Nuclear Theory·nucl-th

Tuesday·October 1, 2024

24 papers—12 primary·12 cross-listed

13
[Submitted on 26 Sept 2024] (cross-list from hep-ph)
Quarks to Cosmos: Particles and Plasma in Cosmological evolution
Johann Rafelski🇺🇸 · Jeremiah Birrell🇺🇸 · Christopher Grayson🇺🇸 · Andrew Steinmetz🇺🇸 · Cheng Tao Yang🇺🇸
We describe in the context of the particle physics (PP) standard model (SM) `PP-SM' the understanding of the primordial properties and composition of the Universe in the temperature range $130 \GeV > T > 20 \keV$ . The Universe evolution is described using FLRW cosmology. We present a global view on particle content across time and describe the different evolution eras using deceleration parameter $q$ . We follow the arrow of time in the expanding and cooling Universe: After the PP-SM heavies $(t, h, W, Z)$ diminish in abundance below $T ≃ 50 \GeV$ , the PP-SM plasma in the Universe is governed by the strongly interacting Quark-Gluon content. Once the temperature drops below $T ≃ 150 \MeV$ , quarks and gluons hadronize into strongly interacting matter particles. Rapid disappearance of baryonic antimatter completes at $T_{B} = 38.2 \MeV$ . We study the ensuing disappearance of strangeness and mesons in general. We show that the different eras defined by particle populations are barely separated from each other with abundance of muons fading out just prior to $T = O (2.5) \MeV$ , the era of emergence of the free-streaming neutrinos. We discuss the two relevant fundamental constants controlling the decoupling of neutrinos. We subsequently follow the primordial Universe as it passes through the hot dense electron-positron plasma epoch. The high density of positron antimatter disappears near $T = 20.3 \keV$ : Nuclear reactions occur in the presence of a highly mobile and relatively strongly interacting electron-positron plasma phase. We apply plasma theory methods to describe the strong screening effects between heavy dust particle (nucleons). We analyze the paramagnetic characteristics of the electron-positron plasma when exposed to an external primordial magnetic field.
Comments:
189 pages review, includes 90 figure frames. Incluses key results from four PhD thesis and two dozen research papers. See Appendix A for these details. Reformatted for new widescreen of The European Physical Journal - Special Topics (EPJ ST) format with a few typos corrected,
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
arXiv:
2409.19031 [pdf]
Eur.Phys.J.ST(2025)·8 citations
14
[Submitted on 27 Sept 2024] (cross-list from hep-ph)
Revisiting Single Inclusive Jet Production: Timelike Factorization and Reciprocity
Kyle Lee🇺🇸 · Ian Moult🇺🇸 · Xiaoyuan Zhang🇺🇸
Factorization theorems for single inclusive jet production play a crucial role in the study of jets and their substructure. In the case of small radius jets, the dynamics of the jet clustering can be factorized from both the hard production dynamics, and the dynamics of the low scale jet substructure measurement, and is described by a matching coefficient that can be computed in perturbative Quantum Chromodynamics (QCD). A proposed factorization formula describing this process has been previously presented in the literature, and is referred to as the semi-inclusive, or fragmenting jets formalism. By performing an explicit two-loop calculation, we show the inconsistency of this factorization formula, in agreement with another recent result in the literature. Building on recent progress in the factorization of single logarithmic observables, and the understanding of reciprocity, we then derive a new all-order factorization theorem for inclusive jet production. Our factorization involves a non-trivial convolution structure, that maintains the universality of the hard function from inclusive fragmentation. We perform an explicit two-loop calculation of the jet function in both $N = 4$ super Yang-Mills (SYM), and for all color channels in QCD, finding exact agreement with the structure derived from our renormalization group equations. In addition, we derive several new results, including an extension of our factorization formula to jet substructure observables, a jet algorithm definition of a generating function for the energy correlators, and new results for exclusive jet functions. Our results are a key ingredient for achieving precision jet substructure at colliders.
Comments:
44 pages + appendix, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2409.19045 [pdf]
JHEP(2025)·34 citations
15
[Submitted on 28 Sept 2024] (cross-list from hep-ph)
Quarkonium production in pp and heavy-ion collisions
Taesoo Song🇩🇪 · Joerg Aichelin🇫🇷 · Jiaxing Zhao🇩🇪 · Pol B. Gossiaux🇫🇷 · Elena Bratkovskaya🇩🇪
We describe bottomonium production not only in pp collisions but also in heavy-ion collisions by using the Remler's formalism where quarkonium density operator is applied to all possible combination of heavy quark and heavy antiquark pairs. In pp collisions heavy (anti)quark momentum is provided by the PYTHIA event generator after rescaling $p_{T}$ and rapidity to imitate the FONLL calculations. Then spatial separation between heavy quark and heavy antiquark is introduced based on the uncertainty principle. In heavy-ion collisions quarkonium wavefunction changes with temperature assuming heavy quark potential equals the free energy of heavy quark and heavy antiquark system in heat bath. The density operator is updated whenever heavy quark or heavy antiquark scatters in QGP produced in heavy-ion collisions. Our results are consistent with the experimental data from ALICE and CMS Collaborations assuming that the interaction rate of heavy (anti)quark in quarkonium is suppressed to 10 \% that of unbound heavy (anti)quark. We also find that off-diagonal recombination of bottomonium barely happens even in Pb+Pb collisions at $s = 5.02$ TeV.
Comments:
4 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.19280 [pdf]
EPJ Web Conf.(2025)·2 citations
16
[Submitted on 28 Sept 2024] (cross-list from hep-ph)
Transport properties of the strongly interacting quark-gluon plasma
Ilia Grishmanovskii🇩🇪 · Taesoo Song🇩🇪 · Olga Soloveva🇩🇪 · Carsten Greiner🇩🇪 · Elena Bratkovskaya🇩🇪
We investigate the transport properties of the strongly interacting quark-gluon plasma (sQGP) by comparing the role of elastic and inelastic (radiative) processes in the sQGP medium within the effective dynamical quasi-particle model (DQPM), constructed for the description of non-perturbative quantum chromodynamic (QCD) phenomena of the sQGP in line with the lattice QCD (lQCD) equation of state. First, we present the results for the energy and temperature dependencies of the total radiative cross sections and compare them to the corresponding elastic cross sections. Second, we perform a calculation of the interaction rate and relaxation time of radiative versus elastic scatterings. Finally, we obtain the jet transport coefficient $q^$ and investigate its dependence on the choice of the strong coupling in thermal, jet parton and radiative vertices.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.19369 [pdf]
PoS(2025)·0 citations
17
[Submitted on 28 Sept 2024] (cross-list from hep-ph)
On the origin of the peak of the sound velocity for isospin imbalanced strongly interacting matter
Alejandro Ayala🇲🇽 · Bruno S. Lopes🇧🇷 · Ricardo L. S. Farias🇧🇷 · Luis C. Parra🇲🇽
We study the properties of a system composed of strongly interacting matter with an isospin imbalance, using as an effective description of QCD the two-flavor Linear Sigma Model with quarks. From the one-loop effective potential, including the two light quarks, pions and sigma contributions, and enforcing the restrictions imposed by chiral symmetry, we show that the development of an isospin condensate comes together with the emergence of a Goldstone mode that provides a constraint for the chiral and isospin condensates as a result of a non-trivial mixing between the charged pions and the sigma. We compute the thermodynamical quantities of interest and in particular the sound velocity squared, showing that it presents a maximum for an isospin chemical potential similar to the one reported by lattice QCD results and also with a similar height. Therefore, we attribute the origin of the peak of the sound velocity to the proper treatment of the Goldstone mode and to the non-trivial mixing of the charged pions and sigma in the isospin condensed phase.
Comments:
7 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2409.19406 [pdf]
PLB(2025)·17 citations
18
[Submitted on 28 Sept 2024] (cross-list from hep-ph)
Hypercontractivity and factorial moment scaling in the symmetry broken phase
Athanasios Brofas🇬🇷 · Manolis Zampetakis🇺🇸 · Fotios Diakonos🇬🇷
The search for remnants of the QCD chiral critical point is a central objective of current and future high-energy ion collision experiments. Previous studies suggest that a scaling law relating higher-order factorial moments of hadron multiplicity fluctuations to the second factorial moment could serve as a tool for detecting the QCD critical point. However, we demonstrate that this scaling law is not unique to critical phenomena. Instead, it emerges as a general property of distributions by extending the concept of hypercontractivity, originally applied to ordinary moments, to factorial moments. We present examples of distribution classes that exhibit the same higher-order factorial moment scaling as multiplicity fluctuations in the symmetry-broken phase. This insight allows us to explain the recent intermittency analysis results from the STAR experiment at RHIC (arXiv:2301.11062), where no indication of criticality was observed.
Comments:
main: 5 pages, 3 figures, supplemental: 4 pages, 1 figure
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:
2409.19412 [pdf]
PLB(2025)·3 citations
19
[Submitted on 28 Sept 2024] (cross-list from hep-ph)
A Deep Learning Based Estimator for Light Flavour Elliptic Flow in Heavy Ion Collisions at LHC Energies
Gergely Gábor Barnaföldi🇭🇺 · Neelkamal Mallick🇭🇺 · Suraj Prasad🇭🇺 · Raghunath Sahoo🇮🇳 · Aditya Nath Mishra🇮🇳
We developed a deep learning feed-forward network for estimating elliptic flow ( $v_{2}$ ) coefficients in heavy-ion collisions from RHIC to LHC energies. The success of our model is mainly the estimation of $v_{2}$ from final state particle kinematic information and learning the centrality and the transverse momentum ( $p_{T}$ ) dependence of $v_{2}$ in wide $p_{T}$ regime. The deep learning model is trained with AMPT-generated Pb-Pb collisions at $s_{NN} = 5.02$ TeV minimum bias events. We present $v_{2}$ estimates for $π^{\pm}$ , $K^{\pm}$ , and $p + p ˉ$ in heavy-ion collisions at various LHC energies. These results are compared with the available experimental data wherever possible.
Comments:
4 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.19462 [pdf]
EPJ Web Conf.(2025)·0 citations
20
[Submitted on 30 Sept 2024] (cross-list from hep-ph)
Phase-Space methods for neutrino oscillations: extension to multi-beams
Denis Lacroix🇫🇷 · Angel Bauge🇫🇷 · Bulent Yilmaz🇹🇷 · Mariane Mangin-Brinet🇫🇷 · Alessandro Roggero🇮🇹 · A. Baha Balantekin🇺🇸
The Phase-Space approach (PSA), which was originally introduced in [Lacroix et al., Phys. Rev. D 106, 123006 (2022)] to describe neutrino flavor oscillations for interacting neutrinos emitted from stellar objects is extended to describe arbitrary numbers of neutrino beams. The PSA is based on mapping the quantum fluctuations into a statistical treatment by sampling initial conditions followed by independent mean-field evolution. A new method is proposed to perform this sampling that allows treating an arbitrary number of neutrinos in each neutrino beam. We validate the technique successfully and confirm its predictive power on several examples where a reference exact calculation is possible. We show that it can describe many-body effects, such as entanglement and dissipation induced by the interaction between neutrinos. Due to the complexity of the problem, exact solutions can only be calculated for rather limited cases, with a limited number of beams and/or neutrinos in each beam. The PSA approach considerably reduces the numerical cost and provides an efficient technique to accurately simulate arbitrary numbers of beams. Examples of PSA results are given here, including up to 200 beams with time-independent or time-dependent Hamiltonian. We anticipate that this approach will be useful to bridge exact microscopic techniques with more traditional transport theories used in neutrino oscillations. It will also provide important reference calculations for future quantum computer applications where other techniques are not applicable to classical computers.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2409.20215 [pdf]
PRD(2024)·15 citations
21
[Submitted on 30 Sept 2024] (cross-list from gr-qc)
Stars and quark stars in bumblebee gravity
Juliano C. S. Neves🇧🇷 · Fernando G. Gardim🇧🇷
In this work, the interior spacetime of stars is built in a Lorentz symmetry breaking model called bumblebee gravity. Firstly, we calculated the modified Tolman-Oppenheimer-Volkoff equation in this context of modified gravity. Then we show that the bumblebee field, responsible for the symmetry breaking, increases the star mass-radius relation when it assumes its vacuum expectation value. When compared to the general relativity mass-radius relation, a Lorentz symmetry breaking context, like the bumblebee gravity, could provide more massive stars, surpassing the $2.5 M_{⊙}$ limit as the interior of the star is described by quark matter with the MIT bag model. Also, we investigate the stability of the solution with the MIT bag equation of state in this context of modified gravity.
Comments:
13 pages, 5 figures and 1 table. V3 with stability analysis section. Published in Annals of Physics
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2409.20360 [pdf]
Annals Phys.(2025)·19 citations
22
[Submitted on 30 Sept 2024] (cross-list from hep-ph)
Breakdown of collinear factorisation in the photoproduction of a $π^{0} γ$ pair with large invariant mass
Saad Nabeebaccus🇫🇷 · Jakob Schoenleber🇩🇪 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷
We identify a $2 \to 3$ exclusive process, where collinear factorisation is broken, namely the exclusive photoproduction of a $π^{0} γ$ pair with large invariant mass. This occurs because the process suffers from gluon exchanges trapped in the Glauber region. Using an explicit example, we show that the Glauber gluon, which is exchanged between a collinear spectator parton from the nucleon sector and a soft spectator parton from the outgoing pion, has both of its lightcone plus and minus components pinched. Therefore, it cannot be deformed to collinear/soft regions, as is often the case for processes that do factorise. We further confirm the leading power behaviour of the identified Glauber region, highlighting that this is the case although it relies on extracting a soft parton from the outgoing pion. We stress that the Glauber pinch for this process is of the leading power, due to the possibility of having two-gluon exchanges between the collinear nucleon sector and hard partonic scattering sub-process. In fact, the Glauber gluon that we identify is one of these two active gluons, and therefore, its effects are observed already at leading order. A direct consequence of our work is that collinear factorisation breaks in the same way for other $2 \to 3$ exclusive processes, where two-gluon exchanges in the $t$ -channel are possible, like in the exclusive production of a photon pair from $π^{0} N$ collisions. However, we highlight that in cases where such two-gluon exchanges do not exist, like in the exclusive $π^{\pm} γ$ photoproduction, the Glauber exchanges that we discuss here do not occur, and hence they do not suffer from factorisation breaking effects.
Comments:
7 pages, 1 figure, Presented by S. Nabeebaccus at the 31st International Workshop on Deep Inelastic Scattering (DIS2024)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.20430 [pdf]
PoS(2025)·1 citation
23
[Submitted on 30 Sept 2024] (cross-list from hep-ph)
Complete 1-loop study of exclusive $J / ψ$ and $Υ$ photoproduction with full GPD evolution
Chris Flett🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Saad Nabeebaccus🇫🇷 · Maxim Nefedov🇫🇷 · Pawel Sznajder🇵🇱 · Jakub Wagner🇵🇱
We discuss the exclusive photoproduction of a heavy vector quarkonium, namely $J / ψ$ and $Υ$ at 1-loop in $α_{s}$ . In collinear factorisation (CF), the amplitude for such a process is obtained by the convolution of a hard partonic sub-amplitude, with a universal generalised parton distribution (GPD). For the first time, we perform a complete calculation at 1-loop including full leading-log (LL) GPD evolution. We first demonstrate the huge instability of the cross section at high energies when the factorisation scale $μ_{F}$ is varied. This instability has been reported previously in the literature, and occurs due to the large logarithms generated by the huge difference between the hard scale of the process, which is the mass of the heavy quarkonium here, and the centre-of-mass energy of the process. This problem was also reported in inclusive heavy vector quarkonium photoproduction. We show that this issue can be resolved by resumming these large logarithms using high-energy factorisation (HEF), by performing a matching with the result in CF using the doubly logarithmic approximation (DLA) in order to be consistent with the fixed order evolution of GPDs. Finally, we show that the cross sections obtained from such a matching, besides being free from the previously mentioned factorisation scale variation instabilities, are consistent with the H1 data for $J / ψ$ production and with the ZEUS data for $Υ$ production.
Comments:
7 pages, 3 figures, Presented by S. Nabeebaccus at the 31st International Workshop on Deep Inelastic Scattering (DIS2024)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2409.20544 [pdf]
PoS(2025)·0 citations
24
[Submitted on 30 Sept 2024] (cross-list from hep-ph)
Sokolov--Ternov effect in rotating systems
Jonathan D. Kroth🇺🇸 · Kirill Tuchin🇺🇸
We study electromagnetic radiation by electrically charged fermions embedded in a rotating medium in an external magnetic field. We compute the dependence of the radiation intensity on the angular velocity $Ω$ of the rotating medium for fermion polarizations along and opposite the magnetic field direction in intense subcritical fields. The polarization dependence of the photon radiation results in the Sokolov--Ternov effect -- the radiative polarization of fermions. We study the dependence of the degree of polarziation on $Ω$ . We found that rotation significantly changes the degree of polarization. We show that the rotating quark-gluon plasma acquires a finite magnetic moment that exhibits complex dependence on $Ω$ .
Comments:
18 pages, v2: minor improvements in figures, expanded conclusions
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2409.20569 [pdf]
PRD(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE