scholarly journals Exploring time like tranistions in pp, πp and AA reactions with HADES

2020 ◽  
Vol 241 ◽  
pp. 01013
Author(s):  
Piotr Salabura ◽  
J. Adamczewski-Musch ◽  
B. Arnoldi-Meadows ◽  
A. Belounnas ◽  
A. Belyaev ◽  
...  
Keyword(s):  
Form Factors ◽  
Radiative Transition ◽  
Heavy Ion ◽  
Proton Scattering ◽  
Proton Proton ◽  
Electromagnetic Transition ◽  
Ion Collisions ◽  
Timelike Region ◽  
Excited Baryon ◽  
Photon Coupling

Radiative transition of an excited baryon to a nucleon with emission of a virtual massive photon converting to dielectron pair (Dalitz decays) provides important information about baryon-photon coupling at low q2 in timelike region. A prominent enhancement in the respective electromagnetic transition Form Factors (etFF) at q2 near vector mesons ρ/ω poles has been predicted by various calculations reflecting strong baryon-vector meson couplings. The understanding of these couplings is also of primary importance for the interpretation of the emissivity of QCD matter studied in heavy ion collisions via dilepton emission. Dedicated measurements of baryon Dalitz decays in proton-proton and pion-proton scattering with HADES detector at GSI/FAIR are presented and discussed. The relevance of these studies for the interpretation of results obtained from heavy ion reactions is elucidated on the example of the HADES results.

scholarly journals Dielectron Production in Proton–Proton Collisions at √s=7 TeV with ALICE

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 24
Author(s):  
Sebastian Scheid
Keyword(s):  
Cross Sections ◽  
Mass Range ◽  
Heavy Ion ◽  
Event Generator ◽  
Leading Order ◽  
Proton Proton ◽  
Total Cross Sections ◽  
Proton Collisions ◽  
Ion Collisions ◽  
Proton Proton Collisions

The ALICE Collaboration measured dielectron production as a function of the invariant mass ( m ee ), the pair transverse momentum ( p T , ee ) and the pair distance of closest approach ( DCA ee ) in pp collisions at s = 7 TeV. Prompt and non-prompt dielectron sources can be separated with the DCA ee , which will give the opportunity in heavy-ion collisions to identify thermal radiation from the medium in the intermediate-mass range dominated by contributions from open-charm and beauty hadron decays. The charm and beauty total cross sections are extracted from the data by fitting the spectra with two different MC generators, i.e., PYTHIA a leading order event generator and POWHEG a next-to-leading order event generator. Significant model dependences are observed, reflecting the sensitivity of this measurement to the heavy-flavour production mechanisms.

scholarly journals Hadron Spectra Parameters within the Non-Extensive Approach

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 122 ◽  
Author(s):  
Keming Shen ◽  
Gergely Gábor Barnaföldi ◽  
Tamás Sándor Biró
Keyword(s):  
High Energy Physics ◽  
Center Of Mass ◽  
Heavy Ion ◽  
High Energy ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Hadron Spectra ◽  
Hadron Mass ◽  
Energy Scaling

We investigate how the non-extensive approach works in high-energy physics. Transverse momentum ( p T ) spectra of several hadrons are fitted by various non-extensive momentum distributions and by the Boltzmann–Gibbs statistics. It is shown that some non-extensive distributions can be transferred one into another. We find explicit hadron mass and center-of-mass energy scaling both in the temperature and in the non-extensive parameter, q, in proton–proton and heavy-ion collisions. We find that the temperature depends linearly, but the Tsallis q follows a logarithmic dependence on the collision energy in proton–proton collisions. In the nucleus–nucleus collisions, on the other hand, T and q correlate linearly, as was predicted in our previous work.

scholarly journals JET RESULTS AND JET RECONSTRUCTION TECHNIQUES IN p+p AND THEIR PROSPECTS IN HEAVY-ION COLLISIONS IN ATLAS

2011 ◽  
Vol 20 (07) ◽  
pp. 1545-1550
Author(s):  
◽  
MARTIN SPOUSTA
Keyword(s):  
Cross Sections ◽  
Heavy Ion Collisions ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Expected Performance ◽  
Jet Shapes ◽  
Jet Cross Sections

