scholarly journals Production of ηQ meson at LHC

2015 ◽  
Vol 30 (07) ◽  
pp. 1550032 ◽  
Author(s):  
A. K. Likhoded ◽  
A. V. Luchinsky ◽  
S. V. Poslavsky

The paper is devoted to theoretical consideration of inclusive ηc, b meson production at LHC. It is shown that existing experimental data on ηc meson production at LHCb detector can be described in the framework of NRQCD formalism and color singlet component with phenomenological value of matrix element |R(0)|2 gives main contribution. Using this model, we present theoretical prediction for integrated cross-sections and transverse momentum distributions for inclusive ηc production at other LHC detectors. The case of ηb meson production at LHC is also considered.

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Wen Qin ◽  
Ling-Yun Dai ◽  
Jorge Portolés

Abstract A coherent study of e+e− annihilation into two (π+π−, K+K−) and three (π+π−π0, π+π−η) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region E ≲ 2 GeV. The work of [L.Y. Dai, J. Portolés, and O. Shekhovtsova, Phys. Rev. D88 (2013) 056001] is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the anomalous magnetic moment of the muon. We also estimate some higher-order additions led by the same hadronic vacuum polarization. Combined with the other contributions from the standard model, the theoretical prediction differs still by (21.6 ± 7.4) × 10−10 (2.9σ) from the experimental value.


2019 ◽  
Vol 34 (23) ◽  
pp. 1950187
Author(s):  
A. R. Gilani ◽  
Z. Wazir ◽  
M. K. Suleymanov ◽  
S. Kanwal ◽  
S. M. Aslam ◽  
...  

In this paper, the transverse momentum and maximum transverse momentum distributions of protons and pions produced in an event for CC collisions at 4.2 A GeV/c have been analyzed. This analysis is based on experimental data obtained from 2 m propane bubble chamber at Joint Institute for Nuclear Research, Dubna, Russia and simulation data obtained from Dubna cascade code. We observed three disparate zones for the transverse momentum distribution of the produced particles. The third zone where transverse momentum is greater than 0.375 GeV/c is restricted only for pions with transverse momentum approximately equal to 1 GeV/c, and for protons the restricted value of [Formula: see text] is [Formula: see text][Formula: see text]1.5 GeV/c. So contribution of pions to this region is less and decreases sharply than the contribution of protons. The results of cascade model are not fully compatible with the experimental results in the third [Formula: see text] region, as this region contains less number of particles for model data as compared with experimental data but is compatible in the case of [Formula: see text].


2019 ◽  
Vol 34 (13) ◽  
pp. 1950090 ◽  
Author(s):  
M. Ajaz ◽  
M. Bilal ◽  
Y. Ali ◽  
M. K. Suleymanov ◽  
K. H. Khan

The pseudorapidity [Formula: see text] dependence of charged-particles ratios in three transverse momentum [Formula: see text] regions, obtained by hadron production models, in proton–proton collisions at 7 TeV are compared with the measurements of LHCb detector. Compared to the experimental data, the [Formula: see text] ratios are independent of [Formula: see text] and [Formula: see text] and are very well predicted by all models (DPMJETIII, EPOS1.99, EPOS-LHC, HIJING1.383, QGSJETII-04 and Sibyll2.3c). All models predict the [Formula: see text] ratio at low [Formula: see text] for [Formula: see text], but underestimate afterward while reproducing the experimental data at medium and high [Formula: see text] very well. The [Formula: see text] ratio is described by the models very well at high [Formula: see text] in the low and medium [Formula: see text] region. At high [Formula: see text], models predict the experimental data well, except Sibyll2.3c that slightly overestimates. The [Formula: see text] ratio is predicted by EPOS1.99, HIJING and Sibyll at low [Formula: see text] and EPOS-LHC, EPOS1.99 and Sibyll predicted at high [Formula: see text] for low [Formula: see text]. For medium [Formula: see text], EPOS1.99 and Sibyll predict very well for [Formula: see text] while EPOS-LHC and HIJING models reproduce the data for [Formula: see text]. All models underpredict the [Formula: see text] ratio for [Formula: see text]. For the [Formula: see text] and [Formula: see text] ratios, only Sibyll and EPOS1.99 models could reproduce some regions of [Formula: see text] and [Formula: see text]. None of the models satisfactorily predict all the ratios. the same particle ratios are well described by most of the models while the discrepancies occur mostly in predicting the different particles ratios.


2019 ◽  
Vol 34 (16) ◽  
pp. 1950120 ◽  
Author(s):  
Q. Ali ◽  
Y. Ali ◽  
M. Haseeb ◽  
M. Ajaz

Transverse momentum distributions and nuclear modification factor of integrated charged particles yield produced in p[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] = 5.02 TeV are investigated in mid-rapidity regions of [Formula: see text] at one event multiplicity class 0–5% in the transverse momentum range of [Formula: see text]20 GeV/c. Simulations with EPOS-1.99, EPOS-LHC and QGSJETII-04 are compared with the ALICE data. All three models are in good agreement with each other up to [Formula: see text]3 GeV/c for transverse momentum distributions but after that QGSJETII-04 overpredicts the experimental data. EPOS-LHC seems to describe the experimental data quite well as compared to the other two models. The ratios of the kaons to pions and protons to pions are also presented where again EPOS-LHC provides good agreement with the ALICE data. In case of the nuclear modification factor, for (anti) pions and (anti) kaons, the model distribution is around 1, whereas it is greater than 1 in case of (anti) protons which shows Cronin enhancement.


2019 ◽  
Vol 34 (19) ◽  
pp. 1950150 ◽  
Author(s):  
Muhammad Ajaz ◽  
Irfan Khan ◽  
M. K. Suleymanov

The transverse momentum distribution of the differential production cross-sections of heavy flavored charm hadrons [Formula: see text], [Formula: see text] in pp collisions at 7 TeV are simulated. Predictions of DPMJETIII.17-1, HIJING1.383 and Sibyll2.3c are compared to the differential cross-section measurements of the LHCb experimental data presented in the region of [Formula: see text] and [Formula: see text], where the pp center of mass frame is used to measure the transverse momentum and rapidity. The models reproduce only some regions of [Formula: see text] and/or bins of [Formula: see text] but none of them predict completely all the [Formula: see text] bins over the entire [Formula: see text] range.


2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Jia-Qi Hui ◽  
Zhi-Jin Jiang

It has long been debated whether the hydrodynamics is suitable for the smaller colliding systems such as p+p collisions. In this paper, by assuming the existence of longitudinal collective motion and long-range interactions in the hot and dense matter created in p+p collisions, the relativistic hydrodynamics incorporating with the nonextensive statistics is used to analyze the transverse momentum distributions of the particles. The investigations of the present paper show that the hybrid model can give a good description of the currently available experimental data obtained in p+p collisions at RHIC and LHC energies, except for p and p¯ produced in the range of pT>3.0 GeV/c at s=200 GeV.


2002 ◽  
Vol 80 (5) ◽  
pp. 525-532
Author(s):  
F -H Liu

Three isotropic emission fireballs are used to describe the rapidity (or pseudorapidity) and transverse momentum distributions of negatively charged particles produced in nucleus–nucleus collisions at high energy. The calculated results are compared and shown to be in agreement with the experimental data of 16O–Au, 32S–S, and 32S–Ag collisions at 200A GeV. PACS Nos.: 25.75-q, 24.10Pa


2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Ya-Ping Xie ◽  
V. P. Gonçalves

AbstractThe exclusive $$J/\Psi $$ J / Ψ and $$\Upsilon $$ Υ photoproduction in fixed - target collisions at the LHC and ep(A) collisions at the Electron ion collider in China (EicC) is investigated considering different models for the treatment of the vector meson production at low energies, close to the threshold. Results for the total cross sections and associated distributions are presented. We predict a large number of $$J/\Psi $$ J / Ψ events at the LHC in the rapidity range covered by the LHCb detector. For the EicC, our predictions point out that a detailed analysis of the near threshold $$J/\Psi $$ J / Ψ and $$\Upsilon $$ Υ photoproduction is feasible. Moreover, our results indicate that the modeling of the near threshold vector meson production can be constrained by future experimental analyzes at the LHC and EicC.


Atoms ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 68 ◽  
Author(s):  
François Frémont

A four-body classical model based on the resolution of Hamilton equations of motion was used here to determine and analyze ionization doubly-differential cross sections following 3.6 MeV/amu Au53+ + He collisions. Our calculation was not able to reproduce the binary peaks experimentally observed in the transverse momentum distributions for electron emission energies larger than 10 eV. Surprisingly, by introducing a large number of free or quasi-free electrons that followed the projectile at the same velocity, the agreement between the experiment and our calculation was improved, since our model reproduced, at least qualitatively, the experimental binary peaks. The origin of the presence of such electrons is discussed.


2002 ◽  
Vol 80 (8) ◽  
pp. 883-891
Author(s):  
F -H Liu

The rapidity and transverse-momentum distributions of particles produced in central Pb–Pb collisions at high energy are analyzed by the thermalized cylinder model. The calculated results are compared and found to be in agreement with the recent experimental data of the NA49 Collaboration. PACS Nos.: 25.75-q, 24.10Pa


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