The production of π±, K±, p and p̄ in p–Pb collisions at sNN = 5.02 TeV

2018 ◽  
Vol 33 (17) ◽  
pp. 1850094 ◽  
Author(s):  
U. Tabassam ◽  
Y. Ali ◽  
M. Suleymanov ◽  
A. S. Bhatti ◽  
M. Ajaz
Keyword(s):  
Transverse Momentum ◽  
Longitudinal Momentum ◽  
Momentum Range ◽  
Text Production ◽  
Cronin Effect ◽  
Protons And Neutrons ◽  
Baryon Resonances ◽  
Rhic Data

In this study, we are reporting comprehensive results on [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production in the transverse momentum range of [Formula: see text] 4 GeV/c at midrapidity of [Formula: see text] 0.5 GeV/c, in p–Pb collisions at [Formula: see text] = 5.02 TeV. HIJING 1.0 and UrQMD 3.4 event generators are used to perform simulations and the results are compared with the ALICE and RHIC data. It is observed from the comparison that the yields for the baryons are more complex compared to the mesons and the complexity in baryons is due to the striping dynamics (spectators, leading particles of projectiles) of inner nucleus protons and neutrons. Though all the mesons could be produced during the interaction, they have maximum longitudinal momentum [Formula: see text]; baryons and mesons could be produced as a result of decay of massive baryon-resonances. Yields for the [Formula: see text] mesons are greater than the yield for the [Formula: see text] mesons. These are the well-known results from the RHIC data, which stated that the Cronin Effect is mainly due to [Formula: see text] mesons that can be produced as a result of multi-particle inner nucleus cascade. There exists the regions where yields for the [Formula: see text] mesons and baryons are same that may be due to the appearance of parton nature. The code used in simulation includes the parton dynamics earlier than it is included in the experiment.

Comparison study of the pT distributions of the charged particles in p–Pb interactions at LHC energies

2017 ◽  
Vol 32 (31) ◽  
pp. 1750167 ◽  
Author(s):  
Y. Ali ◽  
U. Tabassam ◽  
M. Suleymanov ◽  
A. S. Bhatti
Keyword(s):  
Transverse Momentum ◽  
Transport Model ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Medium Effect ◽  
Quantum Molecular Dynamics ◽  
Essential Difference ◽  
Momentum Range ◽  
Cronin Effect ◽  
Model Predictions

Transverse momentum [Formula: see text] distributions of primary charged particles were compared to simulations using the Ultra Relativistic Quantum Molecular Dynamics (UrQMD) transport model and the HIJING 1.0 model in minimum bias p–Pb collisions at [Formula: see text] in the pseudorapidity [Formula: see text] regions: [Formula: see text], [Formula: see text] and [Formula: see text] and in the transverse momentum range [Formula: see text]. The simulated distributions were then compared with the ALICE data and it was observed that UrQMD predicts systematically higher yields than HIJING 1.0. Both codes cannot describe the experimental data in the range of [Formula: see text], though in the region of [Formula: see text] the model predictions are very close to the experimental results for particles with [Formula: see text], [Formula: see text]. The ratio of the yield at forward pseudorapidity to that at [Formula: see text] was also studied. It was observed that the predictions of the models depend on [Formula: see text]. In the experiment there is no essential difference of yields for particles from the intervals of [Formula: see text], [Formula: see text] and [Formula: see text]. The differences are significant for the models where the ratios are systematically less than 1. This means that the results are not connected to a medium effect but reflect the Cronin effect. We are led to conclude that the codes cannot take into account satisfactorily the leading effect due to the asymmetric p–Pb fragmentation.

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 and nuclear modification factor distributions of charged particles in p + Pb and p+p collisions at s NN = 5.02 TeV

2019 ◽  
Vol 34 (16) ◽  
pp. 1950120 ◽  
Author(s):  
Q. Ali ◽  
Y. Ali ◽  
M. Haseeb ◽  
M. Ajaz
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Charged Particles ◽  
Momentum Range ◽  
Nuclear Modification Factor ◽  
Nuclear Modification ◽  
Model Distribution ◽  
Momentum Distributions ◽  
Modification Factor ◽  
Good Agreement

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.

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 ATLAS b-jet identification performance and efficiency measurement with $$t{\bar{t}}$$ events in pp collisions at $$\sqrt{s}=13$$ TeV

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Hadron Collider ◽  
Efficiency Measurement ◽  
Atlas Collaboration ◽  
Centre Of Mass ◽  
Identification Performance ◽  
Momentum Range ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

AbstractThe algorithms used by the ATLAS Collaboration during Run 2 of the Large Hadron Collider to identify jets containing b-hadrons are presented. The performance of the algorithms is evaluated in the simulation and the efficiency with which these algorithms identify jets containing b-hadrons is measured in collision data. The measurement uses a likelihood-based method in a sample highly enriched in $$t{\bar{t}}$$tt¯ events. The topology of the $$t \rightarrow W b$$t→Wb decays is exploited to simultaneously measure both the jet flavour composition of the sample and the efficiency in a transverse momentum range from 20 to 600 GeV. The efficiency measurement is subsequently compared with that predicted by the simulation. The data used in this measurement, corresponding to a total integrated luminosity of 80.5 $$\hbox {fb}^{-1}$$fb-1, were collected in proton–proton collisions during the years 2015–2017 at a centre-of-mass energy $$\sqrt{s}=$$s= 13 TeV. By simultaneously extracting both the efficiency and jet flavour composition, this measurement significantly improves the precision compared to previous results, with uncertainties ranging from 1 to 8% depending on the jet transverse momentum.

Mass and energy dependence of the transverse momentum densities in covariant parton model

2015 ◽  
Vol 30 (27) ◽  
pp. 1550133 ◽  
Author(s):  
M. M. Yazdanpanah ◽  
A. Mirjalili ◽  
A. Behjat Ramezani
Keyword(s):  
Binding Energy ◽  
Transverse Momentum ◽  
Quark Model ◽  
Energy Dependence ◽  
Parton Model ◽  
Longitudinal Momentum ◽  
Transverse Momentum Dependent ◽  
Unpolarized Case ◽  
Covariant Quark Model ◽  
Good Agreement

The parton densities which are dependent on transverse momentum, open a way to understand better the structure of quarks and gluons in a more complete way. We are investigating a method based on the covariant quark model which enables us to extract the transverse momentum dependent (TMD) densities from the usual parton densities which are just dependent on the longitudinal momentum. In continuation, we obtain the dependence of the TMDs on binding energy and the mass of quarks. We do some calculations to obtain the TMDs in the unpolarized case while the mass and binding energy of partons are varying. Considering these effects, the results for TMDs are in good agreement with the results of the recent related models.

scholarly journals Measurement of the inclusive isolated photon production cross section in $$\text{ p }\text{ p }$$ collisions at $$\sqrt{s}=7$$ TeV

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
S. P. Adhya ◽  
A. Adler ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Production Cross Section ◽  
Collision Energy ◽  
Production Cross ◽  
Electromagnetic Calorimeter ◽  
Leading Order ◽  
Alice Experiment ◽  
Momentum Range ◽  
Isolated Photons

Abstract The production cross section of inclusive isolated photons has been measured by the ALICE experiment at the CERN LHC in pp collisions at a centre-of-momentum energy of $$\sqrt{s}=$$s= 7 TeV. The measurement is performed with the electromagnetic calorimeter EMCal and the central tracking detectors, covering a range of $$|\eta |<0.27$$|η|<0.27 in pseudorapidity and a transverse momentum range of $$ 10< p_\mathrm {T}^{\gamma }< 60~\mathrm {GeV}/c$$10<pTγ<60GeV/c. The result extends the $$p_\mathrm {T}$$pT coverage of previously published results of the ATLAS and CMS experiments at the same collision energy to smaller $$p_\mathrm {T}$$pT. The measurement is compared to next-to-leading order perturbative QCD calculations and to the results from the ATLAS and CMS experiments. All measurements and theory predictions are in agreement with each other.

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 On the Hidden Beauty of Trigonometric Functions

2017 ◽  
Vol 9 (2) ◽  
pp. 57
Author(s):  
Jiri Stavek
Keyword(s):  
Transverse Momentum ◽  
Trigonometric Function ◽  
Moving Object ◽  
Longitudinal Momentum ◽  
Trigonometric Functions ◽  
Beta Particles ◽  
Latent Energy ◽  
Old Babylonian ◽  
School Of Athens ◽  
Clay Tablet

In the unit circle with radius R = E0 = mc2 = 1 we have defined the trigonometric function cos(Theta) = v/c. The known trigonometric functions revealed the hidden relationships between sensible energy, latent energy, sensible momentum and latent momentum of the moving object, and the absorbed momentum from outside and the available momentum in the outside of the moving object. We present the trigonometric concept inspired by the old Babylonian clay tablet IM 55357 and based on the knowledge of the School of Athens (the fresco of Raphael) and the work of many generations of the Masters of trigonometry. The concept of the Divided Line of Plato can be now quantitatively tested. For the experimental analysis of this concept we propose to study in details the very well known beta decay of RaE to determine the sensible and latent energy (heat) of those beta particles and the sensible and latent energy of the remaining nucleus. The longitudinal momentum and the transverse (latent) momentum can be studied on the effects of the slow neutrons. The longitudinal momentum and the transverse momentum of photons can be manipulated in a convenient medium in order to prepare slow photons. The photoormi effect might improve the efficiency of the light-to-electricity conversion and the efficiency of the light-to-heat conversion.

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