共查询到20条相似文献,搜索用时 15 毫秒
1.
《Nuclear Physics A》1986,451(4):701-727
The mechanism of the reaction 3He + p → p + p + d is studied by making use of the ITEP 80 cm liquid-hydrogen bubble chamber exposed to a beam of 5 GeV/c 3He nuclei. The reaction cross section is equal to 20.6 ± 0.3 mb. The phase-space regions associated with quasifree scattering (QFS) and final-state interactions (FSI) are selected. Angular, mass and momentum distributions of the reaction products are obtained in the entire kinematically allowed range. The experimental data in the QFS region are compared with theoretical calculations based on the simplest pole-diagram approximation. The 3He and deuteron wave functions (WF) correspond to the realistic RSC potential. The D-wave components of these WF are taken into account. The absolute value of the cross section and shape of the distributions are described as a whole reasonably well within the frame of the model considered in the kinematical region where FSI may be neglected. But at large spectator momenta there is an essential disagreement. The possible reasons for this are discussed. 相似文献
2.
On the basis of T invariance, it is established that the dependence of the effective cross section for a binary reaction of the a+b → c+d type on the polarization vectors of primary particles a and b determines completely the polarization vectors and spin correlations for the same particles in the inverse reaction c+d → a+b induced by collisions between unpolarized primary particles c and d. By using the formalism of helicity amplitudes, polarization effects are studied in the process p+3He → π++4He and in the inverse process π++4He → p+3He. It is shown that, in the reaction π++4He → p+3He, the spins of the final-state particles (proton and 3He nucleus) are strongly correlated. An expression for the correlation tensor is obtained for arbitrary values of the (p, 3He) emission angle. 相似文献
3.
N. B. Ladygina 《Physics of Particles and Nuclei》2014,45(1):187-189
The dd → 3He n reaction is considered at the energies between 200 and 520 MeV. The calculations are performed within relativistic multiple scattering model based on the Alt-Grassberger-Sandhas equations. The angular dependences of the differential cross section and vector and tensor analyzing powers are given in comparison with the experimental data. 相似文献
4.
《中国物理C(英文版)》2010,(9)
The measurement of parity-violating (PV) observables in few-nucleon system can shed light on our current understanding of the weak interaction between nucleons.Theoretical models describe the nucleonnucleon weak interaction at low energies use a series of undetermined parameters.Two parity violating measurements have been considered: the capture of polarized slow neutrons on hydrogen (n + p → d + γ) at Los Alamos National Laboratory for first phase and Oka Ridge National Laboratory for second phase and the helicity dependence of the deuteron photodisintegration cross section using circularly polarized photons (γ + d → n + p) at Shanghai Institute of Applied Physics.The goal of both experiments is to constraint the weak meson-nucleon couplings to a precision of 1 ×10-8 .The introduction of both experiments is presented. 相似文献
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All available data of the mirror fusion reactions D(d, n)3He and D(d, p)3H have been subjected to a new analysis in order to extract the matrix elements of all 16 transitions necessary for inclusion of alll2 waves. Their energy dependence was assumed to be governed solely by Coulomb penetrabilities. The Levenberg-Marquardt algorithm was used to fit all experimental data. The experimental data are reproduced satisfactorily. The results compare well with anR-matrix analysis and with refined resonating group calculations. No suppression of quintet entrance-state transitions and therefore no neutron suppression in polarized fusion can be derived from this analysis.This work was funded by the German Federal Ministers for Research and Technology (BMFT) under the contract numbers 06-OK-153 and 06-OK-272 相似文献
7.
LI Yong-Jiang XU Wang W.M.Snow CAI Xiao-Lu FAN Gong-Tao FAN Guang-Wei LUO Wen PAN Qiang-Yan XU Ben-Ji YANG Li-Feng YAN Zhe 《中国物理C(英文版)》2010,34(9)
The measurement of parity-violating(PV)observables in few-nucleon system can shed light on our current understanding of the week interaction between nucleons.Theoretical models describe the nucleonnucleon weak interaction at low energies use a series of undetermined parameters.Two parity violating measurements have been considered: the capture of polarized slow neutrons on hydrogen((n)+p→d+γ)at Los Alamos National Laboratory for first phase and Oka Ridge National Laboratory for second phase and the helicity dependence of the deuteron photodisintegration cross section using circularly polarized photons((γ)+d→n+p*)at Shanghai Institute of Applied Physics.The goal of both experiments is to constraint the weak meson-nucleon couplings to a precision of 1 × 10-8.The introduction of both experiments is presented. 相似文献
8.
