Nuclear Theory·nucl-th

Tuesday·January 30, 2024

12 papers—5 primary·7 cross-listed

06
Long-lived doubly charged scalars in the left-right symmetric model: catalyzed nuclear fusion and collider implications
Evgeny Akhmedov🇩🇪 · P. S. Bhupal Dev🇺🇸 · Sudip Jana🇩🇪 · Rabindra N. Mohapatra🇺🇸
We show that the doubly charged scalar from the $S U (2)_{R}$ -triplet Higgs field in the Left-Right Symmetric Model has its mass governed by a hidden symmetry so that its value can be much lower than the $S U (2)_{R}$ breaking scale. This makes it a long-lived particle while being consistent with all existing theoretical and experimental constraints. Such long-lived doubly charged scalars have the potential to trigger catalyzed fusion processes in light nuclei, which may have important applications for energy production. We show that it could also bear consequences on the excess of large ionization energy loss ( $d E / d x$ ) recently observed in collider experiments.
↳ hep-phhep-exnucl-exnucl-thPLB(2024)·8 citations
07
Anisotropic flow, flow fluctuation and flow decorrelation in relativistic heavy-ion collisions: the roles of sub-nucleon structure and shear viscosity
Jie Zhu🇨🇳 · Xiang-Yu Wu🇨🇳 · Guang-You Qin🇨🇳
We study the transverse momentum ( $p_{T}$ ) differential anisotropic flow and flow fluctuation in Pb+Pb collisions at $s_{N N}$ =5.02 TeV at the LHC. A (3+1)-dimensional CLVisc hydrodynamics framework with fluctuating TRENTO (or AMPT) initial conditions is utilized to simulate the space-time evolution of the quark-gluon plasma (QGP) medium. The effects of shear viscosity and the sub-nucleon structure on anisotropic flow and flow fluctuation are analyzed. Our result shows that shear viscosity tends to suppress both flow coefficients ( $v_{2} {2}$ , $v_{2} {4}$ , $⟨ v_{2} ⟩$ ) and flow fluctuation ( $σ_{v_{2}}$ ) due to its smearing effect on local density fluctuation. The flow coefficients appear to be insensitive to the sub-nucleon structure, whereas for flow fluctuation $σ_{v_{2}}$ , it tends to be suppressed by the sub-nucleon structure in central collisions but enhanced in peripheral collisions. After taking into account the sub-nucleon structure effect, our numerical result can quantitatively describe the relative flow fluctuations ( $v_{2} {4} / v_{2} {2}$ , $F (v_{2})$ ) measured by the ALICE Collaboration at the LHC. We further investigate the effects of shear viscosity, sub-nucleon structure and initial condition model on the flow angle and flow magnitude decorrelations ( $A_{2}^{f}$ , $M_{2}^{f}$ ) using the four-particle correlation method. We find that the flow decorrelation effect is typically stronger in central collisions than in peripheral collisions. The flow angle decorrelation is found to be insensitive to the shear viscosity and sub-nucleon structure, whereas the flow magnitude decorrelation shows quite different behavior when using TRENTO or AMPT initial condition model. Our study sheds light on the anisotropic flow, transport properties and initial structure of the QGP created in high-energy nuclear collisions.
↳ hep-phnucl-exnucl-thCPC(2025)·13 citations
08
Dissipative effects on the propagation of spin modes
Rajeev Singh🇺🇸 · Victor E. Ambrus🇩🇪 · Radoslaw Ryblewski🇵🇱
In relativistic hydrodynamics with spin, following de Groot--van Leeuwen--van Weert's energy-momentum and spin tensor definitions, we analyze the propagation of spin degrees of freedom. We deduce an analytical formula for spin wave velocity, finding that it approaches half the speed of light in the ultra-relativistic limit. Only transverse degrees of freedom propagate, similar to electromagnetic waves. Additionally, we explore dissipative effects and determine the damping coefficients for Maxwell-Jüttner statistics.
↳ hep-phnucl-thPoS(2024)·0 citations
09
Relativistic magnetohydrodynamics with spin
Samapan Bhadury🇵🇱 · Wojciech Florkowski🇵🇱 · Amaresh Jaiswal🇮🇳 · Avdhesh Kumar🇮🇳 · Radoslaw Ryblewski🇵🇱
In this work, we present a novel framework of relativistic non-resistive dissipative magnetohydrodynamics for spin-polarized particles. Utilizing a classical relativistic kinetic equation for the distribution function in an extended phase-space of position, momentum, and spin, we derive equations of motion for dissipative currents at first-order in spacetime gradients. Our findings reveal a coupling between fluid vorticity and magnetization via an electromagnetic field, leading to relativistic analogs of the Einstein-de Haas and Barnett effects. Our study provides a tool for a better understanding of the polarization phenomena observed in relativistic heavy-ion collisions.
↳ hep-phnucl-thPoS(2024)·3 citations
10
Simultaneous Measurement of Half-Life and Spectral Shape of $^{115}$ In $β$ -decay with an Indium Iodide Cryogenic Calorimeter
L. Pagnanini🇮🇹 · G. Benato🇮🇹 · P. Carniti🇮🇹 · E. Celi🇮🇹 · D. Chiesa🇮🇹 · J. Corbett🇨🇦 · I. Dafinei🇮🇹 · S. Di Domizio🇮🇹 · P. Di Stefano🇨🇦 · S. Ghislandi🇮🇹 · C. Gotti🇮🇹 · D. L. Helis🇮🇹 and 12 other authors
Current bounds on neutrino Majorana mass are affected by significant uncertainties in the nuclear calculations for neutrinoless double-beta decay. A key issue for a data-driven improvement of the nuclear theory is the actual value of the axial coupling constant $g_{A}$ , which can be investigated through forbidden $β$ -decays. We present the first measurement of 4 $^{t h}$ -forbidden $β$ -decay of $^{115}$ In with a cryogenic calorimeter based on Indium Iodide. Exploiting the enhanced spectral shape method for the first time to this isotope, our study accurately determines simultaneously spectral shape, $g_{A}$ , and half-life. The Interacting Shell Model, which best fits our data, indicates a half-life for this decay at $T_{1/2} = (5.26 \pm 0.06) \times 1 0^{14}$ ,yr.
↳ nucl-exnucl-thPRL(2024)·14 citations
11
Photoproduction of the $X (3872)$ beyond vector meson dominance: the open-charm coupled-channel mechanism
Xiong-Hui Cao🇨🇳 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳
Hidden-charm exotic hadrons will be searched for and investigated at future electron-ion colliders. For instance, the $X (3872)$ can be produced through the exclusive process $γ p \to X (3872) p$ . The vector meson dominance model has been commonly employed in estimating the cross sections of such processes. However, the coupled-channel production mechanism through open-charm meson-baryon intermediate states may play a crucial role. To assess the significance of such contributions, we estimate the cross section of the $γ p \to X (3872) p$ reaction assuming the coupled-channel mechanism. For energies near the threshold, the total cross section is predicted to be of tens of nanobarns for $γ p \to X (3872) p$ , which can be measured at future experimental facilities. Furthermore, the open-charm coupled-channel mechanism leads to a distinct line shape of the total cross section that can be utilized to reveal the production dynamics.
↳ hep-phhep-exnucl-exnucl-thJ.Phys.G(2024)·10 citations
12
Astrophysical Equation-of-State Constraints on the Color-Superconducting Gap
Aleksi Kurkela🇳🇴 · Krishna Rajagopal🇺🇸 · Rachel Steinhorst🇺🇸
We demonstrate that astrophysical constraints on the dense-matter equation of state place an upper bound on the color-superconducting gap in dense matter above the transition from nuclear matter to quark matter. Pairing effects in the color-flavor locked (CFL) quark matter phase increase the pressure at high density, and if this effect is sufficiently large then the requirements of causality and mechanical stability make it impossible to reach such a pressure in a way that is consistent with what is known at lower densities. The intermediate-density equation of state is inferred by considering extensions of chiral effective field theory (CEFT) to neutron star densities, and conditioning these using current astrophysical observations of neutron star radius, maximum mass, and tidal deformability (PSR J0348+0432, PSR J1624-2230, PSR J0740+6620, GW170817). At baryon number chemical potential $μ = 2.6 GeV$ we find a 95% upper limit on the CFL pairing gap $Δ$ of $457 MeV$ using overly conservative assumptions and $216 MeV$ with more reasonable assumptions. This constraint may be strengthened by future astrophysical measurements as well as by future advances in high density QCD calculations.
↳ astro-ph.HEhep-phnucl-thPRL(2024)·55 citations

Affiliations

first authorsco-authorsvia INSPIRE

Long-lived doubly charged scalars in the left-right symmetric model: catalyzed nuclear fusion and collider implications

Anisotropic flow, flow fluctuation and flow decorrelation in relativistic heavy-ion collisions: the roles of sub-nucleon structure and shear viscosity

Dissipative effects on the propagation of spin modes

Relativistic magnetohydrodynamics with spin

Simultaneous Measurement of Half-Life and Spectral Shape of 115In β-decay with an Indium Iodide Cryogenic Calorimeter

Photoproduction of the X(3872) beyond vector meson dominance: the open-charm coupled-channel mechanism

Astrophysical Equation-of-State Constraints on the Color-Superconducting Gap

Affiliations

Simultaneous Measurement of Half-Life and Spectral Shape of $^{115}$ In $β$ -decay with an Indium Iodide Cryogenic Calorimeter

Photoproduction of the $X (3872)$ beyond vector meson dominance: the open-charm coupled-channel mechanism