Nuclear Theory·nucl-th

Wednesday·September 18, 2024

10 papers—2 primary·8 cross-listed

03
[Submitted on 13 Sept 2024] (cross-list from hep-ph)
The impact of glasma on heavy flavor azimuthal correlations and spectra
Dana Avramescu🇫🇮 · Vincenzo Greco🇮🇹 · Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · David Müller🇦🇹
We study the phenomenological impact of the pre-equilibrium glasma initial stage of heavy-ion collisions on heavy quark azimuthal correlations and spectra. Using our numerical solver, we simulate the transport of heavy quark test particles in an SU(3) glasma background field. The glasma field equations are formulated using classical real-time lattice gauge theory, and the heavy quark dynamics are described by classical transport equations numerically solved using the colored particle-in-cell method. For the first time, the effect of the glasma stage on the azimuthal correlations of $c c$ and $b b$ pairs is studied. The resulting azimuthal width $σ_{Δ ϕ}$ exhibits a large and quick decorrelation due to the strong glasma fields. Further, we evaluate how the $p_{T}$ -broadening in the glasma affects heavy quark $p_{T}$ -spectra, which are initialized according to the Fixed-Order Next-to-Leading Logarithm (FONLL) heavy quark production calculation. The nuclear modification factor $R_{AA}$ is extracted for $c$ and $b$ quarks in the glasma and additional nuclear PDF effects accounting for gluon shadowing are included.
Comments:
24 pages, 15 figures; v2 published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2409.10564 [pdf]
PRD(2025)·19 citations
04
[Submitted on 13 Sept 2024] (cross-list from hep-ph)
Heavy flavor angular correlations as a direct probe of the glasma
Dana Avramescu🇫🇮 · Vincenzo Greco🇮🇹 · Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · David Müller🇦🇹
We use classical equations of motion for heavy quarks to show that the pre-equilibrium glasma phase of a heavy ion collision has an extremely strong effect on heavy quark angular correlations. At the same time, the effect on the single inclusive spectrum is much more moderate. This suggests that $D D$ meson angular correlations in future LHC measurements could provide direct experimental access to the physics of the pre-equilibrium stage.
Comments:
7 pages, 4 figures; v2 published in PRL
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2409.10565 [pdf]
PRL(2025)·24 citations
05
[Submitted on 15 Sept 2024] (cross-list from hep-ph)
Nuclear-level effective theory of $μ \to e$ conversion: Inelastic process
W. C. Haxton🇺🇸 · Evan Rule🇺🇸
Mu2e and COMET will search for electrons produced via the neutrinoless conversion of stopped muons bound in 1s atomic orbits of $^{27}$ Al, improving existing limits on charged lepton flavor violation (CLFV) by roughly four orders of magnitude. Conventionally, $μ \to e$ conversion experiments are optimized to detect electrons originating from transitions where the nucleus remains in the ground state, thereby maximizing the energy of the outgoing electron. Clearly, detection of a positive signal in forthcoming experiments would stimulate additional work $-$ including subsequent conversion experiments using complementary nuclear targets $-$ to further constrain the new physics responsible for CLFV. Here we argue that additional information can be extracted without the need for additional experiments, by considering inelastic conversion in $^{27}$ Al. Transitions to low-lying nuclear excited states can modify the near-endpoint spectrum of conversion electrons, with the ratio of the elastic and inelastic responses being sensitive to the underlying CLFV operator. We extend the nuclear effective theory of $μ \to e$ conversion to the inelastic case, which adds five new response functions to the six that arise for the elastic process. We evaluate these nuclear response functions in $^{27}$ Al and calculate the resulting conversion-electron signal, taking into account the resolution anticipated in Mu2e/COMET. We find that $^{27}$ Al is an excellent target choice from the perspective of the new information that can be obtained from inelastic $μ \to e$ conversion.
Comments:
31 pages, 7 Figures, 6 Tables. To be submitted to PRC
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2409.10581 [pdf]
PRC(2025)·3 citations
06
[Submitted on 17 Sept 2024] (cross-list from hep-ph)
Thermodynamic properties of gluon plasma: A q-potential approach
Guruprasad Kadam🇮🇳
In this work, we study the thermodynamic properties of quark-gluon plasma using Kramer's $q - p o t e n t ia l$ method. We propose a modification in the first law of thermodynamics by including a temperature-dependent term when single particle energies themselves are temperature-dependent. With this modified first law, we derive an expression for pressure starting from Kramer's $q - p o t e n t ia l$ . We find that to maintain thermodynamic consistency, pressure receives an additional term solely due to medium-dependent dispersion relation. The energy density, by definition, remains a sum over all the single-particle energies with an appropriate weight factor. We confront this quasiparticle model with the lattice QCD data of SU(3) pure gluon plasma.
Comments:
5 pages, 1 captioned figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.11038 [pdf]
0 citations
07
[Submitted on 17 Sept 2024] (cross-list from hep-ph)
Spin kinetic theory with a nonlocal relaxation time approximation
Nora Weickgenannt🇫🇷 · Jean-Paul Blaizot🇫🇷
We present a novel relaxation time approximation for kinetic theory with spin which takes into account the nonlocality of particle collisions. In particular, it models the property of the microscopic nonlocal collision term to vanish in global, but not in local equilibrium. We study the asymptotic distribution function obtained as the solution of the Boltzmann equation within the nonlocal relaxation time approximation in the limit of small gradients and short relaxation time. We show that the resulting polarization agrees with the one obtained from the Zubarev formalism for a certain value of a coefficient that determines the time scale on which orbital angular momentum is converted into spin. This coefficient can be identified with a parameter related to the pseudo gauge choice in the Zubarev formalism. Finally, we demonstrate how the nonlocal collision term generates polarization from vorticity by studying a nonrelativistic rotating cylinder both from kinetic and hydrodynamic approaches, which are shown to be equivalent in this example.
Comments:
16 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.11045 [pdf]
PRD(2025)·17 citations
08
[Submitted on 17 Sept 2024] (cross-list from astro-ph.HE)
Vetting quark-star models with gravitational waves in the hierarchical Bayesian framework
Ziming Wang🇨🇳 · Yong Gao🇩🇪 · Dicong Liang🇨🇳 · Junjie Zhao🇨🇳 · Lijing Shao🇨🇳
The recent discovery of gravitational waves (GWs) has opened a new avenue for investigating the equation of state (EOS) of dense matter in compact stars, which is an outstanding problem in astronomy and nuclear physics. In the future, next-generation (XG) GW detectors will be constructed, deemed to provide a large number of high-precision observations. We investigate the potential of constraining the EOS of quark stars (QSs) with high-precision measurements of mass $m$ and tidal deformability $Λ$ from the XG GW observatories. We adopt the widely-used bag model for QSs, consisting of four microscopic parameters: the effective bag constant $B_{eff}$ , the perturbative quantum chromodynamics correction parameter $a_{4}$ , the strange quark mass $m_{s}$ , and the pairing energy gap $Δ$ . With the help of hierarchical Bayesian inference, for the first time we are able to infer the EOS of QSs combining multiple GW observations. Using the top 25 loudest GW events in our simulation, we find that, the constraints on $B_{eff}$ and $Δ$ are tightened by several times, while $a_{4}$ and $m_{s}$ are still poorly constrained. We also study a simplified 2-dimensional (2-d) EOS model which was recently proposed in literature. The 2-d model is found to exhibit significant parameter-estimation biases as more GW events are analyzed, while the predicted $m$ - $Λ$ relation remains consistent with the full model.
Comments:
19 pages, 4 figures; accepted by JCAP
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2409.11103 [pdf]
JCAP(2024)·8 citations
09
[Submitted on 17 Sept 2024] (cross-list from hep-ph)
Approximation method for the nuclear structure functions at small $x$
G.R.Boroun🇮🇷
We have shown that the relationship between the DIS structure functions is stable for a nuclear target with mass number A at $x \leq 1 0^{- 3}$ . Numerical results are provided for the specific nuclei 12C and 208Pb using the nuclear PDF parameterizations implemented in the HIJING2.0 model. These results fall whithin the EIC kinematic acceptance for heavy ion running. The ratio $R_{F_{L}}^{A}$ is calculated as the ratio $R_{F_{2}}^{A}$ in the HIJING2.0 model.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.11154 [pdf]
Pramana(2025)·1 citation
10
[Submitted on 17 Sept 2024] (cross-list from nucl-ex)
Ultra-low $Q_{β}$ value for the allowed decay of $^{110}$ Ag $^{m}$ confirmed via mass measurements
J. Ruotsalainen · M. Stryjczyk · M. Ramalho · T. Eronen · Z. Ge · A. Kankainen · M. Mougeot · J. Suhonen
The mass of the electron-antineutrino can be determined in dedicated measurements of the $β$ spectral shape near the $β$ endpoint of a $β^{-}$ transition, with a low $Q$ value enhancing the sensitivity of the measurement. One such low- $Q$ -value candidate is the transition between the $6^{+}$ isomer of $^{110}$ Ag and the $5_{2}^{+}$ state in $^{110}$ Cd ( $Q_{β, m}^{*} = - 0.12 (131)$ keV). To reduce the uncertainty of the $Q$ value, we have used the phase-imaging ion-cyclotron-resonance technique with the JYFLTRAP double Penning trap and performed a high-precision atomic-mass measurement of $^{109}$ Ag with $^{110}$ Cd as a reference. Combined with the known spectroscopic data, we obtain a re-evaluated value $Q_{β, m}^{*} = 405 (135)$ eV, for the $^{110} Ag (6_{m}^{+}) \to^{110} Cd (5_{2}^{+})$ transition. This represents the lowest $Q_{β}$ value for any allowed transition observed to date. In order to estimate the partial half-life ( $t_{1/2}$ ) and branching ratio (Br) of the transition, nuclear shell-model calculations were performed using the $j j 45 p nb$ Hamiltonian in combination with state-of-the-art atomic calculations. The computed values $t_{1/2} = 2.2 3_{- 1.28}^{+ 5.24} \times 1 0^{7}$ years and $Br = 3.0 7_{- 2.15}^{+ 4.16} \times 1 0^{- 8}$ , along with the thermal-neutron capture on stable $^{109}$ Ag as a viable production method, make $^{110} Ag^{m}$ a promising candidate for future antineutrino-mass measurements.
Comments:
9 pages, 3 figures, 1 additional figure and 3 tables in Supplemental material
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2409.11203 [pdf]
PRL(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE