Nuclear Theory·nucl-th

Wednesday·January 29, 2020

16 papers—9 primary·7 cross-listed

10
[Submitted on 27 Jan 2020] (cross-list from hep-ph)
Anisotropic momentum broadening in the 2+1D Glasma: analytic weak field approximation and lattice simulations
Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹
In heavy ion collisions, transverse momentum broadening quantifies the modification of a hard probe due to interactions with the quark-gluon plasma (QGP). We calculate momentum broadening in the Glasma, which is the highly non-isotropic precursor stage of the QGP right after the collision. We show that the Glasma leads to anisotropic momentum broadening: high energy partons accumulate more momentum along the beam axis than transverse to it. The physical origin of anisotropic broadening can be traced back to differences in the shapes of chromo-electric and chromo-magnetic flux tubes in the Glasma. We provide semi-analytic results for momentum broadening in the dilute Glasma and numerical results from real-time lattice simulations of the non-perturbative dense Glasma.
Comments:
25 pages, 8 figures; v2: accepted in PRD, new figure 5, fixed typos
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2001.10001 [pdf]
PRD(2020)·68 citations
11
[Submitted on 27 Jan 2020] (cross-list from hep-ph)
Hard probes of non-equilibrium quark-gluon plasma
Sigtryggur Hauksson🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
Jets and photons could play an important role in finding the transport coefficients of the quark-gluon plasma. To this end we analyze their interaction with a non-equilibrium quark-gluon plasma. Using new field-theoretical tools we derive two-point correlators for the plasma which show how instabilities evolve in time. This allows us, for the first time, to derive finite rates of interaction with the medium. We furthermore show that coherent, long-wavelength instability fields in the Abelian limit do not modify the rate of photon emission or jet-medium interaction.
Comments:
4 pages, proceedings for Quark Matter 2019
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2001.10046 [pdf]
NPA(2021)·5 citations
12
[Submitted on 28 Jan 2020] (cross-list from hep-ph)
Photon induced K $Λ$ production on the proton in the low energy region
A. Fatima🇮🇳 · Z. Ahmad Dar🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳
The associated photoproduction of $K Λ$ from the proton in the low energy region is studied using an isobar model in which the non-resonant contributions are obtained from the non-linear sigma model with chiral SU(3) symmetry which predicts, in a natural way, the contact term with its coupling strength along with the coupling strengths of the various Born terms predicted by the non-linear sigma model. The present model is an extension of the non-linear sigma model with chiral SU(2) symmetry, used earlier to study the photo, electro, and neutrino productions of pions. In the resonance sector, the contributions from the well established nucleon resonances ( $R$ ) in the $s$ channel, the hyperon resonances ( $Y^{*}$ ) in the $u$ channel, and the kaon resonances ( $K^{*}$ and $K_{1}$ ) in the $t$ channel having spin $\leq \frac{3}{2}$ and mass $< 2$ GeV with a significant branching ratio in $K Λ$ decay mode, have been considered. The strong and electromagnetic couplings of the $s$ channel nucleon resonances are taken from experiments while the couplings for the resonances in the $t$ and $u$ channels are fitted to reproduce the current data on the associated photoproduction of $K Λ$ in this energy region. The numerical results are presented for the total and differential cross sections and are compared with the available experimental data from CLAS and SAPHIR as well as with some of the recent theoretical models.
Comments:
40 pages, 10 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2001.10201 [pdf]
IJMPE(2020)·12 citations
13
[Submitted on 28 Jan 2020] (cross-list from hep-ph)
Comment on "Heavy Quarkonium in Extreme Conditions"
Masayuki Asakawa🇯🇵
In a recent paper (arXiv:1912.02253), Rothkopf claims that the Bryan method, which is widely used to obtain the solution in the maximum entropy method and makes use of the singular value decomposition of a matrix, limits the search space for the solution. He even presents a counterexample to the Bryan method. In this comment, we first recapitulate the mathematical basis of the Bryan method, and reconfirm that it makes use of no approximations and that it is therefore mathematically rigorous. In the second part, we explicitly show that Rothkopf's ``counterexample'' actually does not constitute a counterexample on the basis of the definition of singular value decomposition itself.
Comments:
3 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2001.10205 [pdf]
7 citations
14
[Submitted on 28 Jan 2020] (cross-list from hep-ph)
