Nuclear Theory·nucl-th

Thursday·October 1, 2015

20 papers—11 primary·9 cross-listed

12
SU(N) Multi-Skyrmions at Finite Volume
Fabrizio Canfora🇨🇱 · Marco Di Mauro🇮🇹 · Maxim A. Kurkov🇮🇹 · Adele Naddeo🇮🇹
We study multi-soliton solutions of the four-dimensional SU(N) Skyrme model by combining the hedgehog ansatz for SU(N) based on the harmonic maps of $S^{2}$ into $C P^{N - 1}$ and a geometrical trick which allows to analyze explicitly finite-volume effects without breaking the relevant symmetries of the ansatz. The geometric setup allows to introduce a parameter which is related to the 't Hooft coupling of a suitable large $N$ limit, in which $N \to \infty$ and the curvature of the background metric approaches zero, in such a way that their product is constant. The relevance of such a parameter to the physics of the system is pointed out. In particular, we discuss how the discrete symmetries of the configurations depend on it.
↳ hep-thhep-phmath-phmath.MP+1EPJC(2015)·29 citations
13
A study of transverse momentum distributions of jets produced in p-p, p-\bar p, d-Au, Au-Au, and Pb-Pb collisions at high energies
Hua-Rong Wei🇨🇳 · Fu-Hu Liu🇨🇳
The transverse momentum distributions of jets produced in p-p, p-\bar p, d-Au, Au-Au, and Pb-Pb collisions at high energies with different selected conditions are analyzed by using a multi-source thermal model. The multi-component (mostly two-component) Erlang distribution used in our description is in good agreement with the experimental data measured by the STAR, D0, CDF II, ALICE, ATLAS, and CMS Collaborations. Related parameters are extracted from the transverse momentum distributions and some information on different interacting systems are obtained. In the two-component Erlang distribution, the first component has usually two or more sources which are contributed by strong scattering interactions between two quarks or more quarks and gluons, while the second component has mostly two sources which are contributed by harder head-on scattering between two quarks.
↳ nucl-exhep-exhep-phnucl-thAdv.High Energy Phys.(2015)·1 citation
14
Physics of neutrino flavor transformation through matter-neutrino resonances
Meng-Ru Wu🇩🇪 · Huaiyu Duan🇺🇸 · Yong-Zhong Qian🇺🇸
In astrophysical environments such as core-collapse supernovae and neutron star-neutron star or neutron star-black hole mergers where dense neutrino media are present, matter-neutrino resonances (MNRs) can occur when the neutrino propagation potentials due to neutrino-electron and neutrino-neutrino forward scattering nearly cancel each other. We show that neutrino flavor transformation through MNRs can be explained by multiple adiabatic solutions similar to the Mikheyev-Smirnov-Wolfenstein mechanism. We find that for the normal neutrino mass hierarchy, neutrino flavor evolution through MNRs can be sensitive to the shape of neutrino spectra and the adiabaticity of the system, but such sensitivity is absent for the inverted hierarchy.
↳ hep-phastro-ph.HEnucl-thPLB(2016)·61 citations
15
New Topological Structures of Skyrme Theory: Baryon Number and Monopole Number
Y.M. Cho🇨🇳 · Kyoungtae Kimm🇰🇷 · J. H. Yoon🇰🇷 · Pengming Zhang🇨🇳
Based on the observation that the skyrmion in Skyrme theory can be viewed as a dressed monopole, we show that the skyrmions have two independent topology, the baryon topology $π_{3} (S^{3})$ and the monopole topology $π_{2} (S^{2})$ . With this we propose to classify the skyrmions by two topological numbers $(m, n)$ , the monopole number $m$ and the shell (radial) number $n$ . In this scheme the popular (non spherically symmetric) skyrmions are classified as the $(m, 1)$ skyrmions but the spherically symmetric skyrmions are classified as the $(1, n)$ skyrmions, and the baryon number $B$ is given by $B = mn$ . Moreover, we show that the vacuum of the Skyrme theory has the structure of the vacuum of the Sine-Gordon theory and QCD combined together, which can also be classified by two topological numbers $(p, q)$ . This puts the Skyrme theory in a totally new perspective.
↳ hep-thnucl-thEPJC(2017)·6 citations
16
Disentangling random thermal motion of particles and collective expansion of source from transverse momentum spectra in high energy collisions
Hua-Rong Wei🇨🇳 · Fu-Hu Liu🇨🇳 · Roy A. Lacey🇺🇸
In the framework of a multisource thermal model, we describe experimental results of the transverse momentum spectra of final-state light flavour particles produced in gold-gold (Au-Au), copper-copper (Cu-Cu), lead-lead (Pb-Pb), proton-lead ( $p$ -Pb), and proton-proton ( $p$ - $p$ ) collisions at various energies, measured by the PHENIX, STAR, ALICE, and CMS Collaborations, by using the Tsallis-standard (Tsallis form of Fermi-Dirac or Bose-Einstein), Tsallis, and two- or three-component standard distributions which can be in fact regarded as different types of "thermometers" or "thermometric scales" and "speedometers". A central parameter in the three distributions is the effective temperature which contains information on the kinetic freeze-out temperature of the emitting source and reflects the effects of random thermal motion of particles as well as collective expansion of the source. To disentangle both effects, we extract the kinetic freeze-out temperature from the intercept of the effective temperature ( $T$ ) curve as a function of particle's rest mass ( $m_{0}$ ) when plotting $T$ versus $m_{0}$ , and the mean transverse flow velocity from the slope of the mean transverse momentum ( $⟨ p_{T} ⟩$ ) curve as a function of mean moving mass ( $m$ ) when plotting $⟨ p_{T} ⟩$ versus $m$ .
↳ nucl-exhep-exhep-phnucl-thJ.Phys.G(2016)·42 citations
17
Radiative lifetime and energy of the low-energy isomeric level in $^{229}$ Th
E. V. Tkalya · Christian Schneider · Justin Jeet · Eric R. Hudson
We estimate the range of the radiative lifetime and energy of the anomalous, low-energy $3/ 2^{+} (7.8 \pm 0.5$ eV) state in the $^{229}$ Th nucleus. Our phenomenological calculations are based on the available experimental data for the intensities of $M 1$ and $E 2$ transitions between excited levels of the $^{229}$ Th nucleus in the $K^{π} [N n_{Z} Λ] = 5/ 2^{+} [633]$ and $3/ 2^{+} [631]$ rotational bands. We also discuss the influence of certain branching coefficients, which affect the currently accepted measured energy of the isomeric state. From this work, we establish a favored region where the transition lifetime and energy should lie at roughly the 90% confidence level. We also suggest new nuclear physics measurements, which would significantly reduce the ambiguity in the present data.
↳ physics.atom-phnucl-thPRC(2015)·89 citations
18
Study of the $f_{2} (1270)$ and $a_{2} (1320)$ resonances in $γ^{*} (Q^{2}) γ$ collisions
N.N. Achasov🇷🇺 · A.V. Kiselev🇷🇺 · G.N. Shestakov🇷🇺
We discuss studies of the $Q^{2}$ dependence of the $f_{2} (1270)$ and $a_{2} (1320)$ production cross sections in $γ^{*} (Q^{2}) γ$ collisions at current and coming into operation colliders with a high luminosity. Changing the dominant helicity amplitude occurs in the reactions $γ^{*} (Q^{2}) γ \to f_{2} (1270)$ and $γ^{*} (Q^{2}) γ \to a_{2} (1320)$ with increasing $Q^{2}$ . This is caused by the coming of the QCD asymptotics. It is shown that the transition to the asymptotic behavior of QCD in the amplitudes $γ^{*} (Q^{2}) γ \to f_{2} (1270), a_{2} (1320)$ is provided by the compensation of the contributions of ground vector states $ρ$ and $ω$ in $Q^{2}$ -channel with the contributions of their radial excitations.
↳ hep-phhep-exnucl-thJETP Lett.(2015)·7 citations
19
Efficient magnetic-field amplification due to the Kelvin-Helmholtz instability in binary neutron star mergers
Kenta Kiuchi · Pablo Cerdá-Durán · Koutarou Kyutoku · Yuichiro Sekiguchi · Masaru Shibata
We explore magnetic-field amplification due to the Kelvin-Helmholtz instability during binary neutron star mergers. By performing high-resolution general relativistic magnetohydrodynamics simulations with a resolution of $17.5$ m for $4$ -- $5$ ms after the onset of the merger on the Japanese supercomputer "K", we find that an initial magnetic field of moderate maximum strength $1 0^{13}$ G is amplified at least by a factor of $\approx 1 0^{3}$ . We also explore the saturation of the magnetic-field energy and our result shows that it is likely to be $≳ 4 \times 1 0^{50}$ erg, which is $≳ 0.1%$ of the bulk kinetic energy of the merging binary neutron stars.
↳ astro-ph.HEastro-ph.COastro-ph.SRgr-qc+1PRD(2015)·278 citations
20
Low Energy Effective Theory of QCD at High Isospin Chemical Potential
Thomas D. Cohen🇺🇸 · Srimoyee Sen🇺🇸
The goal of this paper is to arrive at a low energy effective theory of QCD with two massless flavors of quarks at very high isospin density and zero baryon density. In a seminal paper by Son and Stephanov in the year 2001, it was conjectured that the low energy dynamics of QCD with two light flavors at asymptotically high isospin density was described by that of a pure Yang-Mills effective Lagrangian. Since the existence of a first order deconfinement phase transition with increasing temperature is a feature of every pure SU(N) Yang-Mills theory with N greater than or equal to 3, the regime considered in this paper is also expected to exhibit a first order deconfinement phase transition with increasing temperature. However, the low energy constants(LEC) of this pure Yang-Mills theory have not been calculated till date. We calculate the LEC s for this effective theory which in turn enables us to calculate the critical temperature of the deconfinement transition as a function of the isospin chemical potential $μ_{I}$ .The scaling of the critical temperature as a function of the isospin chemical potential that we find in this paper can be compared with future lattice calculations at finite isospin density.
↳ hep-phnucl-th1 citation

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first authorsco-authorsvia INSPIRE