Nuclear Theory·nucl-th

Monday·October 4, 2021

9 papers—4 primary·5 cross-listed

05
Scalar and tensor resonances in $J / ψ$ radiative decays
JPAC Collaboration: A. Rodas🇺🇸 · A. Pilloni🇮🇹 · M. Albaladejo🇪🇸 · C. Fernandez-Ramirez🇲🇽 · V. Mathieu🇪🇸 · A. P. Szczepaniak🇺🇸
We perform a systematic analysis of the $J / ψ \to γ π^{0} π^{0}$ and $\to γ K_{S}^{0} K_{S}^{0}$ partial waves measured by BESIII. We use a large set of amplitude parametrizations to reduce the model bias. We determine the physical properties of seven scalar and tensor resonances in the 1-2.5 GeV mass range. These include the well known $f_{0} (1500)$ and $f_{0} (1710)$ , that are considered to be the primary glueball candidates. The hierarchy of resonance couplings determined from this analysis favors the latter as the one with the largest glueball component.
↳ hep-phhep-exnucl-thEPJC(2022)·62 citations
06
High-order baryon number fluctuations within the fRG approach
Wei-jie Fu🇨🇳 · Xiaofeng Luo🇨🇳 · Jan M. Pawlowski🇩🇪 · Fabian Rennecke🇺🇸 · Rui Wen🇨🇳 · Shi Yin🇨🇳
We compute high-order baryon number fluctuations at finite temperature and density within a QCD-assisted low energy effective field theory. Quantum, thermal and density fluctuations are incorporated with the functional renormalization group approach. Quantum and in-medium fluctuations are encoded via the evolution of renormalization group flow equations. The resulting fourth- and sixth-order baryon number fluctuations meet the lattice benchmark results at vanishing density. They are consistent with experimental measurements, and in particular, the non-monotonic dependence of the kurtosis of net-baryon number distributions on the collision energy is observed in our calculations. This non-monotonicity arises from the increasingly sharpened chiral crossover with the decrease of collision energy.
↳ hep-phnucl-exnucl-thPoS(2022)·1 citation
07
Non-radial oscillation modes in hybrid stars: consequences of a mixed phase
Deepak Kumar🇮🇳 · Hiranmaya Mishra🇮🇳 · Tuhin Malik🇵🇹
We study the possibility of the existence of a deconfined quark matter in the core of neutron star (NS)s and its relation to non-radial oscillation modes in NSs and hybrid star (HS)s. We use relativistic mean field (RMF) models to describe the nuclear matter at low densities and zero temperature. The Nambu--Jona-Lasinio (NJL) model is used to describe the quark matter at high densities and zero temperature. A Gibbs construct is used to describe the hadron-quark phase transition (HQPT) at large densities. Within the model, as the density increases, a mixed phase (MP) appears at density about $2.5$ times the nuclear matter saturation density $(ρ_{0})$ and ends at density about $5 ρ_{0}$ beyond which the pure quark matter phase appears. It turns out that a stable HS of maximum mass, $M = 2.27 M_{⊙}$ with radius $R = 14$ km (for NL3 parameterisation of nuclear RMF model), can exist with the quark matter in the core in a MP only. HQPT in the core of maximum mass HS occurs at radial distance, $r_{c} = 0.27 R$ where the equilibrium speed of sound shows a discontinuity. Existence of quark matter in the core enhances the non-radial oscillation frequencies in HSs compared to NSs of the same mass. This enhancement is significantly large for the $g$ modes. Such an enhancement of the $g$ modes is also seen for a density dependent Bayesian (DDB) parmeterisation of the nucleonic EOS. The non-radial oscillation frequencies depend on the vector coupling in the NJL model. The values of $g$ and $f$ mode frequencies decrease with increase the vector coupling in quark matter.
↳ hep-phnucl-thJCAP(2023)·33 citations
08
Is $Z_{cs} (3982)$ a molecular partner of $Z_{c} (3900)$ and $Z_{c} (4020)$ states?
V. Baru🇩🇪 · E. Epelbaum🇩🇪 · A. A. Filin🇩🇪 · C. Hanhart🇩🇪 · A. V. Nefediev🇷🇺
We perform an effective-field-theory-based coupled-channel analysis of the recent BES III data on the $e^{+} e^{-}$ annihilation into the final state $K^{+} (D_{s}^{-} D^{* 0} + D_{s}^{*-} D^{0})$ in a wide energy range and extract the poles responsible for the formation of the $Z_{cs} (3982)$ . We identify two scenarios which provide a similar description of the experimental mass distributions but result in utterly different predictions for the spin partners of the $Z_{cs} (3982)$ : although both scenarios are consistent with the $Z_{cs}$ as a $S U (3)$ partner of the $Z_{c} (3900)$ , the $Z_{c} (4020)$ appears naturally as a spin partner of these states only in one of them (fit 1) while in the other (fit 2) its nature has to be different. Also, the $Z_{cs} (3982)$ has a $J^{P} = 1^{+}$ spin partner near the $D ˉ_{s}^{*} D^{*}$ threshold in fit 1, while no such state exists in fit 2. We predict the $D ˉ_{s}^{*} D^{*}$ invariant mass distribution in the $J^{P} = 1^{+}$ channel for the reaction $e^{+} e^{-} \to K^{+} D_{s}^{*-} D^{* 0}$ and argue that this line shape can be used to distinguish between the two scenarios once data in this channel are available.
↳ hep-phhep-exhep-latnucl-thPRD(2022)·36 citations
09
Photons from relativistic nuclear collisions
Hannah Vormann🇩🇪 · Tom Reichert🇩🇪 · Christian Spieles🇩🇪 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
Collisions of atomic nuclei at relativistic velocities allow to recreate the conditions encountered in neutron stars or in the early universe micro-seconds after the Big Bang. These reactions are performed in today's largest accelerator facilities, e.g. at CERN in Geneva, at the Relativistic Heavy Ion Collider at Brookhaven, NY or in the planned FAIR facility in Darmstadt Germany. During such a collision the matter is heated up to hundreds of MeV (billions of degrees) and compressed to densities of $3 - 10$ times the density inside ordinary atomic nuclei (i.e. $1 0^{17} - 1 0^{18}$ kg/m $^{3}$ ). Usually these collisions are studied via the measurement of a multitude of strongly interacting particles, called hadrons, that are emitted at the end of the collision. However, also some photons are created. These photons are of special interest as they allow to look into the early stage of the collisions, because they are only very weakly (namely only electro-magnetically) interacting with the hadrons of the created fireball. This paper elucidates the physics of the photons and what can be learned from them.
↳ physics.pop-phnucl-thEur.J.Phys.(2022)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Scalar and tensor resonances in J/ψ radiative decays

High-order baryon number fluctuations within the fRG approach

Non-radial oscillation modes in hybrid stars: consequences of a mixed phase

Is Zcs​(3982) a molecular partner of Zc​(3900) and Zc​(4020) states?

Photons from relativistic nuclear collisions

Affiliations

Scalar and tensor resonances in $J / ψ$ radiative decays

Is $Z_{cs} (3982)$ a molecular partner of $Z_{c} (3900)$ and $Z_{c} (4020)$ states?