Nuclear Theory·nucl-th

Thursday·September 17, 2015

9 papers—4 primary·5 cross-listed

05
[Submitted on 27 Aug 2015] (cross-list from hep-th)
Quasinormal modes of magnetic and electric black branes versus far from equilibrium anisotropic fluids
Stefan Janiszewski🇨🇦 · Matthias Kaminski🇺🇸
Detailed knowledge about equilibration processes is of interest for various fields of physics, including heavy ion collision experiments and quantum quenched condensed matter systems. We study the approach to equilibrium at late times within two types of strongly coupled thermal systems in 3+1 dimensions: systems in the presence of (i) a non-zero charge density, or (ii) a magnetic field at vanishing charge density. Utilizing the gauge/gravity correspondence, we map the aforementioned problem to the computation of quasinormal frequencies around two particular classes of black branes within the Einstein-Maxwell theory. We compute (i) the tensor and vector quasinormal modes of Reissner-Nordström black branes and (ii) the scalar, as well as tensor quasinormal modes of magnetic black branes. Some of these quasinormal modes correspond to the late-time relaxation of the above systems after starting with initial pressure anisotropy. We provide benchmarks which need to be matched at late-times by all holographic thermalization codes with the appropriate symmetries.
Comments:
v2 (published in Phys. Rev. D): 46 pages, 12 figures, 8 tables, added vector modes for RN AdS5 case, extended discussion of previous results in introduction, additional ancillary files included; v1: 43 pages, 11 figures, 7 tables, 2 Mathematica notebooks
Subjects:
High Energy Physics — Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
1508.06993 [pdf]
PRD(2016)·52 citations
06
[Submitted on 15 Sept 2015] (cross-list from nucl-ex)
The current evaluation of Vud
J.C. Hardy🇺🇸 · I.S. Towner🇨🇦
The Vud element of the Cabibbo-Kobayashi-Maskawa matrix can be determined from several different experimental approaches: either 0+-to-0+ superallowed nuclear beta decays, neutron decay, nuclear mirror decays, or pion beta decay. Currently all give consistent results but, because the nuclear superallowed value has an uncertainty at least a factor of seven less than all other results, it dominates the result. A new survey of world superallowed-decay data establishes the Ft values of 14 separate superallowed transitions to a precision of order 0.1% or better; and all 14 are statistically consistent with one another. This very robust data set yields the result Vud = 0.97417(21), the value we recommend.
Comments:
Talk presented CIPANP2015. 8 pages, LaTeX, 2 eps figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1509.04743 [pdf]
0 citations
07
[Submitted on 16 Sept 2015] (cross-list from hep-ph)
$p ˉ p$ annihilation into $D ˉ D$ meson pair within an effective Lagrangian model
R. Shyam🇮🇳 · H. Lenske🇩🇪
We study the charmed meson pair ( $D ˉ^{0} D^{0}$ and $D^{-} D^{+}$ ) production in $p ˉ p$ annihilation within an effective Lagrangian model that has only the baryon-meson degrees of freedom and involves the physical hadron masses. The reaction amplitudes include terms corresponding to the t-channel $Λ_{c}^{+}$ , $Σ_{c}^{+}$ and $Σ_{c}^{++}$ baryon exchanges and the s-channel excitation, propagation and decay of the $Ψ$ (3770) resonance into the charmed mesons. The initial- and final-state distortion effects have been accounted for by using a simple eikonal approximation-based procedure in the same way as was done in our previous study of the $p ˉ p \to Λ ˉ_{c}^{-} Λ_{c}^{+}$ reaction within a similar model. The $D ˉ^{0} D^{0}$ production reaction is dominated by the $Λ_{c}^{+}$ baryon exchange process, and the corresponding total cross sections are predicted to be in the range of 0.18 - 0.7 $μ$ b for antiproton beam momenta varying between threshold and 20 $G e V / c$ . The $Ψ$ (3770) resonance contributions have a large influence on the differential cross sections of the $D^{-} D^{+}$ production reaction.
Comments:
23 pages, 10 figures, Journal Print version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1509.04786 [pdf]
PRD(2016)·12 citations
08
[Submitted on 16 Sept 2015] (cross-list from hep-ph)
Nuclear modification of forward $J / ψ$ production in proton-nucleus collisions at the LHC
B. Ducloué🇫🇮 · T. Lappi🇫🇮 · H. Mäntysaari🇫🇮
We re-evaluate the nuclear suppression of forward $J / ψ$ production at high energy in the Color Glass Condensate framework. We use the collinear approximation for the projectile proton probed at large $x$ and an up to date dipole cross section fitted to HERA data to describe the target in proton-proton collisions. We show that using the Glauber approach to generalize the proton dipole cross section to the case of a nucleus target leads to a nuclear modification factor much closer to LHC data than previous estimates using the same framework.
Comments:
4 pages, 2 figures. Talk given by B.D. at the 7th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2015), 29 June - 3 July 2015, Montreal, Canada
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1509.04856 [pdf]
Nucl.Part.Phys.Proc.(2016)·2 citations
09
[Submitted on 14 Sept 2015] (cross-list from hep-ph)
Robust characteristics of nongaussian fluctuations from the NJL model
Jiunn-Wei Chen🇩🇪 · Jian Deng🇨🇳 · Hiroaki Kohyama🇹🇼 · Lance Labun🇺🇸
We evaluate the third- and fourth-order baryon, charge and strangeness susceptibilities near a chiral critical point using the Nambu-Jona-Lasinio model. We identify robust qualitative behaviours of the susceptibilities along hypothetical freeze-out lines that agree with previous model studies. Quantitatively, baryon number fluctuations are the largest in magnitude and thus offer the strongest signal when freeze-out occurs farther away from a critical point. Charge and strangeness susceptibilities also diverge at a critical point, but the area where the divergence dominates is smaller, meaning freeze-out must occur closer to a critical point for a signal to be visible in these observables. In case of strangeness, this is attributable to the relatively large strange quark mass. Plotting the third- and fourth-order susceptibilities against each other along the freeze-out line exhibits clearly their non-montonicity and robust features.
Comments:
14 pages, 17 figures, revtex style
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1509.04968 [pdf]
PRD(2016)·52 citations

Affiliations

first authorsco-authorsvia INSPIRE

Quasinormal modes of magnetic and electric black branes versus far from equilibrium anisotropic fluids

The current evaluation of Vud

pˉ​p annihilation into DˉD meson pair within an effective Lagrangian model

Nuclear modification of forward J/ψ production in proton-nucleus collisions at the LHC

Robust characteristics of nongaussian fluctuations from the NJL model

Affiliations

$p ˉ p$ annihilation into $D ˉ D$ meson pair within an effective Lagrangian model

Nuclear modification of forward $J / ψ$ production in proton-nucleus collisions at the LHC