We employ the Langevin equation and Wigner function to describe the bottom quark dynamical evolutions and their formation into a bound state in the expanding Quark Gluon Plasma (QGP). The additional ...suppressions from parton inelastic scatterings are supplemented in the regenerated bottomonium. Hot medium modifications on ϒ(1S) properties are studied consistently by taking the bottomonium potential to be the color-screened potential from Lattice results, which affects both ϒ(1S) regeneration and dissociation rates. Finally, we calculated the ϒ(1S) nuclear modification factor RAArege from bottom quark combination with different diffusion coefficients in Langevin equation, representing different thermalization of bottom quarks. In the central Pb–Pb collisions (b=0) at sNN=5.02 TeV, we find a non-negligible ϒ(1S) regeneration, and it is small in the minimum bias centrality. The connections between bottomonium regeneration and bottom quark energy loss in the heavy ion collisions are also discussed.
We study the J/ψ production based on coalescence model at sNN=2.76 and 5.02 TeV Pb–Pb collisions. With the colliding energy increasing from 2.76 TeV to 5.02 TeV, the number of charm pairs is enhanced ...by more than 50%. However, the ratio of J/ψ inclusive nuclear modification factors RAA5.02 TeV/RAA2.76 TeV is only about 1.1∼1.2. We find that the regeneration of J/ψ is proportional to the densities of charm and anti-charm quarks, instead of their total numbers. The charm quark density is diluted by the strong expansion of quark gluon plasma, which suppresses the combination probability of heavy quarks and J/ψ regeneration. This effect is more important in higher colliding energies where QGP expansion is strong. We also propose the ratio NJ/ψ/(Nc)2 as a measurement of c and c¯ coalescence probability, which is only affected by the heavy quark diffusions in QGP, and does not depend on the inputs such as cold nuclear matter effects and cross sections of charm quark production. Further more, we give the predictions at the energy of Future Circular Collider (sNN=39 TeV).
We employ the time-dependent Schrödinger equation with different complex potentials to study the bottomonium sequential suppression in Pb-Pb collisions at sNN=2.76 TeV and 5.02 TeV and Au-Au ...collisions at sNN=200 GeV. Both color screening effect and the random scatterings with thermal partons are considered in the real and imaginary parts of the heavy-quark potentials. As the real part of the heavy-quark potential is between the free energy F(T,r) and the internal energy U(T,r) of heavy quarkonium, we parametrize different potentials with a function of F and U to evolve the bottomonium wave packages in the medium. We find that when the real part of the potential is close to U(T,r), it can explain well the pattern of bottomonium sequential suppression where their nuclear modification factors satisfy the relation RAA(1s)>RAA(2s)>RAA(3s) observed in experiments. In the other limit of F(T,r), bottomonium wave packages tend to expand due to weak attracted force, which results in evident transitions from ϒ(2s) to ϒ(3s) components and does not satisfy the sequential suppression pattern. We suggest that the bottomonium sequential suppression can be a probe of strong heavy-quark potential in the medium.
Charmonium directed flows are studied based on transport model coupled with the realistic three dimensional expansions of the bulk medium. The non-central symmetric nucleus-nucleus collisions can ...generate the rotating quark-gluon plasma (QGP) with symmetry-breaking longitudinal distributions. In sNN=200 GeV Au+Au semi-central collisions, charmonium are primordially produced in the initial hard process, they are mainly dissociated by the initial tilted source with high temperatures and then move out of the bulk medium to keep the early information of the medium. The momentum distribution of primordially produced charmonia is less affected by the hydrodynamic expansions of QGP where its tilted shape is being diluted. This biased dissociation can generate directed flows of J/ψ and ψ(2S) which are much larger than the values of light charged hadrons and open heavy flavor. Charmonium directed flows can help to quantify the rapidity-odd distributions of QGP initial energy densities in nucleus-nucleus collisions.
The static properties and dynamic evolution of bottomonium states in a hot QCD medium are investigated through the Schrödinger equation with complex heavy quark potentials, which have been presented ...recently in a lattice QCD study and with three different extractions. This approach builds a direct connection between the in-medium heavy quark potentials from the lattice QCD to the experimental observables. The yields and nuclear modification factors
R
AA
of bottomonium in Pb–Pb collisions at
s
NN
=
5.02
TeV are calculated in this work. Our results show a large suppression of the bottomonium yield in heavy ion collisions due to the large imaginary potential. To understand bottomonium
R
AA
based on lattice QCD potentials, we propose a formation time for bottomonium states and find that experimental data can be well explained with the heavy quark potential extracted by the Padé fit, which shows no color screening in the real part potential.
We study the charmonium coherent photoproduction and hadroproduction consistently with modifications from both cold and hot nuclear matters. The strong electromagnetic fields from fast moving nucleus ...interact with the other target nucleus, producing abundant charmonium in the extremely low transverse momentum region pT<0.1 GeV/c. This results in significative enhancement of J/ψ nuclear modification factor in semi-central and peripheral collisions. In the middle pT region such as pT<3∼5 GeV/c, J/ψ final yield is dominated by the combination process of single charm and anti-charm quarks moving in the deconfined matter, c+c¯→J/ψ+g. In the higher pT region, J/ψ production are mainly from parton initial hard scatterings at the beginning of nucleus–nucleus collisions and decay of B hadrons. We include all of these production mechanisms and explain the experimental data well in different colliding centralities and transverse momentum regions.
We study cold and hot nuclear matter effects on charmonium production in p+Pb collisions at sNN=5.02 TeV in a transport approach. At the forward rapidity, the cold medium effect on all the cc¯ states ...and the hot medium effect on the excited cc¯ states only can explain well the J/ψ and ψ′ yield and transverse momentum distribution measured by the ALICE collaboration, and we predict a significantly larger ψ′pT broadening in comparison with J/ψ. However, we can not reproduce the J/ψ and ψ′ data at the backward rapidity with reasonable cold and hot medium effects.
We study the Bc+ production in Pb-Pb collisions at sNN=5.02 TeV. In the quark-gluon plasma (QGP) produced in heavy-ion collisions, heavy quarks make random motions with the energy loss. We employ the ...Langevin equations to study the non-equilibrium distributions of heavy quarks and the Instantaneous Coalescence Model (ICM) to study the hadronization process. Due to abundant charm and bottom quarks in the QGP, their coalescence probability is significantly enhanced compared with the situations in proton-proton collisions. We find that the final production of Bc+ is increased by the coalescence process, which makes the nuclear modification factor (RAA) of Bc+ larger than unit. Our model explains the experimental data well at semi-central and central collisions. The observation of RAA(Bc+)>1 is regarded as an evident and strong signal of the existence of the deconfined medium generated in heavy-ion collisions.
Black holes are a powerful setting for studying general relativity and theories beyond GR. However, analytical solutions for rotating black holes in beyond-GR theories are difficult to find because ...of the complexity of such theories. In this paper, we solve for the deformation to the near-horizon extremal Kerr metric due to two example string-inspired beyond-GR theories: Einstein-dilaton-Gauss-Bonnet and dynamical Chern-Simons theory. We accomplish this by making use of the enhanced symmetry group of NHEK and the weak-coupling limit of EdGB and dCS. We find that the EdGB metric deformation has a curvature singularity, while the dCS metric is regular. From these solutions, we compute orbital frequencies, horizon areas, and entropies. This sets the stage for analytically understanding the microscopic origin of black hole entropy in beyond-GR theories.
Mitochondria are the main sites for oxidative phosphorylation and synthesis of adenosine triphosphate in cells, and are known as cellular power factories. The phrase “secondary mitochondrial ...diseases” essentially refers to any abnormal mitochondrial function other than primary mitochondrial diseases, i.e., the process caused by the genes encoding the electron transport chain (ETC) proteins directly or impacting the production of the machinery needed for ETC. Mitochondrial diseases can cause adenosine triphosphate (ATP) synthesis disorder, an increase in oxygen free radicals, and intracellular redox imbalance. It can also induce apoptosis and, eventually, multi-system damage, which leads to neurodegenerative disease. The catechin compounds rich in tea have attracted much attention due to their effective antioxidant activity. Catechins, especially acetylated catechins such as epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), are able to protect mitochondria from reactive oxygen species. This review focuses on the role of catechins in regulating cell homeostasis, in which catechins act as a free radical scavenger and metal ion chelator, their protective mechanism on mitochondria, and the protective effect of catechins on mitochondrial deoxyribonucleic acid (DNA). This review highlights catechins and their effects on mitochondrial functional metabolic networks: regulating mitochondrial function and biogenesis, improving insulin resistance, regulating intracellular calcium homeostasis, and regulating epigenetic processes. Finally, the indirect beneficial effects of catechins on mitochondrial diseases are also illustrated by the warburg and the apoptosis effect. Some possible mechanisms are shown graphically. In addition, the bioavailability of catechins and peracetylated-catechins, free radical scavenging activity, mitochondrial activation ability of the high-molecular-weight polyphenol, and the mitochondrial activation factor were also discussed.
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