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Wong, Cheuk‐Yin; Wilk, G.

doi:10.5506/aphyspolb.43.2047

Cited by 87 publications

(38 citation statements)

References 23 publications

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“…The pp reference spectrum has a shape similar to that of a Tsallis distribution, including a power law behavior at large p T values. This is consistent with earlier observations that this functional form is able to describe charged-particle p T spectra at LHC energies [40]. The lower panel of Fig.…”

Section: Resultssupporting

confidence: 92%

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Charged-particle nuclear modification factors in XeXe collisions at $$ \sqrt{s_{\mathrm{NN}}} = 5.44 $$ TeV

Sirunyan¹,

Tumasyan²,

Adam³

et al. 2018

J. High Energ. Phys.

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The differential yields of charged particles having pseudorapidity within |η| < 1 are measured using xenon-xenon (XeXe) collisions at √ s NN = 5.44 TeV. The data, corresponding to an integrated luminosity of 3.42 µb −1 , were collected in 2017 by the CMS experiment at the LHC. The yields are reported as functions of collision centrality and transverse momentum, p T , from 0.5 to 100 GeV. A previously reported p T spectrum from proton-proton collisions at √ s = 5.02 TeV is used for comparison after correcting for the difference in center-of-mass energy. The nuclear modification factors using this reference, R * AA , are constructed and compared to previous measurements and theoretical predictions. In head-on collisions, the R * AA has a value of 0.17 in the p T range of 6-8 GeV, but increases to approximately 0.7 at 100 GeV. Above ≈6 GeV, the XeXe data show a notably smaller suppression than previous results for lead-lead (PbPb) collisions at √ s NN = 5.02 TeV when compared at the same centrality (i.e., the same fraction of total cross section). However, the XeXe suppression is slightly greater than that for PbPb in events having a similar number of participating nucleons.The central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic field of 3.8 T. Within the solenoid volume are a silicon pixel and strip tracker, a lead tungstate crystal electromagnetic calorimeter, and a brass and scintillator hadron calorimeter, each composed of a barrel and two endcap sections. Forward calorimeters extend the η coverage provided by the barrel and endcap detectors. Muons are detected in gas-ionization chambers embedded in the steel flux-return yoke outside the solenoid.The silicon tracker measures charged particles within the range |η| < 2.5. It consists of 1856 silicon pixel and 15 148 silicon strip detector modules. For nonisolated particles of 1 < p T < 10 GeV and |η| < 1.4, the track resolutions are typically 25-90 (45-150) µm in the transverse (longitudinal) impact parameter [25].The hadron forward (HF) calorimeter uses steel as an absorber and quartz fibers as the sensitive material. The two halves of the HF are located 11.2 m from the interaction region, one on each end, and together they provide coverage in the range 3.0 < |η| < 5.2.Events of interest are selected using a two-tiered trigger system [26]. During XeXe operation the first level trigger (L1), composed of custom hardware processors, uses information from the calorimeters to select events at a rate of around 4 kHz within a time interval of less than 4 µs. The second level, known as the high-level trigger (HLT), consists of a farm of processors running a version of the full event reconstruction software optimized for fast processing, and reduces the event rate to around 2 kHz before data storage.A more detailed description of the CMS detector, together with a definition of the coordinate system used and the relevant kinematic variables, can be found in Ref. [27].

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Section: Resultssupporting

confidence: 92%

“…At higher p T , a fit to HERWIG++ [39] tune EE5C [32] deviates from the PYTHIA result by no more than 2%. Other functional forms including sigmoid functions and ratios of Tsallis distributions [40] are found to agree with the nominal fit to within 1%.…”

Section: Reference Spectrummentioning

confidence: 60%

Charged-particle nuclear modification factors in XeXe collisions at $$ \sqrt{s_{\mathrm{NN}}} = 5.44 $$ TeV

Sirunyan¹,

Tumasyan²,

Adam³

et al. 2018

J. High Energ. Phys.

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“…The hadron p T spectra in pp collisions are successfully described by Tsallis distribution [5,6] in terms of only two parameters, the Tsallis parameter T and the parameter q which governs the degree of non-thermalization. It is well known [7][8][9] that the functional form of the Tsallis distribution, which describes near-thermal systems is essentially the same as the power law function by Hagedorn which is applicable to the QCD hard scatterings [10,11]. There are numerous studies which show that the Tsallis/Hagedorn distribution gives an excellent description of p T spectra of all identified hadrons measured in pp collisions at SPS, RHIC and LHC energies [7,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Transverse momentum spectra of hadrons in high energy pp and heavy ion collisions

2018

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We present a study of transverse momentum (p T ) spectra of unidentified charged particles in pp collisions at RHIC and LHC energies from s 62.4 GeV = to 13 TeV using Tsallis/Hagedorn function. The power law of Tsallis/Hagedorn form gives very good description of the hadron spectra in p T range from 0.2 to 300 GeV/c. The power index n of the p T distributions is found to follow a function of the type a b s + with asymptotic value a=6.8. The parameter T governing the soft bulk contribution to the spectra remains almost same over wide range of collision energies. We also provide a Tsallis/Hagedorn fit to the p T spectra of hadrons in pPb and different centralities of PbPb collisions at s 5.02 TeV NN =. The data/fit shows deviations from the Tsallis distribution which become more pronounced as the system size increases. We suggest simple modifications in the Tsallis/Hagedorn power law function and show that the above deviations can be attributed to the transverse flow in low p T region and to the in-medium energy loss in high p T region.

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“…in refs. [17,18] to calculate the cross sections for the dissociation of J/ψ and ψ ′ by π and ρ and later the dissociation cross sections for J/ψ, ψ ′ χ, Υ and Υ ′ in collision with π, ρ and K mesons. It is worthwhile judging if this model agrees to the lattice simulations of QCD.…”

Section: Introductionmentioning

confidence: 99%

$$\rho J/\Psi $$ scattering in an improved many-body potential

et al. 2020

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We calculate the cross-sections for the processes ρJ/ψ → D 0D0 , ρJ/ψ → D 0D0 * (D 0 * D0 ) and ρJ/ψ → D 0 * D0 * using a QCD-motivated many-body overlap factor to modify the usual sum of two-body interaction model. The realistic Cornell potential has been used for pairwise interaction in the four quark Hamiltonian and noted to give lesser cross-sections as compared to the quadratic potential. The Resonating group method is employed along with the Born approximation which decouples its integral equations. It is pointed out that the additional QCD effect (a gluonic field ovelap factor) result in a significant suppression in the cross sections as compared to the more popular sum of two-body interaction.PACS numbers:

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Cited by 87 publications

References 23 publications

Charged-particle nuclear modification factors in XeXe collisions at $$ \sqrt{s_{\mathrm{NN}}} = 5.44 $$ TeV

Charged-particle nuclear modification factors in XeXe collisions at $$ \sqrt{s_{\mathrm{NN}}} = 5.44 $$ TeV

Transverse momentum spectra of hadrons in high energy pp and heavy ion collisions

$$\rho J/\Psi $$ scattering in an improved many-body potential

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