Nuclear Theory·nucl-th

Friday·December 29, 2023

22 papers—10 primary·12 cross-listed

01
[Submitted on 23 Dec 2023]
Time Scales in Many-Body Fast Neutrino Flavor Conversion
Ramya Bhaskar🇺🇸 · Alessandro Roggero🇺🇸 · Martin J. Savage🇺🇸
Time scales associated with many-body fast neutrino flavor conversions in core-collapse supernova are explored in the context of an effective two-flavor model with axial symmetry. We present a preliminary study of time scales obtained from a linear stability analysis and from the distributions of Loschmidt echo crossing times (intimately connected to dynamical phase transitions in non-equilibrium systems) determined by time evolution with the exact many-body Hamiltonian. Starting from a tensor-product initial state describing systems of $N$ neutrinos, with $N /2$ electron-type and $N /2$ heavy-type, with uniform angular distributions, the Loschmidt echo crossing times, $t_{L_{\times}}$ , are found to exhibit two distinct time scales that are exponentially separated. The second peak structure at longer times, effectively absent for $N = 4$ , develops with increasing $N$ . When re-scaled in terms of $lo g t_{L_{\times}}$ , the distributions are found to become increasingly well described by the sum of two stable distributions. The distribution of Loschmidt echo crossing times differs somewhat from the results of the (numerical) linear stability analysis, which exhibits a peak at finite frequency and a second peak consistent with zero frequency. The exact analysis suggests that the zero-frequency instability manifests itself as a modest flavor-conversion time scale.
Comments:
13 pages, 5 figures; Updated references, and acknowledgments section
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.16212 [pdf]
8 citations
02
[Submitted on 27 Dec 2023]
Frame transformation and stable-causal hydrodynamic theory
Sayantani Bhattacharyya🇬🇧 · Sukanya Mitra🇮🇳 · Shuvayu Roy🇮🇳
In this work, a connection has been indicated between the different existing formulations of relativistic hydrodynamic theories, which, in order to be causal and stable, (i) either requires `non-fluid' variables apart from velocity and temperature to be promoted to new degrees of freedom, or, (ii) needs to be in a generalized hydrodynamic frame other than those given by Landau or Eckart. The BDNK stress tensor (originally in a general frame) has been rewritten in the Landau frame using linearized all-order gradient-corrected redefinitions of the temperature and velocity fields. The redefinitions indicate that, while the BDNK formalism has a finite number of derivatives in the general frame, when written in the Landau frame, it either has an infinite number of derivatives, or one has to introduce MIS-like `non-fluid' variables by summing the infinite number of derivatives in the field redefinitions. There can be non-unique ways of performing these infinite-order summations. Finally, the dispersion relations and the corresponding spectra of these different systems of MIS type equations have been analyzed to check that the systems of equations presented here are indeed equivalent to the BDNK formalism, at least in the hydrodynamic regime.
Comments:
28 pages
Subjects:
Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2312.16407 [pdf]
10 citations
03
[Submitted on 28 Dec 2023]
Multiphoton fusion of light nuclei in intense laser fields
Binbing Wu · Zhengfeng Fan · Difa Ye · Tao Ye · Congzhang Gao · Chengxin Yu · Xuefeng Xu · Cunbo Zhang · Jie Liu
We investigate the fusion cross sections of light nuclei in the presence of linearly polarized intense laser fields. By combining the Coulomb-Volkov solutions with the complex spherical square-well nuclear potential, we derive an explicit formulation of the multiphoton cross section in a self-consistent manner. Our analysis is specifically focused on deuteron-triton (DT) and proton-boron (p $^{11} B$ ) fusion reactions, both of which have garnered widespread attention. The theoretical results reveal that, under conditions of longer laser wavelengths and lower incident particle kinetic energies, a few thousands of photons can participate in the fusion reactions, resulting in a substantial enhancement of fusion cross sections by almost ten orders of magnitude. We elucidate the multiphoton mechanism underlying these findings and discuss their implications.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.16777 [pdf]
PRC(2024)·6 citations
04
[Submitted on 28 Dec 2023]
The mixed phase quark core in massive hybrid stars
Xuhao Wu🇨🇳 · Peng-Cheng Chu🇨🇳 · Min Ju🇨🇳 · He Liu🇨🇳
We investigate the properties of hybrid star and the mixed phase core to explore the radius ratio of the mixed phase in hybrid star. In the context of observed massive neutron stars (NSs), we examine the internal structure, phase transitions, and the impacts of the equation of state (EOS) in maximum hybrid star. We investigate the stiffness changes in the EOS during the hadron-quark phase transition within the hybrid stars. The relativistic mean-field (RMF) model is used to describe hadronic matter, while to the represent quark matter, the Nambu-Jona-Lasinio (NJL) model is applied. We explore the strength of vector coupling in quark matter, which delays the onset density of the mixed phase and reduces the size of the mixed-phase core in a hybrid star, but does not exhibit a clear correlation with the central density. In a hybrid star with a maximum mass of approximately 2 solar masses ( $M_{⊙}$ ), a mixed-phase core of $\sim$ 5 km may exist, comprising about $40%$ of the total radius. However, our results do not support the existence of a sizable quark core containing the mixed phase ( $R_{MP} > 1/2 R_{total}$ ) for the maximum-mass hybrid star or for a 2~ $M_{⊙}$ massive star.
Comments:
9 fighres
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.16843 [pdf]
EPJC(2025)·5 citations
05
[Submitted on 28 Dec 2023]
Spin alignment of vector mesons by second-order hydrodynamic gradients
Avdhesh Kumar🇹🇼 · Philipp Gubler🇹🇼 · Di-Lun Yang🇯🇵
Starting with the polarization dependent Wigner function of vector mesons, we derive an expression for the 00-component ( $ρ_{00}$ ) of spin density matrix in terms of the second order gradients of the vector meson distribution functions. We further apply a thermal model to analyze the transverse momentum and the azimuthal angle dependence of $ρ_{00}$ for $ϕ$ and $K^{* 0}$ mesons resulting from distribution gradients in Au-Au collisions with $s_{N N} = 130$ GeV at mid-rapidity. Our results for the transverse momentum dependence indicate that the deviations of $ρ_{00}$ from $1/3$ as the signal for spin alignment are greatly enhanced at large transverse momenta and have a strong centrality dependence while analysis of the azimuthal angle ( $ϕ_{q}$ ) dependence suggest that such deviations have a $cos (2 ϕ_{q})$ structure with opposite sign for $ϕ$ and $K^{* 0}$ . Our finding may be considered as a baseline for probing spin-alignment mechanisms beyond hydrodynamic gradients.
Comments:
30 pages, 3 figures, minor revisions, journal version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.16900 [pdf]
PRD(2024)·35 citations
06
[Submitted on 28 Dec 2023]
Constraining the p{\Lambda} interaction from a combined analysis of scattering data and correlation functions
D. L. Mihaylov🇩🇪 · J. Haidenbauer🇩🇪 · V. Mantovani Sarti🇩🇪
This work provides the first combined analysis of low-energy p $Λ$ scattering, considering both cross section and correlation data. The obtained results establish the most stringent constraints to date on the two-body p $Λ$ interaction, pointing to a weaker attraction than so far accepted. The best set of scattering lengths for the spin singlet and triplet are found to range from $f_{0}, f_{1} = (2.1, 1.56)$ to $(3.34, 1.18)$ fm. With a chiral NY potential fine-tuned to those scattering parameters, the in-medium properties of the $Λ$ are explored and a potential depth of $U_{Λ} = - 36.3 \pm 1.3 (stat)_{- 6.2}^{+ 2.5} (syst)$ MeV is found at nuclear matter saturation density.
Comments:
The initial upload contained a wrong entry in Table 1. The 'f1' for point iv) was WRONGLY written as 1.54 fm, whereas the CORRECT value is 1.32 fm
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.16970 [pdf]
PLB(2024)·25 citations
07
[Submitted on 28 Dec 2023]
Production of super-heavy nuclei in hot-fusion reactions
V. Yu. Denisov
A model for hot-fusion reactions leading to the synthesis of super-heavy nuclei is discussed. The values of the hot-fusion cross-sections obtained in the model agree with the available experimental data. The hot-fusion cross-sections are found for two different models of the fission barrier heights of super-heavy nuclei. The calculations of the cross-sections for the various hot-fusion reactions leading to the 119 and 120 elements are presented. Simple expressions useful for qualitative analysis of the cross-section for forming super-heavy nuclei are obtained. It is shown that the super-heavy nuclei production cross section is proportional to the transmission coefficient of the capture barrier, realization probability of the $x n$ -evaporation channel, and exponentially depends on the quasi-elastic barrier, fusion reaction Q-value, compound nucleus formation barrier, neutron separation energies, and fission barrier heights.
Comments:
16 pages, 12 figures, 1 table. arXiv admin note: text overlap with arXiv:2309.14995
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.17084 [pdf]
PRC(2024)·9 citations
08
[Submitted on 28 Dec 2023]
Two-flavor color superconducting quark stars may not exist
Wen-Li Yuan🇨🇳 · Ang Li🇨🇳
Large uncertainties in the determinations of the equation of state of dense stellar matter allow the intriguing possibility that the bulk quark matter in beta equilibrium might be the true ground state of the matter at zero pressure. And quarks will form Cooper pairs very readily since the dominant interaction between quarks is attractive in some channels. As a result, quark matter will generically exhibit color superconductivity, with the favored pairing pattern at intermediately high densities being two-flavor pairing. In the light of several possible candidates for such self-bound quark stars, including the very low-mass central compact object in supernova remnant HESS J1731-347 reported recently, we carry out one field-theoretic model, the Nambu-Jona-Lasinio model, of investigation on the stability of beta-stable two-flavor color superconducting (2SC) phase of quark matter, nevertheless find no physically-allowed parameter space for the existence of 2SC quark stars.
Comments:
13 pages, 6 figures, with appendix; ApJ (2024) accepted
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.17102 [pdf]
ApJ(2024)·18 citations
09
[Submitted on 28 Dec 2023]
Extended Skyrme effective interactions for transport model and neutron stars
Si-Pei Wang🇨🇳 · Rui Wang🇮🇹 · Jun-Ting Ye🇨🇳 · Lie-Wen Chen🇨🇳
It is important to develop a unified theoretical framework to describe the nuclear experiments and astrophysical observations based on the same effective nuclear interactions. Based on the so-called Skyrme pseudopotential up to next-to-next-to-next-to-leading order, we construct a series of extended Skyrme interactions by modifying the density-dependent term and fitting the empirical nucleon optical potential up to above $1$ GeV, the empirical properties of isospin symmetric nuclear matter, the microscopic calculations of pure neutron matter and the properties of neutron stars from astrophysical observations. The modification of the density-dependent term in the extended Skyrme interactions follows the idea of Fermi momentum expansion and this leads to a highly flexible density behavior of the symmetry energy. In particular, the values of the density slope parameter $L$ of the symmetry energy for the new extended Skyrme interactions range from $L = - 5$ MeV to $L = 125$ MeV by construction, to cover the large uncertainty of the density dependence of the symmetry energy. Furthermore, in order to consider the effects of isoscalar and isovector nucleon effective masses, we adjust the momentum dependency of the single-nucleon optical potential and the symmetry potential of these new extended Skyrme interactions and construct a parameter set family, by which we systematically study the impacts of the symmetry energy and the nucleon effective masses on the properties of nuclear matter and neutron stars. The new extended Skyrme interactions constructed in the present work will be useful to determine the equation of state of isospin asymmetric nuclear matter, especially the symmetry energy, as well as the nucleon effective masses and their isospin splitting, in transport model simulations for heavy-ion collisions, nuclear structure calculations and neutron star studies.
Comments:
38 pages, 16 figures, 8 tables. Discussions added and typos fixed. Accepted version to appear in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2312.17105 [pdf]
PRC(2024)·19 citations
10
[Submitted on 28 Dec 2023]
QGP Physics from Attractor Perturbations
Xin An🇵🇱 · Michał Spaliński🇵🇱
The strong longitudinal expansion characteristic of heavy-ion collisions leads to universal attractor behavior of the resulting drop of quark-gluon plasma (QGP) already at very early times. Assuming approximate boost invariance and neglecting transverse expansion at the initial time, we incorporate subsequent transverse dynamics of this system by linearizing the Mueller-Israel-Stewart theory around the transversely homogeneous attractor. The result is a system of coupled ordinary differential equations which describes the proper-time evolution of Fourier modes encoding the transverse structure of the initial energy deposition. The late-time asymptotic behavior of these solutions is described by transseries which make manifest the stability of the attractor against transverse perturbations. In this framework, information about the structure of the plasma in the transverse plane resides mostly in exponentially suppressed corrections to evolution along the attractor, which are not yet negligible at freeze-out. These findings also suggest a simple numerical approach to QGP dynamics using a finite number of Fourier modes. Physical observables can be expressed in terms of the asymptotic data evaluated at freeze-out. We demonstrate the efficacy of this approach by calculating the final multiplicity distributions and collective flow coefficients.
Comments:
A much expanded version, which includes extended discussions and a calculation of flow coefficients. 30 pages and 7 figures. Accepted for publication in PRD
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2312.17237 [pdf]
PRD(2024)·8 citations
11
[Submitted on 26 Dec 2023] (cross-list from hep-ph)
Accelerated quantum circuit Monte-Carlo simulation for heavy quark thermalization
Xiaojian Du🇪🇸 · Wenyang Qian🇪🇸
Thermalization of heavy quarks in the quark-gluon plasma (QGP) is one of the most promising phenomena for understanding the strong interaction. The energy loss and momentum broadening at low momentum can be well described by a stochastic process with drag and diffusion terms. Recent advances in quantum computing, in particular quantum amplitude estimation (QAE), promise to provide a quadratic speed-up in simulating stochastic processes. We introduce and formalize an accelerated quantum circuit Monte-Carlo (aQCMC) framework to simulate heavy quark thermalization. With simplified drag and diffusion coefficients connected by Einstein's relation, we simulate the thermalization of a heavy quark in isotropic and anisotropic mediums using an ideal quantum simulator and compare that to thermal expectations. With Grover-like QAE, we calculate physical observables with quadratically fewer resources, which is a boost over the classical MC simulation that usually requires a large sampling number at the same estimation accuracy.
Comments:
10 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2312.16294 [pdf]
PRD(2024)·15 citations
12
[Submitted on 27 Dec 2023] (cross-list from hep-th)
Convergence of Ginzburg-Landau expansions: superconductivity in the Bardeen-Cooper-Schrieffer theory and chiral symmetry breaking in the Nambu-Jona-Lasinio model
William Gyory🇺🇸 · Naoki Yamamoto🇯🇵
We study the convergence of the Ginzburg-Landau (GL) expansion in the context of the Bardeen-Cooper-Schrieffer (BCS) theory for superconductivity and the Nambu-Jona-Lasinio (NJL) model for chiral symmetry breaking at finite temperature $T$ and chemical potential $μ$ . We present derivations of the all-order formulas for the coefficients of the GL expansions in both systems under the mean-field approximation. We show that the convergence radii for the BCS gap $Δ$ and dynamical quark mass $M$ are given by $Δ_{conv} = π T$ and $M_{conv} = μ^{2} + (π T)^{2}$ , respectively. We also discuss the implications of these results and the quantitative reliability of the GL expansion near the first-order chiral phase transition.
Comments:
21 pages, 3 figures; v2: minor corrections, published version
Subjects:
High Energy Physics — Theory (hep-th); Superconductivity (cond-mat.supr-con); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.16372 [pdf]
PTEP(2024)·1 citation
13
[Submitted on 27 Dec 2023] (cross-list from hep-lat)
Analytic continuation of the finite-volume three-particle amplitudes
Sebastian M. Dawid🇺🇸
One has to study multivariable scattering amplitudes to extract properties of the three-body states from the generalizations of the Lüscher finite-volume formalism. In particular, a three-body amplitude obtained from a Lattice QCD calculation must be analytically continued to unphysical Riemann sheets of the complex energy plane, where resonances of interest appear as poles. In this article, we provide a pedagogical overview of a method for solving and analytically continuing the on-shell integral equations describing a three-body elastic scattering process. We illustrate the procedure by applying it to a relativistic system of three identical bosons characterized by pair-wise interactions. We describe the analytic structure of the reaction amplitude, show how to access its physical and unphysical Riemann sheets, and analyze the behavior of the three-body spectrum under variations of the interaction parameters.
Comments:
12 pages, 2 figures. Proceedings for the 40th Lattice conference at Fermilab from July 31 to August 4, 2023
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2312.16380 [pdf]
PoS(2024)·2 citations
14
[Submitted on 27 Dec 2023] (cross-list from hep-ph)
The Transverse Energy-Energy Correlator at Next-to-Next-to-Next-to-Leading Logarithm
Anjie Gao🇺🇸 · Hai Tao Li🇨🇳 · Ian Moult🇺🇸 · Hua Xing Zhu🇨🇳
We present an operator based factorization formula for the transverse energy-energy correlator in the back-to-back (dijet) region, and uncover its remarkable perturbative simplicity and relation to transverse momentum dynamics. This simplicity enables us to achieve next-to-next-to-next-to leading logarithmic (N $^{3}$ LL) accuracy for a hadron collider dijet event shape for the first time. Our factorization formula applies to color singlet, $W / Z / γ$ + jet, and dijet production, providing a natural generalization of transverse momentum observables to one- and two-jet final states. This provides a laboratory for precision studies of QCD and transverse momentum dynamics at hadron colliders, as well as an opportunity for understanding factorization and its violation in a perturbatively well controlled setting.
Comments:
54 pages, 12 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.16408 [pdf]
JHEP(2024)·40 citations
15
[Submitted on 27 Dec 2023] (cross-list from hep-th)
Field redefinitions and evolutions in relativistic Navier-Stokes
Yago Bea🇪🇸 · Pau Figueras🇬🇧
In recent years the equations of relativistic first-order viscous hydrodynamics, that is, the relativistic version of Navier-Stokes, have been shown to be well posed and causal under appropriate field redefinitions, also known as hydrodynamic frames. We perform real-time evolutions of these equations for a conformal fluid and explore, quantitatively, the consequences of using different causal frames for different sets of initial data. By defining specific criteria, we make precise and provide evidence for the statement that the arbitrarily chosen frame does not affect the physics up to first order, as long as the system is in the effective field theory regime. Motivated by the physics of the quark-gluon plasma created in heavy-ion collisions we also explore systems which are marginally in the effective field theory regime, finding that even under these circumstances the first order physics is robust under field redefinitions.
Comments:
36 pages, 14 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2312.16671 [pdf]
JHEP(2024)·13 citations
16
[Submitted on 27 Dec 2023] (cross-list from hep-lat)
QCD material parameters at zero and non-zero chemical potential from the lattice
D. A. Clarke🇺🇸 · J. Goswami🇯🇵 · F. Karsch🇩🇪 · P. Petreczky🇺🇸
Using an eighth-order Taylor expansion in baryon chemical potential, we recently obtained the (2+1)-flavor QCD equation of state (EoS) at non-zero conserved charge chemical potentials from the lattice. We focused on strangeness-neutral, isospin-symmetric QCD matter, which closely resembles the situation encountered in heavy-ion collision experiments. Using this EoS, we present here results on various QCD material parameters; in particular we compute the specific heat, speed of sound, and compressibility along appropriate lines of constant physics. We show that in the entire range relevant for the beam energy scan at RHIC, the specific heat, speed of sound, and compressibility show no indication for an approach to critical behavior that one would expect close to a possibly existing critical endpoint.
Comments:
4 pages, 1 figure, presented at 30th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (Quark Matter 2023)
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2312.16703 [pdf]
EPJ Web Conf.(2024)·0 citations
17
[Submitted on 28 Dec 2023] (cross-list from hep-ph)
$e^{+} e^{-} \to Λ_{c}^{+} Λ ˉ_{c}^{-}$ cross sections and the $Λ_{c}^{+}$ electromagnetic form factors within the extended vector meson dominance model
Cheng Chen🇨🇳 · Bing Yan🇨🇳 · Ju-Jun Xie🇨🇳
Within the extended vector meson dominance model, we investigate the $e^{+} e^{-} \to Λ_{c}^{+} Λ ˉ_{c}^{-}$ reaction and the electromagnetic form factors of the charmed baryon $Λ_{c}^{+}$ . The model parameters are determined by fitting them to the cross sections of the process $e^{+} e^{-} \to Λ_{c}^{+} Λ ˉ_{c}^{-}$ and the magnetic form factor $∣ G_{M} ∣$ of $Λ_{c}^{+}$ . By considering four charmoniumlike states, called $ψ (4500)$ , $ψ (4660)$ , $ψ (4790)$ , and $ψ (4900)$ , we can well describe the current data on the $e^{+} e^{-} \to Λ_{c}^{+} Λ ˉ_{c}^{-}$ reaction from the reaction threshold up to $4.96 GeV$ . In addition to the total cross sections and $∣ G_{M} ∣$ , the ratio $∣ G_{E} / G_{M} ∣$ and effective form factor $∣ G_{eff} ∣$ for $Λ_{c}^{+}$ are also calculated, and found that these calculations are consistent with the experimental data. Within the fitted model parameters, we have also estimated the charge radius of the charmed $Λ_{c}^{+}$ baryon.
Comments:
7 pages, 6 figures. Published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.16753 [pdf]
Chin.Phys.Lett.(2024)·15 citations
18
[Submitted on 28 Dec 2023] (cross-list from nucl-ex)
Search for the 6 $α$ condensed state in $^{24}$ Mg using the $^{12} C +^{12} C$ scattering
Y. Fujikawa · T. Kawabata · S. Adachi · S. Enyo · T. Furuno · Y. Hijikata · K. Himi · K. Hirose · Y. Honda · K. Inaba · H. Makii · K. Miyamoto and 9 other authors
We searched for the 6 $α$ -condensed state in $^{24}$ Mg by measuring the $^{12} C +^{12} C$ scattering with the SAKRA Si detector array at $E_\rm{cm}$ = 17.5-25.0 MeV. By using the invariant-mass method for the detected 3 $α$ particles, the inclusive cross sections for the $^{12} C +^{12} C \to^{12} C (0_{2}^{+}) + X$ and $^{12} C (3_{1}^{-}) + X$ reactions were determined. In addition, the missing-mass spectroscopy was successfully utilized to determine the excitation energy of the residual $^{12} C$ nucleus and the exclusive cross sections for the $^{12} C +^{12} C \to^{12} C (0_{2}^{+}) +^{12} C (0_{1}^{+})$ , $^{12} C (0_{2}^{+}) +^{12} C (2_{1}^{+})$ , and $^{12} C (0_{2}^{+}) +^{12} C (0_{2}^{+})$ reactions. In both the inclusive $^{12} C (0_{2}^{+}) + X$ channel and the exclusive $^{12} C (0_{2}^{+}) +^{12} C (0_{1}^{+})$ channel, the cross section peaked at $E_{r} m c m$ = 19.4 MeV, which correspond to the excitation energy of $E_{x}$ = 33.3 MeV in $^{24} Mg$ . This 19.4-MeV state is a candidate for the 6 $α$ -condensed state because of the agreement of the excitation energy with the theoretical value and its decay property. In the exclusive $^{12} C (0_{2}^{+}) +^{12} C (0_{2}^{+})$ channel, a broad state was observed at $E_\rm{cm}$ = 22.5 MeV, which correspond to the excitation energy of $E_{x}$ = 36.4 MeV in $^{24} Mg$ . From the angular distribution of the differential cross section, the spin and parity of this 22.5-MeV state was assigned to be $4^{+}$ . In addition, a $2^{+}$ state was suggested at the low-energy side of the 22.5-MeV state. Because their excitation energies are higher than the theoretical value of the 6 $α$ -condensed state, these states might be excited states of the 6 $α$ -condensed state such as the $2_{2}^{+}$ and $4_{1}^{+}$ states in $^{12} C$ .
Comments:
8 pages, 6 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.16861 [pdf]
PLB(2024)·12 citations
19
[Submitted on 28 Dec 2023] (cross-list from hep-th)
Higgs-Confinement Transitions in QCD from Symmetry Protected Topological Phases
Thomas T. Dumitrescu🇺🇸 · Po-Shen Hsin🇺🇸
In gauge theories with fundamental matter there is typically no sharp way to distinguish confining and Higgs regimes, e.g. using generalized global symmetries acting on loop order parameters. It is standard lore that these two regimes are continuously connected, as has been explicitly demonstrated in certain lattice and continuum models. We point out that Higgsing and confinement sometimes lead to distinct symmetry protected topological (SPT) phases -- necessarily separated by a phase transition -- for ordinary global symmetries. We present explicit examples in 3+1 dimensions, obtained by adding elementary Higgs fields and Yukawa couplings to QCD while preserving parity P and time reversal T. In a suitable scheme, the confining phases of these theories are trivial SPTs, while their Higgs phases are characterized by non-trivial P- and T-invariant theta-angles $θ_{f}, θ_{g} = π$ for flavor or gravity background gauge fields, i.e. they are topological insulators or superconductors. Finally, we consider conventional three-flavor QCD (without elementary Higgs fields) at finite $U (1)_{B}$ baryon-number chemical potential $μ_{B}$ , which preserves P and T. At very large $μ_{B}$ , three-flavor QCD is known to be a completely Higgsed color superconductor that also spontaneously breaks $U (1)_{B}$ . We argue that this high-density phase is in fact a gapless SPT, with a gravitational theta-angle $θ_{g} = π$ that safely co-exists with the $U (1)_{B}$ Nambu-Goldstone boson. We explain why this SPT motivates unexpected transitions in the QCD phase diagram, as well as anomalous surface modes at the boundary of quark-matter cores inside neutron stars.
Comments:
79 pages, 9 figures
Subjects:
High Energy Physics — Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.16898 [pdf]
SciPost Phys.(2024)·27 citations
20
[Submitted on 28 Dec 2023] (cross-list from hep-ph)
Light-by-Light Scattering at Next-to-Leading Order in QCD and QED
Ajjath A H🇫🇷 · Ekta Chaubey🇩🇪 · Mathijs Fraaije🇨🇭 · Valentin Hirschi🇨🇭 · Hua-Sheng Shao🇫🇷
The recent experimental observation of Light-by-Light (LbL) scattering at the Large Hadron Collider has revived interest in this fundamental process, and especially of the accurate prediction of its cross-section, which we present here for the first time at Next-to-Leading Order (NLO) in both QCD and QED. We compare two radically different computational approaches, both exact in the fermion mass dependence, thus offering a strong cross-check of our results. The first approach is a fully analytic method to calculate compact and well-organized two-loop helicity amplitudes. The second one is entirely numerical and leverages the Local Unitarity construction. Our two calculations agree with each other and conclude that including the exact fermion mass contribution typically increases the size of the NLO corrections. Moreover, we find that the exact result converges slowly to the massless limit of the high-energy regime, thus emphasizing the importance of including the full mass dependence at NLO. We also compare our results with the ATLAS measurement of LbL in ultra-peripheral lead-lead collisions, and find that the inclusion of exact NLO corrections reduces, but does not eliminate, the existing tension with theoretical predictions.
Comments:
11 pages, 6 figures (including appendix) v2: minor corrections and journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.16956 [pdf]
PLB(2024)·33 citations
21
[Submitted on 28 Dec 2023] (cross-list from hep-ph)
Mass spectrum of spin-one hadrons in dense two-color QCD: Novel predictions by extended linear sigma model
Daiki Suenaga🇯🇵 · Kotaro Murakami🇯🇵 · Etsuko Itou🇯🇵 · Kei Iida🇯🇵
We construct an extended version of the linear sigma model in such a way as to describe spin- $1$ hadrons as well as spin- $0$ hadrons in two-color QCD (QC $_{2}$ D) by respecting the Pauli-Gürsey $S U (4)$ symmetry. Within a mean-field approximation, we therefrom examine a mass spectrum of the spin- $1$ hadrons at finite quark chemical potential ( $μ_{q}$ ) and zero temperature. Not only mean fields of scalar mesons and scalar-diquark baryons but also of vector mesons and vector-diquark baryons are incorporated. As a result, we find that, unless all of those four types of mean fields are taken into account, neither lattice result for the critical $μ_{q}$ that corresponds to the onset of baryon superfluidity nor for $μ_{q}$ dependence of the pion mass can be reproduced. We also find that a slight suppression of the $ρ$ meson mass in the superfluid phase, which was suggested by the lattice simulation, is reproduced by subtle mixing effects between spin- $0$ and spin- $1$ hadrons. Moreover, we demonstrate the emergence of an axialvector condensed phase and possibly of a vector condensed phase by identifying the values of $μ_{q}$ at which the corresponding hadron masses vanish. The possible presence of iso-triplet $1^{-}$ diquarks that may be denoted by a tensor-type quark bilinear field is also discussed.
Comments:
24 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2312.17017 [pdf]
PRD(2024)·14 citations
22
[Submitted on 28 Dec 2023] (cross-list from hep-lat)
Static force from generalized Wilson loops on the lattice using the gradient flow
Nora Brambilla🇩🇪 · Viljami Leino🇩🇪 · Julian Mayer-Steudte🇩🇪 · Antonio Vairo🇩🇪
The static QCD force from the lattice can be used to extract $Λ_{MS}$ , which determines the running of the strong coupling. Usually, this is done with a numerical derivative of the static potential. However, this introduces additional systematic uncertainties; thus, we use another observable to measure the static force directly. This observable consists of a Wilson loop with a chromoelectric field insertion. We work in the pure SU(3) gauge theory. We use gradient flow to improve the signal-to-noise ratio and to address the field insertion. We extract $Λ_{MS}^{n_{f} = 0}$ from the data by exploring different methods to perform the zero-flow-time limit. We obtain the value $8 t_{0} Λ_{MS}^{n_{f} = 0} = 0.62 9_{- 26}^{+ 22}$ , where $t_{0}$ is a flow-time reference scale. We also obtain precise determinations of several scales: $r_{0} / r_{1}$ , $8 t_{0} / r_{0}$ , $8 t_{0} / r_{1}$ and we compare these to the literature. The gradient flow appears to be a promising method for calculations of Wilson loops with chromoelectric and chromomagnetic insertions in quenched and unquenched configurations
Comments:
27 pages, 19 figures The latest version matches the reviewed and accepted version
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2312.17231 [pdf]
PRD(2024)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE