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1.
An explicit evaluation of the spin asymmetry of the deuteron and the associated Gerasimov-Drell-Hearn sum rule is presented which includes photodisintegration, and single and double pion and eta production as well. Photodisintegration is treated with a realistic retarded potential and a corresponding meson exchange current. For single pion and eta production the elementary operator from MAID is employed, whereas for double pion production, an effective Lagrangian approach is used. A large cancellation between the disintegration and the meson production channels yields for the explicit GDH integral a value of 27.31 microb to be compared to the sum rule value 0.65 microb. 相似文献
2.
Amarian M Auerbach L Averett T Berthot J Bertin P Bertozzi W Black T Brash E Brown D Burtin E Calarco JR Cates GD Chai Z Chen JP Choi S Chudakov E Cisbani E De Jager CW Deur A DiSalvo R Dieterich S Djawotho P Finn M Fissum K Fonvieille H Frullani S Gao H Gao J Garibaldi F Gasparian A Gilad S Gilman R Glamazdin A Glashausser C Goldberg E Gomez J Gorbenko V Hansen JO Hersman FW Holmes R Huber GM Hughes EW Humensky TB Incerti S Iodice M Jensen S Jiang X Jones C Jones GM Jones M Jutier C Ketikyan A 《Physical review letters》2002,89(24):242301
We present data on the inclusive scattering of polarized electrons from a polarized 3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5 degrees. Our data include measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference sigma(1/2)-sigma(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q2 of 0.1-0.9 GeV2. 相似文献
3.
Miroslav Pardy 《International Journal of Theoretical Physics》1973,8(1):31-37
The Feynman integral is generalised so as to involve the fluctuations of vacuum, from this integral the generalised Schrödinger equation is derived and the energy spectrum for the Coulomb potential determined. 相似文献
4.
M. Modarres M. M. Yazdanpanah F. Zolfagharpour 《The European Physical Journal A - Hadrons and Nuclei》2007,32(3):327-333
The electromagnetic polarizabilities of the nucleon are shown to be essentially composed of the nonresonant α
p(E
0+) = + 3.2, α
n(E
0+) = + 4.1, the t-channel α
t
p, n = - β
t
p, n = + 7.6 and the resonant β
p, n(P
33(1232)) = + 8.3 contributions (in units of 10-4fm^3). The remaining deviations from the experimental data Δα
p = 1.2±0.6, Δβ
p = 1.2±0.6, Δα
n = 0.8±1.7 and Δβ
n = 2.0±1.8 are contributed by a larger number of resonant and nonresonant processes with cancellations between the contributions.
This result confirms that dominant contributions to the electric and magnetic polarizabilities may be represented in terms
of two-photon coupling to the σ-meson having the predicted mass m
σ
= 666MeV and two-photon width Γ
γγ
= 2.6keV. 相似文献
5.
6.
The processes of deuteron photodisintegration by a gamma-quantum and the radiative capture of a neutron by a proton with the emission of a gamma-quantum are considered. Interaction between nucleons is described by a nonlocal potential of the Yamaguchi type but allowing for repulsion due to the nucleon cores. In contrast to other potentials, the Schroedinger equation is solved exactly for the proposed potential. The potential is more exactly defined in comparison with the previously obtained values for the parameters; information on this potential is important in solving certain fundamental problems in nuclear theory. The effective cross sections for photodisintegration of a deuteron and for radiative capture are computed. Calculations show that the proposed potential makes it possible to describe the photodisintegration processes quite accurately for intermediate (up to 20 MeV) energies. The cross section computed for radiative capture is in somewhat better agreement with experiment than is the same cross section determined for other potentials. 相似文献
7.
F. Gray 《The European physical journal. Special topics》2008,162(1):231-237
By measuring the lifetime of the negative muon in pure protium (1H), the MuCap experiment determines the rate of muon capture on the proton, from which the proton’s pseudoscalar coupling
g
p
may be inferred. A precision of 15% for g
p
has been published; this is a step along the way to a goal of 7%. This coupling can be calculated precisely from heavy baryon
chiral perturbation theory and therefore permits a test of QCD’s chiral symmetry. Meanwhile, the MuSun experiment is in its
final design stage; it will measure the rate of muon capture on the deuteron using a similar technique. This process can be
related through pionless effective field theory and chiral perturbation theory to other two-nucleon reactions of astrophysical
interest, including proton-proton fusion and deuteron breakup.
for the MuCap [1] and MuSun [2] Collaborations 相似文献
8.
William M. Morse 《Hyperfine Interactions》2011,199(1-3):93-101
I discuss the progression of ideas over the last decade that has led to extremely sensitive dedicated electric dipole moment (edm) storage ring designs. These ideas grew out of our experience in BNL E821: a precision measurement of the anomalous magnetic moment of the muon (Bennett et al. Phys Rev D73:072003, 2006). 相似文献
9.
The relation between the generalised Eshelby integral and the generalised BCS and DB modelsvspace1mm 下载免费PDF全文
The generalised BCS dislocation group model and the generalised DB atomic cohesive force zone model have obtained the same results on nonlinear fracture study of some one-, two- and three-dimensional quasicrystals. This work reveals some inherent connection between the two models, and finds that their common basis is the generalised Eshelby integral based on the generalised Eshelby energy--momentum tensor for quasicrystals. Further applications of the theory in solving nonlinear fracture problems of the materials are also discussed. 相似文献
10.
Lundin M Adler JO Boland M Fissum K Glebe T Hansen K Isaksson L Kaltschmidt O Karlsson M Kossert K Levchuk MI Lilja P Lindner B L'vov AI Nilsson B Oner DE Poech C Proff S Sandell A Schröder B Schumacher M Sims DA 《Physical review letters》2003,90(19):192501
Differential cross sections for Compton scattering from the deuteron were measured at MAX-Lab for incident photon energies of 55 and 66 MeV at nominal laboratory angles of 45 degrees, 125 degrees, and 135 degrees. Tagged photons were scattered from liquid deuterium and detected in three NaI spectrometers. By comparing the data with theoretical calculations in the framework of a one-boson-exchange potential model, the sum and the difference of the isospin-averaged nucleon polarizabilities, alpha(N)+beta(N)=17.4+/-3.7 and alpha(N)-beta(N)=6.4+/-2.4 (in units of 10(-4) fm(3)), have been determined. By combining the latter with the global-averaged value for alpha(p)-beta(p) and using the predictions of the Baldin sum rule for the sum of the nucleon polarizabilities, we have obtained values for the neutron electric and magnetic polarizabilities of alpha(n)=8.8+/-2.4(total)+/-3.0(model) and beta(n)=6.5-/+2.4(total)-/+3.0(model), respectively. 相似文献
11.
2D deuteron exchange NMR and 87Rb spin-lattice relaxation time measurements in proton and deuteron glasses show that the O-H..O dipoles are not completely frozen out at low temperatures but show dynamic features characteristic of incoherent tunneling. RADP and DRADP are thus quantum glasses. 相似文献
12.
13.
《Physics letters. [Part B]》1988,208(2):175-180
We present a phenomenological model for the spin-dependent structure functions g1(x) of the proton and neutron. The model is an extension of the one proposed by Carlitz and Kaur. We use improved unpolarized structure functions and include effects due to the mass difference between up and down quark and due to the mass difference between spin and baryons. Our results for the proton agree with the data. 相似文献
14.
S. Simula 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):603-605
We summarize the results of a recent global analysis of proton and deuteron F2 structure function world data performed over a large range of kinematics, including recent measurements done at JLab with
the CLAS detector. From these data the lowest moments (n≤10) of the unpolarized structure functions are determined with good statistics and systematics. The Q2 evolution of the extracted moments is analyzed in terms of an OPE-based twist expansion, taking into account soft-gluon effects
at large x. A clean separation among the leading- and higher-twist terms is achieved. By combining proton and deuteron measurements
the lowest moments of the neutron F2 structure function are determined and its leading-twist term is extracted. Particular attention is paid to nuclear effects
in the deuteron, which become increasingly important for the higher moments. Our results for the non-singlet, isovector (p-n) combination of the leading-twist moments are used to test recent lattice simulations. We also determine the lowest few moments
of the higher-twist contributions, and find these to be approximately isospin independent, suggesting the possible dominance
of ud correlations over uu and dd in the nucleon. 相似文献
15.
16.
A. N. Prokofiev C. E. Allgower L. S. Azhgirej J. Ball M. Beddo Y. Bedfer A. Boutefnouchet J. Bystricky Ph. Demierre J. -M. Fontaine V. Ghazikhanian D. Grosnick Z. Janout Z. F. Janout V. A. Kalinnikov T. E. Kasprzyk B. A. Khachaturov R. Kunne F. Lehar A. de Lesquen D. Lopiano V. N. Matafonov I. L. Pisarev N. M. Piskunov A. A. Popov D. Rapin J. -L. Sans H. M. Spinka G. D. Stoletov S. Trentalange Yu. A. Usov V. V. Vikhrov B. Vuaridel C. A. Whitten A. A. Zhdanov 《Czechoslovak Journal of Physics》1999,49(2):29-36
Method and results of the beam polarization measurements are presented. The measurements were carried out at the proton polarized beam of Saturne-II accelerator as well as at the JINR (Dubna) synchrophasotron vector polarized deuteron beam. The analysis of the elastic (quasi-elastic) pp-scattering polarization is used as a method of the polarization measurements. The energy range of the measurement is 1.0≤T p ≤2.8 GeV for polarized proton and 1.66≤T d ≤7.3 GeV for polarized deuteron beams. 相似文献
17.
18.
Miller GA 《Physical review letters》2007,99(11):112001
A model-independent analysis of the infinite-momentum-frame charge density of partons in the transverse plane is presented for the nucleon. We find that the neutron-parton charge density is negative at the center, so that the square of the transverse charge radius is positive, in contrast with many expectations. Additionally, the proton's central d quark charge density is larger than that of the u quark by about 30%. The proton (neutron) charge density has a long range positively (negatively) charged component. 相似文献
19.
G. Raimann 《Zeitschrift für Physik A Hadrons and Nuclei》1993,347(1):73-74
Reaction rates are calculated for recently available low-energy data on7Li(p,α)4He,6Li(p,3He)4He and6Li(d,α)4He and compared to literature values. While the new rates are considered to be more accurate, their absolute magnitude agrees within about 10% with the most recent compilation. 相似文献
20.
A. M. Gorbatov P. V. Komarov P. Yu. Nikishov A. V. Germanov D. V. Nechaev 《Physics of Atomic Nuclei》2001,64(2):228-232
Low-energy neutron-deuteron scattering is calculated within the collective adiabatic approach by using a few versions of realistic NN interaction. The resulting integrated cross sections for the process are in good agreement with experimental data. 相似文献