Nuclear Theory·nucl-th

Friday·November 16, 2018

10 papers—5 primary·5 cross-listed

01
Pauli rearrangement potential for a scattering state with the interaction in chiral effective field theory
M. Kohno
The Pauli rearrangement potential given by the second-order diagram is evaluated for a nucleon optical model potential (OMP) with $G$ matrices of the nucleon-nucleon interaction in chiral effective field theory. The results obtained in nuclear matter are applied for $^{40}$ Ca in a local-density approximation. The repulsive effect is of the order of 5MeV at the normal density. The density dependence indicates that the real part of the microscopic OMP becomes shallower in a central region, but is barely affected in a surface area. This improves the overall resemblance of the microscopic OMP to the empirical one.
nucl-thPRC(2018)·8 citations
02
Anisotropic flow in the few collisions regime: application to bottomonia
Nina Kersting🇩🇪 · Nicolas Borghini🇩🇪 · Steffen Feld🇩🇪
Considering the kinetic Boltzmann equation in the limit of very few collisions, we study the evolution of the phase space distribution of bottomonia interacting with an expanding gas of massless partons. We investigate the scaling of the anisotropic flow coefficients on the initial eccentricities and the inverse Knudsen number, and compute their transverse momentum dependence.
nucl-thhep-phMDPI Proc.(2019)·8 citations
03
Impact of Magnetic field on neutron star properties
Tuhin Malik🇮🇳 · Debashree Sen🇮🇳 · T. K. Jha🇮🇳 · Hiranmaya Mishra🇮🇳
We derive an equation of state for magnetized charge neutral nuclear matter relevant for neutron star structure. The calculations are performed within an effective chiral model based on generalization of sigma model with nonlinear self interactions of the sigma mesons along with vector mesons and a $ρ - σ$ cross-coupling term. The effective chiral model is extended by introducing the contributions of strong magnetic field on the charged particles of the model. The contributions arising from the effects of magnetic field on the Dirac sea of charged baryons are also included. The resulting equation of state for the magnetized dense matter is used to investigate the neutron star properties, like, mass-radius relation and tidal deformability. The dimensionless tidal deformability of $1.4 M_{⊙}$ NS is found to be $Λ_{1.4} = 526$ , which is consistent with recent observation of GW170817. The maximum mass of neutron star in presence of strong magnetic field is consistent with the observational constraints on mass of neutron star from PSR~ J0348 - 0432 and the radius at $1.4 M_{⊙}$ mass of the neutron star is within the empirical bounds.
nucl-thhep-ph1 citation
04
Can generalized TOV equations explain neutron star macroscopic properties?
Clésio E. Mota🇧🇷 · Guilherme Grams🇧🇷 · Débora P. Menezes🇧🇷
In the quest for describing massive neutron stars with radii compatible with recent expectations, we take a different approach in the present paper and, instead of tuning the equations of state, we use an appropriate parameterization of the TOV equations that result in increasing the maximum mass and decreasing the respective radius and consequently, also the radius of canonical stars.
nucl-th5 citations
05
The QCD critical point hunt: emergent new ideas and new dynamics
Yi Yin🇺🇸
The QCD critical point is a landmark point on the QCD phase diagram, with potential connections to a plethora of deep questions on the properties of thermal nuclear matter. Future heavy-ion collision experiments, in particular, the second phase of beam energy scan (BES-II), will explore the QCD phase diagram with an unprecedented precision and would potentially discover the QCD critical point. In this short review, I discuss and summarize recent new ideas, such as `rapidity scan', and new theoretical developments, in particular in the qualitative characterization and quantitative descriptions of the critical fluctuations in the expanding fireball. Those new ideas and developments together would enhance the prospect of locating the QCD critical point.
nucl-thhep-ph30 citations
06
On the origin of forward-backward multiplicity correlations in $pp$ collisions at ultrarelativistic energies
L.V. Bravina🇳🇴 · J. Bleibel🇩🇪 · E.E. Zabrodin🇳🇴
