Nuclear Theory·nucl-th

Monday·July 10, 2017

11 papers—1 primary·10 cross-listed

01
[Submitted on 7 Jul 2017]
Spin-tensor decomposition of nuclear transition matrix elements for neutrinoless double- $β$ decay of $^{76}$ Ge and $^{82}$ Se nuclei within PHFB approach
P. K. Rath🇮🇳 · R. Chandra🇮🇳 · A. Kumar🇮🇳 · P. K. Raina🇮🇳 · B. M. Dixit🇮🇳
Employing the PHFB model, nuclear transition matrix elements $M^{(K)}$ for the neutrinoless double- $β^{-}$ decay of $^{76}$ Ge and $^{82}$ Se isotopes are calculated within mechanisms involving light as well as heavy Majorana neutrinos, and classical Majorons by considering the spin-tensor decomposition of realistic KUO and empirical JUN45 effective two-body interaction. It is noticed that the effects due to the SRC on NTMEs $M^{(0 ν)}$ and $M^{(0 N)}$ due to the exchange of light and heavy Majorana neutrinos, respectively, is maximally incorporated by the central part of the effective two-body interaction, which varies by a small amount with the inclusion of spin-orbit and tensor components. The maximum uncertainty in the average NTMEs $M^{(0 ν)}$ and $M^{(0 N)}$ turns out to be about 10\% and 37\%, respectively.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1707.02135 [pdf]
1 citation
02
[Submitted on 5 Jul 2017] (cross-list from astro-ph.HE)
A New Open-Source Nuclear Equation of State Framework based on the Liquid-Drop Model with Skyrme Interaction
Andre da Silva Schneider (1) · Luke F. Roberts (2) · Christian D. Ott (1) ((1) TAPIR · Caltech · (2) MSU/NSCL)
The equation of state (EOS) of dense matter is an essential ingredient for numerical simulations of core-collapse supernovae and neutron star mergers. The properties of matter near and above nuclear saturation density are uncertain, which translates into uncertainties in astrophysical simulations and their multi-messenger signatures. Therefore, a wide range of EOSs spanning the allowed range of nuclear interactions are necessary for determining the sensitivity of these astrophysical phenomena and their signatures to variations in input microphysics. We present a new set of finite temperature EOSs based on experimentally allowed Skyrme forces. We employ a liquid drop model of nuclei to capture the non-uniform phase of nuclear matter at sub-saturation density, which is blended into a nuclear statistical equilibrium EOS at lower densities. We also provide a new, open-source code for calculating EOSs for arbitrary Skyrme parametrizations. We then study the effects of different Skyrme parametrizations on thermodynamical properties of dense astrophysical matter, the neutron star mass-radius relationship, and the core collapse of 15 and 40 solar mass stars.
Comments:
30 pages, 16 figures. Submitted to PRC. Source code and EOS tables available at https://stellarcollapse.org/SROEOS Comments welcome. We have fixed an error with chemical potential normalization in our code. Results in the simulation section have been updated
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
1707.01527 [pdf]
PRC(2017)·147 citations
03
[Submitted on 6 Jul 2017] (cross-list from nucl-ex)
Measurement of the neutron lifetime using an asymmetric magneto- gravitational trap and in situ detection
R. W. Pattie Jr. · N. B. Callahan · C. Cude-Woods · E. R. Adamek · L. J. Broussard · S. M. Clayton · S. A. Currie · E. B. Dees · X. Ding · E. M. Engel · D. E. Fellers · W. Fox and 26 other authors
The precise value of the mean neutron lifetime, $τ_{n}$ , plays an important role in nuclear and particle physics and cosmology. It is a key input for predicting the ratio of protons to helium atoms in the primordial universe and is used to search for new physics beyond the Standard Model of particle physics. There is a 3.9 standard deviation discrepancy between $τ_{n}$ measured by counting the decay rate of free neutrons in a beam (887.7 $\pm$ 2.2 s) and by counting surviving ultracold neutrons stored for different storage times in a material trap (878.5 $\pm$ 0.8 s). The experiment described here eliminates loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls and neutrons in quasi-stable orbits rapidly exit the trap. As a result of this approach and the use of a new in situ neutron detector, the lifetime reported here (877.7 $\pm$ 0.7 (stat) +0.4/-0.2 (sys) s) is the first modern measurement of $τ_{n}$ that does not require corrections larger than the quoted uncertainties.
Comments:
9 pages, 3 figures, 2 tables
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1707.01817 [pdf]
Science(2018)·180 citations
04
[Submitted on 6 Jul 2017] (cross-list from hep-ph)