We present the measurement of jet production performed with the ATLAS detector in proton-proton collisions at center-of-mass energy of 7 TeV, using an integrated luminosity of 17 nb−1. We show the inclusive jet cross sections and jet shapes. The expected performance and strategy for the jet reconstruction in heavy ion collisions is also discussed.

scholarly journals Antimatter production in proton-proton and heavy-ion collisions at ultrarelativistic energies

2011 ◽  
Vol 84 (5) ◽  
Author(s):  
J. Cleymans ◽  
S. Kabana ◽  
I. Kraus ◽  
H. Oeschler ◽  
K. Redlich ◽  
...  
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Proton Proton ◽  
Ion Collisions

scholarly journals Recent results from the ALICE Experiment at LHC

2018 ◽  
Vol 191 ◽  
pp. 01004
Author(s):  
Catalin Ristea
Keyword(s):  
System Size ◽  
Heavy Ion ◽  
Dense Medium ◽  
Production Flow ◽  
Alice Experiment ◽  
Final State ◽  
Proton Proton ◽  
Ion Collisions ◽  
Flow Phenomena ◽  
Nuclear Modification Factors

ALICE (A Large Ion Collider Experiment) at the LHC performed high statistics measurements in Pb-Pb collisions at the top LHC energy, complemented with large recent reference datasets in elementary proton-proton collisions at the same energy. Elementary pp collisions are serving as baseline for testing QCD properties and allow the study of the changes induced by the hot and dense medium produced in heavy ion collisions. Key observables like nuclear modification factors, jet production, flow phenomena and spectra for identified particles, related to the different stages of collision evolution, are presented and compared with the most recent results from p-Pb and Xe-Xe collisions, thus allowing to probe both initial cold nuclear matter and final state effects, combined with the system size dependence of the measurements.

The effects of nucleus form factors on the electromagnetically produced heavy lepton pairs

2016 ◽  
Vol 25 (02) ◽  
pp. 1650006 ◽  
Author(s):  
M. Y. Şengül
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Form Factors ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Lepton Pairs ◽  
Heavy Lepton ◽  
Ion Collisions ◽  
Realistic Form ◽  
The Cross

In this paper, the effects of different nucleus form factors to the cross-sections of electromagnetically produced heavy lepton pairs such as muons and tauons from the ultra-relativistic heavy ion collisions have been calculated. Nucleus form factors play important roles in the calculation of the cross-sections, because the Compton wavelengths of muon and tauon are comparable to the radius of the colliding ions. Some realistic form factors in these calculations have been used and compared the results among them. It has been shown that nucleus form factors reduce the cross-section calculations for muon and tauon pair production very strongly especially at RHIC energies.

scholarly journals OPEN CHARM ANALYSIS ON THE FIRST PP COLLISIONS AT $\sqrt{s} = 7~{\rm TeV}$ WITH ALICE

2011 ◽  
Vol 02 ◽  
pp. 25-30 ◽  
Author(s):  
◽  
GIACOMO ORTONA
Keyword(s):  
Production Cross ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Nucleon Nucleon ◽  
Relativistic Heavy Ion Collisions ◽  
Alice Experiment ◽  
Proton Proton ◽  
Ion Collisions ◽  
Density State ◽  
Energy Domain

A Large Ion Collider Experiment (ALICE) is one of the four large experiments at the Large Hadron Collider (LHC), and the one dedicated to ultra relativistic heavy ion collisions, aiming at investigating the properties of the high-density state of QCD matter produced in such events. ALICE started to collect data in proton-proton collisions at the LHC at CERN in November 2009 (with a centre of mass energy [Formula: see text]). Since March 2010 data are being recorded at an energy of [Formula: see text] while from November 7 to December 6 LHC provided Pb-Pb collisions at an energy of [Formula: see text] per nucleon-nucleon pair. In Pb-Pb collisions heavy quarks are regarded as sensitive probes of the interaction dynamics between the parton and medium produced in the collisions, and the energies available at LHC will allow to study the production of heavy flavours with high statistics. Proton-proton data will be used to measure the heavy flavours production cross section to compare with perturbative QCD calculations in an unexplored energy domain and they will provide the reference for the study of Pb-Pb collisions. After a description of the ALICE experiment focused on its heavy flavour related performance, the status of the first analysis on charm production, measured by reconstructing the decays of D0, D+, D*+, and Ds into hadronic and semi-leptonic channels will be presented. An outlook of the same measurements for the upcoming Pb-Pb run will also be discussed.

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