Nuclear Theory·nucl-th
19 papers—8 primary·11 cross-listed
N. N. Achasov🇷🇺 · G. N. Shestakov🇷🇺
It is shown that the values of the ratios and , recently measured by the BESIII Collaboration, are naturally explained in the four-quark model of the resonance.
P. Müller🇩🇪 · S. Kaufmann🇩🇪 · T. Miyagi🇩🇪 · J. Billowes🇬🇧 · M.L. Bissell🇬🇧 · K. Blaum🇩🇪 · B. Cheal🇬🇧 · R.F. Garcia Ruiz🇨🇭 · W. Gins🇧🇪 · C. Gorges🇩🇪 · H. Heylen🇩🇪 · A. Kanellakopoulos🇧🇪 and 15 other authors
The magnetic dipole and the spectroscopic quadrupole moments of the nuclear ground states in the odd-mass nickel isotopes Ni have been determined using collinear laser spectroscopy at the CERN-ISOLDE facility. They are compared to ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) calculations including contributions of two-body currents as well as to shell-model calculations. The two-body-current contributions significantly improve the agreement with experimental data, reducing the mean-square deviation from the experimental moments by a factor of 3 to 5, depending on the employed interaction. For all interactions, the largest contributions are obtained for the () isotopes Ni (Ni), which is ascribed to the high angular momentum of the orbitals. Our results demonstrate that the inclusion of two-body-current contributions to the magnetic moment in an isotopic chain of complex nuclei can be handled by the VS-IMSRG and can outperform phenomenological shell-model calculations using effective -factors in the nickel region.
This paper describes my personal appreciation for some of the great research achievements of Mitya Diakonov, Vitya Petrov, and Maxim Polyakov and how my own research career has followed the paths they opened. Among the topics where they have been the most influential have been the pursuit and study of the exotic pentaquark. The search for exotics may require a complementary approach, such as experimental and theoretical activity. Here, I would like to focus on a story of in which I was involved.
Alessandro Bacchetta🇮🇹 · Valerio Bertone🇫🇷 · Chiara Bissolotti🇺🇸 · Giuseppe Bozzi🇮🇹 · Matteo Cerutti🇺🇸 · Filippo Delcarro🇮🇹 · Marco Radici🇮🇹 · Lorenzo Rossi🇮🇹 · Andrea Signori (the MAP Collaboration)🇮🇹
We present an extraction of the unpolarized transverse-momentum-dependent parton distribution and fragmentation functions that takes into account possible differences between quark flavors and final-state hadrons. The extraction is based on experimental measurements from Drell-Yan processes and semi-inclusive deep-inelastic scattering, whose combination is essential to distinguish flavor differences. The analysis is carried out at NLL accuracy. The extracted flavor-dependent distributions give a very good description of the data (). The resulting uncertainties take fully into account also the uncertainties in the determination of the corresponding collinear distributions.
Dhananjaya Sahoo · A. Y. Deo · Madhu · Khamosh Yadav · S. S. Tiwary · P. C. Srivastava · R. Palit · S. K. Tandel · Anil Kumar · P. Dey · Biswajit Das · Vishal Malik and 5 other authors
High-spin states in the transitional Ac nucleus are established up to 3.8 MeV excitation energy and 41/2 with the addition of around 20 new transitions. The structure of the yrast and near-yrast states below the 29/2 isomer is revisited. The inconsistencies in the level schemes reported earlier are resolved. The level structure above the 29/2 isomer is established for the first time. Large-basis shell-model calculations with the KHPE interaction are performed to compare the experimentally observed level energies with the theoretical predictions. A comparison with the systematics of the N = 128 isotones suggests that the yrast structures result from a weak coupling of the odd proton to the even-even 216Ra core, which is consistent with the shell-model configurations. Furthermore, alpha decay of the 29/2 isomer is revisited and the decay scheme established from this work is discussed in the framework of the shell model.
A. B. Balantekin🇺🇸 · Anna M. Suliga🇺🇸
Motivated by the growing interest in the applications of quantum information science in astrophysical settings, especially for the neutrino transport in compact objects where three-flavors of neutrinos need to be mapped on qutrits, we review properties of one- and two-qudit systems. We contrast two-qubit and two-qudits systems by pointing out how some of the properties of two-qubit systems generalize to higher dimensions and explore emerging new properties for dimensions three or higher. One example is provided by the Werner states: when the density operator is written in the fundamental representation, we show that only two-qubit Werner states can be pure states, but not two-qudit Werner states when the qudit dimension is larger than two.
