共查询到20条相似文献,搜索用时 10 毫秒
1.
Estimates for electroproduction of pseudoscalar mesons at small values of skewness are presented. Cross-sections and asymmetries
for these processes are calculated within the handbag approach which is based on factorization in hard parton subprocesses
and soft generalized parton distributions (GPDs). The latter are constructed from double distributions. Transversity GPDs
are taken into account; they are accompanied by twist-3 meson wave functions. For most pseudoscalar-meson channels a combination
of ˜T and [`(E)]T \bar{{E}}_{T}^{} plays a particularly prominent role. This combination of GPDs, which we constrain by moments obtained from lattice QCD, leads,
with the exception of the p+ \pi^{+}_{} and h¢ \eta^{\prime}_{} channels, to large transverse cross-sections. 相似文献
2.
R. M. Davidson 《Czechoslovak Journal of Physics》1994,44(4-5):365-403
The lecture provides an elementary introduction to photo and electroproduction of pseudoscalar mesons in the resonance region. After discussing the general structure of the elementary production amplitude and its symmetry properties the formalism is applied to some interesting physical problems.Lecture presented at the Indian-Summer School on Interaction in Hadronic Systems, Praha (The Czech Republic), 25–31 August 1993.I would like to thank the organizers of the school for the invitation and congratulate them on the success of the school. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 201). 相似文献
3.
Eta photo- and electroproduction off the nucleon is investigated in an effective lagrangian approach that contains Born terms and both vector meson and nucleon resonance contributions. In particular, we review and develop the formalism for coincidence experiments with polarization degrees of freedom. The different response functions appearing in single and double polarization experiments have been studied. We will present calculations for structure functions and kinematical conditions that are most sensitive to details of the lagrangian, in particular with regard to contributions of nucleon resonances beyond the dominantS
11(1535) resonance.This work has been supported by the Deutsche Forschungsgemeinschaft (SFB 201) 相似文献
4.
J. Bartels M.A. Braun D. Colferai G.P. Vacca 《The European Physical Journal C - Particles and Fields》2001,20(2):323-331
Using a set of new odderon states, we calculate their contribution to the diffractive photo- and electroproduction process. Compared to previous simple 3-gluon exchange calculations we find an enhancement of
about one order of magnitude in the cross section. The t-dependence of the cross section exhibits a dip structure in the small t region.
Received: 18 March 2001 / Published online: 11 May 2001 相似文献
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Assuming the proton's light-cone wave function to be dominated by small parton virtualities and small intrinsic transverse
momenta, we show that the electroproduction amplitudes at large momentum transfer factorize into parton-level subprocess amplitudes
and form factors representing 1/x-moments of skewed parton distributions. On the basis of a wave function overlap model for the form factors we present detailed
predictions for the electroproduction cross sections. We also comment on large momentum transfer photoproduction.
Received: 9 June 2000 / Revised version: 27 July 2000 / Published online: 25 September 2000 相似文献
7.
We report the results of form factors, charge radii and decay constants of both light and heavy flavoured pseudoscalar mesons
in a QCD inspired quark model. We use the quantum mechanical perturbation theory and discuss its limitations in the present
problem. Several predictions are also made for bottom and top flavours. 相似文献
8.
Zeitschrift für Physik C Particles and Fields - In this paper, we study the pseudoscalar-scalar meson (PS) weak decays ofD-mesons in the non-relativistic quark model using factorization... 相似文献
9.
The data collected by the KLOE Collaboration at the Frascati φ-factory DAФNE from 2001 to 2006 have been used for extensive studies in meson spectroscopy. The decays of the scalar mesons a0(980) and f0(980) into two pseudoscalar mesons have been exploited to measure the relevant parameters of those resonances. The radiative decays φ →ηγ and η'γ have been used for the determination of the pseudoscalar mixing angle and to search for a possible gluonium content in the η'. The dynamics of the η → 3π decay has been studied and the Dalitz Plot parameters have been measured. The large amount of η mesons produced allowed also to study interesting rare η decays. 相似文献
10.
P.Gauzzi 《中国物理C(英文版)》2010,34(6)
The data collected by the KLOE Collaboration at the Frascati φ-factory DAΦNE from 2001 to 2006 have been used for extensive studies in meson spectroscopy.The decays of the scalar mesons a0(980) and f0(980) into two pseudoscalar mesons have been exploited to measure the relevant parameters of those resonances.The radiative decays φ→ηγ and ηγ have been used for the determination of the pseudoscalar mixing angle and to search for a possible gluonium content in the η.The dynamics of the η→ 3π decay has been studied and the Dalitz Plot parameters have been measured.The large amount of η mesons produced allowed also to study interesting rare η decays. 相似文献
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R. Decker E. Mirkes R. Sauer Z. Was 《Zeitschrift fur Physik C Particles and Fields》1993,58(3):445-451
In this paper we compute the branching ratios of the tau decays into three mesons. The hadronic matrix elements are obtained by first using the structure of the chiral currents and that of the Wess-Zumino anomaly and finally implementing all possible low-lying resonances in the different channels. 相似文献
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The P/V ratio of directly produced pseudoscalar (P) to vector (V) mesons is analysed using the data on the K0S and K*(892) total inclusive cross sections in pp, π+p and K±p reactions. The indication for a change of P/V from a value of about 1 at low energies, where the fragmentation processes dominate, to a value of 1/3, suggested by spin-statistics, at high energies is discussed. 相似文献
16.
The paper considers the processes of formation of pseudoscalar mesons by the interaction of an antineutrino with a leptonv
ll K, , K.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 139–143, August, 1974. 相似文献
17.
Abdul Ebrahim 《Physics letters. [Part B]》1977,70(4):421-424
Assuming that quark flavors beyond isospin, strangeness, and charm exist, we use the relationship between the structure of chiral symmetry breaking of the strong interaction and the Cabibbo angle in order to estimate the masses of the pseudoscalar and vector mesons carrying the fifth (beauty), sixth (truth), and seventh (illusion) quark flavors. 相似文献
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R. Enberg B. Pire L. Szymanowski 《The European Physical Journal C - Particles and Fields》2006,47(1):87-94
The chiral-odd generalized parton distribution (GPD), or transversity GPD, of the nucleon can be accessed experimentally through
the photoproduction or electroproduction of two vector mesons on a polarized nucleon target, γ(*)N→ρ1ρ2N’, where ρ1 is produced at large transverse momentum, ρ2 is transversely polarized, and the mesons are separated by a large rapidity gap. We predict the cross section for this process
for both transverse and longitudinal ρ2 production. To this end, we propose a model for the transversity GPD HT(x,ξ,t) and give an estimate of the relative sizes of the transverse and longitudinal ρ2 cross sections. We show that a dedicated experiment at high energy should be able to measure the transversity content of
the proton. 相似文献
20.
We investigate the weak leptonic decays of light and heavy pseudoscalar mesons in a relativistic quark model of independent
quarks. We perform a static calculation of the decay constantf
M purely on grounds of simplicity. In order to minimize the possible uncertainty in the static calculation, we estimate the
ratios of the decay constants which are found to be in good agreement, in the heavy flavor sector, with the predictions of
other models available in the literature and existing experimental data. However, there is a noticeable discrepancy in the
current prediction for pion decay constant which demonstrates the inherent limitations of the static approximation in the
study of non-strange light mesons. 相似文献