Nuclear Theory·nucl-th

Thursday·November 30, 2017

16 papers—9 primary·7 cross-listed

10
The impact of $S$ -wave thresholds $D_{s 1} D ˉ_{s} + c . c .$ and $D_{s 0} D ˉ_{s}^{*} + c . c .$ on vector charmonium spectrum
Zheng Cao🇨🇳 · Qiang Zhao🇨🇳
By investigating the very closely lied $D_{s 1} D ˉ_{s} + c . c .$ and $D_{s 0} D ˉ_{s}^{*} + c . c .$ thresholds at about 4.43 GeV we propose that the $ψ (4415)$ and $ψ (4160)$ can be mixing states between the dynamic generated states of the strong $S$ -wave $D_{s 1} D ˉ_{s} + c . c .$ and $D_{s 0} D ˉ_{s}^{*} + c . c .$ interactions and the quark model states $ψ (4 S)$ and $ψ (2 D)$ . We investigate the $J / ψ K K ˉ$ final states and invariant mass spectrum of $J / ψ K$ to demonstrate that nontrivial lineshapes can arise from such a mechanism. This process, which goes through triangle loop transitions, is located in the vicinity of the so-called "triangle singularity (TS)" kinematics. As a result, it provides a special mechanism for the production of exotic states $Z_{cs}$ , which is the strange partner of $Z_{c} (3900)$ , but with flavor contents of $c c ˉ q s ˉ$ (or $c c ˉ s q ˉ$ ) with $q$ denoting $u / d$ quarks. The lineshapes of the $e^{+} e^{-} \to J / ψ K K ˉ$ cross sections and $J / ψ K (J / ψ K ˉ)$ spectrum are sensitive to the dynamically generated state, and we demonstrate that a pole structure can be easily distinguished from open threshold CUSP effects if an exotic state is created. A precise measurement of the cross section lineshapes can test such a mixing mechanism and provide navel information for the exotic partners of the $Z_{c} (3900)$ in the charmonium spectrum.
↳ hep-phnucl-exnucl-thPRD(2019)·20 citations
11
Anomaly matching for phase diagram of massless $Z_{N}$ -QCD
Yuya Tanizaki🇺🇸 · Yuta Kikuchi🇯🇵 · Tatsuhiro Misumi🇯🇵 · Norisuke Sakai🇯🇵
We elucidate that the phase diagram of massless $N$ -flavor QCD under $Z_{N}$ flavor-twisted boundary condition (massless $Z_{N}$ -QCD) is constrained by an 't Hooft anomaly involving two-form gauge fields. As a consequence, massless $Z_{N}$ -QCD turns out to realize persistent order at any temperatures and quark chemical potentials, namely, the symmetric and gapped phase is strictly forbidden. This is the first result on the finite- $(T, μ)$ phase diagram in QCD-type theories based on anomaly matching related to center and discrete axial symmetries.
↳ hep-thcond-mat.str-elhep-lathep-ph+1PRD(2018)·96 citations
12
Effective field theory for one-dimensional nonrelativistic particles with contact interaction
Soke Yuen Yong · Dam Thanh Son
We consider a field theory describing interacting nonrelativistic particles of two types, which map to each other under time reversal, with point-like interaction. We identify a new type of interaction which depends on the relative velocity between the particles. We compute the renormalization group running of the coupling constants and find a fixed point and a fixed line. We show that the scattering amplitudes can be expressed in terms of three parameters. The result matches with a quantum mechanical analysis and represents the most general point-like interaction consistent with unitarity and time reversal invariance.
↳ cond-mat.quant-gasnucl-thquant-phPRA(2018)·3 citations
13
Molecular $Ω_{b}$ states
Wei-Hong Liang🇨🇳 · J. M. Dias🇧🇷 · V. R. Debastiani🇪🇸 · E. Oset🇪🇸
Motivated by the recent finding of five $Ω_{c}$ states by the LHCb collaboration, and the successful reproduction of three of them in a recent approach searching for molecular states of meson-baryon with the quantum numbers of $Ω_{c}$ , we extend these ideas and make predictions for the interaction of meson-baryon in the beauty sector, searching for poles in the scattering matrix that correspond to physical states. We find several $Ω_{b}$ states: two states with masses 6405~MeV and 6465~MeV for $J^{P} = \frac{1}{2}^{-}$ ; two more states with masses 6427~MeV and 6665~MeV for $\frac{3}{2}^{-}$ ; and three states between 6500 and 6820~MeV, degenerate with $J^{P} = \frac{1}{2}^{-}, \frac{3}{2}^{-}$ , stemming from the interaction of vector-baryon in the beauty sector.
↳ hep-phnucl-thNPB(2018)·35 citations
14
Overlap between Lattice QCD and HRG with in-medium effects and parity doubling
Kenji Morita🇵🇱 · Chihiro Sasaki🇵🇱 · Pok Man Lo🇩🇪 · Krzysztof Redlich🇵🇱
We investigate the fluctuations and correlations involving baryon number in hot hadronic matter with modified masses of negative-parity baryons, in the context of the hadron resonance gas. Temperature-dependent masses are adopted from the recent lattice QCD results and from a chiral effective model which implements the parity doubling structure with respect to the chiral symmetry. Confronting the baryon number susceptibility, baryon-charge correlation, and baryon-strangeness correlation and their ratios with the lattice QCD data, we show that the strong downward mass shift in hyperons can accidentally reproduce some correlation ratios, however it also tends to overshoot the individual fluctuations and correlations. This indicates, that in order to correctly account for the influence of the chiral symmetry restoration on the fluctuation observables, a consistent framework of in-medium effects beyond hadron mass shifts is required.
↳ hep-phhep-latnucl-thEPJ Web Conf.(2018)·4 citations
15
Pole structure and compositeness
J.A. Oller🇪🇸
We present in this talk a series of new results on the nature of a bound state or resonance based on the calculation of the expectation values of the number operators of the free particles in the state of interest. In this way, a new universal criterion for the elementariness of a bound state emerges. In the case of large particle wavelengths compared to the range of their interaction, a new closed formula for the compositeness of a bound state in a two-particle continuum is obtained. The extension of these results to resonances with respect to the open channels can be given by making use in addition of suitable phase-factor transformations as also reviewed here. We end with a discussion on the $X (3872)$ as possible double- or triple-pole virtual state, which would be the first case in particle phenomenology.
↳ hep-phhep-thnucl-thPoS(2018)·1 citation
16
Quantum and Classical Dynamics of Heavy Quarks in a Quark-Gluon Plasma
Jean-Paul Blaizot🇫🇷 · Miguel Angel Escobedo🇫🇮
We derive equations for the time evolution of the reduced density matrix of a collection of heavy quarks and antiquarks immersed in a quark gluon plasma. These equations, in their original form, rely on two approximations: the weak coupling between the heavy quarks and the plasma, the fast response of the plasma to the perturbation caused by the heavy quarks. An additional semi-classical approximation is performed. This allows us to recover results previously obtained for the abelian plasma using the influence functional formalism. In the case of QCD, specific features of the color dynamics make the implementation of the semi-classical approximation more involved. We explore two approximate strategies to solve numerically the resulting equations in the case of a quark-antiquark pair. One involves Langevin equations with additional random color forces, the other treats the transition between the singlet and octet color configurations as collisions in a Boltzmann equation which can be solved with Monte Carlo techniques.
↳ hep-phnucl-thJHEP(2018)·128 citations

Affiliations

first authorsco-authorsvia INSPIRE

The impact of S-wave thresholds Ds1​Dˉs​+c.c. and Ds0​Dˉs∗​+c.c. on vector charmonium spectrum

Anomaly matching for phase diagram of massless ZN​-QCD

Effective field theory for one-dimensional nonrelativistic particles with contact interaction

Molecular Ωb​ states

Overlap between Lattice QCD and HRG with in-medium effects and parity doubling

Pole structure and compositeness

Quantum and Classical Dynamics of Heavy Quarks in a Quark-Gluon Plasma

Affiliations

The impact of $S$ -wave thresholds $D_{s 1} D ˉ_{s} + c . c .$ and $D_{s 0} D ˉ_{s}^{*} + c . c .$ on vector charmonium spectrum

Anomaly matching for phase diagram of massless $Z_{N}$ -QCD

Molecular $Ω_{b}$ states