4,798 research outputs found

    Comparison of model predictions for elliptic flow with experiment for Pb+Pb collisions at sqrt{sNN}=2.76 TeV

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    A simple kinematic model based on the superposition of p+p collisions, relativistic geometry and hadronic rescattering is used to predict the elliptic flow observable in sqrt{sNN} = 2.76 TeV Pb+Pb collisions. A short proper time for hadronization is assumed. The predictions are compared with recent experimental measurements of elliptic flow which have been made for this colliding system and energy. It is found that the model predictions do a reasonable job in describing the experimental results, suggesting that the parton phase in these collisions may be short-lived.Comment: 4 pages, 2 figures, submitted to Physical Review, typo corrected, discussion augmente

    Central Coulomb Effects on Pion Interferometry

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    Using a simple final-state rescattering model coupled with a simple Coulomb model, the effects of the central Coulomb potential on pion interferometry measurements in 158 GeV/nucleon Pb+Pb collisions are explored. Although the central Coulomb potential does not introduce correlations between pions, it does prevent an accurate measurement of the momentum difference. This momentum difference smearing effect leads to a reduction in the measured correlation radii and lambda parameters. These distortions are important in 158 GeV/nucleon Pb+Pb collisions because of large source sizes and the strong central Coulomb potential.Comment: 6 pages, Latex, 2 postscript figure

    Signatures for flow effects in s**(1/2) = 200 GeV proton-proton collisions

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    A simple model based on relativistic geometry and final-state hadronic rescattering is used to predict pion source parameters extracted in two-pion femtoscopy studies of proton-proton collisions at s**(1/2) = 200 GeV. From studying the momentum and particle multiplicity dependences of these parameters in the context of this model and assuming a very short hadronization time, flow-like behavior is seen which resembles the flow behavior commonly observed in relativistic heavy-ion collisions.Comment: 10 pages, 3 figures, submitted to Physical Revie

    Comparison of hadronic rescattering calculations of elliptic flow and HBT with measurements from RHIC

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    Results from the data obtained in the first physics run of the Relativistic Heavy Ion Collider (RHIC) have shown suprisingly large elliptic flow and suprisingly small HBT radii. Attempts to explain both results in a consistant picture have so far been unsuccessful. The present work shows that a simple thermal-like initial state model coupled to a hadronic rescattering calculation can explain reasonably well both elliptic flow and HBT results from RHIC. The calculation suggests a very early hadronization time of about 1 fm/c after the initial collision of the nuclei.Comment: 6 pages, 6 figure

    Hadronic observables from Au+Au collisions at s(NN)**(1/2)=200 GeV and Pb+Pb collisions at s(NN)**(1/2)=5.5 TeV from a simple kinematic model

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    A simple kinematic model based on superposition of p+p collisions, relativistic geometry and final-state hadronic rescattering is used to calculate various hadronic observables in s(NN)**(1/2) = 200 GeV Au+Au collisions and s(NN)**(1/2) = 5.5 TeV Pb+Pb collisions. The model calculations are compared with experimental results from several s(NN)**(1/2) = 200 GeV Au+Au collision studies. If a short hadronization time is assumed in the model, it is found that this model describes the trends of the observables from these experiments surprisingly well considering the model's simplicity. This also gives more credibility to the model predictions presented for s(NN)**(1/2) = 5.5 TeV Pb+Pb collisions.Comment: 32 pages, 21 figures, figure and text added for version of paper published in Physical Review

    Extracting the hadronization timescale in sqrt{s}=7 TeV proton-proton collisions from pion and kaon femtoscopy

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    A hadronic rescattering model with the proper hadronization time width as the free parameter is compared with charged pion and charged and neutral kaon femtoscopy measurements from the LHC ALICE experiment for sqrt{s}=7 TeV proton-proton collisions. Comparisons between the model and measurements are made for one-dimensional source parameters in several charged multiplicity and transverse particle pair momentum bins. It is found that a reasonable description of the measured source parameters by the model is obtained for a hadronization proper time width of 0.4 +- 0.1 fm/c, which is in agreement with an estimate based on the uncertainty principle. The model calculations also suggest that 1) some form of collectivity is necessary to describe the multiplicity dependence of the measured radius parameters, and 2) the underlying physical size and timescale of the collision is significantly larger than what the extracted radius parameters and hadronization proper time width would imply.Comment: 13 pages, 5 figures, accepted for publication in J. Phys.

    Signatures for Black Hole production from hadronic observables at the Large Hadron Collider

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    The concept of Large Extra Dimensions (LED) provides a way of solving the Hierarchy Problem which concerns the weakness of gravity compared with the strong and electro-weak forces. A consequence of LED is that miniature Black Holes (mini-BHs) may be produced at the Large Hadron Collider in p+p collisions. The present work uses the CHARYBDIS mini-BH generator code to simulate the hadronic signal which might be expected in a mid-rapidity particle tracking detector from the decay of these exotic objects if indeed they are produced. An estimate is also given for Pb+Pb collisions.Comment: 11 pages, 9 figures, ISHIP 2006 conference proceedin
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