Nuclear Theory·nucl-th
14 papers—8 primary·6 cross-listed
Tracie Michlin🇺🇸 · W.N. Polyzou🇺🇸 · Fatih Bulut🇹🇷
We investigate both theoretical and computational aspects of using wavelet bases to decouple physics on different scales in quantum field theory.
Fabian Rennecke🇩🇪 · Bernd-Jochen Schaefer🇩🇪
The low-energy sector of QCD with dynamical quark flavors at non-vanishing chemical potential and temperature is studied with a non-perturbative functional renormalization group method. The analysis is performed in different truncations in order to explore fluctuation-induced modifications of the quark-meson correlations as well as quark and meson propagators on the chiral phase transition of QCD. Depending on the chosen truncation significant quantitative implications on the phase transition are found. In the chirally symmetric phase, the quark flavor composition of the pseudoscalar -meson complex turns out to be drastically sensitive to fluctuation-induced modifications in the presence of the axial anomaly. This has important phenomenological consequences for the assignment of chiral partners to these mesons.
A. Li · N. B. Zhang · B. Qi · G. F. Burgio
For the propose of confronting updated pulsar observations with developed neutron star equation of states (EoSs), we employ four unified EoSs for both the core and the crust, namely BCPM, BSk20, BSk21, Shen-TM1, as well as two non-unified EoSs widely used in the literature, i.e. APR and GM1 EoS, which are commonly matched with the Negele-Vautherin and the Baym-Pethick-Sutherland crust EoS. All the core EoSs satisfy the recent observational constraints of the two massive pulsars whose masses are precisely measured. We show that the NS mass-equatorial radius relations are slightly affected by the smoothness at the core-crust matching interface. Moreover, the uncertainties in the crust EoS and the matching interface bring insignificant changes, even at maximally rotating (Keplerian) configurations. We also find that for all four unified EoSs, rotation can increase the star's gravitational mass up to and the equatorial radius by , which are consistent with the previous calculations using non-unified EoSs. For stars as heavy as 1.4 M, the radius increase is more pronounced, reaching , i.e. km. Moreover, by confronting the results using unified EoSs, which give the correct empirical values at saturation density, with two controversial determinations of the radius for the fast rotator 4U 1608-52, we address that a small radius may be better justified for this source.
Akira Watanabe🇹🇼 · Chung Wen Kao🇹🇼 · Katsuhiko Suzuki🇯🇵
We investigate the valence quark distribution function of the pion in the framework of the chiral constituent quark model and evaluate the meson cloud effects on . We explicitly demonstrate how the meson cloud effects affect in detail. We find that the meson cloud correction causes an overall 32\% reduction of the valence quark distribution and an enhancement at the small Bjorken regime. Besides, we also find that the dressing effect of the meson cloud will make the valence quark distribution to be softer in the large region.
Yacine Mehtar-Tani🇺🇸 · Konrad Tywoniuk🇨🇭
We argue that contemporary jet substructure techniques might facilitate a more direct measurement of hard medium-induced gluon bremsstrahlung in heavy-ion collisions, and focus specifically on the "soft drop declustering" procedure that singles out the two leading jet substructures. Assuming coherent jet energy loss, we find an enhancement of the distribution of the energy fractions shared by the two substructures at small subjet energy caused by hard medium-induced gluon radiation. Departures from this approximation are discussed, in particular, the effects of colour decoherence and the contamination of the grooming procedure by soft background. Finally, we propose a complementary observable, that is the ratio of the two-pronged probability in Pb-Pb to proton-proton collisions and discuss its sensitivity to various energy loss mechanisms.
Mamiya Kawaguchi🇯🇵 · Shinya Matsuzaki🇯🇵
It is simply anticipated that in a strong magnetic configuration, the Landau quantization ceases the neutral rho meson to decay to the charged pion pair, so the neutral rho meson will be long-lived. To closely access this naive observation, we explicitly compute the charged pion-loop in the magnetic field at the one-loop level, to evaluate the magnetic dependence of the lifetime for the neutral rho meson as well as its mass.Due to the dimensional reduction induced by the magnetic field (violation of the Lorentz invariance), the polarization (spin ) modes of the rho meson, as well as the corresponding pole mass and width, are decomposed in a nontrivial manner compared to the vacuum case. To see the significance of the reduction effect, we simply take the lowest-Landau level approximation to analyze the spin-dependent rho masses and widths. We find that the "fate" of the rho meson may be more complicated because of the magnetic-dimensional reduction: as the magnetic field increases, the rho width for the spin starts to develop, reach a peak, to be vanishing at the critical magnetic field to which the folklore refers. On the other side, the decay rates of the other rhos for monotonically increase as the magnetic field develops. The correlation between the polarization dependence and the Landau-level truncation is also addressed.
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