scholarly journals Freeze-out condition from lattice QCD and the role of additional strange hadrons

2015 ◽  
Author(s):  
Swagato Mukherjee
Keyword(s):  
Lattice Qcd ◽  
Freeze Out

scholarly journals On SU(3) Effective Models and Chiral Phase Transition

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Abdel Nasser Tawfik ◽  
Niseem Magdy
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Lattice Qcd ◽  
High Energy ◽  
Particle Model ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Thermal Models ◽  
Qcd Phase Diagram ◽  
Freeze Out

Sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL) model and Polyakov linear sigma-model (PLSM) has been utilized in studying QCD phase-diagram. From quasi-particle model (QPM) a gluonic sector is integrated into LSM. The hadron resonance gas (HRG) model is used in calculating the thermal and dense dependence of quark-antiquark condensate. We review these four models with respect to their descriptions for the chiral phase transition. We analyze the chiral order parameter, normalized net-strange condensate, and chiral phase-diagram and compare the results with recent lattice calculations. We find that PLSM chiral boundary is located in upper band of the lattice QCD calculations and agree well with the freeze-out results deduced from various high-energy experiments and thermal models. Also, we find that the chiral temperature calculated from HRG is larger than that from PLSM. This is also larger than the freeze-out temperatures calculated in lattice QCD and deduced from experiments and thermal models. The corresponding temperature and chemical potential are very similar to that of PLSM. Although the results from PNJL and QLSM keep the same behavior, their chiral temperature is higher than that of PLSM and HRG. This might be interpreted due the very heavy quark masses implemented in both models.

scholarly journals Stringy excitation and role of IR/UV gluons in lattice QCD

2012 ◽  
Author(s):  
Hiroshi Ueda ◽  
Takahiro M Doi ◽  
Sho Fujibayashi ◽  
Shoichiro Tsutsui ◽  
Takumi Iritani ◽  
...  
Keyword(s):  
Lattice Qcd

scholarly journals Formation of interstellar propanal and 1-propanol ice: a pathway involving solid-state CO hydrogenation

2019 ◽  
Vol 627 ◽  
pp. A1 ◽  
Author(s):  
D. Qasim ◽  
G. Fedoseev ◽  
K.-J. Chuang ◽  
V. Taquet ◽  
T. Lamberts ◽  
...  
Keyword(s):  
Solid State ◽  
Co Hydrogenation ◽  
Theoretical Calculations ◽  
Interstellar Space ◽  
Activation Barriers ◽  
Reflection Absorption Infrared Spectroscopy ◽  
Core Phase ◽  
Temperature Programmed ◽  
Freeze Out

Context. 1-propanol (CH3CH2CH2OH) is a three carbon-bearing representative of the primary linear alcohols that may have its origin in the cold dark cores in interstellar space. To test this, we investigated in the laboratory whether 1-propanol ice can be formed along pathways possibly relevant to the prestellar core phase. Aims. We aim to show in a two-step approach that 1-propanol can be formed through reaction steps that are expected to take place during the heavy CO freeze-out stage by adding C2H2 into the CO + H hydrogenation network via the formation of propanal (CH3CH2CHO) as an intermediate and its subsequent hydrogenation. Methods. Temperature programmed desorption-quadrupole mass spectrometry (TPD-QMS) was used to identify the newly formed propanal and 1-propanol. Reflection absorption infrared spectroscopy (RAIRS) was used as a complementary diagnostic tool. The mechanisms that can contribute to the formation of solid-state propanal and 1-propanol, as well as other organic compounds, during the heavy CO freeze-out stage are constrained by both laboratory experiments and theoretical calculations. Results. Here it is shown that recombination of HCO radicals formed upon CO hydrogenation with radicals formed via C2H2 processing – H2CCH and H3CCH2 – offers possible reaction pathways to solid-state propanal and 1-propanol formation. This extends the already important role of the CO hydrogenation chain to the formation of larger complex organic molecules. The results are compared with ALMA observations. The resulting 1-propanol:propanal ratio concludes an upper limit of <0.35−0.55, which is complemented by computationally derived activation barriers in addition to the experimental results.

scholarly journals Determination of freeze-out conditions from lattice QCD calculations

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Frithjof Karsch
Keyword(s):  
Lattice Qcd ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Experimental Results ◽  
Ion Collisions ◽  
Theoretical Predictions ◽  
Freeze Out

AbstractFreeze-out conditions in Heavy Ion Collisions are generally determined by comparing experimental results for ratios of particle yields with theoretical predictions based on applications of the Hadron Resonance Gas model. We discuss here how this model dependent determination of freeze-out parameters may eventually be replaced by theoretical predictions based on equilibrium QCD thermodynamics.

scholarly journals van der Waals Interactions and Hadron Resonance Gas: Role of resonance widths modeling on conserved charges fluctuations

2018 ◽  
Vol 171 ◽  
pp. 14006
Author(s):  
Volodymyr Vovchenko ◽  
Paolo Alba ◽  
Mark I. Gorenstein ◽  
Horst Stoecker
Keyword(s):  
Lattice Qcd ◽  
Temperature Region ◽  
Van Der Waals ◽  
Baryon Number ◽  
The Other ◽  
Van Der Waals Interactions ◽  
Crossover Temperature ◽  
Lattice Data ◽  
The Ideal

The quantum van der Waals (QvdW) extension of the ideal hadron resonance gas (HRG) model which includes the attractive and repulsive interactions between baryons – the QvdW-HRG model – is applied to study the behavior of the baryon number related susceptibilities in the crossover temperature region. Inclusion of the QvdW interactions leads to a qualitatively different behavior of susceptibilities, in many cases resembling lattice QCD simulations. It is shown that for some observables, in particular for χBQ11/χB2, effects of the QvdW interactions essentially cancel out. It is found that the inclusion of the finite resonance widths leads to an improved description of χB2, but it also leads to a worse description of χBQ11/χB2, as compared to the lattice data. On the other hand, inclusion of the extra, unconfirmed baryons into the hadron list leads to a simultaneous improvement in the description of both observables.

scholarly journals Strangeness freeze-out: role of system size and missing resonances

2018 ◽  
Vol 171 ◽  
pp. 14002
Author(s):  
Sandeep Chatterjee ◽  
Sabita Das ◽  
Ajay Kumar Dash ◽  
Debadeepti Mishra ◽  
Bedangadas Mohanty ◽  
...  
Keyword(s):  
Size Dependence ◽  
System Size ◽  
Conventional Approach ◽  
Strangeness Production ◽  
Additional Parameter ◽  
Theoretical Approaches ◽  
Missing Resonances ◽  
Freeze Out

The conventional approach to treat strangeness freezeout has been to consider a unified freezeout scheme where strangeness freezes out along with the nonstrange hadrons (1CFO), with or without an additional parameter accounting for out-of-equilibrium strangeness production (γS). Several alternate scenarios have been formulated lately. Here, we will focus on flavor dependent freezeout with early freezeout of strangeness (2CFO) in comparison to 1CFO and its variants with respect to the roles played by the system size and missing resonances predicted by different theoretical approaches but yet to be seen in experiments. In contrast to the performance of 1CFO with/without γS that is insensitive to system size, 2CFO exhibits a clear system size dependence-while for Pb+Pb the χ2/NDF is around 0-2, for smaller system size in p+Pb and p+p, the χ2/NDF> 5 and larger than 1CFO+γS. This clearly shows a system size dependence of the preference for the freezeout scheme, while 2CFO is preferred in Pb+Pb, 1CFO+γS is preferred in p+Pb and p+p. We have further investigated the role of the missing resonances on strangeness freezeout across SPS to LHC beam energies.

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