M. P. Rekalo 《Russian Physics Journal》1986,29(10):779-783
T-odd correlations that are possible in the processes n + p d + and n + p d + e+ + ee- and that arise due to the capture of thermal neutrons are determined in terms of threshold amplitudes (for the process n + p d + @#@) or electromagnetic inelastic form factors (for the process n + p d+ e+ + ee§-). The mechanism of these reactions is not given in concrete form, but those general properties of the electromagnetic hadronic current are used that are preserved with three-dimensional reflections.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 8–13, October, 1986. 相似文献
9.
S. Pomp G. Ingelman T. Johansson S. Ohlsson 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):517-522
The observed polarisation of Λ hyperons from the inclusive pA → ΛX reaction at high energies has previously been well described within the Lund string model through polarised sˉs quark pair production in the string breaking hadronisation process. This model is here applied to the exclusive ˉpp → ˉΛΛ reaction at low energies and compared to available data sets down to an incident-beam momentum of 1.835 GeV/c. This required an extension of the diquark scattering model to involve three components: an isotropic part relevant close
to the threshold, a spectator part and a forward-scattering part as in pA → ΛX at high energies. The observed angular distributions are then reproduced and, for momentum transfers above | t'| = 0.2 GeV2, agreement with the measured polarisation is also obtained.
Received: 2 April 2002 / Accepted: 24 July 2002 / Published online: 3 December 2002
RID="a"
ID="a"Present address: Department of Neutron Research, Uppsala University, Box 525, S-75120 Uppsala, Sweden; e-mail: Stephan.Pomp@tsl.uu.se.
RID="b"
ID="b"Present address: ESRF, F-38043 Grenoble, France.
Communicated by A. Sch?fer 相似文献
10.
The spin structure of the nucleon charge-exchange process n + p → p + n is investigated. Analysis shows that the spin-dependent part of the differential cross section of the process n + p → p + n at zero angle, which is proportional to the differential cross section of the deuteron charge-exchange breakup d + p → (pp) + n in the “forward” direction, plays the predominant role in the wide range of neutron momenta. 相似文献
11.
There may be unique (“smoking-gun”) signatures of the breakdown of CPT symmetry, induced in some models of Quantum Gravity entailing decoherence for quantum matter. Such effects can be observed in entangled states of neutral mesons via modifications of the respective Einstein-Podolsky-Rosen (EPR) correlators (“ω-effect”). In the talk I discuss experimental signatures and bounds of the ω-effect in Φ- and B-factories, and argue that the effect might be falsifiable at the next generation facilities. 相似文献
12.
O. Dumbrajs W. Dutty J. Franz E. Rössle H. Schmitt L. Schmitt 《Zeitschrift für Physik A Hadrons and Nuclei》1984,316(1):43-47
Experimental values of the differential cross section for the reactionn+d→π 0+t at large angles (θ?50°) in the neutron energy range 460–560 MeV and the known values of the coupling constants \(G_{nn\pi ^O }^2 \) andG tdn 2 are used to predictdσ/dΩ at smaller angles. The method is based on the use of general analytic properties of the differential cross section in the cosgq-plane. 相似文献
13.
Berteloite C Lara M Bergeat A Le Picard SD Dayou F Hickson KM Canosa A Naulin C Launay JM Sims IR Costes M 《Physical review letters》2010,105(20):203201
We report combined studies on the prototypical S(1D2) + H2 insertion reaction. Kinetics and crossed-beam experiments are performed in experimental conditions approaching the cold energy regime, yielding absolute rate coefficients down to 5.8 K and relative integral cross sections to collision energies as low as 0.68 meV. They are supported by quantum calculations on a potential energy surface treating long-range interactions accurately. All results are consistent and the excitation function behavior is explained in terms of the cumulative contribution of various partial waves. 相似文献
14.
M. Bruno F. Cannata M. D'Agostino M. L. Fiandri M. Frisoni M. Lombardi 《Few-Body Systems》1986,1(1):63-68
Differential cross sections of the reactiond+3He3H+p+p have been measured atE
d
=23.083 MeV in two different kinematical configurations. A gas target was used in order to obtain absolute differential cross sections and two E–E telescopes allowed a very good identification of the various particles coming from thed+3He reaction. The role of the finalstate interactions and repulsive Coulomb effects appears rather distinctly. 相似文献
15.
N. A. Burkova K. A. Zhaksybekova M. A. Zhusupov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(3):411-414
Angular distributions for the 6He(p, γ0 + 1)7Li process at the energy E γ = 40 MeV are calculated within the potential cluster approach. It is shown that the observed cross section is well reproduced when E1 and E2 transitions are taken into account; in this case, unlike the case in the RGM calculations, the dominating mechanism is direct capture to the ground state of the 7Li nucleus. Total cross sections for direct photodisintegration 7Li (γ, p0)6He in the energy interval E γ = 22–30 MeV are calculated. 相似文献
16.
O. O. Beliuskina V. I. Grantsev K. K. Kisurin S. E. Omelchuk Yu. S. Roznyuk B. A. Rudenko V. S. Semenov L. I. Slusarenko B. G. Struzhko 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(7):893-899
The energy and angular distributions of deuterons from the D + D → p + n + d reaction are experimentally and theoretically studied. The experiment is conducted on the U-240 cyclotron at the Institute for Nuclear Research in an extracted beam of deuterons with energy E D = 36.9 MeV. A theoretical analysis has been performed using the microscopic diffraction nuclear model, within which the final-state interaction is considered and simple expressions for internal wave functions and approximations that include quasibinary mechanisms are employed. 相似文献
17.
I. Schulday R. Lawall J. Barth K. -H. Glander S. Goers J. Hannappel N. Jöpen F. Klein E. Klempt D. Menze E. Paul W. J. Schwille 《The European Physical Journal A - Hadrons and Nuclei》2011,47(4):1-6
The reactions γp → K+ Σ± π? were studied with the SAPHIR detector using a tagged photon beam at the electron stretcher facility ELSA in Bonn. The decays Σ ? → nπ ? and Σ + → nπ +, pπ 0 were fully reconstructed. Reaction cross-sections were measured as a function of the photon energy from threshold up to 2.6 GeV with considerably improved statistics compared to a previous bubble chamber measurement. The cross-sections rise monotonically with increasing photon energy. The two-particle mass distributions of Σ ± π ? and K + π ? show substantial production of resonant states. 相似文献
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I. I. Strakovsky 《Czechoslovak Journal of Physics》1986,36(2):225-229
Conclusion The joint efforts of the laboratories with intermediate energies accelerators at ANL, KEK, LANL, LNPI, Saclay, SIN and TRIUMF produced a rather definite picture of the
+pp reaction in the isobar region. However the problem of anomalies for the square-root branch point due to the production of isobar in the intermediate state have not been resolved so far. The poles obtained in different phenomenological analyses could be just the effective parametrization of these cuts (see e.g. [13]). Anyway, some singularities are definitely necessary to describe the data.The experimental data in regions s < 2·05 GeV and s < 2·25 GeV are clearly insufficient. Further accumulation of the data in these regions is necessary. Polarized deuteron data are badly needed in the whole kinematical range [13]. Besides as it was mentioned before it is necessary to measure accurately cross sections of other inelastic reactions which are important for the investigation (observation?) of dibaryonsNN N, NN andd N, NN [21]. It would be of interest also to measure cross sections of non quasi two-particle channels likeNN N, 2N andd N, 2N [22]. (In the case ofNN scattering quasi two-particle channels are known to dominate in a wide energy range.)Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985.I am grateful to L. A. Kondratyuk, M. G. Ryskin and M. I. Strikman for valuable discussions of the considered problems. 相似文献