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.

scholarly journals Recent results for UPC at the LHC

2019 ◽  
Vol 206 ◽  
pp. 06002
Author(s):  
Mariola Kłusek-Gawenda
Keyword(s):  
Light Scattering ◽  
Cross Section ◽  
Heavy Ion Collisions ◽  
Resonance Scattering ◽  
Heavy Ion ◽  
Regge Model ◽  
Two Photon ◽  
Ion Collisions ◽  
Nuclear Cross Section ◽  
Good Agreement

Ultraperipheral heavy ion collisions are a source of photons which can collide with each other producing a pair of particles. This work will be focused on analysis of the light-by-light scattering. Here contribution from fermionic boxes, resonance scattering, VDM-Regge model, two-gluon exchange and pionic background will be compared. Each of these processes dominate at different ranges of two-photon invariant masses. Our calculated nuclear cross section is in good agreement with recently measured ATLAS and CMS data. Predictions including ALICE and LHCb experimental cuts for the next run at the LHC will be shown.

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 Exotic charmonium and light-by-light scattering in heavy ion collisions

2018 ◽  
Author(s):  
Fernando Silveira Navarra ◽  
Victor Goncalves ◽  
Bruno Moreira ◽  
Raquel Molina
Keyword(s):  
Light Scattering ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Ion Collisions
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