Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
 Title Keywords Abstract Author All
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
 Page 1 /100 Display every page 5 10 20 Item
 Physics , 2012, DOI: 10.1007/s00601-012-0479-y Abstract: We compare results from the traditional partial wave treatment of deuteron electro-disintegration with a new approach that uses three dimensional formalism. The new framework for the two-nucleon (2N) system using a complete set of isospin - spin states made it possible to construct simple implementations that employ a very general operator form of the current operator and 2N states.
 Physics , 1997, Abstract: The deuteron disintegration process with the emission of fast proton in the vicinity of the kinematical boundary of the reaction, when Feynman variable $x\to 2$, is studied. The consideration is fulfilled in the framework of the quark-parton model of cumulative phenomena based on perturbative QCD calculations of the corresponding quark diagrams near the thresholds, at which some quarks ("donors") in the nuclear flucton transfer all their longitudinal momenta to the distinguished active quarks and become soft. The presence of the multi-quark $6q$-configuration in a deuteron is essentially exploited in the consideration. The different versions of hadronization mechanisms of the produced cumulative quarks into cumulative particles are analyzed. It is shown that in the case of the production of cumulative protons from deuteron the hadronization through the coalescence of three cumulative quarks is favorable and leads to the $(2-x)^5$ cross section threshold behavior whereas the usual hadronization through one cumulative quark fragmentation into proton the same as the calculations predicts for the deuteron structure function $F^d_2(x)$ at $x\to 2$ in DIS processes. The results of the calculations are compared with the available experimental data.
 Physics , 1999, DOI: 10.1103/PhysRevC.59.1780 Abstract: Cross sections for the disintegration of the deuteron via neutral-current (NCD) and charged-current (CCD) interactions with reactor antineutrinos are measured to be 6.08 +/- 0.77 x 10^(-45) cm-sq and 9.83 +/- 2.04 x 10^(-45) cm-sq per neutrino, respectively, in excellent agreement with current calculations. Since the experimental NCD value depends upon the CCD value, if we use the theoretical value for the CCD reaction, we obtain the improved value of 5.98 +/- 0.54 x 10^(-45) for the NCD cross section. The neutral-current reaction allows a unique measurement of the isovector-axial vector coupling constant in the hadronic weak interaction (beta). In the standard model, this constant is predicted to be exactly 1, independent of the Weinberg angle. We measure a value of beta^2 = 1.01 +/- 0.16. Using the above improved value for the NCD cross section, beta^2 becomes 0.99 +/- 0.10.
 Physics , 2000, Abstract: We calculate P-odd difference of the total cross-sections of the deuteron disintegration by left and right polarized photons. The relative magnitude of this difference in the threshold region is about 10^{-7}. Its experimental measurement would give valuable information on the weak nucleon-nucleon interaction at short distances.
 Shung-ichi Ando Physics , 2005, Abstract: We review our recent calculations of electroweak processes involving the deuteron, based on pionless effective field theory with dibaryon fields. These calculations are concerned with neutron-neutron fusion and np -> d gamma at BBN energies.
 Physics , 2004, DOI: 10.1103/PhysRevC.69.065503 Abstract: We analyze the energy dependence for two types of parity-non-conserving (PNC) asymmetries in the reaction $\gamma D\to np$ in the near-threshold region. The first one is the asymmetry in reaction with circularly polarized photon beam and unpolarized deuteron target. The second one corresponds to those with an unpolarized photon beam and polarized target. We find that the two asymmetries have quite different energy dependence, and their shapes are sensitive to the PNC-meson exchange coupling constants. The predictions for the future possible experiments to provide definite constraints for the PNC-coupling constants are discussed.
 Physics , 2015, DOI: 10.1103/PhysRevD.92.053006 Abstract: Deuteron disintegration by charged-current neutrino (CC$\nu$) scattering offers the possibility to determine the energy of the incident neutrino by measuring in coincidence two of the three resulting particles: a charged lepton (usually a muon) and two protons, where we show that this channel can be isolated from all other, for instance, from those with a pion in the final state. We discuss the kinematics of the process for several detection scenarios, both in terms of kinematic variables that are natural from a theoretical point of view and others that are better matched to experimental situations. The deuteron structure is obtained from a relativistic model (involving an approximation to the Bethe-Salpeter equation) as an extension of a previous, well-tested model used in deuteron electrodisintegration. We provide inclusive and coincidence (semi-inclusive) cross sections for a variety of kinematic conditions, using the plane-wave impulse approximation, introducing final-state hadronic exchange terms (plane-wave Born approximation) and final-state hadronic interactions (distorted-wave Born approximation).
 Physics , 1998, Abstract: The relativistic field theory model of the deuteron (RFMD) is applied to the calculation of the astrophysical factor S_{pp}(0) for the process of the solar proton burning p + p -> D + e^+ + \nu_e and the cross sections for the disintegration of the deuteron by photons gamma + D -> n + p and anti-neutrinos \bar{\nu}_e + D -> e^+ + n + n. Our theoretical value of the astrophysical factor S_{pp}(0) = 4.02 x 10^{-25} MeV b agrees with the classical result obtained by Bahcall and Kamionkowski S_{pp}(0) = 3.89 x 10^{-25} MeV b in the potential model approach (PMA). The cross sections for the disintegration of the deuteron by photons and anti-neutrinos calculated near thresholds are in good agreement with the PMA. An extrapolation of the cross sections for energies far from thresholds is suggested and related to the inclusion of form factors describing spatial smearing of the deuteron and the NN system. The extrapolated cross section for the disintegration of the deuteron by anti-neutrinos agrees with that calculated in the PMA in the anti-neutrino energy region from threshold up to 10 MeV. The extrapolated cross section averaged over the reactor anti-neutrino energy spectrum is obtained in agreement with the experimental data. It is shown that the RFMD enables to describe elastic low-energy NN scattering in accordance with low-energy nuclear phenomenology.
 Physics , 1997, DOI: 10.1016/S0375-9474(97)88187-0 Abstract: For deuteron electroweak disintegration, parity violating effects are investigated which arise from the interference of $\gamma$ and $Z$ exchange as well as from the hadronic sector via a small parity violating component in the deuteron. The general formalism for the differential cross section and polarization observables of electromagnetic deuteron disintegration is extended to incorporate parity violating contributions. Formal expressions for the additional structure functions are derived. Results are presented for these parity violating structure functions for quasifree kinematics neglecting final state interaction and two-body effects. Both types of parity violating contributions to the asymmetry of the inclusive reaction with respect to longitudinally polarized electrons are evaluated. The one from parity violating deuteron components is negligible over the whole range of momentum transfers considered.
 Physics , 1999, Abstract: The cross sections for the M1-capture n + p -> D + gamma, the photo-magnetic and anti-neutrino disintegration of the deuteron are evaluated in the relativistic field theory model of the deuteron (RFMD). The cross section for M1-capture is evaluated by taking into account the contributions of chiral one-meson loop corrections and the Delta(1232) resonance. The cross sections for the photo-magnetic and anti-neutrino disintegration of the deuteron are evaluated by accounting for final-state interaction of the nucleon pair in the spinsinglet S-wave state. The amplitudes of low-energy elastic np and nn scattering contributing to these processes are obtained in terms of the S-wave scattering lengths and the effective ranges. This relaxes substantially the statement by Bahcall and Kamionkowski (Nucl. Phys. A625 (1997) 893) that the RFMD is unable to describe a non-zero effective range for low-energy elastic nucleon-nucleon scattering. The cross sections for the anti-neutrino disintegration of the deuteron averaged over the anti-neutrino energy spectrum agree good with experimental data.
 Page 1 /100 Display every page 5 10 20 Item

 Home Copyright © 2008-2017 Open Access Library. All rights reserved.