Nuclear Theory·nucl-th

Tuesday·May 3, 2016

13 papers—9 primary·4 cross-listed

10
[Submitted on 29 Apr 2016] (cross-list from hep-ph)
$Z_{c} (3900)$ as a $D D ˉ^{*}$ molecule from the pole counting rule
Qin-Rong Gong🇨🇳 · Zhi-Hui Guo🇨🇳 · Ce Meng🇨🇳 · Guang-Yi Tang🇨🇳 · Yu-Fei Wang🇨🇳 · Han-Qing Zheng🇨🇳
A comprehensive study on the nature of the $Z_{c} (3900)$ resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the $J / ψ π$ and $π π$ invariant mass distributions from the $e^{+} e^{-} \to J / ψ π π$ process, the $h_{c} π$ distribution from $e^{+} e^{-} \to h_{c} π π$ and also the $D D ˉ^{*}$ spectrum in the $e^{+} e^{-} \to D D ˉ^{*} π$ process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that $Z_{c} (3900)$ is of $D D ˉ^{*}$ molecular nature, according to the pole counting rule method~[Nucl.~Phys.~A543, 632 (1992); Phys.~Rev.~D 35,~1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the $D D ˉ^{*}$ contact interactions and the explicit $Z_{c}$ exchanges are introduced in our analyses and they lead to the same conclusion.
Comments:
21 pages, 9 figures. To match the published version in PRD. Additional discussion on the spectral density function is included
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1604.08836 [pdf]
PRD(2016)·47 citations
11
[Submitted on 29 Apr 2016] (cross-list from cond-mat.quant-gas)
String-Theory-Based Predictions for Nonhydrodynamic Collective Modes in Strongly Interacting Fermi Gases
H. Bantilan🇬🇧 · J.T. Brewer🇺🇸 · T. Ishii🇺🇸 · W.E. Lewis🇺🇸 · P. Romatschke🇺🇸
Very different strongly interacting quantum systems such as Fermi gases, quark-gluon plasmas formed in high energy ion collisions and black holes studied theoretically in string theory are known to exhibit quantitatively similar damping of hydrodynamic modes. It is not known if such similarities extend beyond the hydrodynamic limit. Do non-hydrodynamic collective modes in Fermi gases with strong interactions also match those from string theory calculations? In order to answer this question, we use calculations based on string theory to make predictions for novel types of modes outside the hydrodynamic regime in trapped Fermi gases. These predictions are amenable to direct testing with current state-of-the-art cold atom experiments.
Comments:
8 pages, 2 figures, 2 tables; v2: matches published version
Subjects:
Quantum Gases (cond-mat.quant-gas); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1605.00014 [pdf]
PRA(2016)·8 citations
12
[Submitted on 1 May 2016] (cross-list from hep-ph)
Jet quenching parameter of quark-gluon plasma in strong magnetic field: Perturbative QCD and AdS/CFT correspondence
Shiyong Li🇺🇸 · Kiminad A. Mamo🇺🇸 · Ho-Ung Yee🇺🇸
We compute the jet quenching parameter $q^$ of QCD plasma in the presence of strong magnetic field in both weakly and strongly coupled regimes. In weakly coupled regime, we compute $q^$ in perturbative QCD at complete leading order (that is, leading log as well as the constant under the log) in QCD coupling constant $α_{s}$ , assuming the hierarchy of scales $α_{s} e B ≪ T^{2} ≪ e B$ . We consider two cases of jet orientations with respect to the magnetic field: 1) the case of jet moving parallel to the magnetic field, 2) the case jet moving perpendicular to the magnetic field. In the former case, we find $q^\sim α_{s}^{2} (e B) T lo g (1/ α_{s})$ , while in the latter we have $q^\sim α_{s}^{2} (e B) T lo g (T^{2} / α_{s} e B)$ . In both cases, this leading order result arises from the scatterings with thermally populated lowest Landau level quarks. In strongly coupled regime described by AdS/CFT correspondence, we find $q^\sim λ (e B) T$ or $q^\sim λ e B T^{2}$ in the same hierarchy of $T^{2} ≪ e B$ depending on whether the jet is moving parallel or perpendicular to the magnetic field, respectively, which indicates a universal dependence of $q^$ on $(e B) T$ in both regimes for the parallel case, the origin of which should be the transverse density of lowest Landau level states proportional to $e B$ . Finally, the asymmetric transverse momentum diffusion in the case of jet moving perpendicular to the magnetic field may give an interesting azimuthal asymmetry of the gluon Bremsstrahlung spectrum in the BDMPS-Z formalism.
Comments:
39 pages, 2 figures; v2: two minor typos fixed, a reference added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1605.00188 [pdf]
PRD(2016)·51 citations
13
[Submitted on 2 May 2016] (cross-list from nucl-ex)
Accessing proton generalized parton distributions and pion distribution amplitudes with the exclusive pion-induced Drell-Yan process at J-PARC
Takahiro Sawada🇹🇼 · Wen-Chen Chang🇹🇼 · Shunzo Kumano🇯🇵 · Jen-Chieh Peng🇺🇸 · Shinya Sawada🇯🇵 · Kazuhiro Tanaka🇯🇵
Generalized parton distributions (GPDs) encoding multidimensional information of hadron partonic structure appear as the building blocks in a factorized description of hard exclusive reactions. The nucleon GPDs have been accessed by deeply virtual Compton scattering and deeply virtual meson production with lepton beam. A complementary probe with hadron beam is the exclusive pion-induced Drell-Yan process. In this paper, we discuss recent theoretical advances on describing this process in terms of nucleon GPDs and pion distribution amplitudes. Furthermore, we address the feasibility of measuring the exclusive pion-induced Drell-Yan process $π^{-} p \to μ^{+} μ^{-} n$ via a spectrometer at the High Momentum Beamline being constructed at J-PARC in Japan. Realization of such measurement at J-PARC will provide a new test of perturbative QCD descriptions of a novel class of hard exclusive reactions. It will also offer the possibility of experimentally accessing nucleon GPDs at large timelike virtuality.
Comments:
35 pages and 16 figures. Replaced with published version. Added the journal reference and DOI
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1605.00364 [pdf]
PRD(2016)·63 citations

Affiliations

first authorsco-authorsvia INSPIRE

Zc​(3900) as a DDˉ∗ molecule from the pole counting rule

String-Theory-Based Predictions for Nonhydrodynamic Collective Modes in Strongly Interacting Fermi Gases

Jet quenching parameter of quark-gluon plasma in strong magnetic field: Perturbative QCD and AdS/CFT correspondence

Accessing proton generalized parton distributions and pion distribution amplitudes with the exclusive pion-induced Drell-Yan process at J-PARC

Affiliations

$Z_{c} (3900)$ as a $D D ˉ^{*}$ molecule from the pole counting rule