Nuclear Theory·nucl-th

Monday·November 29, 2021

21 papers—7 primary·14 cross-listed

08
Implementing the three-particle quantization condition for $π^{+} π^{+} K^{+}$ and related systems
Tyler D. Blanton🇺🇸 · Fernando Romero-López🇺🇸 · Stephen R. Sharpe🇺🇸
Recently, the formalism needed to relate the finite-volume spectrum of systems of nondegenerate spinless particles has been derived. In this work we discuss a range of issues that arise when implementing this formalism in practice, provide further theoretical results that can be used to check the implementation, and make available codes for implementing the three-particle quantization condition. Specifically, we discuss the need to modify the upper limit of the cutoff function due to the fact that the left-hand cut in the scattering amplitudes for two nondegenerate particles moves closer to threshold; we describe the decomposition of the three-particle amplitude $K_{df,3}$ into the matrix basis used in the quantization condition, including both $s$ and $p$ waves, with the latter arising in the amplitude for two nondegenerate particles; we derive the threshold expansion for the lightest three-particle state in the rest frame up to $O (1/ L^{5})$ ; and we calculate the leading-order predictions in chiral perturbation theory for $K_{df,3}$ in the $π^{+} π^{+} K^{+}$ and $π^{+} K^{+} K^{+}$ systems. We focus mainly on systems with two identical particles plus a third that is different ("2+1" systems). We describe the formalism in full detail, and present numerical explorations in toy models, in particular checking that the results agree with the threshold expansion, and making a prediction for the spectrum of $π^{+} π^{+} K^{+}$ levels using the two- and three-particle interactions predicted by chiral perturbation theory.
↳ hep-lathep-phnucl-thJHEP(2022)·42 citations
09
Mounting Evidence for the Violation of Lepton Flavor Universality
Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭
The Standard Model (SM) of particle physics was finalized in its current form in the mid-1970s, and has been extensively tested and confirmed ever since, with the discovery of the Higgs boson in 2012 being the last missing piece. While no new particles have been directly discovered at the Large Hadron Collider (LHC) at CERN so far, precision observables sensitive to quantum effects of new particles have accumulated intriguing hints for physics beyond the SM. All these anomalies can be interpreted from the point of view of lepton flavor universality, i.e., as hints that electrons, muons, and tau leptons differ much more than predicted by the SM. These tensions can be explained by postulating the existence of new exotic particles. Future measurements will be able to conclusively test this hypothesis, potentially providing long-awaited evidence how the SM needs to be extended at high energies.
↳ hep-phhep-exhep-latnucl-ex+1Science(2021)·47 citations
10
Electric dipole moments of baryons with bottom quarks
Y. Ünal🇩🇪 · D. Severt🇩🇪 · J. de Vries🇳🇱 · C. Hanhart🇩🇪 · Ulf-G. Meißner🇩🇪
Triggered by experimental prospects to measure electromagnetic dipole moments of baryons containing a bottom quark, we calculate the CP-odd electric dipole moments (EDMs) of spin-1/2 single-bottom baryons. We consider CP-violating dimension-six operators in the Standard Model Effective Field Theory that involve bottom quarks, and apply heavy-baryon chiral perturbation theory to compute the EDMs of several baryons. We discuss the expected size of the EDMs for beyond-the-Standard Model physics appearing at the TeV scale.
↳ hep-phhep-exnucl-thPRD(2022)·7 citations
11
T-violating effect in $ν_{τ} (ν ˉ_{τ}) -$ nucleon quasielastic scattering
A. Fatima🇮🇳 · M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳
The production cross sections and polarization observables of the $τ$ leptons produced in the $∣Δ S ∣ = 0$ and $1$ induced $ν_{τ} (ν ˉ_{τ}) - N$ quasielastic scattering have been studied. The effect of T violation, in the case of $Δ S = 0$ and 1 processes, and the SU(3) symmetry breaking effects, in the case of $Δ S = 1$ processes, on the total scattering cross sections as well polarization observables are explored. Experimentally, it would be possible to observe these effects in the forthcoming (anti)neutrino experiments like DUNE, SHiP and DsTau.
↳ hep-phhep-exnucl-thSciPost Phys.Proc.(2025)·1 citation
12
Accessing ground state and excited states energies in many-body system after symmetry restoration using quantum computers
E. A. Ruiz Guzman🇫🇷 · D. Lacroix🇫🇷
We explore the possibility to perform symmetry restoration with the variation after projection technique on a quantum computer followed by additional post-processing. The final goal is to develop configuration interaction techniques based on many-body trial states pre-optimized on a quantum computer. We show how the projection method used for symmetry restoration can prepare optimized states that could then be employed as initial states for quantum or hybrid quantum-classical algorithms. We use the quantum phase estimation and quantum Krylov approaches for the post-processing. The latter method combined with the quantum variation after projection (Q-VAP) leads to very fast convergence towards the ground-state energy. The possibility to access excited states energies is also discussed. Illustrations of the different techniques are made using the pairing hamiltonian.
↳ quant-phcond-mat.supr-connucl-exnucl-thPRC(2022)·53 citations
13
Lattice QCD with an inhomogeneous magnetic field background
B. B. Brandt🇩🇪 · F. Cuteri🇩🇪 · G. Endrődi🇩🇪 · G. Markó🇩🇪 · A. D. M. Valois🇩🇪
The magnetic fields generated in non-central heavy-ion collisions are among the strongest fields produced in the Universe, reaching magnitudes comparable to the scale of the strong interactions. Backed by model simulations, the resulting field is expected to be spatially modulated, deviating significantly from the commonly considered uniform profile. To improve our understanding of the physics of quarks and gluons under such extreme conditions, we use lattice QCD simulations with $2 + 1$ staggered fermion flavors with physical quark masses and an inhomogeneous magnetic background for a range of temperatures covering the QCD phase transition. We assume a $1/ cosh^{2}$ function to model the field profile and vary its strength to analyze the impact on the computed observables and on the transition. We calculate local chiral condensates, local Polyakov loops and estimate the size of lattice artifacts. We find that both observables show non-trivial spatial features due to the interplay between the sea and the valence effects.
↳ hep-lathep-thnucl-thPoS(2022)·6 citations
14
Constraints on the fermionic dark matter from observations of neutron stars
V. Sagun🇵🇹 · E. Giangrandi🇵🇹 · O. Ivanytskyi🇵🇱 · I. Lopes🇵🇹 · K. A. Bugaev🇺🇦
We study an impact of asymmetric fermionic dark matter on neutron star properties, including tidal deformability, mass, radius, etc. We present the conditions at which dark matter particles tend to form a compact structure in a core of the star or create an extended halo around it. We show that compact core of dark matter leads to a decrease of the total gravitational mass and tidal deformability compared to a pure baryonic star, while presence of a dark matter halo increases those observable quantities. By imposing an existing astrophysical and gravitational wave constraints set by LIGO/Virgo Collaboration together with the recent results on the spatial distribution of dark matter in the Milky Way we determine a new upper limit on the mass and fraction of dark matter particles inside compact stars. Furthermore, we show that the formation of an extended halo around a NS is incompatible with the GW170817 tidal deformability constraint.
↳ astro-ph.HEhep-phnucl-thPoS(2022)·19 citations
15
Charge-changing cross sections for $^{42 - 51}$ Ca and effect of charged-particle evaporation induced by neutron removal reaction
M. Tanaka · M. Takechi · A. Homma · A. Prochazka · M. Fukuda · D. Nishimura · T. Suzuki · T. Moriguchi · D.S. Ahn · A. Aimaganbetov · M. Amano · H. Arakawa and 56 other authors
Charge-changing cross sections $σ_{CC}$ for $^{42 - 51}$ Ca on a carbon target at around 280~MeV/nucleon have been measured. The measured $σ_{CC}$ values differ significantly from the previously developed calculations based on the Glauber model. However, through introduction of the charged-particle evaporation effect induced by the neutron-removal reaction in addition to the Glauber-model calculation, experimental $σ_{CC}$ values on $^{12}$ C at around 300~MeV/nucleon for nuclides from C to Fe isotopes are all reproduced with approximately 1\% accuracy. This proposed model systematically reproduces $σ_{CC}$ data without phenomenological corrections, and can also explain experimental $σ_{CC}$ values obtained in other energy regions.
↳ nucl-exnucl-thPRC(2022)·21 citations
16
Multi-Source Thermal Model Describing Transverse Momentum Spectra of Final-State Particles in High Energy Collisions
Fu-Hu Liu🇨🇳 · Jia-Yu Chen🇨🇳 · Qiang Zhang🇨🇳
In this mini review article, the transverse momentum spectra of final-state particles produced in high energy hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions described by the multi-source thermal model at the quark or parton level is summarized. In the model, the participant or contributor quarks or partons are considered to contribute together to the transverse momentum distribution of final-state particles with different modes of contributions. The concrete mode of contribution is generally determined by the difference of azimuthal angles of contributor partons in their emissions.
↳ hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2022)·4 citations
17
$D^{+} D^{-}$ hadronic atom and its production in $pp$ and $p p ˉ$ collisions
Pan-Pan Shi🇨🇳 · Zhen-Hua Zhang🇨🇳 · Feng-Kun Guo🇨🇳 · Zhi Yang🇨🇳
There must be Coulomb bound states of a pair of hadrons, which are stable against the strong interaction, with opposite electric charges. Such bound states are hadronic atoms. We study the properties and the production of the ground-state $D^{+} D^{-}$ hadronic atom $A_{D^{+} D^{-}}$ , called dionium, with quantum numbers $J^{P C} = 0^{++}$ . Using a nonrelativistic effective field theory for the $D^{0} D ˉ^{0}$ - $D^{+} D^{-}$ coupled-channel system, the mass of the ground-state dionium is predicted to be $(3739.3 \pm 0.1) MeV$ , with the binding energy reduced by about 10% compared to the Coulomb binding energy due to the strong interaction. Its width for the decay into the neutral $D^{0} D ˉ^{0}$ channel is predicted to be $1. 8_{- 0.6}^{+ 1.4}$ keV using lattice inputs for the $D D ˉ$ strong interaction. The cross section for the inclusive prompt production of the dionium at CMS and LHCb and that for the direct production $p p ˉ \to A_{D^{+} D^{-}}$ at PANDA are estimated at an order-of-magnitude level. In particular, we expect that $O (1 0^{3} \sim 1 0^{5})$ events of the reaction chain $p p ˉ \to A_{D^{+} D^{-}} \to D^{0} D ˉ^{0} \to K^{-} π^{+} K^{+} π^{-}$ can be collected at PANDA, and valuable information on the charmed meson interaction and on understanding charmoniumlike states will be obtained.
↳ hep-phhep-exnucl-exnucl-thPRD(2022)·13 citations
18
Bottomonium observables in an open quantum system using the quantum trajectories method
Peter Vander Griend🇩🇪
We solve the Lindblad equation describing the Brownian motion of a Coulombic heavy quark-antiquark pair in a strongly coupled quark gluon plasma using the Monte Carlo wave function method. The Lindblad equation has been derived in the framework of pNRQCD and fully accounts for the quantum and non-Abelian nature of the system. The hydrodynamics of the plasma is realistically implemented through a 3+1D dissipative hydrodynamics code. We compute the bottomonium nuclear modification factor and elliptic flow and compare with the most recent LHC data. The computation does not rely on any free parameter, as it depends on two transport coefficients that have been evaluated independently in lattice QCD. Our final results, which include late-time feed down of excited states, agree well with the available data from LHC 5.02 TeV PbPb collisions.
