scholarly journals OBSERVATION OF ΔφΔη SCALED CORRELATION SIGNALS WHICH INCREASE WITH CENTRALITY OF AuAu COLLISIONS AT $\sqrt{^SNN} = 200\ {\rm GeV}$

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2149-2153 ◽  
Author(s):  
◽  
R. S. LONGACRE
Keyword(s):  
Charged Particle ◽  
Transverse Momentum ◽  
Hot Spots ◽  
Poster Session ◽  
Pair Correlation ◽  
Wave Model ◽  
Minimum Bias ◽  
Momentum Range ◽  
Selection Of ◽  
Star Detector

We show the preliminary charged-particle pair correlation analyses presented in a poster session at the 2006 International Quark Matter Conference in Shanghai China. The correlation analysis space of Δφ (azimuth) and Δη (pseudo-rapidity) are considered as a function of centrality for minimum bias Au + Au collisions in the mid-transverse momentum range in the STAR detector. The analyses involve unlike-sign charge pairs and like-sign charge pairs, which are transformed into charge-dependent (CD) signals and charge-independent (CI) signals. We use a multiplicity scale to compare the different centralities. We find the signals increase with increasing centrality. A model featuring dense gluonic hot spots as first proposed by van Hove predicts that the observables under investigation would have sensitivity to such a substructure should it occur. A blast wave model including multiple hot spots motivates the selection of transverse momenta in the range 0.8 GeV /c < pt < 4.0 GeV /c.

scholarly journals Measurement of flow harmonics correlations with mean transverse momentum in lead–lead and proton–lead collisions at $$\sqrt{s_{\mathrm{NN}}} = 5.02~\hbox {TeV}$$ with the ATLAS detector

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Charged Particle ◽  
Transverse Momentum ◽  
Correlation Coefficient ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Gluon Plasma ◽  
Pearson Correlation Coefficient ◽  
Order Flow ◽  
Momentum Range ◽  
Ion Collisions

AbstractTo assess the properties of the quark–gluon plasma formed in ultrarelativistic ion collisions, the ATLAS experiment at the LHC measures a correlation between the mean transverse momentum and the flow harmonics. The analysis uses data samples of lead–lead and proton–lead collisions obtained at the centre-of-mass energy per nucleon pair of 5.02 TeV, corresponding to total integrated luminosities of $$22~\upmu \text {b}^{-1}$$22μb-1 and $$28~\text {nb}^{-1}$$28nb-1, respectively. The measurement is performed using a modified Pearson correlation coefficient with the charged-particle tracks on an event-by-event basis. The modified Pearson correlation coefficients for the 2nd-, 3rd-, and 4th-order flow harmonics are measured in the lead–lead collisions as a function of event centrality quantified as the number of charged particles or the number of nucleons participating in the collision. The measurements are performed for several intervals of the charged-particle transverse momentum. The correlation coefficients for all studied harmonics exhibit a strong centrality evolution, which only weakly depends on the charged-particle momentum range. In the proton–lead collisions, the modified Pearson correlation coefficient measured for the 2nd-order flow harmonics shows only weak centrality dependence. The lead-lead data is qualitatively described by the predictions based on the hydrodynamical model.

Transverse momentum distribution of primary charged particles in the p–Pb interactions using HIJING 1.0

2016 ◽  
Vol 31 (24) ◽  
pp. 1650136 ◽  
Author(s):  
U. Tabassam ◽  
Y. Ali ◽  
M. Suleymanov ◽  
A. S. Bhatti ◽  
J. B. Butt ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Momentum Distribution ◽  
Charged Particles ◽  
Simulated Data ◽  
Transverse Momentum Distribution ◽  
Minimum Bias ◽  
Pseudorapidity Distribution ◽  
Momentum Range ◽  
Comparison Of Results

The shape of the transverse momentum [Formula: see text] distribution of primary charged particles in minimum bias (nonsingle-diffractive) p–Pb collisions at [Formula: see text] is studied in the pseudorapidity regions: [Formula: see text], [Formula: see text] and [Formula: see text] and in the transverse momentum range [Formula: see text] using simulated data produced with the HIJING 1.0 code. These are compared with the ALICE data measured by the ALICE detector at the LHC. In the model, the central and forward [Formula: see text]-regions differ more than in the ALICE data and due to this fact HIJING 1.0 cannot describe well the high [Formula: see text] region in the [Formula: see text] distributions. The comparison of results from simulation implies that the HIJING 1.0 considered narrower pseudorapidity distribution for the charged particles than it is in the ALICE data. It cannot take into account satisfactorily leading effect due to the asymmetric p–Pb fragmentation.

scholarly journals Distortion Effects in Equal Area Unit Maps

2021 ◽  
Author(s):  
Jochen Schiewe
Keyword(s):  
Hot Spots ◽  
Extreme Values ◽  
Generation Process ◽  
Equal Area ◽  
Topological Relationships ◽  
Area Unit ◽  
Task Oriented ◽  
Local Topology ◽  
Selection Of ◽  
Local Extreme

AbstractMaps that correctly represent the geographic size and shape of regions, taking into account scaling and generalization, have the disadvantage that small regions can easily be overlooked or not seen at all. Hence, for some map use tasks where small regions are of importance, alternative map types are needed. One option is the so-called equal area unit maps (EAUMs), where every enumeration unit has the same area size, possibly also the same basic shape such as squares or hexagons. The geometrical distortion of EAUMs, however, leads to a more difficult search for regions as well as a falsification of topological relationships and spatial patterns. To describe these distortions, a set of analytical measures is proposed. But it turns out that the expressiveness of these measures is rather limited. To better understand and to model the influence of distortions, two user studies were conducted. The study on the search in EAUMs (also with the aim of reconstruct the search strategies of the users) revealed how important it is to consider the local topology (e.g. corner or border positions of regions) during the generation process. With regard to pattern identification, it could be shown that EAUMs significantly increase the detection rate of local extreme values. On the other hand, global lateral gradients or geostatistical hot spots often get blurred or even lost. As a consequence, a task-oriented selection of map types and further developments are recommended.

scholarly journals Study of Dependence of Kinetic Freezeout Temperature on the Production Cross-Section of Particles in Various Centrality Intervals in Au–Au and Pb–Pb Collisions at High Energies

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 488
Author(s):  
Muhammad Waqas ◽  
Guang-Xiong Peng
Keyword(s):  
Transverse Momentum ◽  
Flow Velocity ◽  
Production Cross ◽  
Center Of Mass ◽  
Wave Model ◽  
Transverse Flow ◽  
Peripheral Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Transverse Flow Velocity

Transverse momentum spectra of π+, p, Λ, Ξ or Ξ¯+, Ω or Ω¯+ and deuteron (d) in different centrality intervals in nucleus–nucleus collisions at the center of mass energy are analyzed by the blast wave model with Boltzmann Gibbs statistics. We extracted the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume from the transverse momentum spectra of the particles. It is observed that the non-strange and strange (multi-strange) particles freezeout separately due to different reaction cross-sections. While the freezeout volume and transverse flow velocity are mass dependent, they decrease with the resting mass of the particles. The present work reveals the scenario of a double kinetic freezeout in nucleus–nucleus collisions. Furthermore, the kinetic freezeout temperature and freezeout volume are larger in central collisions than peripheral collisions. However, the transverse flow velocity remains almost unchanged from central to peripheral collisions.

scholarly journals Analyzing Transverse Momentum Spectra of Pions, Kaons and Protons in p–p, p–A and A–A Collisions via the Blast-Wave Model with Fluctuations

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 803
Author(s):  
Hai-Ling Lao ◽  
Fu-Hu Liu ◽  
Bo-Qiang Ma
Keyword(s):  
Transverse Momentum ◽  
Flow Velocity ◽  
Blast Wave ◽  
Proper Time ◽  
Wave Model ◽  
Transverse Flow ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Transverse Flow Velocity ◽  
Freeze Out

The transverse momentum spectra of different types of particles, π±, K±, p and p¯, produced at mid-(pseudo)rapidity in different centrality lead–lead (Pb–Pb) collisions at 2.76 TeV; proton–lead (p–Pb) collisions at 5.02 TeV; xenon–xenon (Xe–Xe) collisions at 5.44 TeV; and proton–proton (p–p) collisions at 0.9, 2.76, 5.02, 7 and 13 TeV, were analyzed by the blast-wave model with fluctuations. With the experimental data measured by the ALICE and CMS Collaborations at the Large Hadron Collider (LHC), the kinetic freeze-out temperature, transverse flow velocity and proper time were extracted from fitting the transverse momentum spectra. In nucleus–nucleus (A–A) and proton–nucleus (p–A) collisions, the three parameters decrease with the decrease of event centrality from central to peripheral, indicating higher degrees of excitation, quicker expansion velocities and longer evolution times for central collisions. In p–p collisions, the kinetic freeze-out temperature is nearly invariant with the increase of energy, though the transverse flow velocity and proper time increase slightly, in the considered energy range.

On transverse momentum spectra of negative pions in 12C+181Ta collisions at 4.2A GeV/c

2014 ◽  
Vol 23 (12) ◽  
pp. 1450084 ◽  
Author(s):  
Khusniddin K. Olimov ◽  
Akhtar Iqbal ◽  
S. L. Lutpullaev ◽  
Imran Khan ◽  
Viktor V. Glagolev ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Projectile Fragmentation ◽  
Minimum Bias ◽  
Fragmentation Region ◽  
Rapidity Range ◽  
Gaussian Functions ◽  
Collision Centrality ◽  
Hadron Spectra ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra

We studied the dependences of the experimental transverse momentum spectra of the negative pions, produced in minimum bias 12 C +181 Ta collisions at a momentum of 4.2 GeV/c per nucleon, on the collision centrality and the pion rapidity range. To examine quantitatively, the change in the shape of the pt spectra of π- mesons with the change of collision centrality and the pion rapidity range, all the extracted pt spectra were fitted by the four different functions commonly used for describing the hadron spectra. The extracted values of the spectral temperatures T1 and T2 were consistently larger for the pt spectra of π- mesons coming from midrapidity range as compared to those of the negative pions generated in the target and projectile fragmentation regions. The spectral temperatures of the negative pions coming from projectile fragmentation region proved to be larger than the respective temperatures of the negative pions coming from target fragmentation region. The extracted spectral temperatures T1 and T2 of the pt spectra of π- mesons were compatible within the uncertainties for the peripheral, semicentral and central 12 C +181 Ta collision events, selected using the number of participant protons. It was observed that Hagedorn and Boltzmann functions are more appropriate for describing the transverse momentum spectra of the negative pions as contrasted to Simple Exponential and Gaussian functions.

scholarly journals Research progress of analysis method of slope stability combined with hot spots

2020 ◽  
Vol 198 ◽  
pp. 02008
Author(s):  
XIE Qiao ◽  
ZHANG Jia-sheng ◽  
Wang Xuan
Keyword(s):  
Slope Stability ◽  
Hot Spots ◽  
Development Trend ◽  
Research Progress ◽  
Analysis Methods ◽  
Scope Of Application ◽  
The Times ◽  
The Development Trend ◽  
Selection Of

The analysis methods and theories of slope stability are constantly improving and developing, and more methods in line with the development characteristics of the times have been put forward by scholars at home and abroad. Combined with the latest research hot spots in the direction of analysis methods of slope stability in the world, the analysis methods of slope stability are systematically classified and summarized; The principles, characteristics, scope of application of various methods are summarized; The development trend of slope stability analysis is comprehensively analyzed from various aspects. It provides the follow-up scholars with the research of new methods. It can provide reference for the selection of evaluation methods of practical slope engineering stability.

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