Nuclear Theory·nucl-th

Tuesday·December 28, 2021

26 papers—13 primary·13 cross-listed

14
[Submitted on 28 Sept 2021] (cross-list from astro-ph.HE)
$g$ -modes of neutron stars with hadron-to-quark crossover transitions
Constantinos Constantinou🇮🇹 · Sophia Han🇺🇸 · Prashanth Jaikumar🇺🇸 · Madappa Prakash🇺🇸
We perform the first study of the principal core $g$ -mode oscillation in hybrid stars containing quark matter, utilizing a crossover model for the hadron-to-quark transition inspired by lattice QCD. The ensuing results are compared with our recent findings of $g$ -mode frequencies in hybrid stars with a first-order phase transition using Gibbs constructions. We find that models using Gibbs construction yield $g$ -mode amplitudes and the associated gravitational energy radiated that dominate over those of the chosen crossover model owing to the distinct behaviors of the equilibrium and adiabatic sound speeds in the various models. Based on our results, we conclude that were $g$ -modes to be detected in upgraded LIGO and Virgo detectors it would indicate a first-order phase transition akin to a Gibbs construction.
Comments:
15 pages, 11 figures, 3 tables; refs. and discussion added, accepted for publication in PRD
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2109.14091 [pdf]
PRD(2021)·50 citations
15
[Submitted on 22 Dec 2021] (cross-list from hep-ph)
Imaging nuclear modifications on parton distributions with triple-differential dijet cross sections in proton-nucleus collisions
Shuwan Shen🇨🇳 · Peng Ru🇨🇳 · Ben-Wei Zhang🇨🇳
Dijet production in proton-nucleus ( $p$ A) collisions at the LHC provides invaluable information on the underlying parton distributions in nuclei, especially the gluon distributions. Triple-differential dijet cross sections enable a well-controlled kinematic scan (over momentum fraction $x$ and probing scale $Q^{2}$ ) of the nuclear parton distribution functions (nPDFs), i.e., $f_{i}^{A} (x, Q^{2})$ . In this work, we study several types of triple-differential cross sections for dijet production in proton-proton ( $pp$ ) and proton-lead ( $p$ Pb) collisions at the LHC, to next-to-leading order within the framework of perturbative quantum chromodynamics (pQCD). Four sets of nPDF parametrizations, EPPS16, nCTEQ15, TUJU19, and nIMParton16 are employed in the calculations for $p$ Pb collisions. We show that the observable nuclear modification factor $R_{p Pb}$ of such cross sections can serve as a nice image of the nuclear modifications on parton distributions, quantified by the ratio $r_{i}^{A} (x, Q^{2}) = f_{i}^{A,proton} (x, Q^{2}) / f_{i}^{proton} (x, Q^{2})$ . Considerable differences among the $R_{p Pb}$ predicted by the four nPDF sets can be observed and intuitively understood. Future measurements of such observables are expected to not only constrain the nPDF parametrizations, but also help confirm various nuclear effects, e.g., shadowing, anti-shadowing, EMC, and Fermi motion in different regions of $x$ and their variations with probing scale $Q^{2}$ .
Comments:
15 pages, 15 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.11819 [pdf]
PRD(2022)·5 citations
16
[Submitted on 23 Dec 2021] (cross-list from hep-ph)
$T_{cc}^{+}$ and its partners
Chengrong Deng🇨🇳 · Shi-Lin Zhu🇨🇳
Inspired by the $T_{cc}^{+}$ signal discovered by the LHCb Collaboration, we systematically investigate the doubly heavy tetraquark states with the molecule configuration $[Q_{1} q ˉ_{2}] [Q_{3} q ˉ_{4}]$ ( $Q = c$ and $b$ , $q = u$ , $d$ and $s$ ) in a nonrelativistic quark model. The model involves a color screening confinement potential, meson-exchange interactions and one-gluon-exchange interactions. The $T_{cc}^{+}$ state with $I J^{P} = 0 1^{+}$ is a very loosely bound deuteron-like state with a binding energy around 0.34 MeV and a huge size of 4.32 fm. Both the meson exchange force and the coupled channel effect play a pivotal role. Without the meson exchange force, there does not exist the $T_{cc}^{+}$ molecular state. In strong contrast, the QCD valence bond forms clearly in the $T_{bb}^{+}$ system when we turn off the meson-exchange force, which is very similar to the hydrogen molecule in QED. Moreover, the $T_{bb}^{+}$ becomes a helium-like QCD-atom if we increase the bottom quark mass by a factor of three. Especially, the $T_{bb}^{+}$ states with $0 1^{+}$ , $T_{b c}^{+}$ with $0 0^{+}$ and $0 1^{+}$ and the $V$ -spin antisymmetric states $T_{bb s}^{+}$ with $\frac{1}{2} 1^{+}$ , $T_{b cs}^{+}$ with $\frac{1}{2} 0^{+}$ and $\frac{1}{2} 1^{+}$ can form a compact, hydrogen molecule-like or deuteron-like bound state with different binding dynamics. The high-spin states $T_{b c}^{+}$ with $0 2^{+}$ and $T_{b cs}^{+}$ with $\frac{1}{2} 2^{+}$ can decay into $D$ -wave $B ˉ D$ and $B ˉ_{s} D$ although they are below the thresholds $B ˉ^{*} D^{*}$ and $B ˉ_{s}^{*} D^{*}$ , respectively. The isospin and $V$ -spin symmetric states are unbound. We also calculate their magnetic moments and axial charges.
Comments:
11 pages, 1 figures, 5 tables, comments are welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.12472 [pdf]
PRD(2022)·99 citations
17
[Submitted on 23 Dec 2021] (cross-list from hep-th)
Relativistic Hydrodynamics: A Singulant Perspective
Michal P. Heller🇩🇪 · Alexandre Serantes🇫🇮 · Michał Spaliński🇫🇮 · Viktor Svensson🇩🇪 · Benjamin Withers🇬🇧
There is growing evidence that the hydrodynamic gradient expansion is factorially divergent. We advocate for using Dingle's singulants as a way to gain analytic control over its large-order behaviour for nonlinear flows. Within our approach, singulants can be viewed as new emergent degrees of freedom which reorganise the large-order gradient expansion. We work out the physics of singulants for longitudinal flows, where they obey simple evolution equations which we compute in Müller-Israel-Stewart-like models, holography and kinetic theory. These equations determine the dynamics of the large-order behaviour of the hydrodynamic expansion, which we confirm with explicit numerical calculations. One of our key findings is a duality between singulant dynamics and a certain linear response theory problem. Finally, we discuss the role of singulants in optimal truncation of the hydrodynamic gradient expansion. A by-product of our analysis is a new Müller-Israel-Stewart-like model, where the qualitative behaviour of singulants shares more similarities with holography than models considered hitherto.
Comments:
v1: 19 pages + appendices, many colourful figures; v2: 24 pages + appendices, 13 figures. Added clarifications, extended Outlook discussion, and appendix on stability & causality of the new Müller-Israel-Stewart-like model in the linear response regime. Matches version published in PRX
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2112.12794 [pdf]
PRX(2022)·30 citations
18
[Submitted on 22 Dec 2021] (cross-list from gr-qc)
Analytical model on mass limit of strange stars
Sajahan Molla · Masum Murshid · Mehedi Kalam
In this paper, we present a new kind of stellar model using the Nariai IV metric. This model can be used to study the strange/quark stars(which is our present interest, though it can also be applicable to neutron stars). We present a mass-radius region where all the regularity conditions, energy conditions, the TOV equation, and stability conditions are satisfied. According to our model, strange stars having mass up to $1.9165 M_{⊙} (= 2.81 k m)$ is stable. A strange star having a mass greater than $1.9165 M_{⊙}$ violates the stability conditions. This model can be very useful to predict the radius of strange stars of mass greater than $1 M_{⊙}$ .
Comments:
12 pages, 10 figures, 2 tables; Accepted in Astrophysics and Space Science
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2112.12807 [pdf]
Astrophys.Space Sci.(2022)·2 citations
19
[Submitted on 25 Dec 2021] (cross-list from hep-ph)
Equation-of-motion and Lorentz-invariance relations for tensor-polarized parton distribution functions of spin-1 hadrons
S. Kumano🇯🇵 · Qin-Tao Song🇨🇳
Structure functions of polarized spin-1 hadrons will be measured at various accelerator facilities in the near future. Recently, transverse-momentum-dependent and collinear parton distribution functions were theoretically proposed at twist 3 and twist 4 in addition to the twist-2 ones, so that full investigations became possible for structure functions of spin-1 hadrons in the same level with those of the spin-1/2 nucleons. Furthermore, twist-3 tensor-polarized multiparton distribution functions were also recently found for spin-1 hadrons. In this work, we show relations among the collinear parton- and multiparton-distribution functions for spin-1 hadrons by using equation of motion for quarks. These relations are valuable in constraining the distribution functions and learning about multiparton correlations in spin-1 hadrons.
Comments:
5 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.13218 [pdf]
PLB(2022)·16 citations
20
[Submitted on 25 Dec 2021] (cross-list from hep-ph)
Analysis of identified particle transverse momentum spectra produced in pp, p--Pb and Pb--Pb collisions at the LHC using Tsallis--Pareto-type function
Pei-Pin Yang🇨🇳 · Mai-Ying Duan🇨🇳 · Fu-Hu Liu🇨🇳 · Raghunath Sahoo🇮🇳
In the framework of a multi-source thermal model at the partonic-level, we have analyzed transverse momentum spectra of hadrons measured by the ALICE Collaboration in proton-proton ( $pp$ or $p$ - $p$ ) collisions at the center-of-mass energy of $s = 7$ and 13 TeV, proton-lead ( $p$ -Pb) collisions at $s_{NN} = 5.02$ TeV, and lead-lead (Pb-Pb) collisions at $s_{NN} = 2.76$ TeV. For meson(baryon), the contributions of two(three) constituent quarks are considered, in which each quark contributes to hadron transverse momentum to obey the revised phenomenological Tsallis transverse momentum distribution for the Maxwell-Boltzmann particles (the TP-like function in short) with isotropic random azimuthal angle. Three main parameters, namely, the revised index $a_{0}$ , effective temperature $T$ , and entropy-related index $n$ are obtained, which show the same tendency for small and large systems with respect to the centrality (or multiplicity) of events, rest mass of hadrons, and constituent mass of quarks.
Comments:
Please see the published version in the journal Symmetry following the reference and DOI
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2112.13223 [pdf]
Symmetry(2022)·13 citations
21
[Submitted on 25 Dec 2021] (cross-list from quant-ph)
Closest approach of a quantum projectile
A Kumar🇮🇳 · T Krisnanda🇸🇬 · P Arumugam🇮🇳 · T Paterek🇸🇬
We consider the simplest case of Rutherford scattering, i.e. the head-on collision, where the projectile is treated quantum mechanically. The convexity of repulsive Coulomb force invokes a disagreement between the Ehrenfest's and Hamilton's dynamics. We show that the quantum projectile cannot approach as close as the corresponding classical one, and that the average distance of closest approach depends on the position spread of the wave function describing the projectile.
Comments:
ICMMCMSE 2020, Alagappa University (India)
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2112.13296 [pdf]
J.Phys.Conf.Ser.(2021)·1 citation
22
[Submitted on 26 Dec 2021] (cross-list from astro-ph.HE)
Cooling of Isolated Neutron Stars with Pion Condensation: Possible Fast Cooling in a Low-Symmetry-Energy Model
Akira Dohi🇯🇵 · Helei Liu🇨🇳 · Tsuneo Noda🇯🇵 · Masa-aki Hashimoto🇯🇵
We studied thermal evolution of isolated neutron stars (NSs) including the pion condensation core, with an emphasis on the stiffness of equation of state (EOS). Many temperature observations can be explained by the minimal cooling scenario which excludes the fast neutrino cooling process. However, several NSs are cold enough to require it. The most crucial problem for NS cooling theory is whether the nucleon direct Urca (DU) process is open. The DU process is forbidden if the nucleon symmetry energy is significantly low. Hence, another fast cooling process is required in such an EOS. As the candidate to solve this problem, we consider the pion condensation. We show that the low-symmetry-energy model can account for most cooling observations including cold NSs, with strong neutron superfluidity. Simultaneously, it holds the $2 M_{⊙}$ observations even if the pion condensation core exists. Thus, we propose the possibility of pion condensation, as an exotic state to solve the problem in low-symmetry-energy EOSs. We examined the consistency of our EOSs with other various observations as well.
Comments:
21 pages, 8 figures, accepted by Int. J. Mod. Phys. E
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.13302 [pdf]
IJMPE(2022)·9 citations
23
[Submitted on 26 Dec 2021] (cross-list from hep-ph)
Novel approaches in Hadron Spectroscopy
JPAC Collaboration: Miguel Albaladejo🇪🇸 · Lukasz Bibrzycki🇵🇱 · Sebastian M. Dawid🇺🇸 · Cesar Fernandez-Ramirez🇲🇽 · Sergi Gonzalez-Solis🇺🇸 · Astrid N. Hiller Blin🇺🇸 · Andrew W. Jackura🇺🇸 · Vincent Mathieu🇪🇸 · Mikhail Mikhasenko🇩🇪 · Victor I. Mokeev🇺🇸 · Emilie Passemar🇺🇸 · Alessandro Pilloni🇮🇹 and 5 other authors
The last two decades have witnessed the discovery of a myriad of new and unexpected hadrons. The future holds more surprises for us, thanks to new-generation experiments. Understanding the signals and determining the properties of the states requires a parallel theoretical effort. To make full use of available and forthcoming data, a careful amplitude modeling is required, together with a sound treatment of the statistical uncertainties, and a systematic survey of the model dependencies. We review the contributions made by the Joint Physics Analysis Center to the field of hadron spectroscopy.
Comments:
98 pages, 58 figures. To appear in Progress in Particle and Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2112.13436 [pdf]
PPNP(2022)·85 citations
24
[Submitted on 27 Dec 2021] (cross-list from hep-lat)
Fifty ways to build a deuteron: a variational calculation of two-nucleon systems
Michael L. Wagman (for the NPLQCD collaboration)🇺🇸
A variational study of two-nucleon systems with lattice quantum chromodynamics is performed using a wide range of interpolating operators: dibaryon operators built from products of momentum-projected nucleons, hexaquark operators built from six spatially localized quarks, and quasi-local operators inspired by two-nucleon bound-state wavefunctions in nuclear effective field theories. Correlation-function matrices involving products of these operators are constructed by computing timeslice-to-all quark propagators with sparsening techniques. Comparisons between results obtained using the same gauge-field ensemble but different interpolating-operator sets demonstrate that interpolating-operator dependence can lead to significant effects on the two-nucleon energy spectra obtained using both variational and non-variational methods.
Comments:
13 pages, 2 figures, Proceedings for The 38th International Symposium on Lattice Field Theory, LATTICE2021, 26th-30th July, 2021
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.13474 [pdf]
PoS(2022)·3 citations
25
[Submitted on 27 Dec 2021] (cross-list from hep-ph)
QCD knows new quarks
Chuan-Xin Cui🇨🇳 · Hiroyuki Ishida🇨🇳 · Mamiya Kawaguchi🇯🇵 · Jin-Yang Li🇨🇳 · Shinya Matsuzaki🇨🇳 · Akio Tomiya🇺🇸
We find that a big gap between indicators for the breaking strengths of the global chiral SU(2) and U(1) axial symmetries in QCD of the Standard Model (SM) can be interpreted as a new fine-tuning problem. This may thus imply calling for a class of Beyond the SM, which turns out to favor having a new chiral symmetry and the associated massless new quark insensitive to the chiral SU(2) symmetry for the lightest up and down quarks, so that the fine-tuning is relaxed. Our statistical estimate shows that QCD of the SM is by more than 300 standard deviations off the desired parameter space, which is free from the fine-tuning, and the significance will be greater as the lattice measurements on the QCD hadron observables get more accurate. As one viable candidate, we introduce a dark QCD model with massless new quarks, which can survive current experimental, cosmological, and astrophysical limits, and also leave various phenomenological and cosmological consequences, to be probed in the future. This is a new indication from QCD, which gives a new avenue to deeper understand QCD, and provides a new guideline to consider going beyond the SM.
Comments:
22 pages, 5 figures; analysis updated, several discussions and references added; claims further refined
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.13533 [pdf]
Universe(2024)·1 citation
26
[Submitted on 27 Dec 2021] (cross-list from hep-ph)
Light pseudoscalar meson and heavy meson scattering lengths to $O (p^{4})$ in heavy meson chiral perturbation theory
Bo-Lin Huang🇨🇳 · Zi-Yang Lin🇨🇳 · Shi-Lin Zhu🇨🇳
We calculate the threshold $T$ matrices of the light pseudoscalar meson and heavy meson scattering to fourth order in heavy meson chiral perturbation theory. We determine the low-energy constants by fitting to the lattice QCD data points through both the perturbative and iterated methods and obtain the physical scattering lengths in both formalisms. The values of the scattering lengths tend to be convergent at fourth order for most of the channels in the perturbative method. The value of the scattering length for the channel $D K (I = 0)$ , which involves the bound state $D_{s 0}^{*} (2317)$ , is obtained correctly in the iterated method. Based on the heavy diquark-antiquark symmetry, we also estimate the meson and doubly charmed (bottom) baryon scattering lengths, and find that the bound states can be generated with high probability in the channels $K ˉ Ξ_{cc} (I = 0)$ and $K ˉ Ξ_{bb} (I = 0)$ . We strongly urge the LHCb Collaboration to look for the very narrow $K ˉ Ξ_{cc}$ state with $I J^{P} = 0 \frac{1}{2}^{-}$ through either the electromagnetic decay or the iso-spin violating strong decay $Ω_{cc} π$ .
Comments:
21 pages, 3 figures, 12 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.13702 [pdf]
PRD(2022)·26 citations

Affiliations

first authorsco-authorsvia INSPIRE