Regimes of the Pomeron and its Intrinsic Entropy
Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸
We suggest that the perturbative and non-perturbative descriptions of the Pomeron can be viewed as complementary descriptions of different phases in the Pomeron phase diagram, with a phase boundary where the proper description of the produced systems are "string balls". Their intrinsic entropy is calculated and turned out to be the same, as the recently reported perturbative entanglement entropy. The distribution of large multiplicities stemming from the string balls is also wide, with its moments close to those reported for hadrons in $pp$ collisions at the LHC. At low-x, the quantum string is so entangled that sufficiently weak string self-attraction can cause it to turn to a string ball dual to a black hole. We suggest that low-x saturation occurs when the density of wee-strings reaches the Bekenstein bound, with a proton size that freezes with increasing rapidity. Some of these observations maybe checked at the future eIC.
Comments:
14 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1707.01885 [pdf]
Annals Phys.(2018)·26 citations
05
[Submitted on 6 Jul 2017] (cross-list from math-ph)
Richardson's solutions in the real- and complex-energy spectrum
Rodolfo M. Id Betan
The constant pairing Hamiltonian holds exact solutions worked out by Richardson in the early Sixties. This exact solution of the pairing Hamiltonian regained interest at the end of the Nineties. The discret complex-energy states had been included in the Richardson's solutions by Hasegawa et al. [1]. In this contribution we reformulate the problem of determining the exact eigenenergies of the pairing Hamiltonian when the continuum is included through the single particle level density. The solutions with discret complex-energy states is recovered by analytic continuation of the equations to the complex energy plane. This formulation may be applied to loosely bound system where the correlations with the continuum-spectrum of energy is really important. Some details are given to show how the many-body eigenenergy emerges as sum of the pair-energies.
Comments:
10 pages, 4 appendices, 15 References
Subjects:
Mathematical Physics (math-ph); Superconductivity (cond-mat.supr-con); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
1707.01893 [pdf]
J.Phys.Conf.Ser.(2017)·4 citations
06
[Submitted on 6 Jul 2017] (cross-list from hep-ph)
Counting states and the Hadron Resonance Gas: Does X(3872) count?
Pablo G. Ortega🇪🇸 · David R. Entem🇪🇸 · Francisco Fernandez🇪🇸 · Enrique Ruiz Arriola🇪🇸
We analyze how the renowned X(3872), a weakly bound state right below the $D D ˉ^{*}$ threshold, should effectively be included in a hadronic representation of the QCD partition function. This can be decided by analyzing the $D D ˉ^{*}$ scattering phase-shifts in the $J^{P C} = 1^{++}$ channel and their contribution to the level density in the continuum from which the abundance in a hot medium can be determined. We show that in a purely molecular picture the bound state contribution cancels the continuum providing a vanishing occupation number density at finite temperature and the $X (3872)$ does not count below the Quark-Gluon Plasma crossover happening at $T \sim 150$ MeV. In contrast, within a coupled-channels approach, for a non vanishing $c c ˉ$ content the cancellation does not occur due to the onset of the $X (3940)$ which effectively counts as an elementary particle for temperatures above $T ≳ 250$ MeV. Thus, a direct inclusion of the $X (3872)$ in the Hadron Resonance Gas is not justified. We also estimate the role of this cancellation in X(3872) production in heavy-ion collision experiments in terms of the corresponding $p_{T}$ distribution due to a finite energy resolution.
Comments:
7 pages, 6 figures and 1 table. Version accepted for publication in Phys. Lett. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1707.01915 [pdf]
PLB(2018)·14 citations
07
[Submitted on 6 Jul 2017] (cross-list from nucl-ex)
The Way Forward - Closing Remarks at Quark Matter 2017
W.A. Zajc🇺🇸
This contribution is a written version of my closing talk presented at the Quark Matter 2017 conference. Neither the talk nor this contribution to the conference proceedings is intended as a comprehensive summary. Rather, a brief discussion is presented of emerging themes and challenges in the field of relativistic heavy ion physics.
Comments:
9 pages, 6 figures. Closing talk at Quark Matter 2017 (The XXVIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions)
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1707.01993 [pdf]
NPA(2017)·1 citation
08
[Submitted on 7 Jul 2017] (cross-list from hep-ph)
Inhomogeneous Chiral Phase in Quark Matter
Toshitaka Tatsumi🇯🇵
Recent development of inhomogeneous chiral phase in Kyoto group is briefly reviewed. First, the nesting effect of the Fermi surface is emphasized as a key mechanism leading to inhomogeneous chiral phase. After introduction of inhomogeneous chiral phase, some topological aspect is discussed in 1+1 dimensions and in the presence of the magnetic field in 1+3 dimensions. Spectral asymmetry gives rise to anomalous quark number and is closely related to chiral anomaly. It may induce spontaneous magnetization and a novel Lifshitz point may appear on the line $μ = 0$ . Some astronomical implications are briefly discussed. Finally, the effects of the fluctuations around the order parameter are discussed; the propagator of the fluctuations exhibits a singularity at finite momentum and changes the properties of the phase transition through loop diagrams.
Comments:
8 pages,3 figures, Proc. of QCS2017 (Kyoto, Japan)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1707.02061 [pdf]
JPS Conf.Proc.(2018)·2 citations
09
[Submitted on 7 Jul 2017] (cross-list from hep-ph)
Studies of the hydrodynamic evolution of the dense baryonic matter produced in relativistic heavy ion collisions
Gong-Ming Yu🇨🇳 · Jian-Song Wang🇨🇳
We use the relativistic perfect-fluid hydrodynamics to describe the space-time evolution of dense baryonic matter produced in the central nucleus-nucleus collisions at HIRFL-CSR, HIAF, FAIR-CBM, NICA-MPD, and RHIC-BES. The transverse flow of the fireball with cylindrical symmetry and boost invariant along the longitudinal direction is also analyzed. Based on the relativistic kinetic theory, we also present the first preliminary calculation on the production of low-mass dileptons and low-pT photons can be considered as the signals of the dense baryonic matter produced in the central Au-Au and U-U collisions. We find that the rapid cooling of the expanding dense baryonic matter with transverse flow effect can lead to the suppression of the low-mass dileptons and low-pT photons production at HIRFL-CSR, HIAF, FAIR-CBM, NICA-MPD, and RHIC-BES energies.
Comments:
5 pages,5 figures,1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1707.02137 [pdf]
1 citation
10
[Submitted on 7 Jul 2017] (cross-list from hep-lat)
Three particle quantization condition in a finite volume: 2. general formalism and the analysis of data
H.-W. Hammer🇩🇪 · J.-Y. Pang🇩🇪 · A. Rusetsky🇩🇪
We derive the three-body quantization condition in a finite volume using an effective field theory in the particle-dimer picture. Moreover, we consider the extraction of physical observables from the lattice spectrum using the quantization condition. To illustrate the general framework, we calculate the volume-dependent three-particle spectrum in a simple model both below and above the three-particle threshold. The relation to existing approaches is discussed in detail.
Comments:
36 pages, 9 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1707.02176 [pdf]
JHEP(2017)·211 citations
11
[Submitted on 7 Jul 2017] (cross-list from hep-ph)
New theories of relativistic hydrodynamics in the LHC era
Wojciech Florkowski🇵🇱 · Michal P. Heller🇩🇪 · Michal Spalinski🇵🇱
The success of relativistic hydrodynamics as an essential part of the phenomenological description of heavy-ion collisions at RHIC and the LHC has motivated a significant body of theoretical work concerning its fundamental aspects. Our review presents these developments from the perspective of the underlying microscopic physics, using the language of quantum field theory, relativistic kinetic theory, and holography. We discuss the gradient expansion, the phenomenon of hydrodynamization, as well as several models of hydrodynamic evolution equations, highlighting the interplay between collective long-lived and transient modes in relativistic matter. Our aim to provide a unified presentation of this vast subject -- which is naturally expressed in diverse mathematical languages -- has also led us to include several new results on the large-order behaviour of the hydrodynamic gradient~expansion.
Comments:
Invited review for Reports on Progress in Physics. V2: numerous and significant improvements and additional references. V3: various clarifications
Subjects:
High Energy Physics — Phenomenology (hep-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1707.02282 [pdf]
Rept.Prog.Phys.(2018)·410 citations

Affiliations

first authorsco-authorsvia INSPIRE