scholarly journals Charged Lepton Spectra from Hot-Spot Evaporation

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Julian Moosmann ◽  
Ralf Hofmann
Keyword(s):  
Invariant Mass ◽  
Hot Spots ◽  
Charged Lepton ◽  
Hot Spot ◽  
Heavy Ion ◽  
Yang Mills ◽  
Correlated Electron ◽  
Ion Collisions ◽  
Large Impact Parameter ◽  
Charged Leptons

Spectra for the emission of charged leptons from evaporating hot-spots of preconfining phase in SU(2) Yang-Mills thermodynamics are computed. Specifically, we consider charged single and dileptons with their spectra being functions of energy and invariant mass, respectively. In the former case, our results relate to narrow and correlated electron and positron peaks measured in supercritical heavy-ion collisions performed at GSI in the 1980s. In the latter case, we point out how strongly the spectra depend on typical kinematic cuts (CDF analysis of Tevatron Run II data). We also propose a scenario on how muon events of anomalously high multiplicity and large impact-parameter modulus arise in the Tevatron data.

Contribution ofπ0and η Dalitz decays to the dilepton invariant-mass spectrum in1AGeV heavy-ion collisions

1997 ◽  
Vol 56 (6) ◽  
pp. R2920-R2923 ◽  
Author(s):  
R. Holzmann ◽  
M. Appenheimer ◽  
R. Averbeck ◽  
Y. Charbonnier ◽  
H. Delagrange ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Invariant Mass ◽  
Heavy Ion Collisions ◽  
Invariant Mass Spectrum ◽  
Heavy Ion ◽  
Dilepton Invariant Mass ◽  
Ion Collisions

SEARCH FOR NEUTRAL BOSONS IN RELATIVISTIC HEAVY-ION COLLISIONS

2008 ◽  
Vol 17 (05) ◽  
pp. 759-770 ◽  
Author(s):  
P. L. JAIN
Keyword(s):  
Invariant Mass ◽  
Heavy Ion Collisions ◽  
Life Time ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Electron Pairs ◽  
Ion Collisions ◽  
Low Mass

In this talk, I will describe results on 1,220 electron pairs produced from a 207 Pb beam at 160A GeV in a nuclear experiment EMU 11 conducted at the CERN SPS. These electron pairs were produced at a distance of more than 50 μm from the primary interactions, which eliminates contamination due to Dalitz pairs. Results on electron pairs with invariant mass Q ranging between 1 and 100 MeV and life-time τ between 10−15 s and 10−12 s were analyzed. After subtracting background pairs from the materialization of photons and from the decays of π0 to photons from the data, they exhibit an enhancement at low mass Q = 6 – 20 MeV with narrow peaks at 7 ± 1 MeV , 19 ± 1 MeV and τ ≤ 10−13 s .

scholarly journals Apparent and Actual Shifts in Mass and Width of ϕ Mesons Produced in Heavy-Ion Collisions

1997 ◽  
Vol 12 (02) ◽  
pp. 127-134 ◽  
Author(s):  
R. S. Bhalerao ◽  
S. K. Gupta
Keyword(s):  
Invariant Mass ◽  
Preliminary Data ◽  
Heavy Ion Collisions ◽  
Mass Spectra ◽  
Dense Matter ◽  
Heavy Ion ◽  
High Energy ◽  
Mass Shift ◽  
Ion Collisions ◽  
Invariant Mass Spectra

We present a method of analyzing invariant-mass spectra of kaon pairs resulting from decay of ϕ mesons produced in high-energy heavy-ion collisions. It can be used to extract the shifts in the mass and the width (ΔM and ΔΓ) of the ϕ mesons when they are inside the dense matter formed in these collisions. We illustrate our method with the help of available preliminary data. Extracted values of ΔM and ΔΓ are significantly larger than those obtained with an earlier method. Our results are consistent with the experimentally observed pT dependence of the mass shift. Finally, we present a phenomenological relation between ΔM and ΔΓ. It provides a useful constraint on theories which predict the values of these two quantities.

scholarly journals Importance of mesons in light-by-light scattering in ultraperipheral lead-lead collisions at the LHC

2019 ◽  
Vol 199 ◽  
pp. 05004 ◽  
Author(s):  
Mariola Kłusek-Gawenda
Keyword(s):  
Light Scattering ◽  
Invariant Mass ◽  
Heavy Ion Collisions ◽  
Resonance Scattering ◽  
Heavy Ion ◽  
Ion Collisions

Possibility of PbPb→PbPbγγ measurement at smaller (< 5 GeV) diphoton invariant mass will be presented. Analysis focuses only on ultraperipheral heavy-ion collisions. This estimate shows that the γγ → γγ collisions can be measured at the LHC by ALICE and LHCb experiments for diphoton invariant mass > 2 GeV. Predictions for the γγ → η, γγ → η′ resonance scattering shows that these resonances can be measured with rather good statistics. A possible observation of peaks related to intermediate η, η′(958), ηc(1S), ηc(2S), χc0(1P) mesons will be presented too. Attempts of reduction of background which comes from dipion production will be considered.

HEAVY ION COLLISIONS AND BLACK HOLE DYNAMICS

2008 ◽  
Vol 17 (03n04) ◽  
pp. 673-678 ◽  
Author(s):  
STEVEN S. GUBSER
Keyword(s):  
Black Hole ◽  
Gauge Theory ◽  
Heavy Ion Collisions ◽  
Equations Of Motion ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Thermalization Time ◽  
Yang Mills ◽  
Ion Collisions

Relativistic heavy ion collisions create a strongly coupled quark–gluon plasma. Some of the plasma's properties can be approximately understood in terms of a dual black hole. These properties include shear viscosity, thermalization time, and drag force on heavy quarks. They are hard to calculate from first principles in QCD. Extracting predictions about quark–gluon plasmas from dual black holes mostly involves solving Einstein's equations and classical string equations of motion. AdS/CFT provides a translation from gravitational calculations to gauge theory predictions. The gauge theory to which the predictions apply is [Formula: see text] super-Yang–Mills theory. QCD is different in many respects from super-Yang–Mills, but it seems that its high temperature properties are similar enough for us to make some meaningful comparisons.

ARE NARROW POSITRON-ELECTRON LINES CREATED BY DECAY OF EXCITED VACUUM-LIKE SYSTEMS FORMED FROM A COHERENT PIONIC PHASE PRESENT IN HEAVY-ION COLLISIONS?

1992 ◽  
Vol 07 (20) ◽  
pp. 1843-1853 ◽  
Author(s):  
SAUL BARSHAY
Keyword(s):  
Heavy Ion Collisions ◽  
Electron Pair ◽  
Experimental Tests ◽  
Heavy Ion ◽  
Opening Angle ◽  
Vacuum Condensate ◽  
Final State ◽  
Correlated Electron ◽  
Ion Collisions ◽  
Electron Positron

A novel description of several narrow, correlated electron-positron lines observed in heavy-ion collisions, arises from a physical picture involving the decay of a group of related, excited coherent bosonic states, which resemble an excited, chira σ vacuum-condensate. These systems are formed in the collision of a coherent pionic phase present in the heavy ions. Further experimental tests of the idea, involve the specific form of the opening angle correlation between the positron-electron pair, and possibly, the nature of the charge states of the final-state ions.

scholarly journals Low-mass dielectrons in pp, p–Pb and Pb–Pb collisions measured by the ALICE Experiment

2018 ◽  
Vol 171 ◽  
pp. 18011 ◽  
Author(s):  
Ivan Vorobyev
Keyword(s):  
Invariant Mass Distribution ◽  
Black Body ◽  
Heavy Ion ◽  
Black Body Radiation ◽  
Relativistic Heavy Ion Collisions ◽  
Vector Mesons ◽  
Alice Experiment ◽  
Final State ◽  
Correlated Electron ◽  
Ion Collisions

Dielectrons produced in ultra-relativistic heavy-ion collisions at the LHC provide a unique probe of the system evolution as they are unperturbed by final-state interactions. The dielectron continuum is extremely rich in physics sources: on top of ordinary Dalitz and resonance decays of pseudoscalar and vector mesons, thermal black-body radiation is of particular interest as it carries information about the temperature of the hot and dense system created in such collisions. The dielectron invariant-mass distribution is furthermore sensitive to medium modifications of the spectral function of short-lived vector mesons that are linked to the potential restoration of chiral symmetry at high temperatures. Correlated electron pairs from semi-leptonic charm and beauty decays provide complementary information about the heavy-quark energy loss.

Sign in / Sign up

Export Citation Format

Share Document