Chimera distribution amplitudes for the pion and the longitudinally polarized $ρ$-meson
N. G. Stefanis, A. V. Pimikov
备注:
13 pages, 4 figures. In v2 a typo in Eq. (12) corrected. V3 contains clarifications in text; typos corrected; Table expanded; new references included and discussed; conclusions unchanged; matches version to be published in Nucl. Phys. A. V4: typos in AdS/QCD entries in Table I and in text, bottom of page 5, corrected. In v6 typo in expression for gauge link below Eq. (1) corrected
发表信息:
Nuclear Physics, Section A, Volume/issue: 945C (2016) pp. 248-268
Using QCD sum rules with nonlocal condensates, we show that the distribution amplitude of the longitudinally polarized $ρ$-meson may have a shorttailed platykurtic profile in close analogy to our recently proposed platykurtic distribution amplitude for the pion. Such a chimera distribution de facto amalgamates the broad unimodal profile of the distribution amplitude, obtained with a Dyson-Schwinger equations-based computational scheme, with the suppressed tails characterizing the bimodal distribution amplitudes derived from QCD sum rules with nonlocal condensates. We argue that pattern formation, emerging from the collective synchronization of coupled oscillators, can provide a single theoretical scaffolding to study unimodal and bimodal distribution amplitudes of light mesons without recourse to particular computational schemes and the reasons for them.
Previous Lattice QCD calculations of nucleon transverse momentum-dependent parton distributions (TMDs) focused on the case of transversely polarized nucleons, and thus did not encompass two leading-twist TMDs associated with longitudinal polarization, namely, the helicity TMD and the worm-gear TMD corresponding to transversely polarized quarks in a longitudinally polarized nucleon. Based on a definition of TMDs via hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections, TMD observables characterizing the aforementioned two TMDs are evaluated, utilizing a…
We investigate the quark Wigner distributions of the pion to reveal the multidimensional picture of pion. We have used the spin improved wave functions of pion deduced from the light-front holographic model of mesons. By using the Fock-state overlap representation, the Wigner distributions of an unpolarized, longitudinally polarized and transversely polarized quark inside the pion are calculated. We have presented the results of transverse Wigner distributions in impact-parameter space as well as in momentum space. In order to understand the role of skewness which gives the longitudinal moment…
We study the quark Wigner distributions of the pion meson which are the phase-space distributions containing the most general one-parton information.Using the pion wavefunctions deduced from a light-cone quark model, we calculate the Wigner distributions of the unpolarized, longitudinally polarized and transversely polarized quarks inside the pion meson via the Fock-state overlap representation, respectively.We present the numerical results of the transverse Wigner distributions in which the longitudinal momentum fraction is integrated out. The mixed Wigner distributions as functions of $b_y$ …
Understanding the proton spin composition from the quarks and gluons spin polarization and their motion is important to test various kinds of sum rules and nonperturbative properties of hadrons. At the Relativistic Heavy Ion Collider (RHIC), we collide longitudinally polarized proton beams and measure the double helicity asymmetry $A_{LL}$, which is an important physical quantity for extracting the polarized parton distribution functions (PDFs) of the proton. Direct photon, jet and charged pion production are good channels to probe the gluon spin polarization inside the proton, with the abilit…
We present the first lattice QCD calculation of the distribution amplitudes of longitudinally and transversely polarized vector mesons $K^*$ and $ϕ$ using large momentum effective theory. We use the clover fermion action on three ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ) action, generated by MILC collaboration, at physical pion mass and \{0.06, 0.09, 0.12\} fm lattice spacings, and choose three different hadron momenta $P_z=\{1.29, 1.72, 2.15\}$ GeV. The resulting lattice matrix elements are nonperturbatively renormalized in a hybrid scheme proposed recently. An e…
$q \to Λ$ Fragmentation Function and Nucleon Transversity Distribution in a Diquark Model
基于一个简单的夸克-双夸克模型,通过拟合$e^+ e ^- $湮灭过程中的非极化$Λ$产生数据,提出了一组非极化、纵向极化和横向极化的$Λ$碎裂函数.结果发现,螺旋度结构的$Λ$碎裂功能的支持所有可用的实验数据的纵向$Λ$极化。在双夸克模型的同一框架内,核子的横向分布和一致的描述的方位角自旋不对称性的π电产生的HERMES数据。此外,还预测了横向极化核子靶上带电轻子DIS中横向极化$Λ$的自旋转移。
We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic $^{14}$NH$_3$ target, and extracted double and single target spin asymmetries for $ep\rightarrow e^\primeπ^0X$ in multidimensional bins in four-momentum transfer ($1.0<Q^2<3.2$ GeV$^2$), Bjorken-$x$ ($0.12<x<0.48$), hadron energy fraction ($0.4<z<0.7$), transverse pion …
A lattice QCD determination of the $Λ_c \to N$ vector, axial vector, and tensor form factors is reported. The calculation was performed with $2+1$ flavors of domain wall fermions at lattice spacings of $a\approx 0.11\:{\rm fm},\:0.085\:{\rm fm}$ and pion masses in the range $230\:{\rm MeV} \lesssim m_π\lesssim 350$ MeV. The form factors are extrapolated to the continuum limit and the physical pion mass using modified $z$ expansions. The rates of the charged-current decays $Λ_c \to n\, e^+ ν_e$ and $Λ_c \to n\, μ^+ ν_μ$ are predicted to be $\left( 0.405 \pm 0.016_{\,\rm stat} \pm 0.020_{\,\rm s…
Probing hard/soft factorization via beam-spin asymmetry in exclusive pion electroproduction from the proton
University of Regina(里贾纳大学);Thomas Jefferson National Accelerator Facility(托马斯·杰斐逊国家加速器设施);Catholic University of America(美利坚天主教大学);University of York(约克大学);Florida International University(佛罗里达国际大学);Ohio University(俄亥俄大学);Research Institute of Basic Sciences, Korea Aerospace University(韩国航空大学基础科学研究院);Department of Physics, Yonsei University(延世大学物理系)
Toward Precision Helicity PDFs from Global DIS and SIDIS Fits with Projected EIC Measurements
AGH University(AGH科技大学);School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM)(基本科学研究所粒子与加速器学院);Institut für Theoretische Physik, Universität Münster(明斯特大学理论物理研究所);Istituto Nazionale di Fisica Nucleare, Gruppo collegato di Cosenza(意大利国家核物理研究所科森扎协作组);Helmholtz-Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn(波恩大学斯特拉斯曼和核物理亥姆霍兹研究所及贝特理论物理中心);Institute for Advanced Simulation (IAS-4), Forschungszentrum Jülich(于利希研究中心先进模拟研究所(IAS-4));Peng Huanwu Collaborative Center for Research and Education, International Institute for Interdisciplinary and Frontiers, Beihang University(北京航空航天大学国际交叉前沿研究院彭桓武教研合作中心)