Andrew G. Sullivan · Roger W. Romani
PSR J2215+5135 (J2215) is a `redback' spider pulsar, where the intrabinary shock (IBS) wraps around the pulsar rather than the stellar-mass companion. Spider orbital light curves are modulated, dominated by their binary companion thermal emission in the optical bands and by IBS synchrotron emission in the X-rays. We report on new XMM-Newton X-ray and U-band observations of J2215. We produce orbital light curves and use them to model the system properties. Our best-fit optical light model gives a neutron star mass M, lower than previously reported. However, uncertainty in the stellar atmosphere metallicity, a parameter to which J2215 is unusually sensitive, requires us to consider an acceptable systematic plus statistical range of M. From the X-ray analysis, we find that the IBS wraps around the pulsar, but with a pulsar wind to companion wind momentum ratio unusually close to unity, implying a flatter IBS geometry than seen in other spiders. Estimating the companion wind momentum and speed from the X-ray light curve, we find a companion mass-loss rate of M yr, so that J2215 may become an isolated millisecond pulsar in Gyr. Our X-ray analyses place constraints on the magnetization and particle density of the pulsar wind and support models of magnetic reconnection and particle acceleration in the highly magnetized relativistic IBS.
Wei-Yang Liu🇺🇸 · Edward Shuryak🇺🇸 · Christian Weiss🇺🇸 · Ismail Zahed🇺🇸
The pion form factors of the QCD energy-momentum tensor (EMT) are studied in the instanton liquid model (ILM) of the QCD vacuum. In this approach the breaking of conformal symmetry is encoded in the form of stronger-than-Poisson fluctuations in the number of instantons. For the trace of the EMT, it is shown that the gluonic trace anomaly term contributes half the pion mass, with the other half coming from the quark-mass-dependent sigma term. The dependence of the form factors is governed by glueball and scalar meson exchanges. For the traceless EMT, the spin-0 and 2 form factors are computed at next-to-leading order in the instanton density using effective quark operators. Relations between the gluon and quark contributions to the EMT form factors are derived. The form factors are also expressed in terms of the pion light-front wave functions in the ILM. The results at the low resolution scale of the inverse instanton size are evolved to higher scales using the renormalization group equation. The ILM results compare well with those of recent lattice QCD calculations.
Hao-Song You🇨🇳 · Huai-Min Chen🇨🇳 · Jian-Feng Xu🇨🇳 · Cheng-Jun Xia🇨🇳 · Ren-Xin Xu🇨🇳 · Guang-Xiong Peng🇨🇳
We study the properties of strangelets at finite temperature , employing an equivparticle model that incorporates both linear confinement and leading-order perturbative interactions with density-dependent quark masses. The shell effects are analyzed by solving the Dirac equations for quarks within the mean-field approximation. As temperature increases, these effects weaken due to the occupation probability of single-particle levels being governed by the Fermi-Dirac statistics, a phenomenon known as shell dampening. Surprisingly, the surface tension, derived from a liquid-drop formula, does not decrease with temperature but instead rises until it peaks at MeV. At this temperature, shell corrections become negligible, and the formula provides a reasonable approximation for the free energy per baryon of strangelets. However, the curvature term decreases with despite the presence of shell effects. The neutron and proton emission rates are determined microscopically by the external nucleon gas densities that are in equilibrium with strangelets. These emission rate generally increases with for stable strangelets, but decrease for those that are unstable to nucleon emission at = 0. The other properties of -stable strangelets obtained with various parameter sets are presented as well. The results indicated in this work are useful for understanding the products of binary compact star mergers and heavy-ion collisions.
I. Zanon🇮🇹 · E. Clément🇫🇷 · A. Goasduff🇮🇹 · J. Menéndez🇪🇸 · T. Miyagi🇩🇪 · M. Assié🇫🇷 · M. Ciemała🇵🇱 · F. Flavigny🇫🇷 · A. Lemasson🇫🇷 · A. Matta🇫🇷 · D. Ramos🇫🇷 · M. Rejmund🇫🇷 and 69 other authors
The excited states of unstable O were investigated via -ray spectroscopy following the OO reaction at 8 MeV. By exploiting the Doppler Shift Attenuation Method, the lifetime of the 2 and 3 states were firmly established. From the -ray branching and E2/M1 mixing ratios for transitions deexciting the 2 and 3 states, the B(E2) and B(M1) were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of -ray transition probabilities with the valence space in medium similarity renormalization group ab-initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab-initio approaches using chiral EFT forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab-initio models.
Francesco Giovanni Celiberto🇪🇸 · Gabriele Gatto🇮🇹 · Alessandro papa🇮🇹
We investigate the inclusive production of fully charmed tetraquarks, or radial excitations, in high-energy proton collisions. We build our study upon the collinear fragmentation of a single parton in a variable-flavor number scheme, suited to describe the tetraquark formation mechanism from moderate to large transverse-momentum regimes. To this extent, we derive a novel set of DGLAP-evolving collinear fragmentation functions, named TQ4Q1.0 determinations. They encode initial-scale inputs corresponding to both gluon and heavy-quark fragmentation channels, defined within the context of quark-potential and spin-physics inspired models, respectively. We work within the NLL/NLO hybrid factorization and make use of the JETHAD numeric interface along with the symJETHAD symbolic calculation plugin. With these tools, we provide predictions for high-energy observables sensitive to plus jet emissions at center-of-mass energies ranging from 14 TeV at the LHC to the 100 TeV nominal energy of the FCC.
first authorsco-authorsvia INSPIRE