Nuclear Theory·nucl-th

Monday·October 10, 2016

11 papers—6 primary·5 cross-listed

01
Viscosity of a net-baryon fluid near the QCD critical point
N.G. Antoniou🇬🇷 · F.K. Diakonos🇬🇷 · A.S. Kapoyannis🇬🇷
In the dynamics of the QCD critical point, the net-baryon fluid, linked to the slow component of the order parameter, relaxes to a 3d Ising system in equilibrium. An analytical study of shear and bulk viscosity, with constraints imposed by the dynamics of the critical net-baryon fluid, the universality property and the requirements of a class of strong coupling theories, is performed in the neighbourhood of the critical point. It is found that the shear viscosity of the net-baryon fluid is restricted in the domain $1.6 \leq 4 π \frac{η}{s} \leq 3.7$ for $T_{c} < T \leq 2 T_{c}$ whereas the bulk viscosity is small, $4 π \frac{ζ}{s} < 0.05$ (for $T > 1.27 T_{c}$ ) but rising towards the singularity at $T = T_{c}$ .
nucl-thhep-phPRC(2017)·7 citations
02
Signature of the N=126 shell closure in dwell times of alpha-particle tunneling
N. G. Kelkar · M. Nowakowski
Characteristic quantities such as the penetration and preformation probabilities, assault frequency and tunneling times in the tunneling description of alpha decay of heavy nuclei are explored to reveal their sensitivity to neutron numbers in the vicinity of the magic neutron number $N$ = 126. Using realistic nuclear potentials, the sensitivity of these quantities to the parameters of the theoretical approach is also tested. An investigation of the region from $N = 116$ to $N = 132$ in Po nuclei reveals that the tunneling $α$ particle spends the least amount of time with an $N = 126$ magic daughter nucleus. The shell closure at $N = 126$ seems to affect the behaviour of the dwell times of the tunneling alpha particles and this occurs through the influence of the $Q$ -values involved.
nucl-thJ.Phys.G(2016)·13 citations
03
Double Resonance in Dalitz Plot of M(pLambda)-M(KLambda) in DISTO Data on p+p rightarrow p+Lambda+K+ at 2.85 GeV
K. Suzuki🇦🇹 · T. Yamazaki🇯🇵 · M. Maggiora🇮🇹 · P. Kienle (for the DISTO collaboration)🇦🇹
The X(2265) resonance was previously observed in DISTO data of p+p rightarrow p+Lambda+K+ at 2.85 GeV on an attempt of searching for the kaonic nuclear state K-pp rightarrow p + Lambda. In the present paper we report an additional finding, namely, a double resonance type phenomena, not only with a peak at M(pLambda) = 2265 MeV/c2 but also a broad bump at M(K+ Lambda) ~ 1700 MeV/c2. This "double-resonance" zone is expressed as XY(2265, 1700). The latter bump may result from nearby nucleon resonances, typically N*(1710), as well as by attractive K - Lambda final-state interaction. We point out that this double resonance XY(2265, 1700) as seen in DISTO at 2.85 GeV cannot be populated kinematically in a HADES experiment at 3.5 GeV.
nucl-thnucl-exJPS Conf.Proc.(2017)·1 citation
04
New exact solutions of hydrodynamics for rehadronizing fireballs with lattice QCD equation of state
T. Csörgő🇭🇺 · G. Kasza🇭🇺
We describe fireballs that rehadronize from a perfectly fluid quark matter to a chemically frozen, multi-component hadron gas. In the hydrodynamics of these fireballs, we utilize the lattice QCD equation of state, however, we also apply non-relativistic kinematics for simplicity and clarity. Two new classes of exact, analytic solutions of fireball hydrodynamics are presented: the first class describes triaxially expanding, non-rotating ellipsoidal fireballs, while the second class of exact solutions corresponds to spheroidally symmetric, rotating fireballs. In both classes of solutions, we find evidence for a secondary explosion, that happens just after hadrochemical freeze-out. A realistic, linear mass scaling of the slope parameters of the single particle spectra of various hadronic species is obtained analytically, as well as an also realistic, linear mass scaling of the inverse of the squared HBT radius parameters of the Bose-Einstein correlation functions.
nucl-thJOURNAL OF CENTRAL EUROPEAN GREEN INNOVAT…·2 citations
05
The properties of nuclear matter with lattice $N N$ potential in relativistic Brueckner-Hartree-Fock theory
Jinniu Hu🇨🇳 · Hiroshi Toki🇯🇵 · Hong Shen🇨🇳
We study the properties of nuclear matter with lattice nucleon-nucleon ( $N N$ ) potential in the relativistic Brueckner-Hartree-Fock (RBHF) theory. To use this potential in such a microscopic many-body theory, we firstly have to construct a one-boson-exchange potential (OBEP) based on the latest lattice $N N$ potential. Three mesons, pion, $σ$ meson, and $ω$ meson, are considered. Their coupling constants and cut-off momenta are determined by fitting the on-shell behaviors and phase shifts of the lattice force, respectively. Therefore, we obtain two parameter sets of the OBEP potential (named as LOBEP1 and LOBEP2) with these two fitting ways. We calculate the properties of symmetric and pure neutron matter with LOBEP1 and LOBEP2. In non-relativistic Brueckner-Hartree-Fock case, the binding energies of symmetric nuclear matter are around $- 3$ and $- 5$ MeV at saturation densities, while it becomes $- 8$ and $- 12$ MeV in relativistic framework with $^{1} S_{0},^{3} S_{1},$ and $^{3} D_{1}$ channels using our two parameter sets. For the pure neutron matter, the equations of state in non-relativistic and relativistic cases are very similar due to only consideration $^{1} S_{0}$ channel with isospin $T = 1$ case.
nucl-th0 citations
06
Analysis of hadron yield data within hadron resonance gas model with multi-component eigenvolume corrections
Volodymyr Vovchenko🇩🇪 · Horst Stoecker🇩🇪
We analyze the sensitivity of thermal fits to heavy-ion hadron yield data of ALICE and NA49 collaborations to the systematic uncertainties in the hadron resonance gas (HRG) model related to the modeling of the eigenvolume interactions. We find a surprisingly large sensitivity in extraction of chemical freeze-out parameters to the assumptions regarding eigenvolumes of different hadrons. We additionally study the effect of including yields of light nuclei into the thermal fits to LHC data and find even larger sensitivity to the modeling of their eigenvolumes. The inclusion of light nuclei yields, thus, may lead to further destabilization of thermal fits. Our results show that modeling of eigenvolume interactions plays a crucial role in thermodynamics of HRG and that conclusions based on a non-interacting HRG are not unique.
nucl-thhep-phJ.Phys.Conf.Ser.(2017)·15 citations
07
The Asymptotic Form of Non-Global Logarithms, Black Disc Saturation, and Gluonic Deserts
Duff Neill🇺🇸
We develop an asymptotic perturbation theory for the large logarithmic behavior of the non-linear integro-differential equation describing the soft correlations of QCD jet measurements, the Banfi-Marchesini-Smye (BMS) equation. This equation captures the late-time evolution of radiating color dipoles after a hard collision. This allows us to prove that at large values of the control variable (the non-global logarithm, a function of the infra-red energy scales associated with distinct hard jets in an event), the distribution has a gaussian tail. We compute the decay width analytically, giving a closed form expression, and find it to be jet geometry independent, up to the number of legs of the dipole in the active jet. Enabling the asymptotic expansion is the correct perturbative seed, where we perturb around an anzats encoding formally no real emissions, an intuition motivated by the buffer region found in jet dynamics. This must be supplemented with the correct application of the BFKL approximation to the BMS equation in collinear limits. Comparing to the asymptotics of the conformally related evolution equation encountered in small-x physics, the Balitisky-Kovchegov (BK) equation, we find that the asymptotic form of the non-global logarithms directly maps to the black-disc unitarity limit of the BK equation, despite the contrasting physical pictures. Indeed, we recover the equations of saturation physics in the final state dynamics of QCD.
↳ hep-phnucl-thJHEP(2017)·27 citations
08
Effective field theory approach to open heavy flavor production in heavy-ion collisions
Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸
We develop a version of Soft Collinear Effective Theory (SCET) which includes finite quark masses, as well as Glauber gluons that describe the interaction of collinear partons with QCD matter. In the framework of this new effective field theory, labeled SCET $_{M, G}$ , we derive the massive splitting functions in the vacuum and the QCD medium for the processes $Q \to Q g$ , $Q \to g Q$ and $g \to Q Q ˉ$ . The numerical effects due to finite quark masses are sizable and our results are consistent with the traditional approach to parton energy loss in the soft gluon emission limit. In addition, we present a new framework for including the medium-induced full splitting functions consistent with next-to-leading order calculations in QCD for inclusive hadron production. Finally, we show numerical results for the suppression of $D$ - and $B$ -mesons in heavy ion collisions at $s_{NN} = 5.02$ TeV and 2.76 TeV and compare to available data from the LHC.
↳ hep-phhep-exnucl-exnucl-thJHEP(2017)·114 citations
09
K-K-pp - an important gateway toward multi-kaonic nuclei
Shuji Maeda🇯🇵 · Yoshinori Akaishi🇯🇵 · Toshimitsu Yamazaki🇯🇵
Based on our Faddeev-Yakubowsky calculations of four-body kaonic nuclear systems it was revealed that the structure of K-K-pp is well approximated by two Lambda*=K-p's with strong mutual attraction. It is vitally important to study this nucleus, as it is an essential gateway toward multi-Lambda* nuclei. Two experimental proposals are presented: i) production of K-K-pp by p+p reactions at T_p = 7 GeV, and ii) search for K-K-pp from the invariant mass of M(Lambda-Lambda) around 2.6 GeV/c2 in high-energy HI reactions.
↳ nucl-exnucl-thJPS Conf.Proc.(2017)·3 citations
10
Prompt photon production and photon-hadron jet correlations with POWHEG
T. Jezo🇮🇹 · M. Klasen🇩🇪 · F. König🇩🇪
We present a calculation of direct photon production at next-to-leading order of QCD and a matching of this calculation with parton showers using POWHEG BOX. Based on simulations with POWHEG+PYTHIA, we perform a detailed phenomenological analysis of PHENIX data on prompt photon production and photon-hadron jet correlations in pp collisions at RHIC, considerably improving the description of these data with respect to previous calculations, and we suggest additional interesting analyses.
↳ hep-phhep-exnucl-exnucl-thJHEP(2016)·30 citations
11
Binding Blocks: building the Universe one nucleus at the time
C. Aa. Diget · A. Pastore · K. Leech · T. Haylett · S. Lock · T. Sanders · M. Shelley · H. V. Willett · J. Keegans · L. Sinclair · E. C. Simpson
We present a new teaching and outreach activity based around the construction of a three-dimensional chart of isotopes using LEGO $^{®}$ bricks. The activity, \emph{Binding Blocks}, demonstrates nuclear and astrophysical processes through a seven-meter chart of all nuclear isotopes, built from over 26,000 LEGO $^{®}$ bricks. It integrates A-level and GCSE curricula across areas of nuclear physics, astrophysics, and chemistry, including: nuclear decays (through the colours in the chart); nuclear binding energy (through tower heights); production of chemical elements in the cosmos; fusion processes in stars and fusion energy on Earth; as well as links to medical physics, particularly diagnostics and radiotherapy.
↳ physics.ed-phnucl-exnucl-thphysics.pop-phPhys.Educ.(2017)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE