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Related papers: Spin alignment of vector meson in e+e- annihilatio…

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The large statistics of millions of hadronic Z0 decays, accumulated by the four LEP experiments between 1989 and 1995, allowed for detailed investigations of the fragmentation process. Inclusive Lambda_b baryons and Lambda hyperons at…

High Energy Physics - Experiment · Physics 2007-05-23 Thomas Kress

We calculate the process-independent fragmentation functions for a $\bar b$ antiquark to fragment into longitudinally and transversely polarized $B_c^*$ ($^3S_1$) mesons to leading order in the QCD strong coupling constant. In the special…

High Energy Physics - Phenomenology · Physics 2011-01-27 Kingman Cheung , Tzu Chiang Yuan

We discuss the consequence of global polarization of the produced quarks in non-central heavy-ion collisions on the spin alignment of vector mesons. We show that the alignment is quite different for different hadronization scenarios. These…

Nuclear Theory · Physics 2014-11-18 Zuo-Tang Liang , Xin-Nian Wang

We present the results of an O(alpha_s) calculation of the transverse polarization of top quarks produced in e+e- annihilation. In a first step we determine the transverse polarization of the top with regard to the hadron plane spanned by…

High Energy Physics - Phenomenology · Physics 2011-02-09 S. Groote , J. G. Körner

In this work, we systematically investigate the evolution of spin polarization and quantum entanglement in cascade decays of baryon-antibaryon pairs, which are produced in electron-positron annihilation. We derive a fully analytical spin…

High Energy Physics - Phenomenology · Physics 2026-03-26 Cheng Chen , Ju-Jun Xie

Quark spin effects in $e^+e^-$ annihilation to pseudoscalar and vector mesons are implemented for the first time in the PYTHIA Monte Carlo event generator. The spin-dependent fragmentation of the string stretched between the produced…

High Energy Physics - Phenomenology · Physics 2024-07-11 A. Kerbizi , L. Lönnblad , A. Martin

We investigate the spin alignment of vector mesons arising from locally polarized quarks and anti-quarks (local spin alignment) in heavy-ion collisions. We find that $\rho_{00}\neq 1/3$ does not necessarily signal the global polarization of…

Nuclear Theory · Physics 2021-04-30 Xiao-Liang Xia , Hui Li , Xu-Guang Huang , Huan Zhong Huang

The quark spin effects are introduced for the first time in the string fragmentation routine of the Pythia 8 Monte Carlo event generator for the simulation of $e^+e^-$ annihilation to hadrons. To describe the spin effects the…

High Energy Physics - Phenomenology · Physics 2023-12-29 A. Kerbizi , L. Lönnblad , A. Martin

A non-relativistic quark coalescence model is formulated for polarized vector mesons and baryons of spin-1/2 octet and spin-3/2 decuplet. With the spin density matrix, one can compute in a uniform way the polarizations of vector mesons and…

Nuclear Theory · Physics 2018-04-04 Yang-guang Yang , Ren-hong Fang , Qun Wang , Xin-nian Wang

This review covers the recent experimental development on spin alignment measurements of $K^{*0}$ and $\phi$ vector mesons in heavy-ion and pp collisions at RHIC and LHC energies. Measurements in $e^+e^-$ collisions at LEP energies are also…

Nuclear Experiment · Physics 2022-01-26 Bedangadas Mohanty , Sourav Kundu , Subhash Singha , Ranbir Singh

The recently developed quantum mechanical string+${}^3P_0$ model of polarized quark fragmentation with pseudoscalar and vector meson production has been implemented in a stand alone Monte Carlo program. The simulation enables the detailed…

High Energy Physics - Phenomenology · Physics 2023-01-18 Albi Kerbizi , Xavier Artru , Anna Martin

We suggested that longitudinal polarization of Lambda produced in e+e- annihilation at LEP energies can provide useful information on hadronization mechanism in general and on testing the validity of different pictures for the spin content…

High Energy Physics - Phenomenology · Physics 2007-05-23 Liang Zuo-tang

In the center-of-mass frame, the spin density matrix for octet baryon-antibaryon pairs produced in polarized electron-positron annihilation is unambiguously determined within the one-photon-exchange approximation. The formalism…

High Energy Physics - Phenomenology · Physics 2026-03-24 Chun-Qiu Zhao , Xu Cao , Jian-Ping Dai

Electron-positron annihilation into a pair of top quarks is considered at the energy of the future collider CLIC. Polarization components of the top quark are calculated with the $\gamma t \bar{t}$ and $Z t \bar{t}$ interactions which…

High Energy Physics - Phenomenology · Physics 2019-05-28 I. V. Truten , A. Yu. Korchin

We propose an improved quark coalescence model for spin alignment of vector mesons by spin density matrix with phase space dependence. Within this model we propose an understanding of spin alignments of vector mesons $\phi$ and $K^{*0}$ in…

High Energy Physics - Phenomenology · Physics 2022-02-16 Xin-Li Sheng

Using the same method as that used in $e^+e^-$ annihilation and lepton-nucleon deep-inelastic scattering, we calculate the spin alignment of vector mesons with high transverse momenta in high energy $pp$ collisions with one longitudinally…

High Energy Physics - Phenomenology · Physics 2009-11-10 Qing-hua Xu , Zuo-tang Liang

We investigate the degree of spin polarization of single top quarks in the $e\gamma$ collision via the process $e^{+} \gamma \to t \bar{b} \bar{\nu_{e}}$ with center of mass energies $\sqrt{s}$=0.5, 1 and 1.5 TeV of the parental linear…

High Energy Physics - Phenomenology · Physics 2008-04-02 B. Sahin , I. Sahin

The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e+e- annihilation the product of two interference…

The spin alignment matrix element rho_{00} for the vector mesons K^{*0} and phi(1020) has been measured in RHIC at central rapidities. These measurements are consistent with the absence of polarization with respect to the reaction plane in…

High Energy Physics - Phenomenology · Physics 2009-12-22 Alejandro Ayala , Eleazar Cuautle , G. Herrera Corral , J. Magnin , Luis Manuel Montano

Unexpectedly large and puzzling spin alignment, and thus tensor polarization, of vector mesons has been observed in heavy-ion collisions. Given that tensor polarization represents a fluctuation of spin, we derive, for the first time, a…

Nuclear Theory · Physics 2025-11-18 Feng Li , Shuai Y. F. Liu