Nuclear Theory·nucl-th

Tuesday·April 5, 2022

22 papers—9 primary·13 cross-listed

10
[Submitted on 1 Apr 2022] (cross-list from hep-ph)
Searching for QGP droplets with high- $p_{T}$ hadrons and heavy flavor
Weiyao Ke🇺🇸 · Ivan Vitev🇺🇸
The search for the smallest quark-gluon plasma (QGP) droplets in nature has motivated recent small collisions system programs at RHIC and LHC. Unambiguous identification of jet quenching due to final-state interactions is key to confirming QGP formation in these reactions. We compute the nuclear modification factors $R_{AA}$ and $R_{p (d) A}$ of charged hadrons and heavy flavor mesons in large (Au-Au, Xe-Xe, Pb-Pb) and small ( $d$ -Au, $p$ -Pb, O-O) colliding systems, respectively. Our results include the Cronin effect and initial-state parton energy loss in cold nuclear matter. In the final state, hard partons undergo collisional energy loss and branching that was recently derived using Soft-Collinear-Effective-Theory with Glauber Gluon (SCET $_{G}$ ). In large colliding systems, medium-modified QCD evolution of the fragmentation functions dominates the nuclear correction. As the system size decreases, we find that cold nuclear matter effects, collisional energy loss, and QGP-induced radiations can become equally important. A systematic scan over the medium size and mass/flavor dependence of $R_{AA}$ provides the opportunity to separate these individual contributions and identify QGP signatures in small systems. Predictions for $R_{AA}^{h}$ , $R_{AA}^{D}$ , $R_{AA}^{B}$ in O-O collisions at $s = 7$ TeV are presented with and without the formation of a QGP and contrasted with the corresponding $R_{p (d) A}$ calculations. Upcoming single-hadron measurements at the LHC will not only test the O-O predictions for both light and heavy flavor production, but will shed light on the possibly very different dynamics of $p$ -A and A-A reactions at similar soft particle production multiplicities.
Comments:
33 pages, 15 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.00634 [pdf]
PRC(2023)·38 citations
11
[Submitted on 2 Apr 2022] (cross-list from hep-ph)
Dilepton production from chirally asymmetric matter
Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳 · Sourav Sarkar🇮🇳 · Pradip Roy🇮🇳
We evaluate the dilepton production rate (DPR) from hot and dense chirally asymmetric quark matter. The presence of a finite chiral chemical potential (CCP) in the electromagnetic spectral function results in the appearance of new cut structures signifying additional scattering processes in the medium which leads to a significant enhancement in the DPR at lower values of invariant mass. The constituent quark mass evaluated using a 3-flavour Nambu--Jona-Lasinio model is also non-trivially affected by the CCP. These are found to result in a continuous dilepton production rate as a function of the invariant mass for higher values of temperature and baryonic chemical potential.
Comments:
Version published in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.00892 [pdf]
PRD(2022)·6 citations
12
[Submitted on 3 Apr 2022] (cross-list from nucl-ex)
Exploring terra incognita in the phase diagram of strongly interacting matter -- Experiments at FAIR and NICA
Peter Senger🇩🇪
The fundamental properties of dense nuclear matter, as it exists in the core of massive stellar objects, are still largely unknown. The investigation of the high-density equation of state (EOS), which determines mass and radii of neutron stars and the dynamics of neutron star mergers, is in the focus of astronomical observations and of laboratory experiments with heavy-ion collisions. Moreover, the microscopic degrees-of-freedom of strongly interacting matter at high baryon densities are also unknown. While Quantum-Chromo-Dynamics (QCD) calculations on the lattice find a smooth chiral crossover between hadronic matter and the quark-gluon plasma for high temperatures at zero baryon chemical potential, effective models predict a 1st order chiral transition with a critical endpoint for matter at large baryon chemical potentials. Up to date, experimental data both on the high-density EOS and on a possible phase transition in dense baryonic matter are very scarce. In order to explore this terra incognita, dedicated experimental programs are planned at future heavy-ion research centres: the CBM experiment at FAIR, and the MPD and BM@N experiments at NICA. The research programs and the layout of these experiments will be presented. The future results of these laboratory experiments will complement astronomical observations concerning the EOS, and, in addition, will shed light on the microscopic degrees of freedom of QCD matter at neutron star core densities.
Comments:
21 pages, 15 figures, ICNFP 21, to be published in Physica Scripta
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2204.01056 [pdf]
Phys.Scripta(2022)·10 citations
13
[Submitted on 3 Apr 2022] (cross-list from hep-ph)
Inclusive jet and hadron suppression in a multistage approach
A. Kumar🇨🇦 · Y. Tachibana🇯🇵 · C. Sirimanna🇺🇸 · G. Vujanovic🇺🇸 · S. Cao🇨🇳 · A. Majumder🇺🇸 · Y. Chen🇺🇸 · L. Du🇨🇦 · R. Ehlers🇺🇸 · D. Everett🇺🇸 · W. Fan🇺🇸 · Y. He🇨🇳 and 48 other authors
We present a new study of jet interactions in the quark-gluon plasma created in high-energy heavy-ion collisions, using a multistage event generator within the JETSCAPE framework. We focus on medium-induced modifications in the rate of inclusive jets and high transverse momentum (high- $p_{T}$ ) hadrons. Scattering-induced jet energy loss is calculated in two stages: A high virtuality stage based on the MATTER model, in which scattering of highly virtual partons modifies the vacuum radiation pattern, and a second stage at lower jet virtuality based on the LBT model, in which leading partons gain and lose virtuality by scattering and radiation. Coherence effects that reduce the medium-induced emission rate in the MATTER phase are also included. The TRENTo model is used for initial conditions, and the (2+1)dimensional VISHNU model is used for viscous hydrodynamic evolution. Jet interactions with the medium are modeled via 2-to-2 scattering with Debye screened potentials, in which the recoiling partons are tracked, hadronized, and included in the jet clustering. Holes left in the medium are also tracked and subtracted to conserve transverse momentum. Calculations of the nuclear modification factor ( $R_{AA}$ ) for inclusive jets and high- $p_{T}$ hadrons are compared to experimental measurements at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). Within this framework, we find that with one extra parameter which codifies the transition between stages of jet modification -- along with the typical parameters such as the coupling in the medium, the start and stop criteria etc. -- we can describe these data at all energies for central and semicentral collisions without a rescaling of the jet transport coefficient $q^$ .
Comments:
34 pages, 23 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01163 [pdf]
PRC(2023)·88 citations
14
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
Enhanced Magnetic Quadrupole Moments in Nuclei with Octupole Deformation and their CP-violating effects in molecules
V. V. Flambaum🇦🇺 · A. J. Mansour🇦🇺
Nuclei with an octupole deformation have a non-zero electric octupole moment, electric dipole moment (EDM), Schiff moment and magnetic quadrupole moment (MQM) in the intrinsic frame which rotates with the nucleus. In a state with definite angular momentum in the laboratory frame, these moments are forbidden by parity (P) and time reversal invariance (T) conservation, meaning their expectation values vanish due to nuclear rotation. However, nuclei with an octupole deformation have doublets of close opposite parity rotational states with the same spin, which are mixed by T,P-odd nuclear forces. This mixing produces the orientation of the nuclear axis along nuclear spin and all moments existing in the intrinsic frame appear in the laboratory frame (provided the nuclear spin I is sufficiently large to allow such moment). Such a mechanism produces enhanced T,P-violating nuclear moments. This enhancement also takes place in nuclei with a soft octupole vibration mode. Schiff moments in such nuclei have been calculated in previous works. In the present paper we consider the magnetic quadrupole moment which appears in isotopes with nuclear spin $I \geq 1$ . Magnetic interaction between the nuclear MQM and electrons produces an atomic EDM and T,P-violating nuclear spin - molecular axis interaction constants for molecules in electronic states with non-zero electron angular momentum. Measurements of these constants may be used to test CP-violation theories and search for axion dark matter in atomic, molecular and solid state experiments. Potential candidate nuclei include 153Eu, 161Dy, 221Fr, 223Fr, 223Ra, 223Rn, 225Ac, 227Ac, 229Th, 229Pa, 233U and 235U. We subsequently consider molecules containing these nuclei (EuO, EuN+, RaF, AcO, AcN+, AcF+, ThO and ThF+).
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2204.01290 [pdf]
PRC(2022)·18 citations
15
[Submitted on 4 Apr 2022] (cross-list from cond-mat.quant-gas)
Dominant Andreev Reflection through Nonlinear Radio-Frequency Transport
Tingyu Zhang · Hiroyuki Tajima · Yuta Sekino · Shun Uchino · Haozhao Liang
We theoretically propose the laser-induced Andreev reflection between two-component Fermi superfluid and normal states via spatially-uniform Rabi couplings. By analyzing the tunneling current between the superfluid and normal states up to the fourth order in the Rabi couplings, we find that the Andreev current exhibits unconventional non-Ohmic transport at zero temperature. Remarkably, the Andreev current gives the only contribution in the synthetic junction system at zero detunings regardless of the ratio of the chemical potential bias to the superfluid gap, which is in sharp contrast to that in the conventional superconductor-normal metal junction. Our result may also pave a way for understanding the black hole information paradox through the Andreev reflection as a quantum-information mirror.
Comments:
7 pages, 5 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); Superconductivity (cond-mat.supr-con); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2204.01356 [pdf]
Commun.Phys.(2023)·2 citations
16
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
On the deuteron relativistic charge distributions
Cédric Lorcé (Ecole Polytechnique, CPHT)🇫🇷 · Pierre Wang (ENSTA Paris)🇫🇷
We study the relativistic 2D charge distributions in the case of a spin- $1$ target. These charge distributions are based on a phase-space approach allowing one to study their frame dependence, and hence to relate the familiar rest-frame picture with the light-front picture developed in the last two decades. Like in the spin- $1/2$ case, we show that relativistic kinematical effects associated with spin are responsible for the distortions of the charge distributions seen in a moving frame. Applying our results to the deuteron, we observe a mild frame dependence compared to the nucleon case.
Comments:
12 pages, 6 figures, to appear in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01465 [pdf]
PRD(2022)·23 citations
17
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
Back-to-back azimuthal correlations in Z+jet events at high transverse momentum in the TMD parton branching method at next-to-leading order
H. Yang🇨🇳 · A. Bermudez Martinez🇩🇪 · L.I. Estevez Banos🇩🇪 · F. Hautmann🇨🇭 · H. Jung🇩🇪 · M. Mendizabal🇩🇪 · K. Moral Figueroa🇬🇧 · S. Prestel🇸🇪 · S. Taheri Monfared🇩🇪 · A.M. van Kampen🇧🇪 · Q. Wang🇨🇳 · K. Wichmann🇩🇪
Azimuthal correlations in Z+jet production at large transverse momenta are computed by matching Parton - Branching (PB) TMD parton distributions and showers with NLO calculations via MCatNLO. The predictions are compared with those for dijet production in the same kinematic range. The azimuthal correlations $Δ ϕ$ between the Z boson and the leading jet are steeper compared to those in dijet production at transverse momenta $O (100)$ GeV, while they become similar for very high transverse momenta $O (1000)$ GeV. The different patterns of Z+jet and dijet azimuthal correlations can be used to search for potential {\it factorization - breaking} effects in the back-to-back region, which depend on the different color and spin structure of the final states and their interferences with the initial states. In order to investigate these effects experimentally, we propose to measure the ratio of the distributions in $Δ ϕ$ for Z+jet - and multijet production at low and at high transverse momenta, and compare the results to predictions obtained assuming factorization. We examine the role of theoretical uncertainties by performing variations of the factorization scale, renormalization scale and matching scale. In particular, we present a comparative study of matching scale uncertainties in the cases of PB-TMD and collinear parton showers.
Comments:
Replaced with version accepted for publication in EPJC
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01528 [pdf]
EPJC(2022)·37 citations
18
[Submitted on 4 Apr 2022] (cross-list from nucl-ex)
Tomography of Ultra-relativistic Nuclei with Polarized Photon-gluon Collisions
STAR Collaboration: M. S. Abdallah🇪🇬 · B. E. Aboona🇺🇸 · J. Adam🇺🇸 · L. Adamczyk🇵🇱 · J. R. Adams🇺🇸 · J. K. Adkins🇺🇸 · G. Agakishiev🇷🇺 · I. Aggarwal🇮🇳 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · A. Aitbaev🇷🇺 · I. Alekseev🇷🇺 and 382 other authors
A linearly polarized photon can be quantized from the Lorentz-boosted electromagnetic field of a nucleus traveling at ultra-relativistic speed. When two relativistic heavy nuclei pass one another at a distance of a few nuclear radii, the photon from one nucleus may interact through a virtual quark-antiquark pair with gluons from the other nucleus forming a short-lived vector meson (e.g. $ρ^{0}$ ). In this experiment, the polarization was utilized in diffractive photoproduction to observe a unique spin interference pattern in the angular distribution of $ρ^{0} \to π^{+} π^{-}$ decays. The observed interference is a result of an overlap of two wave functions at a distance an order of magnitude larger than the $ρ^{0}$ travel distance within its lifetime. The strong-interaction nuclear radii were extracted from these diffractive interactions, and found to be $6.53 \pm 0.06$ fm ( $^{197} Au$ ) and $7.29 \pm 0.08$ fm ( $^{238} U$ ), larger than the nuclear charge radii. The observable is demonstrated to be sensitive to the nuclear geometry and quantum interference of non-identical particles.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2204.01625 [pdf]
Sci.Adv.(2023)·80 citations
19
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
Shear Viscosity of hadronic matter at finite temperature and magnetic field
Ritesh Ghosh🇮🇳 · Najmul Haque🇮🇳
We calculate the transport coefficient of hadronic matter in the presence of temperature and magnetic field using the linear sigma model. In the relaxation time approximation, we estimate the shear viscosity over entropy density $η / s$ . The point-like interaction rates of hadrons are evaluated through the $S$ -matrix approach in the presence of a magnetic field to obtain the temperature and magnetic field-dependent relaxation time. We observe that the transport coefficients are anisotropic in the presence of the magnetic field. We calculate the temperature and magnetic field-dependent anisotropic shear viscosity coefficients by incorporating the estimated relaxation time. The value of viscosity over entropy density is lower in the presence of a magnetic field than the value of it in a thermal medium. The behavior of the perpendicular components of the shear-viscous coefficient is also discussed. We consider the temperature-dependent hadron masses from mean-field effects in this work.
Comments:
21 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01639 [pdf]
PRD(2022)·27 citations
20
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
Highlights of pion and kaon structure from continuum analyses
Khépani Raya🇪🇸 · José Rodríguez-Quintero🇪🇸
One of the biggest challenges in contemporary physics is understanding the origin and dynamics of the internal structure of hadrons which, at a fundamental level, is described by quantum chromodynamics (QCD). Taking great prominence amongst hadrons are pions and kaons which, despite being the lightest hadrons in nature, their very existence is intimately connected to those mechanisms responsible for almost all of the mass of the visible matter. In this manuscript we discuss many aspects of the pion and kaon structure via light front wave functions and generalized parton distributions, and a collection of other distributions and structural properties that are inferred therefrom.
Comments:
Invited plenary talk given at the 19th International Conference on Hadron Spectroscopy and Structure in memoriam Simon Eidelman (HADRON2021), 26-31 July (2021), Mexico City (Mexico). 8 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01642 [pdf]
Rev.Mex.Fis.Suppl.(2022)·11 citations
21
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
Dyson-Schwinger equations and the muon g-2
Khépani Raya🇪🇸 · Adnan Bashir🇲🇽 · Ángel S. Miramontes🇲🇽 · Pablo Roig🇲🇽
We present a brief introduction to the Dyson-Schwinger equations (DSEs) approach to hadron and high-energy physics. In particular, how this formalism is applied to calculate the electromagnetic form factors $γ^{*} γ^{*} \to P^{0}$ and $γ^{*} P^{\pm} \to P^{\pm}$ (with $P^{\pm}$ and $P^{0}$ charged and neutral ground-state pseudoscalar mesons, respectively) is discussed. Subsequently, the corresponding contributions of those form factors to the muon anomalous magnetic moment ( $g - 2$ ) are estimated. We look forward to promoting the DSE approach to address theoretical aspects of the muon $g - 2$ , highlighting some calculations that could be carried out in the future.
Comments:
Contribution to the XXXV Annual Meeting of the DPyC-SMF (May 11-13, 2021) and XIX Mexican School on Particles and Fields (August 9-13, 2021). Published in Suplemento de la Revista Mexicana de Física. 9pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01652 [pdf]
Rev.Mex.Fis.Suppl.(2022)·5 citations
22
[Submitted on 4 Apr 2022] (cross-list from hep-ph)
Kaon, Nucleon and $Δ^{*}$ Resonances with Hidden Charm
Brenda B. Malabarba🇧🇷 · A. M. Torres🇧🇷 · K.P. Khemchandani🇧🇷 · Xiu-Lei Ren🇩🇪 · Li-Sheng Geng🇨🇳
In this presentation we discuss the generation of hadrons with an exotic quark content and hidden charm emerging from three-body interactions. To be more specific, we have studied the $K D D ˉ^{*} / K D ˉ D^{*}$ and $N D D ˉ^{*} / N D ˉ D^{*}$ systems and predicted states generated from the respective three-body dynamics. In the case of the $K D D ˉ^{*} / K D ˉ D^{*}$ system we predict the formation of a meson state with mass around $4307$ MeV and quantum numbers $I (J^{P}) = 1/2 (1^{-})$ , $K^{*} (4307)$ , and from the study of the $N D D ˉ^{*} / N D ˉ D^{*}$ system we found $N^{*}$ states with masses in the range $4400 \sim 4600$ MeV, width of $2 \sim 20$ MeV and positive parity.
Comments:
proceedings XV International Workshop on Hadron Physics (XV Hadron Physics), 13 -17 September 2021
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.01658 [pdf]
PoS(2022)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE