Azimuthal Angle Correlations for Rapidity Separated Hadron Pairs ind+AuCollisions atsNN=200  GeV

Initial large global angular momentum in non-central relativistic heavy-ion collisions can produce strong vorticity, and through the spin-orbit couping, causes the spin of particles to align with the system’s global angular momentum. We present the azimuthal angle dependent (relative to the first-order plane) global polarization for Λ hyperons in midcentral Au+Au collisions at $ \sqrt {S_{NN} } $ = 200 GeV. We also present the polarization of Λ hyperons along the beam direction as a function of Λ hyperons’ emission angle relative to the second-order event plane at $ \sqrt {S_{NN} } $ = 200 GeV. This longitudinal polarization is found to increase in more peripheral collision. The implications of the results are discussed.

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Fractal study of pion void probability distribution in ultrarelativistic nuclear collision and its target dependence

Modern Physics Letters A ◽

10.1142/s0217732316501583 ◽

2016 ◽

Vol 31 (27) ◽

pp. 1650158 ◽

Cited By ~ 10

Author(s):

Susmita Bhaduri ◽

Dipak Ghosh

Keyword(s):

Probability Distribution ◽

Production Process ◽

Particle Production ◽

Azimuthal Angle ◽

High Energy ◽

Nuclear Collision ◽

Visibility Graph ◽

Scaling Behavior ◽

200 Gev ◽

Visibility Graph Analysis

There are numerous existing works on investigating the dynamics of particle production process in ultrarelativistic nuclear collision. In the past, fluctuation of spatial pattern has been analyzed in terms of the scaling behavior of voids. But analysis of the scaling behavior of the void in fractal scenario has not been explored yet. In this work, we have analyzed the fractality of void probability distribution with a completely different and rigorous method called visibility graph analysis, analyzing the void-data produced out of fluctuation of pions in [Formula: see text]S–AgBr interaction at 200 GeV in pseudo-rapidity [Formula: see text] and azimuthal angle [Formula: see text] space. The power of scale-freeness of visibility graph denoted by PSVG is a measure of fractality, which can be used as a quantitative parameter for the assessment of the state of chaotic system. As the behavior of particle production process depends on the target excitation, we can dwell down the void probability distribution in the event-wise fluctuation resulted out of the high energy interaction for different degree of target excitation, with respect to the fractal scenario and analyze the scaling behavior of the voids. From the analysis of the PSVG parameter, we have observed that scaling behavior of void probability distribution in multipion production changes with increasing target excitation. Since visibility graph method is a classic method of complex network analysis, has been applied over fractional Brownian motion (fBm) and fractional Gaussian noises (fGn) to measure the fractality and long-range dependence of a time series successfully, we can quantitatively confirm that fractal behavior of the void probability distribution in particle production process depends on the target excitation.

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ϕ Meson Spin Alignment and the Azimuthal Angle Dependence of Λ (Λ) Polarization in Au+Au collisions at RHIC

EPJ Web of Conferences ◽

10.1051/epjconf/201817116007 ◽

2018 ◽

Vol 171 ◽

pp. 16007

Author(s):

Biao Tu

Keyword(s):

Angular Momentum ◽

Azimuthal Angle ◽

Heavy Ion ◽

Relativistic Heavy Ion Collisions ◽

Spin Orbit Coupling ◽

Spin Alignment ◽

Angle Dependence ◽

Ion Collisions ◽

200 Gev ◽

Strong Vorticity

Initial large global angular momentum in non-central relativistic heavy-ion collisions can produce strong vorticity, and through the spin-orbit coupling, causes the spin of particles to align with the system’s global angular momentum. We present the azimuthal angle dependent (relative to the reaction plane) polarization for Λ and Λ in mid-central Au+Au collisions at [see formula in PDF] = 200 GeV. We also present the ϕ meson spin alignment parameter, ρ00 in Au+Au collisions at [see formula in PDF] = 19.6, 27, 39, 62.4 and 200 GeV. The implications of the results are discussed.

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Two-particle correlations in azimuthal angle and pseudorapidity in central $$^7\hbox {Be}+{}^9\hbox {Be}$$ collisions at the CERN Super Proton Synchrotron

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08675-4 ◽

2020 ◽

Vol 80 (12) ◽

Author(s):

A. Aduszkiewicz ◽

◽

E. V. Andronov ◽

T. Antićić ◽

V. Babkin ◽

...

Keyword(s):

Azimuthal Angle ◽

Incident Beam ◽

Charged Hadron ◽

Proton Synchrotron ◽

Super Proton Synchrotron ◽

Proton Proton ◽

Pair Correlations ◽

Proton Collisions ◽

Hadron Pairs ◽

Proton Proton Collisions

AbstractA measurement of charged hadron pair correlations in two-dimensional $$\Delta \eta \Delta \phi $$ Δ η Δ ϕ space is presented. The analysis is based on total 30 million central Be + Be collisions observed in the NA61/SHINE detector at the CERN SPS for incident beam momenta of 19A, 30A, 40A, 75A, and 150A $$\text {Ge} \text {V}/c$$ Ge / c . Measurements were carried out for unlike-sign and like-sign charge hadron pairs independently. The $$C(\Delta \eta ,\Delta \phi )$$ C ( Δ η , Δ ϕ ) correlation functions were compared with results from a similar analysis on p + p interactions at similar beam momenta per nucleon. General trends of the back-to-back correlations are similar in central Be + Be collisions and p + p interactions, but are suppressed in magnitude due to the increased combinatorial background. Predictions from the Epos and UrQMD models are compared to the measurements. Evolution of an enhancement around $$(\Delta \eta ,\Delta \phi ) = (0,0)$$ ( Δ η , Δ ϕ ) = ( 0 , 0 ) with incident energy is observed in central Be + Be collisions. It is not predicted by both models and almost non-existing in proton–proton collisions at the same momentum per nucleon.

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Three-fold astigmatism: An important TEM aberration

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150691 ◽

1993 ◽

Vol 51 ◽

pp. 972-973 ◽

Cited By ~ 1

Author(s):

O.L. Krivanek ◽

M.L. Leber

Keyword(s):

High Resolution ◽

Spatial Frequency ◽

Field Emission ◽

Azimuthal Angle ◽

Hollow Cone ◽

Small Probe ◽

Wide Range ◽

High Resolution Images ◽

Image Position

Three-fold astigmatism resembles regular astigmatism, but it has 3-fold rather than 2-fold symmetry. Its contribution to the aberration function χ(q) can be written as:where A3 is the coefficient of 3-fold astigmatism, λ is the electron wavelength, q is the spatial frequency, ϕ the azimuthal angle (ϕ = tan-1 (qy/qx)), and ϕ3 the direction of the astigmatism.Three-fold astigmatism is responsible for the “star of Mercedes” aberration figure that one obtains from intermediate lenses once their two-fold astigmatism has been corrected. Its effects have been observed when the beam is tilted in a hollow cone over a wide range of angles, and there is evidence for it in high resolution images of a small probe obtained in a field emission gun TEM/STEM instrument. It was also expected to be a major aberration in sextupole-based Cs correctors, and ways were being developed for dealing with it on Cs-corrected STEMs.

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