Coulomb-nuclear interference in elastic scattering: eikonal calculation to all orders of $α$
Jan Kašpar🇨🇿
The Coulomb-nuclear interference (CNI) has recently been used by the TOTEM Collaboration to analyse proton-proton elastic-scattering data from the LHC and to draw physics conclusions. This paper will present an eikonal calculation of the CNI effects performed to all orders of the fine structure constant, $α$ . This calculation will be used as a reference to benchmark several widely-used CNI formulae and to verify several recent claims by other authors.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2001.10227 [pdf]
Acta Phys.Polon.B(2021)·9 citations
15
[Submitted on 28 Jan 2020] (cross-list from nucl-ex)
In-beam gamma-ray and electron spectroscopy of $^{249, 251}$ Md
R. Briselet🇫🇷 · Ch. Theisen🇫🇷 · B. Sulignano🇫🇷 · M. Airiau🇫🇷 · K. Auranen🇫🇮 · D. M. Cox🇫🇮 · F. Déchery🇫🇷 · A. Drouart🇫🇷 · Z. Favier🇫🇷 · B. Gall🇫🇷 · T. Goigoux🇫🇷 · T. Grahn🇫🇮 and 31 other authors
The odd- $Z$ $^{251}$ Md nucleus was studied using combined $γ$ -ray and conversion-electron in-beam spectroscopy. Besides the previously observed rotational band based on the $[521] 1/ 2^{-}$ configuration, another rotational structure has been identified using $γ$ - $γ$ coincidences. The use of electron spectroscopy allowed the rotational bands to be observed over a larger rotational frequency range. Using the transition intensities that depend on the gyromagnetic factor, a $[514] 7/ 2^{-}$ single-particle configuration has been inferred for this band, i.e., the ground-state band. A physical background that dominates the electron spectrum with an intensity of $≃$ 60% was well reproduced by simulating a set of unresolved excited bands. Moreover, a detailed analysis of the intensity profile as a function of the angular momentum provided a method for deriving the orbital gyromagnetic factor, namely $g_{K} = 0.6 9_{- 0.16}^{+ 0.19}$ for the ground-state band. The odd- $Z$ $^{249}$ Md was studied using $γ$ -ray in-beam spectroscopy. Evidence for octupole correlations resulting from the mixing of the $Δ l = Δ j = 3$ $[521] 3/ 2^{-}$ and $[633] 7/ 2^{+}$ Nilsson orbitals were found in both $^{249, 251}$ Md. A surprising similarity of the $^{251}$ Md ground-state band transition energies with those of the excited band of $^{255}$ Lr has been discussed in terms of identical bands. Skyrme-Hartree-Fock-Bogoliubov calculations were performed to investigate the origin of the similarities between these bands.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2001.10235 [pdf]
PRC(2020)·10 citations
16
[Submitted on 28 Jan 2020] (cross-list from astro-ph.HE)
Equation of State and Progenitor Dependence of Stellar-Mass Black-Hole Formation
A.S. Schneider · E. O'Connor · E. Granqvist · A. Betranhandy · S.M. Couch
The core collapse of a massive star results in the formation of a proto-neutron star (PNS). If enough material is accreted onto a PNS it will become gravitationally unstable and further collapse into a black-hole (BH). We perform a systematic study of failing core-collapse supernovae in spherical symmetry for a wide range of presupernova progenitor stars and equations of state (EOSs) of nuclear matter. We analyze how variations in progenitor structure and the EOS of dense matter above nuclear saturation density affect the PNS evolution and subsequent BH formation. Comparisons of core-collapse for a given progenitor star and different EOSs show that the path traced by the PNS in mass-entropy phase space $M_{grav}^{PNS} - s ~$ is well correlated with the progenitor compactness and almost EOS independent, apart from the final endpoint. Furthermore, BH formation occurs, to a very good approximation, soon after the PNS overcomes the maximum \textit{gravitational} mass supported by a hot NS with constant entropy equal to $s ~$ . These results show a path to constraining the temperature dependence of the EOS through the detection of neutrinos from a failed galactic supernova.
Comments:
22 pages, 13 figures, 3 tables
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2001.10434 [pdf]
ApJ(2020)·74 citations

Affiliations

first authorsco-authorsvia INSPIRE

Anisotropic momentum broadening in the 2+1D Glasma: analytic weak field approximation and lattice simulations

Hard probes of non-equilibrium quark-gluon plasma

Photon induced KΛ production on the proton in the low energy region

Comment on "Heavy Quarkonium in Extreme Conditions"

Coulomb-nuclear interference in elastic scattering: eikonal calculation to all orders of α

In-beam gamma-ray and electron spectroscopy of 249,251Md

Equation of State and Progenitor Dependence of Stellar-Mass Black-Hole Formation

Affiliations

Photon induced K $Λ$ production on the proton in the low energy region

Coulomb-nuclear interference in elastic scattering: eikonal calculation to all orders of $α$

In-beam gamma-ray and electron spectroscopy of $^{249, 251}$ Md