We present pion and kaon parton distribution functions from a global QCD analysis of the experimental data within the framework of dynamical parton model. We use the DGLAP equations with ...parton–parton recombination corrections and the valence input of uniform distribution which maximizes the information entropy. At our input scale
Q
0
2
, there are no sea quark and gluon distributions. All the sea quarks and gluons of the pion and the kaon are completely generated from the parton splitting processes. The mass-dependent parton splitting kernel is applied for the strange quark distribution in the kaon. The obtained valence quark and sea quark distributions at high
Q
2
(
Q
2
>
5
GeV
2
) are compatible with the existed experimental measurements. Furthermore, the asymptotic behaviours of parton distribution functions at small and large
x
have been studied for both the pion and the kaon. Lastly, the first three moments of parton distributions at high
Q
2
scale are calculated, which are consistent with other theoretical predictions.
We present the polarized parton distribution functions from a QCD analysis of the worldwide polarized deep inelastic scattering data, based on the dynamical parton distribution model. All the sea ...quarks and gluons are dynamically generated from QCD radiations, with the nonperturbative input comprising only the polarized valence quark distributions. This approach leads to a simple parametrization, which has only seven free parameters. In the analysis, we apply the DGLAP equations with parton-parton recombination corrections. For the first step, the DGLAP equations, parton-parton recombination corrections, and experimental observable g1 are all evaluated at the leading order. The parameterized nonperturbative input at an extremely low Q02 reproduces well the spin-dependent structure functions measured at high Q2. Comparisons with experimental observations and some other polarized parton distribution functions are also shown. Our results are in good agreement with the experimental data and consistent with some other parameterized models. Furthermore, our analysis presents the positive polarized gluon distribution and it suggests that the gluon distribution plays an important role to the proton spin content. The polarized antiquark distributions are non-zero at high Q2 but quite small compared to polarized valence quark distributions, based on this dynamical parton model analysis. This analysis gives smaller statistical uncertainties for the polarized sea quark and gluon distributions, thanks to the fewer free parameters used for the parametrization of the initial polarized PDFs.
We present the gluon distribution functions of the pion and kaon in small-
x
and large-
x
regions, and compare them with the results obtained from lattice QCD and continuum Schwinger function ...methods. Whether in the small-
x
region or the large-
x
region, our gluon distribution of the pion is consistent with the results of lattice QCD and continuum Schwinger function methods. We also calculate the first four moments of gluon distributions of the pion and kaon at different
Q
2
scales. In addition, we present the mass decomposition of the pion and kaon with the dynamical parton distribution functions calculated by the DGLAP equation with parton–parton recombination corrections. The mass structures of the pion and kaon are completely different from that of the proton.
Valence quark distributions of pion at very low resolution scale Q02∼0.1 GeV2 are deduced from a maximum entropy method, under the assumption that pion consists of only a valence quark and a valence ...anti-quark at such a low scale. Taking the obtained initial quark distributions as the nonperturbative input in the modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (with the GLR-MQ-ZRS corrections) evolution, the generated valence quark distribution functions at high Q2 are consistent with the measured ones from a Drell-Yan experiment. The maximum entropy method is also applied to estimate the valence quark distributions at relatively higher Q2=0.26GeV2. At this higher scale, other components (sea quarks and gluons) should be considered in order to match the experimental data. The first three moments of pion quark distributions at high Q2 are calculated and compared with the other theoretical predictions.
Electron-ion collider in China Anderle, Daniele P.; Bertone, Valerio; Cao, Xu ...
Frontiers of physics,
12/2021, Letnik:
16, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion ...collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a po- larization of 80%) and protons (with a polarization of 70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2-3)×10 33 cm −2*s −1. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC.
The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies.
This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China.
We calculate the valence quark distribution functions of the π meson using the non-relativistic chiral constituent quark model. The π wave function is obtained by solving the two-body Schrödinger ...equation within the framework of constituent quark model. We transform the π wave function from the rest frame to the light cone or infinite momentum frame based on the Lorentz boost. The valence quark distributions at the initial evolution scale are obtained. The QCD evolution is given with the DGLAP equations with parton-parton recombination corrections. With tuning the valence up (down) quark mass to 70 MeV, the calculated valence up quark distributions at Q2=20 GeV2 are in good agreement with the E615 experimental data. The structure functions F2π(x,Q2) of pion are also calculated which consist with the H1 experimental data. The proposed mechanisms here could be also used to study other hadrons.
We report the first results on collision energy and particle mass dependence of directed flow v 1 of light- and hyper-nuclei in mid-central Au+Au collisions at center of mass energies per nucleon ...pair of 3.0, 3.2, 3.5, and 3.9 GeV. All data have been collected by the STAR experiment in the fixed-target mode during the second phase of the RHIC beam energy scan. The mid-rapidity v 1 slope, dv 1 / dy | y =0 , of hyper-nuclei shows a similar energy and particle mass dependence to that of light-nuclei. The results suggest that the coalescence mechanism plays a dominant role in the formation of light- and hyper-nuclei.
Capsicum annuum is one of the oldest domesticated crops in the Americas, which is also the most widely grown spice crop in the world. The complete chloroplast genome of C. annuum has been assembled ...and annotated in this paper. Its length was 156,781 bp, containing a large single-copy region of 87,367 bp, a small single-copy region of 17,850 bp, and a pair of IR regions of 25,782 bp in each. The whole chloroplast genome of C. annuum contains 135 genes, including 89 protein-coding genes (PCGs), 38 transfer RNA genes (tRNAs), and 8 ribosome RNA genes (rRNAs). The overall nucleotide composition is: A of 30.8%, T of 31.5%, C of 19.1% and G of 18.6%, with a total GC content of the chloroplast genome 37.7% and AT of 62.3%. Phylogenetic relationship analysis was based on 10 plant species using the maximum-likelihood (ML) methods, which showed that the position of C. annuum clustered with C. galapagoense.
Recent heavy-ion collision experiments reported a surprisingly short lifetime for the hypertriton, which has been recognized as the hypertriton lifetime puzzle. Our J-PARC E73 experiment contributes ...to solve this puzzle with an independent experimental method by employing
3
He(
K
−
,
π
0
)
3
Λ
H reaction. In this contribution, we will demonstrate our capability to provide
3
Λ
H binding energy information by deriving the production cross section ratio,
σ
3
Λ
H
/
σ
4
Λ
H
. The production cross section data for
3
Λ
H and
4
Λ
H are already available as the pilot run of E73 experiment and data analysis is in progress.
The interaction of vector meson with nucleon, vector meson-nucleon scattering length
|
α
VN
|
, is an important component of the study of hadronic interactions. Nowadays many scattering length values ...have been reported using the recent photoproduction experiment data or quasidata. In addition, the study of trace anomalous energy contribution to the proton mass is also a hot topic in non-perturbative QCD and hadron physics. In this work, we established the relationship between the scattering length of the vector meson-proton
|
α
Vp
|
and the trace anomaly contribution of the proton mass
T
A
. With the scattering length values extracted by using the Vector Meson Dominance model, we obtained the trace anomaly contribution of the proton mass
T
A
= (19.0
%
± 0.8
%
), which is of similar order of magnitude as the 23
%
given by Lattice QCD calculation.
PDF