We study multiplicity correlations of hadrons in forward and backward hemispheres in $pp$ inelastic interactions at energies 200GeV $\leq s \leq$ 13TeV within the microscopic quark-gluon string model. The model correctly describes (i) the almost linear dependence of average multiplicity in one hemisphere on the particle multiplicity in other hemisphere in the center-of-mass frame; (ii) the increase of the slope parameter $b_{cor r}$ with rising collision energy; (iii) the quick falloff of the correlation strength with increase of the midrapidity gap; (iv) saturation of the forward-backward correlations at very high multiplicities. Investigation of the sub-processes on partonic level reveals that these features can be attributed to short-range partonic correlations within a single string and superposition of several sub-processes containing different numbers of soft and hard Pomerons with different mean multiplicities. If the number of Pomerons in the event is fixed, no forward-backward correlations are observed. Predictions are made for the top LHC energy $s = 13$ TeV.
↳ hep-phhep-exnucl-thPLB(2018)·12 citations
07
QCD at nonzero isospin asymmetry
Bastian B. Brandt🇩🇪 · Gergely Endrodi🇩🇪 · Sebastian Schmalzbauer🇩🇪
We study the phase diagram and the thermodynamic properties of QCD at nonzero isospin asymmetry at physical quark masses with staggered quarks. In particular, continuum results for the phase boundary between the normal and the pion condensation phases and the chiral/deconfinement transition are presented. Our findings indicate that the pion condensation phase is restricted to $T ≲ 170$ ~MeV for isospin chemical potentials up to 325~MeV. We also use the data to test the range of validity of the Taylor expansion method and show first results for the equation of state.
↳ hep-lathep-phnucl-thPoS(2018)·21 citations
08
Understanding the energy resolution of liquid argon neutrino detectors
Alexander Friedland🇺🇸 · Shirley Weishi Li🇺🇸
Available estimates for the energy resolution of DUNE vary by as much as a factor of four. To address this controversy, and to connect the resolution to the underlying physical processes, we build an independent simulation pipeline for neutrino events in liquid argon, combining the public tools GENIE and FLUKA. Using this pipeline, we first characterize the channels of non-hermeticity of DUNE, including subthreshold particles, charge recombination, and nuclear breakup. Particular attention is paid to the role of neutrons, which are responsible for a large fraction of missing energy in all channels. Next, we determine energy resolution, by quantifying event-to-event stochastic fluctuations in missing energy. This is done for several sets of assumptions about the reconstruction performance, including those available in the literature. The resulting migration matrices, connecting true and reconstructed neutrino energies, are presented. Finally, we quantify the impact of different improvements on the experimental performance. For example, we show that dropping particle identification information degrades the resolution by a factor of two, while omitting charge deposits from de-excitation gammas worsens it by about 25%. In the future, this framework can be used to assess the impact of cross section uncertainties on the oscillation sensitivity.
↳ hep-phhep-exnucl-exnucl-thPRD(2019)·87 citations
09
Derivation of spontaneously broken gauge symmetry from the consistency of effective field theory II: Scalar field self-interactions and the electromagnetic interaction
D. Djukanovic🇩🇪 · J. Gegelia🇩🇪 · Ulf-G. Meißner🇩🇪
We extend our study of deriving the local gauge invariance with spontaneous symmetry breaking in the context of an effective field theory by considering self-interactions of the scalar field and inclusion of the electromagnetic interaction. By analyzing renormalizability and the scale separation conditions of three-, four- and five-point vertex functions of the scalar field, we fix the two couplings of the scalar field self-interactions of the leading order Lagrangian. Next we add the electromagnetic interaction and derive conditions relating the magnetic moment of the charged vector boson to its charge and the masses of the charged and neutral massive vector bosons to each other and the two independent couplings of the theory. We obtain the bosonic part of the Lagrangian of the electroweak Standard Model as a unique solution to the conditions imposed by the self-consistency conditions of the considered effective field theory.
↳ hep-thhep-lathep-phnucl-thPLB(2019)·1 citation
10
Small- $x$ physics at the LHeC
Heikki Mäntysaari🇫🇮
The Large Hadron-electron Collider LHeC is a proposed upgrade of the LHC. It would add an electron beam to the LHC, and make it possible to study electron-proton and electron-nucleus collisions at very high energies. We present some of the highlights of the LHeC physics program related to the studies of partonic structure of protons and nuclei, and to the non-linear QCD phenomena visible at small $x$ .
↳ hep-phnucl-exnucl-thPoS(2018)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE