Within the most recent extension of the quark-jet hadronization framework, we explore the transverse-polarization-dependent dihadron fragmentation functions (DiFFs) $H_1^\sphericalangle$ and $H_1^\perp$ of a quark into $π^+π^-$ pairs. Monte Carlo (MC) simulations are employed to model polarized quark hadronization and calculate the corresponding number densities. These, in turn, are used to extract the Fourier cosine moments of the DiFFs $H_1^\sphericalangle$ and $H_1^\perp$. A notable finding is that there are previously unnoticed apparent discrepancies between the definitions of the so-called interference DiFF (IFF) $H_1^\sphericalangle$, entering the cross sections for two-hadron semi-inclusive electroproduction, and those involved in the production of two pairs of hadrons from back-to-back jets in electron-positron annihilation. This manuscript completes the studies of all four leading twist DiFFs for unpolarized hadron pairs within the quark-jet framework, following our previous work on the helicity-dependent DiFF $G_1^\perp$.
Evolution of the parton dihadron fragmentation functions
研究了e+e-湮灭过程中夸克和胶子部分子双强子碎裂函数及其演化。我们提供了这样的双强子碎裂函数的部分子矩阵元素的定义，并推导出动量和规则及其连接到单强子碎裂函数。我们将Lund Monte Carlo模型JETSET的结果作为Q_0^2=2 GeV^2部分子双强子碎裂函数的初始条件。数值求解了夸克和胶子碎裂函数的演化方程，在不同的高尺度Q^2下的结果与JETSET的结果符合得很好。从单一的碎片功能的输入的重要性指出。
We estimate the unpolarized dihadron fragmentation functions (uDiFFs) within the framework of the single-cascade jet algorithm. We first obtain the elementary fragmentation functions generating the single hadron fragmentation functions by using the single-cascade jet algorithm. These results are very close to the empirical parametrizations of the single hadron fragmentation functions which are extracted from the experimental data of the $e^+e^-$ annihiliation and semi-inclusive deeply inelastic scatterings (SIDIS). We then use those elementary fragmentation functions to generate the dihadron f…
Probing Gluon Linear Polarization with Dihadron Fragmentation in $χ_b$ Decays
Beijing University of Chemical Technology（北京化工大学）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；China Center of Advanced Science and Technology（中国科学技术中心）；Center for High Energy Physics, Peking University（北京大学高能物理中心）
We study the dihadron fragmentation functions (DiFF) of longitudinally polarized quarks into pion pairs. The quark-jet framework is used to model the sequential hadronization of a polarized quark into hadrons, where the polarization transfer to the remnant quark in each hadron emission step is calculated using the spin density matrix formalism. Using Monte Carlo (MC) simulations of the hadronization process, we find a nonvanishing helicity dependent DiFF, $G_1^\perp$ , which is also related to the longitudinal jet handedness. A method is developed for extracting the angular moments of this DiF…
We report on the phenomenological results obtained through Dihadron Fragmentation Functions related processes. In 2015, an update on the fitting techniques for the Dihadron Fragmentation Functions has led to an improved extraction of the transversity PDF and, as a consequence, the nucleon tensor charge. We discuss the impact of the determination of the latter on search for physics Beyond the Standard Model, focusing on the error treatment. We also comment on the future of the extraction of the subleading-twist PDF $e(x)$ from JLab soon-to-be-released Beam Spin Asymmetry data.
Transverse-spin dependent energy-energy correlators in proton-proton collisions within the dihadron fragmentation framework
University of California, Los Angeles（加州大学洛杉矶分校）；Mani L. Bhaumik Institute for Theoretical Physics, University of California, Los Angeles（加州大学洛杉矶分校马尼·L·布海米克理论物理研究所）；Center for Frontiers in Nuclear Science, Stony Brook University（纽约州立大学石溪分校核科学前沿中心）；Temple University（天普大学）；Lebanon Valley College（黎巴嫩谷学院）
Dihadron fragmentation framework for near-side energy-energy correlators
University of California, Los Angeles（加州大学洛杉矶分校）；Mani L. Bhaumik Institute for Theoretical Physics, University of California, Los Angeles（加州大学洛杉矶分校马尼·L·巴乌米克理论物理研究所）；Stony Brook University（石溪大学）；Temple University（天普大学）；Lebanon Valley College（黎巴嫩谷学院）
We have calculated the unpolarized dihadron fragmentation functions (uDiFFs) of pions and kaons using the nonlocal chiral-quark model (NLChQM) and evolved our results to the transferred momentum scale Q$^2$=4$\mathrm{GeV}^2$ by the QCD evolution equations. These uDiFFs have also been computed in the Nambu--Jona-Lasinio-jet (NJL-jet) model for the sake of comparison. We find that there is substantial difference between the results of these two models. Furthermore, the DiFFs of $u\to π^{+}π^{-}$ and $g\to π^{+}π^{-}$ at $Q^2=109\,\mathrm{GeV}^2$ in these two models are presented in comparison wi…
We present preliminary results for an updated extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. Data for proton and deuteron targets by HERMES and COMPASS allow for a flavor separation of the valence components of transversity, while di-hadron fragmentation functions are taken from the semi-inclusive production of two pion pairs in back-to-back jets in $e^+ e^-$ annihilation. The latter data from Belle have been reanalyzed using the replica method and a mor…
We present a study on the double longitudinal-spin asymmetry of dihadron production in semi-inclusive deep inelastic scattering, in which the total transverse momentum of the final-state hadron pairs is integrated out. In particular, we investigate the origin of the $\cosϕ_R$ azimuthal asymmetry for which we take into account the coupling of the helicity distribution $g_1$ and the twist-3 dihadron fragmentation function $\widetilde{D}^{\sphericalangle}$. We calculate the $s$-wave and $p$-wave interference term $\widetilde{D}^{\sphericalangle}_{ot}$ in a spectator model. We estimate the $\cosϕ_…
Unveiling Light-Quark Yukawa Flavor Structure via Dihadron Fragmentation at Lepton Colliders
School of Physics, Peking University（北京大学物理学院）；School of Physics, Zhengzhou University（郑州大学物理学院）；Center for High Energy Physics, Peking University（北京大学高能物理中心）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；China Center of Advanced Science and Technology（中国高等科学技术中心）
Azimuthal correlations in two hadron production in deep inelastic scattering of unpolarized leptons off transversely polarized nucleon are discussed. Specifically, a simple approach for accessing ratios of structure functions corresponding to Sivers effect and transversity induced single spin azimuthal asymmetries to unpolarized structure functions is presented. This approach is then applied to a sample pseudo-data generated by a modified version of the LEPTO Monte Carlo event generator that includes the Sivers effect. Using this data it is shown, that the azimuthal correlations in the Sivers-…
Transverse spin correlation of back-to-back dihadron in unpolarized collisions
Institute of Frontier and Interdisciplinary Science, Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University（山东大学前沿交叉科学研究中心，粒子物理与粒子辐照教育部重点实验室）；School of Physics and Technology, University of Jinan（济南大学物理科学与技术学院）
We summarize recent results obtained thanks to the phenomenology of Dihadron Fragmentation Functions. The results include the update on the fitting techniques for both the Dihadron Fragmentation Functions themselves and the transversity PDF. The determination of the tensor charge of the nucleons as well as the impact of the latter on search for physics beyond the standard model are also discussed. So is the future extraction of the subleading-twist PDF $e(x)$ from JLab soon-to-be-released Beam Spin Asymmetry data.
We have updated our extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. The most recent COMPASS data for proton and deuteron targets, complemented by previous HERMES data on the proton, make it possible to perform a flavor separation of the valence components of the transversity distribution, using di-hadron fragmentation functions taken from the semi-inclusive production of two pion pairs in back-to-back jets in $e^+ e^-$ annihilation. The $e^+ e^-$ data fro…
We calculate the one-loop corrections to dihadron production in Deep Inelastic Scattering (DIS) at small x using the Color Glass Condensate formalism. We show that all UV and soft singularities cancel while the collinear divergences are absorbed into quark and anti quark-hadron fragmentation functions. Rapidity divergences lead to JIMWLK evolution of dipoles and quadrupoles describing multiple-scatterings of the quark anti-quark dipole on the target proton/nucleus. The resulting cross section is finite and can be used for phenomenological studies of dihadron angular correlations at small x in …
We study the single longitudinal-spin asymmetry of dihadron production in semi-inclusive deep inelastic scattering process. We consider the collinear picture in which the transverse momentum of the final-state hadron pair is integrated out, such that the $\sin ϕ_R$ azimuthal asymmetry arises from the coupling $h_L\, H_{1}^{\sphericalangle}$ as well as the coupling $g_1 \,\widetilde{G}^{\sphericalangle}$. We calculate the unknown twist-3 dihadron fragmentation function $\widetilde{G}^{\sphericalangle}$ using a spectator model which is successful in describing the dihadron production in the unpo…
We present an updated extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. Data for proton and deuteron targets make it possible to perform a flavor separation of the valence components of the transversity distribution, using di-hadron fragmentation functions taken from the semi-inclusive production of two pion pairs in back-to-back jets in e+e- annihilation. The e+e- data from Belle have been reanalyzed using the replica method and a more realistic estimate o…
Probing the Color-Octet Mechanism via Dihadron Fragmentation in $χ_b$ Decays
Beijing University of Chemical Technology（北京化工大学）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；China Center of Advanced Science and Technology（中国高等科学技术中心）；Center for High Energy Physics, Peking University（北京大学高能物理中心）
Dihadron azimuthal asymmetry and light-quark dipole moments at the Electron-Ion Collider
School of Physics, Peking University（北京大学物理学院）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；China Center of Advanced Science and Technology（中国科学技术大学北京校区）；Center for High Energy Physics, Peking University（北京大学高能物理中心）；Theory Center, Jefferson Lab（杰斐逊实验室理论中心）；High EnergyTheory Group, Physics Department,Brookhaven National Laboratory（布鲁克海文国家实验室物理系高能理论组）；Department of Physics and Astronomy, Michigan State University（密歇根州立大学物理与天文学系）
The correlation between the longitudinal polarization of a fragmenting quark and the transverse momenta of the produced hadrons was predicted over two decades ago. Nevertheless, experimental searches in the electron-positron annihilation process, both through the so-called jet handedness measurements by the {\tt SLD} Collaboration and more recently via the measurements of the azimuthal asymmetry containing the helicity-dependent dihadron fragmentation function (DiFF) by the $\textrm{BELLE}$ Collaboration, did not yield a signal. We will first discuss our recent explanation of the zero result a…
The longitudinal spin transfer represents the probability density of producing longitudinally polarized hadrons from longitudinally polarized quarks or circularly polarized gluons. It thus was usually measured in polarized reactions or high-energy collisions where weak interaction dominates. In this work, we propose the dihadron polarization correlation as a novel probe of this quantity. Such an observable does not require the fragmenting partons to be polarized and therefore can be measured in the currently available experimental facilities, such as Belle, RHIC, Tevatron, and the LHC. We make…
