Nuclear Theory·nucl-th

Tuesday·March 15, 2016

12 papers—8 primary·4 cross-listed

09
[Submitted on 12 Mar 2016] (cross-list from hep-ph)
Thermo-magnetic effects in quark matter: Nambu--Jona-Lasinio model constrained by lattice QCD
R. L. S. Farias🇧🇷 · V. S. Timoteo🇧🇷 · S. S. Avancini🇧🇷 · M. B. Pinto🇧🇷 · G. Krein🇧🇷
The phenomenon of inverse magnetic catalysis of chiral symmetry in QCD predicted by lattice simulations can be reproduced within the Nambu--Jona-Lasinio model if the coupling~ $G$ of the model decreases with the strength $B$ of the magnetic field and temperature~ $T$ . The thermo-magnetic dependence of $G (B, T)$ is obtained by fitting recent lattice QCD predictions for the chiral transition order parameter. Different thermodynamic quantities of magnetized quark matter evaluated with $G (B, T)$ are compared with the ones obtained at constant coupling, $G$ . The model with $G (B, T)$ predicts a more dramatic chiral transition as the field intensity increases. In addition, the pressure and magnetization always increase with $B$ for a given temperature. Being parametrized by four magnetic field dependent coefficients and having a rather simple exponential thermal dependence our accurate ansatz for the coupling constant can be easily implemented to improve typical model applications to magnetized quark matter.
Comments:
13 pages, 9 figures, v3 EPJA version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1603.03847 [pdf]
EPJA(2017)·146 citations
10
[Submitted on 12 Mar 2016] (cross-list from hep-ph)
Evidence for Some New Hyperon Resonances -- to be Checked by $K_{L}$ Beam Experiments
B. S. Zou🇨🇳
Quenched and unquenched quark models predict very different patterns for the spectrum of the low excited hyperon states. Evidence is accumulating for the existence of some new hyperon resonances, such as a $Σ^{*}$ of spin-parity $J^{P} = 1/ 2^{-}$ around 1400 MeV instead of 1620 MeV as listed in PDG, a new $Σ (1540) 3/ 2^{-}$ resonance, a new narrow $Λ (1670) 3/ 2^{-}$ resonance and a new $Λ (1680) 3/ 2^{+}$ resonance. All these new hyperon resonances fit in the predicted pattern of the unquenched quark models very well. It is extremely important to check and establish the spectrum of these low excited hyperon states by the proposed $K_{L}$ beam experiments at JLAB.
Comments:
Talk for the workshop on Physics with Neutral Kaon beam at JLab
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1603.03927 [pdf]
4 citations
11
[Submitted on 14 Mar 2016] (cross-list from hep-ph)
Hadronic molecular states from the $K K ˉ^{*}$ interaction
Pei-Liang Lü🇨🇳 · Jun He🇨🇳
In this work, the $K K ˉ^{*}$ interaction is studied in a quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model. With the help of the hidden-gauge Lagrangian, the exchanges of pseudoscalar mesons ( $π$ and $η$ ) and vector mesons ( $ρ$ , $ω$ and $ϕ$ ) are considered to describe the $K K ˉ^{*}$ interaction. Besides the direct vector-meson exchange which can be related to the Weinberg-Tomozawa term, pseudoscalar-meson exchanges also play important roles in the mechanism of the $K K ˉ^{*}$ interaction. The poles of scattering amplitude are searched to find the molecular states produced from the $K K ˉ^{*}$ interaction. In the case of quantum number $I^{G} (J^{P C}) = 0^{+} (1^{++})$ , a pole is found with a reasonable cutoff, which can be related to the $f_{1} (1285)$ in experiment. Another bound state with $0^{-} (1^{+-})$ is also produced from the $K K ˉ^{*}$ interaction, which can be related to the $h_{1} (1380)$ . In the isovector sector, the interaction is much weaker and a bound state with $1^{+} (1^{+})$ relevant to the $b_{1} (1235)$ is produced but at a larger cutoff. Our results suggest that in the hadronic molecular state picture the $f_{1} (1285)$ and $b_{1} (1235)$ are the strange partners of the $X (3872)$ and $Z_{c} (3900)$ , respectively.
Comments:
5 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1603.04168 [pdf]
EPJA(2016)·20 citations
12
[Submitted on 14 Mar 2016] (cross-list from hep-ph)
Evidence of strong proton shape fluctuations from incoherent diffraction
Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸
We show within the saturation framework that measurements of exclusive vector meson production at high energy provide evidence for strong geometric fluctuations of the proton. In comparison, the effect of saturation scale and color charge fluctuations is weak. This knowledge will allow detailed future measurements of the incoherent cross section to tightly constrain the fluctuating geometry of the proton as a function of the parton momentum fraction $x$ .
Comments:
7 pages, 4 figures. v2: typos fixed and references added. To be published in PRL
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1603.04349 [pdf]
PRL(2016)·248 citations

Affiliations

first authorsco-authorsvia INSPIRE

Thermo-magnetic effects in quark matter: Nambu--Jona-Lasinio model constrained by lattice QCD

Evidence for Some New Hyperon Resonances -- to be Checked by KL​ Beam Experiments

Hadronic molecular states from the KKˉ∗ interaction

Evidence of strong proton shape fluctuations from incoherent diffraction

Affiliations

Evidence for Some New Hyperon Resonances -- to be Checked by $K_{L}$ Beam Experiments

Hadronic molecular states from the $K K ˉ^{*}$ interaction