295.

Texte intégral

Résumé :

The new experimental data of the 12С(15N,14N)13С reaction cross-sections at the energy Еlab(15N) = 81 MeV were measured for the ground and excited states of 14N and 13C nuclei. The experimental data were analyzed within the coupled-reaction-channels method (CRC) using channels-coupling scheme with the 15N + 12С elastic scattering and one- as well as two-step transfers of nucleons and clusters performing CRC-calculations with the Woods - Saxon potentials (WS) for the entrance and exit reaction channels. The WS potential parameters for the 12С + 15N nuclear interaction were taken from the previously studied elastic and inelastic scattering of 15N ions by 12С nuclei at the energy 81 MeV, and the WS potential parameters for the 14N + 13С reaction exit channel were deduced from fitting of the 12С(15N,14N)13C reaction data. The spectroscopic factors (amplitudes) of transferred in the reaction nucleons and clusters, used in the CRC-calculations, were computed within translational invariant shell model of 1p-shell. It was found that transfers of neutrons (n) and deuterons (d) dominate in this reaction. Multi-step transfers of nucleons and clusters give small contributions to the reaction data.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Kuo, S. P. "Mitigation of energetic electrons in the magnetosphere by amplified whistler wave under double cyclotron resonances." Nonlinear Processes in Geophysics 15, no. 5 (2008): 773–82. http://dx.doi.org/10.5194/npg-15-773-2008.

Texte intégral

Résumé :

Abstract. An optimal approach reducing the population of MeV electrons in the magnetosphere is presented. Under a double resonance condition, whistler wave is simultaneously in cyclotron resonance with keV and MeV electrons. The injected whistler waves is first amplified by the background keV electrons via loss-cone negative mass instability to become effective in precipitating MeV electrons via cyclotron resonance elevated chaotic scattering. The numerical results show that a small amplitude whistler wave can be amplified by more than 25 dB. The amplification factor reduces only about 10 dB with a 30 dB increase of the initial wave intensity. Use of an amplified whistler wave to scatter 1.5 MeV electrons from an initial pitch angle of 86.5°to a pitch angle <50° is demonstrated. The ratio of the required wave magnetic field to the background magnetic field is calculated to be about 8×10−4.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Mahalanabis, Jayanti. "Determination of antiproton-neutron amplitude from elastic�p-deuteron scattering at 600 MeV/c." Zeitschrift f�r Physik A Hadrons and Nuclei 342, no. 1 (1992): 101–5. http://dx.doi.org/10.1007/bf01294494.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

41

Rudchik, A. T., A. A. Rudchik, O. O. Chepurnov, et al. "6Li(10B,9Be)7Be reaction mechanisms. Structure and interaction of 9Be + 7Be nuclei." Nuclear Physics and Atomic Energy 22, no. 3 (2021): 230–36. http://dx.doi.org/10.15407/jnpae2021.03.230.

Texte intégral

Résumé :

New experimental data of angular distributions for the 6Li(10B,9Be)7Be reaction were measured at the energy Elab(10B) = 51 MeV for the ground states of nuclei and excited 0.429 - 7.2 MeV states of 7Be. The reaction experimental data were analyzed within coupled-reaction-channels method (CRC) for many types of the nucleon and cluster transfers which spectroscopic amplitudes (factors) in the 9Be and 7Be nuclei were calculated using translation invariant shell model. The Woods - Saxon potential was used for CRC-calculations. The 6Li + 10B potential parameters were deduced before from the analysis of experimental data of 10B ions scattering by 6Li nuclei at the energy Elab(10B) = 51 MeV, and the 9Be + 7Be potential parameters for exit reaction channel were deduced from the CRC calculations fitting to the reaction experimental data. Thus, the information about the 9Be + 7Be optical potential, the basic reaction mechanisms and the 9Be and 7Be nuclei structures were deduced.

Styles APA, Harvard, Vancouver, ISO, etc.

42

AHMAD, I., and M. A. ALVI. "EIKONAL PHENOMENOLOGY FOR HEAVY-ION SCATTERING AT INTERMEDIATE ENERGIES." International Journal of Modern Physics E 13, no. 06 (2004): 1225–37. http://dx.doi.org/10.1142/s0218301304002685.

Texte intégral

Résumé :

Working within the framework of the Coulomb modified Glauber model and the optical limit approximation, we propose a phenomenological method of analysis for heavy-ion elastic scattering data at intermediate energies. Instead of using the commonly employed Gaussian approximation for the input NN amplitude that is deficient in some respects at low intermediate energies, we evaluate it in terms of a three parameter phenomenological NN phase shift function. The application of the method to some 12 C -nucleus and 16 O -nucleus systems shows that a very good description of the elastic scattering data at several energies can be obtained in this way. In particular, the 12 C –12 C elastic scattering data at 200 MeV/nucleon is very well reproduced. We also calculate the effective NN potential using the phenomenological NN phase shift function by the method of inversion. The calculated potential shows the expected behavior and is found to vary smoothly with energy.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Tonoian, D. S., A. V. Artemyev, X. J. Zhang, M. M. Shevelev, and D. L. Vainchtein. "Resonance broadening effect for relativistic electron interaction with electromagnetic ion cyclotron waves." Physics of Plasmas 29, no. 8 (2022): 082903. http://dx.doi.org/10.1063/5.0101792.

Texte intégral

Résumé :

Relativistic electron scattering by electromagnetic ion cyclotron (EMIC) waves is one of the most effective mechanisms for >1 MeV electron flux depletion in the Earth's radiation belts. Resonant electron interaction with EMIC waves is traditionally described by quasi-linear diffusion equations, although spacecraft observations often report EMIC waves with intensities sufficiently large to trigger nonlinear resonant interaction with electrons. An important consequence of such nonlinear interaction is the resonance broadening effect due to high wave amplitudes. In this study, we quantify this resonance broadening effect in electron pitch-angle diffusion rates. We show that resonance broadening can significantly increase the pitch-angle range of EMIC-scattered electrons. This increase is especially important for [Formula: see text] MeV electrons, where, without the resonance broadening, only those near the loss cone (with low fluxes) can resonate with EMIC waves.

Styles APA, Harvard, Vancouver, ISO, etc.

44

JAIN, B. K., та A. B. SANTRA. "PARAMETRIZED t-MATRIX FOR pp → n Δ++ PROCESS". International Journal of Modern Physics E 01, № 01 (1992): 201–13. http://dx.doi.org/10.1142/s0218301392000096.

Texte intégral

Résumé :

Considering that, in pp scattering, the pp → n Δ++ transition occurs mainly from the elastic channel, a t-matrix for this process was constructed by us earlier. This t-matrix describes the measured cross-sections on the p (p, n) Δ++ process very well from threshold to a few GeV. The transition potential in it is described by the one pion-exchange potential and the elastic scattering wave function through the "measured" elastic scattering amplitude. In this paper, we have parametrized this t-matrix so that it can be used for describing the (p, Δ++) reaction in nuclei. The parametrized t-matrix has been found to have a structure similar to one pion-exchange potential except that it has a softer form factor (Λ ≈ 650–800 MeV/c ) and it has a Migdal term (g′ ≈ 0.65) in the central term. The imaginary part of the t-matrix is weak. In the single scattering approximation this t-matrix describes the measured cross-sections on p(3 He , t) Δ++ and 6 Li (p, Δ++)6 He reactions very well. It is also found that with this t-matrix, the "projectile excitation" contribution to the reaction is small.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Barabash, O. "Calculation the production cross-section of the BSM boson via photon fusion reaction." Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics, no. 2 (2019): 94–97. http://dx.doi.org/10.17721/1812-5409.2019/2.12.

Texte intégral

Résumé :

The production cross-section of the beyond the standard model (BSM) scalar boson (S-boson) have been considered it the article. Scalar boson produced via photon fusion reaction in the deep inelastic scattering of a charged particle (proton or electron) on heavy nucleus of the target. This process is one of the possible mecha- nisms of BSM boson production at the SHiP (Search for Hidden Particles) experiment at the CERN LHC and may be dominating among others processes due to large nuclear charge. In a low-energy case for which virtual photon wavelength similar or bigger nuclear size one can consider nucleus as an elementary particle with the charge Z. Corresponding amplitude is proportional to Z and the cross-section proportional to Z^2. Due to this the alpha_{EM}^2 suppression of the production cross-section is approximately compensated by the charge number factor Z^2. The mass of boson cannot exceed 4 MeV for the incident proton (or less than 80 MeV for electron). We calculated amplitude and the production cross-section of this reaction directly without using equivalent photon approximation. Interaction between photon and neutral boson is described by triangular diagrams with the loop containing all charged leptons, quarks and W-bosons. For this interaction we used effective lagrangian. The found cross-section was analyzed for the case of proton scattering on the lead nucleous and compared with the production cross-section in the decay of Ds mesons. It was found that the photon fusion reaction becomes effective only with a S-boson mass less than 0.1 keV.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Nikoukar, Romina, Matthew E. Hill, Lawrence Brown, et al. "On the Energy Dependence of Galactic Cosmic Ray Anisotropies in the Very Local Interstellar Medium." Astrophysical Journal 934, no. 1 (2022): 41. http://dx.doi.org/10.3847/1538-4357/ac6fe5.

Texte intégral

Résumé :

Abstract We report on the energy dependence of Galactic cosmic rays (GCRs) in the very local interstellar medium (VLISM) as measured by the Low Energy Charged Particle (LECP) instrument on the Voyager 1 spacecraft. The LECP instrument includes a dual-ended solid-state detector particle telescope mechanically scanning through 360° across eight equally spaced angular sectors. As reported previously, LECP measurements showed a dramatic increase in GCR intensities for all sectors of the ≥211 MeV count rate (CH31) at the Voyager 1 heliopause (HP) crossing in 2012; however, since then the count rate data have demonstrated systematic episodes of intensity decrease for particles around 90° pitch angle. To shed light on the energy dependence of these GCR anisotropies over a wide range of energies, we use Voyager 1 LECP count rate and pulse height analyzer (PHA) data from ≥211 MeV channel together with lower-energy LECP channels. Our analysis shows that, while GCR anisotropies are present over a wide range of energies, there is a decreasing trend in the amplitude of second-order anisotropy with increasing energy during anisotropy episodes. A stronger pitch angle scattering at higher velocities is argued as a potential cause for this energy dependence. A possible cause for this velocity dependence arising from weak rigidity dependence of the scattering mean free path and resulting velocity-dominated scattering rate is discussed. This interpretation is consistent with a recently reported lack of corresponding GCR electron anisotropies.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Alexander, N., K. Amos, and L. Berge. "Corrigendum: Mott?Schwinger Effect in the Elastic Scattering of Neutrons from 209Bi." Australian Journal of Physics 48, no. 4 (1995): 737. http://dx.doi.org/10.1071/ph950737.

Texte intégral

Résumé :

The results presented in our recent paper are in error. All of the theoretical developments contained therein are correct but the Mott-Schwinger (MS) interaction was doubly counted for small radii in our computations. That had a significant effect upon the exact values of the small-f partial wave phase shifts. In fact, the correct variation of the first 20 partial wave phase shifts from purely nuclear scattering are much smaller than we presented before. Consequently the variation caused by the MS effect in predictions of the observables is smaller than previously indicated, and particularly so for scattering angles in excess of 20� for the cases of neutrons scattered from bismuth that were considered. At small angles, there are still characteristic and noticeable differences caused by the MS interaction for the scattering of 0�5, 14�5 and 24 MeV neutrons from 209Bi. With the differential cross section, the forward angle effect remains as shown previously; that is, dominated by the cot (~O) element in the scattering amplitudes due to the infinite partial wave sum of MS phase contributions. But the deviations to the higher angle cross sections reported earlier are very much reduced. The major effects of the correction, however, are with the predictions of the spin-dependent measureables and the exact results for P(O) and the two general variables, Xvar(O) and Yvar(O).

Styles APA, Harvard, Vancouver, ISO, etc.

48

Kim, Yong Joo, and Moon Hoe Cha. "Tangential Velocity Corrections to a Second-Order Coulomb-Modified Eikonal Model for Heavy-Ion Elastic Scattering." International Journal of Modern Physics E 12, no. 04 (2003): 479–92. http://dx.doi.org/10.1142/s0218301303001399.

Texte intégral

Résumé :

We present the tangential velocity corrections to the second-order Coulomb-modified eikonal model at the distance of closest approach. It has been applied to elastic angular distributions of the 16 O +16 O system at E lab =350 and 480 MeV. The calculated results with tangential velocity show better agreements with the experimental data compared to those with asymptotic velocity. The Fraunhöfer oscillations observed in the elastic angular distributions can be explained by the strong interference between the near- and the far-side amplitudes. Airy structures can be shown by reducing the effective imaginary potential strength. It is found that the Airy minimum is more visible as the effective imaginary potential strength is reduced. Deep real potentials associated with rather weak imaginary ones are found to be essential to describe the refractive 16 O +16 O elastic scatterings at E lab =350 and 480 MeV.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Mezhevych, S. Yu, A. T. Rudchik, K. Rusek, et al. "Reaction 14C(11B, 12C)13B at Elab(11B) = 45 MeV, interaction of 13B + 12C versus that of 10,11,12B + 12C." Nuclear Physics and Atomic Energy 23, no. 1 (2022): 12–19. http://dx.doi.org/10.15407/jnpae2022.01.012.

Texte intégral

Résumé :

New experimental data for differential cross-sections of the 14C(11B, 12C)13B reaction obtained recently at the energy Еlab(11B) = 45 MeV for the ground states of 13B and 12C were analyzed within the coupled reaction channels (CRC) method that included the 11B + 14C elastic scattering channel as well as channels for one- and two-step transfers of nucleons in the coupling scheme. The necessary 11B + 14C Woods - Saxon (WS) optical potential parameters for the entrance reaction channel were obtained from 11B elastic scattering in the previous work, while those for 12C + 13B interaction were deduced from fitting the CRC calculations to the 14C(11B, 12C)13B reaction data. Needed spectroscopic amplitudes of transferred nucleons and clusters were calculated within the translational-invariant shell model. The data are well described by the direct transfer of a proton while contributions from two-step transfers were found to be negligible. The deduced 13B + 12C WS optical potential parameters are compared with those of the 10,11,12B + 12C nuclei interactions. The effect of isotopic differences in these interactions was observed.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Tsurutani, B. T., L. D. Zhang, G. L. Mason, et al. "Particle transport in <sup>3</Sup>He-rich events: wave-particle interactions and particle anisotropy measurements." Annales Geophysicae 20, no. 4 (2002): 427–44. http://dx.doi.org/10.5194/angeo-20-427-2002.

Texte intégral

Résumé :

Abstract. Energetic particles and MHD waves are studied using simultaneous ISEE-3 data to investigate particle propagation and scattering between the source near the Sun and 1 AU. 3 He-rich events are of particular interest because they are typically low intensity "scatter-free" events. The largest solar proton events are of interest because they have been postulated to generate their own waves through beam instabilities. For 3 He-rich events, simultaneous interplanetary magnetic spectra are measured. The intensity of the interplanetary "fossil" turbulence through which the particles have traversed is found to be at the "quiet" to "intermediate" level of IMF activity. Pitch angle scattering rates and the corresponding particle mean free paths lW - P are calculated using the measured wave intensities, polarizations, and k directions. The values of lW - P are found to be ~ 5 times less than the value of lHe , the latter derived from He intensity and anisotropy time profiles. It is demonstrated by computer simulation that scattering rates through a 90° pitch angle are lower than that of other pitch angles, and that this is a possible explanation for the discrepancy between the lW - P and lHe values. At this time the scattering mechanism(s) is unknown. We suggest a means where a direct comparison between the two l values could be made. Computer simulations indicate that although scattering through 90° is lower, it still occurs. Possibilities are either large pitch angle scattering through resonant interactions, or particle mirroring off of field compression regions. The largest solar proton events are analyzed to investigate the possibilities of local wave generation at 1 AU. In accordance with the results of a previous calculation (Gary et al., 1985) of beam stability, proton beams at 1 AU are found to be marginally stable. No evidence for substantial wave amplitude was found. Locally generated waves, if present, were less than 10-3 nT 2 Hz-1 at the leading proton event edge, where dispersion effects (beaming) are the greatest, and at the point of peak proton flux, where the particle energy flux is the greatest.Key words. Interplanetary physics (energetic particles; MHD waves and turbulence) – Space plasma physics (charged particle motion and acceleration; wave-particle interactions)

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « MHV scattering amplitudes »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres