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Related papers: Vector and Tensor Spin Polarization for Vector Bos…

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A generalized vector particle theory with the use of an extended set of Lorentz group irredicible representations, including scalar, two 4-vectors, and antisymmetric 2-rang tensor, is investigated. Initial equations depend upon four complex…

High Energy Physics - Theory · Physics 2007-05-23 V. V. Kisel , N. G. Tokarevskaya , A. A. Bogush , V. M. Red'kov

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

The tensor and spin-orbit forces contribute essentially to the formation of the spin mean field, and give rise to the same dynamical effect, namely spin polarization. In this paper, based on time-dependent density functional calculations,…

Nuclear Theory · Physics 2011-08-25 Yoritaka Iwata , Joachim A. Maruhn

We derive the collision term in the Boltzmann equation using the equation of motion for the Wigner function of massive spin-1/2 particles. To next-to-lowest order in $\hbar$ it contains a nonlocal contribution, which is responsible for the…

High Energy Physics - Phenomenology · Physics 2021-08-04 Nora Weickgenannt , Enrico Speranza , Xin-li Sheng , Qun Wang , Dirk H. Rischke

The concept of the Wigner function is used to construct a semi-classical kinetic theory describing the evolution of the axial-current phase-space density of spin-1/2 particles in the relaxation time approximation. The resulting approach can…

High Energy Physics - Phenomenology · Physics 2021-02-01 Samapan Bhadury , Wojciech Florkowski , Amaresh Jaiswal , Avdhesh Kumar , Radoslaw Ryblewski

We solve the Wigner equation for massless spin-1/2 charged fermions near global equilibrium. The Wigner function can be obtained order by order in the power expansion of the vorticity and electromagnetic field. The Wigner function has been…

High Energy Physics - Phenomenology · Physics 2021-01-04 Shi-Zheng Yang , Jian-Hua Gao , Zuo-Tang Liang , Qun Wang

We calculate the Wigner function for massive spin-1/2 particles in an inhomogeneous electromagnetic field to leading order in the Planck constant $\hbar$. Going beyond leading order in $\hbar$ we then derive a generalized Boltzmann equation…

High Energy Physics - Phenomenology · Physics 2019-10-02 Nora Weickgenannt , Xin-li Sheng , Enrico Speranza , Qun Wang , Dirk H. Rischke

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

We critically compare thermodynamic and kinetic approaches, that have been recently used to study relations between the spin polarization and fluid vorticity in systems consisting of spin-one-half particles. The thermodynamic approach…

High Energy Physics - Phenomenology · Physics 2018-10-31 Wojciech Florkowski , Avdhesh Kumar , Radoslaw Ryblewski

The string-inspired technique is used for a first calculation of the one-loop axialvector vacuum polarisation in a general constant electromagnetic field. A compact result is reached for the difference between this tensor and the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Holger Gies , Christian Schubert

We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward…

High Energy Physics - Theory · Physics 2016-07-12 Pavel Kovtun

We derive the Boltzmann equation and the collision kernel for massive spin-1/2 particles, using the Wigner-function formalism and employing an expansion in powers of $\hbar$. The phase space is enlarged to include a variable related to the…

Nuclear Theory · Physics 2021-08-04 Nora Weickgenannt , Enrico Speranza , Xin-li Sheng , Qun Wang , Dirk H. Rischke

We systematically analyze the effects of the derivatives of the hydrodynamic fields on axial Wigner function that describes the spin polarization vector in phase space. We have included all possible first-order derivative contributions that…

High Energy Physics - Phenomenology · Physics 2021-08-18 Shuai Y. F. Liu , Yi Yin

We present an extension of relativistic single-particle distribution function for weakly interacting particles at local thermodynamical equilibrium including spin degrees of freedom, for massive spin 1/2 particles. We infer, on the basis of…

Nuclear Theory · Physics 2015-06-15 F. Becattini , V. Chandra , L. Del Zanna , E. Grossi

We analyze the spin alignment of vector mesons stemming from spin correlation of the quark and antiquark induced by background color fields in relativistic heavy ion collisions. The quark-coalescence equation relating the collision kernel…

Nuclear Theory · Physics 2025-03-11 Di-Lun Yang

It has been realized that thermal shear plays a similar role as thermal vorticity in polarizing spin of particles in heavy ion collisions. We point out that shear has a fundamental difference that it leads to particle redistribution in the…

High Energy Physics - Phenomenology · Physics 2022-12-28 Shu Lin , Ziyue Wang

Using the expansion of Zubarev's density operator, we develop a linear response approach to study various spin physics in a locally equilibrated medium, particularly focusing on various polarization phenomena in heavy-ion collisions.…

Nuclear Theory · Physics 2025-01-30 Youyu Li , Shuai Y. F. Liu

We propose a relativistic theory for spin density matrices of vector mesons based on Kadanoff-Baym equations in the closed-time-path formalism. The theory puts the calculation of spin observables such as the spin density matrix element…

High Energy Physics - Phenomenology · Physics 2023-01-03 Xin-Li Sheng , Lucia Oliva , Zuo-Tang Liang , Qun Wang , Xin-Nian Wang

Recently advocated expressions for the phase-space dependent spin-1/2 density matrices of particles and antiparticles are analyzed in detail and reduced to the forms linear in the Dirac spin operator. This allows for a natural determination…

As the core ingredient for spin polarization, the local equilibrium spin distribution function is derived from the detailed balance principle. The kinetic theory for interacting fermionic systems is applied to the Nambu--Jona-Lasinio model…

High Energy Physics - Theory · Physics 2021-09-29 Ziyue Wang , Xingyu Guo , Pengfei Zhuang