↳ hep-phnucl-exnucl-thphysics.comp-phEPJ Web Conf.(2022)·4 citations
19
How many particles do make a fluid? Qualifying collective behavior in expanding ultracold gases
Stefan Floerchinger🇩🇪 · Giuliano Giacalone🇩🇪 · Lars H. Heyen🇩🇪 · Leena Tharwat🇩🇪
Collective phenomena in quantum many-body systems are often described in terms of hydrodynamics, an appropriate framework when the involved particle numbers are effectively macroscopic. We propose to use experiments on expanding clouds of few and many interacting cold atoms to investigate the emergence of hydrodynamics as a function of particle number. We consider gases confined in two-dimensional elliptically-deformed traps, and we employ the manifestation of elliptic flow as an indicator of collective behavior. We quantify the response of the gas to the deformation of the trapping potential, and show how such information can be used to establish how many atoms are needed for the system to develop a degree of collectivity comparable to that expected in the hydrodynamic limit. This method permits one, in particular, to exploit observations made in expanding atomic gases to shed light on the apparent hydrodynamic behaviour of mesoscopic systems of quarks and gluons formed in the scattering of light ions in high-energy collider experiments.
↳ cond-mat.quant-gasnucl-exnucl-thPRC(2022)·16 citations
20
Out-of-Equilibrium Photon Production in the Late Stages of Relativistic Heavy-Ion Collisions
Anna Schäfer · Oscar Garcia-Montero · Jean-François Paquet · Hannah Elfner · Charles Gale
In this work, we assess the importance of non-equilibrium dynamics in the production of photons from the late stages of relativistic heavy-ion collisions. The p $_{T}$ -differential spectra and $v_{2}$ of photons from the late hadronic stage are computed within a non-equilibrium hadron transport approach, and compared to the results of a local equilibrium evolution using ideal relativistic hydrodynamics. It is found that non-equilibrium dynamics enhance the late-stage photon production at low p $_{T}$ and decreases it at higher p $_{T}$ compared to the estimate from hydrodynamics. This same comparison points to a significant increase in the momentum anisotropies of these photons due to non-equilibrium dynamics. Once combined with photons produced above the particlization temperature in the hydrodynamics evolution, the differences between the two approaches appear modest in what concerns the p $_{T}$ differential spectra, but are clearly noticeable at low p $_{T}$ for the elliptic flow: non-equilibrium dynamics enhance the photon $v_{2}$ below p $_{T}$ $\approx 1.4$ GeV.
↳ hep-phnucl-thPRC(2022)·26 citations
21
Heavy-Light Susceptibilities in a Strongly Coupled Quark-Gluon Plasma
Shuai Y. F. Liu🇨🇳 · Ralf Rapp🇺🇸
Quark number susceptibilities as computed in lattice QCD are commonly believed to provide insights into the microscopic structure of QCD matter, in particular its degrees of freedom. We generalize a previously constructed partonic $T$ -matrix approach to finite chemical potential to calculate various susceptibilities, in particular for configurations containing a heavy charm quark. At vanishing chemical potential and moderate temperatures, this approach predicts large collisional widths of partons generated by dynamically formed hadronic resonance states which lead to transport parameters characteristic for a strongly coupled system. The quark chemical potential dependence is implemented into the propagators and the in-medium color potential, where two newly introduced parameters for the thermal and screening masses are fixed through a fit to the baryon number susceptibility, $χ_{2}^{B}$ . With this setup, we calculate heavy-light susceptibilities without further tuning; the results qualitatively agree with the lattice-QCD (lQCD) data for both $χ_{11}^{u c}$ and $χ_{22}^{u c}$ . This implies that the lQCD results are compatible with a significant content of broad $D$ -meson and charm-light diquark bound states in a moderately hot QGP.
↳ hep-phhep-latnucl-exnucl-thPRC(2022)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE