Nuclear Theory·nucl-th

Tuesday·May 10, 2022

11 papers—6 primary·5 cross-listed

07
[Submitted on 6 May 2022] (cross-list from hep-ph)
Conformal Colliders Meet the LHC
Kyle Lee🇺🇸 · Bianka Meçaj🇺🇸 · Ian Moult🇺🇸
The remarkably high energies of the Large Hadron Collider (LHC) have allowed for the first measurements of the shapes and scalings of multi-point correlators of energy flow operators, $⟨ Ψ∣ E (n_{1}) E (n_{2}) \dots E (n_{k}) ∣Ψ ⟩$ , providing new insights into the Lorentzian dynamics of quantum chromodynamics (QCD). In this Letter, we use recent advances in effective field theory to derive a rigorous factorization theorem for the light-ray density matrix, $ρ = ∣Ψ ⟩ ⟨ Ψ∣$ , inside high transverse momentum jets at the LHC. Using the light-ray operator product expansion, the scaling behavior of multi-point correlators can be computed from the expectation value of the twist-2 spin- $J$ light-ray operators, $O^{[J]}$ , in this state, $Tr [ρ O^{[J]}]$ . We compute the light-ray density matrix at next-to-leading order, and combine this with results for the next-to-leading logarithmic scaling behavior of the correlators up to six-points, comparing with CMS Open Data. This theoretical accuracy allows us to resolve the quantum scaling dimensions of QCD light-ray operators inside jets at the LHC. Our factorization theorem for the light-ray density matrix at the LHC completes the link between recent developments in the study of energy correlators and LHC phenomenology, opening the door to a wide variety of precision jet substructure studies.
Comments:
5 pages, 4 colorful figures of light-ray operator scaling
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.03414 [pdf]
PRD(2025)·133 citations
08
[Submitted on 8 May 2022] (cross-list from astro-ph.HE)
Nonparametric Representation of Neutron Star Equation of State Using Variational Autoencoder
Ming-Zhe Han · Shao-Peng Tang · Yi-Zhong Fan
We introduce a new nonparametric representation of the neutron star (NS) equation of state (EoS) by using the variational autoencoder (VAE). As a deep neural network, the VAE is frequently used for dimensionality reduction since it can compress input data to a low-dimensional latent space using the encoder component and then reconstruct the data using the decoder component. Once a VAE is trained, one can take the decoder of the VAE as a generator. We employ 100,000 EoSs that are generated using the nonparametric representation method based on \citet{2021ApJ...919...11H} as the training set and try different settings of the neural network, then we get an EoS generator (trained VAE's decoder) with four parameters. We use the mass\textendash{}tidal-deformability data of binary neutron star (BNS) merger event GW170817, the mass\textendash{}radius data of PSR J0030+0451, PSR J0740+6620, PSR J0437-4715, and 4U 1702-429, and the nuclear constraints to perform the joint Bayesian inference. The overall results of the analysis that includes all the observations are $R_{1.4} = 12.5 9_{- 0.42}^{+ 0.36} km$ , $Λ_{1.4} = 48 9_{- 110}^{+ 114}$ , and $M_{max} = 2.2 0_{- 0.19}^{+ 0.37} M_{⊙}$ ( $90%$ credible levels), where $R_{1.4}$ / $Λ_{1.4}$ are the radius/tidal-deformability of a canonical $1.4 M_{⊙}$ NS, and $M_{max}$ is the maximum mass of a non-rotating NS. The results indicate that the implementation of the VAE techniques can obtain the reasonable results, while accelerate calculation by a factor of $\sim$ 3\textendash10 or more, compared with the original method.
Comments:
10 pages, 4 figures, 1 table, published in ApJ
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Nuclear Theory (nucl-th)
arXiv:
2205.03855 [pdf]
ApJ(2023)·19 citations
09
[Submitted on 8 May 2022] (cross-list from astro-ph.HE)
Gravitational Wave Signal for Quark Matter with Realistic Phase Transition
Yuki Fujimoto🇯🇵 · Kenji Fukushima🇯🇵 · Kenta Hotokezaka🇯🇵 · Koutarou Kyutoku🇯🇵
The cores of neutron stars (NSs) near the maximum mass realize the most highly compressed matter in the universe where quark degrees of freedom may be liberated. Such a state of dense matter is hypothesized as quark matter (QM) and its presence has awaited to be confirmed for decades in nuclear physics. Gravitational waves from binary NS mergers are expected to convey useful information called the equation of state (EOS). However, the signature for QM with realistic EOS is not yet established. Here, we show that the gravitational wave in the post-merger stage can distinguish the theory scenarios with and without a transition to QM. Instead of adopting specific EOSs as studied previously, we compile reliable EOS constraints from the ab initio approaches. We demonstrate that early collapse to a black hole after NS merger signifies softening of the EOS associated with the onset of QM in accord with ab initio constraints. Nature of hadron-quark phase transition can be further constrained by the condition that electromagnetic counterparts need to be energized by the material left outside the remnant black hole.
Comments:
20 pages, 5 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2205.03882 [pdf]
PRL(2023)·87 citations
10
[Submitted on 9 May 2022] (cross-list from hep-ph)
Mixing effects on 1S and 2S state heavy mesons in the light-front quark model
Ahmad Jafar Arifi🇰🇷 · Ho-Meoyng Choi🇰🇷 · Chueng-Ryong ji🇺🇸 · Yongseok Oh🇰🇷
The mass spectra and wave functions of both $1 S$ and $2 S$ state heavy pseudoscalar ( $P$ ) and vector ( $V$ ) mesons are analyzed within the light-front quark model. Important empirical constraints employed in our analysis of the mass spectra and wave functions are the experimental mass-gap relation, $Δ M_{P} > Δ M_{V}$ , where $Δ M_{P (V)} = M_{P (V)}^{2 S} - M_{P (V)}^{1 S}$ and the hierarchy of the decay constants, $f_{1 S} > f_{2 S}$ , between $1 S$ and $2 S$ meson states. We maintain the orthogonality of the trial wave functions of the $1 S$ and $2 S$ states in our variational calculation of the Hamiltonian with the Coulomb plus confining potentials and treat the hyperfine interaction perturbatively for the heavy-heavy and heavy-light $P$ and $V$ mesons due to the nature of the heavy quark symmetry. Realizing that the empirical constraints cannot be satisfied without mixing of the $1 S$ and $2 S$ states, we find the lower bound of the mixing angle $θ$ between $1 S$ and $2 S$ states as $θ_{c} = cot^{- 1} (26) /2 ≃ 6^{\circ}$ and obtain the optimum value of the mixing angle around $1 2^{\circ}$ to cover both the charm and bottom flavors of the heavy quark. The mixing effects are found to be more significant to the $2 S$ state mesons than to the $1 S$ state mesons. The properties of $1 S$ and $2 S$ state mesons including the mass spectra, decay constants, twist-2 distribution amplitudes, and electromagnetic form factors are computed. Our results are found to be in a good agreement with the available data and lattice simulations. In particular, the $2 S$ state pseudoscalar $D_{s}$ meson is predicted to have a mass of $2600$ MeV, which is very close to the mass of the newly discovered $D_{s 0} (2590)^{+}$ meson by the LHCb Collaboration. This supports the interpretation of the observed state as a radial excitation of the $D_{s}^{+}$ meson.
Comments:
17 pages, 8 figures, 6 tables. Comments are welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2205.04075 [pdf]
PRD(2022)·48 citations
11
[Submitted on 9 May 2022] (cross-list from hep-ph)
In-medium polarization tensor in strong magnetic fields (I): Magneto-birefringence at finite temperature and density
Koichi Hattori🇨🇳 · Kazunori Itakura🇯🇵
We investigate in-medium polarization effects of the fermion and antifermion pairs at finite temperature and density in strong magnetic fields within the lowest Landau level approximation. Inspecting the integral representation of the polarization tensor by analytic and numerical methods, we provide both the real and imaginary parts of the polarization tensor obtained after delicate interplay between the vacuum and medium contributions essentially due to the Pauli-blocking effect. Especially, we provide a complete analytic form of the polarization tensor at zero temperature and finite density that exhibits an exact cancellation and associated relocation of the singular threshold behaviors for a single photon decay to a fermion and antifermion pair. As a physical application of the in-medium polarization tensor, we discuss the magneto-birefringence that is polarization-dependent dispersion relations of photons induced by the strong magnetic fields.
Comments:
A typo corrected. Published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2205.04312 [pdf]
Annals Phys.(2022)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE

Conformal Colliders Meet the LHC

Nonparametric Representation of Neutron Star Equation of State Using Variational Autoencoder

Gravitational Wave Signal for Quark Matter with Realistic Phase Transition

Mixing effects on 1S and 2S state heavy mesons in the light-front quark model

In-medium polarization tensor in strong magnetic fields (I): Magneto-birefringence at finite temperature and density

Affiliations