The X17 boson and the ${}^3$H$(p,e^{+}{e}^{-}{)}^4$He and ${}^3$He$(n,e^{+}{e}^{-}{)}^4$He processes: a theoretical analysis

Abstract

The present work deals with $e^{+}$-$e^{-}$ pair production in the four-nucleon system. We first analyze the process as a purely electromagnetic one in the context of a state-of-the-art approach to nuclear strong-interaction dynamics and nuclear electromagnetic currents, derived from chiral effective field theory ($\chi$EFT). Next, we examine how the exchange of a hypothetical low-mass boson would impact the cross section for such a process. We consider several possibilities, that this boson is either a scalar, pseudoscalar, vector, or axial particle. The ab initio calculations use exact hyperspherical-harmonics methods to describe the bound state and low-energy spectrum of the $A$=$4$ continuum, and fully account for initial state interaction effects in the $3+1$ clusters. While electromagnetic interactions are treated to high orders in the chiral expansion, the interactions of the hypothetical boson with nucleons are modeled in leading-order $\chi$EFT (albeit, in some instances, selected subleading contributions are also accounted for). We also provide an overview of possible future experiments probing pair production in the $A$=$4$ system at a number of candidate facilities.facilities.

arXiv comment32 pages, 17 figures. Corrected version, having fixed a problem with a phase in the multipolar expansions. Only Figs. 4 and 10 change significantly, the rest only marginally. The conclusions are unchanged. We include also a number of improvements: 1) better wave functions, 2) the isoscalar pseudoscalar case, and 3) the comparison with the new ATOMKI data (see new Fig. 17)

References in corpus (61)

• Chiral effective field theory and nuclear forces
• Accurate Charge-Dependent Nucleon-Nucleon Potential at Fourth Order of Chiral Perturbation Theory
• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• A History of Dark Matter
• Secluded WIMP Dark Matter
• Leading hadronic contribution to the muon magnetic moment from lattice QCD
• Quantum Monte Carlo methods for nuclear physics
• FLAG Review 2019
• Three-Nucleon Forces from Chiral Effective Field Theory
• The Belle II Physics Book
• Ab initio calculation of the neutron-proton mass difference
• Observation of Anomalous Internal Pair Creation in ${}^8$Be: A Possible Signature of a Light, Neutral Boson
• U-boson production in e+e- annihilations, psi and Upsilon decays, and Light Dark Matter
• Pion-nucleon scattering in chiral perturbation theory I: Isospin-symmetric case
• Heavy Baryon Chiral Perturbation Theory with Light Deltas
• The design of the MEG II experiment
• New Limits on Hidden Photons from Past Electron Beam Dumps
• A high-precision variational approach to three- and four-nucleon bound and zero-energy scattering states
• The chiral effective pion-nucleon Lagrangian of order p^4
• Roy-Steiner-equation analysis of pion-nucleon scattering
• Protophobic Fifth Force Interpretation of the Observed Anomaly in ${}^8$Be Nuclear Transitions
• New constraints on light vectors coupled to anomalous currents
• Local chiral potentials and the structure of light nuclei
• Electromagnetic Currents and Magnetic Moments in $\chi$EFT
• Light-nuclei spectra from chiral dynamics
• Accurate evaluation of hadronic uncertainties in spin-independent WIMP-nucleon scattering: Disentangling two- and three-flavor effects
• Two-pion exchange electromagnetic current in chiral effective field theory using the method of unitary transformation
• Search for a Hypothetical 16.7 MeV Gauge Boson and Dark Photons in the NA64 Experiment at CERN
• Limit on the production of a low-mass vector boson in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to \mathrm{U}\gamma$, $\mathrm{U}\to {\mathrm{e}}^{+}{\mathrm{e}}^{-}$ with the KLOE experiment
• Improved limits on a hypothetical X(16.7) boson and a dark photon decaying into $e^{+}{e}^{-}$ pairs
• Two-nucleon electromagnetic current in chiral effective field theory: one-pion exchange and short-range contributions
• Electromagnetic structure of A=2 and 3 nuclei in chiral effective field theory
• Electromagnetic two-body currents of one- and two-pion range
• A viable QCD axion in the MeV mass range
• The two-nucleon electromagnetic charge operator in chiral effective field theory ($\chi$EFT) up to one loop
• Up, down, and strange nucleon axial form factors from lattice QCD
• A new anomaly observed in ${}^4$He supports the existence of the hypothetical X17 particle
• Local chiral interactions, the tritium Gamow-Teller matrix element, and the three-nucleon contact term
• Extracting the sigma-term from low-energy pion-nucleon scattering
• Constraints on a very light CP-odd Higgs of the NMSSM and other axion-like particles
• Weak proton capture on 3He
• P- and T-Violating Lagrangians in Chiral Effective Field Theory and Nuclear Electric Dipole Moments
• Light Axial Vectors, Nuclear Transitions, and the ${}^8$Be Anomaly
• Explanation of the 17 MeV Atomki Anomaly in a $U(1{)}^{\prime }$-Extended 2-Higgs Doublet Model
• Electromagnetic Structure of Few-Nucleon Ground States
• Can nuclear physics explain the anomaly observed in the internal pair production in the Beryllium-8 nucleus?
• Benchmark calculation of n-3H and p-3He scattering
• Dynamical Evidence For a Fifth Force Explanation of the ATOMKI Nuclear Anomalies
• Weak Transitions in A=6 and 7 Nuclei
• Local chiral interactions and magnetic structure of few-nucleon systems
• Atomki Anomaly in Family-Dependent $U(1{)}^{\prime }$ Extension of the Standard Model
• Implication of the hidden sub-GeV bosons for the $(g-2{)}_{\mu }$, ${}^8$Be-${}^4$He anomaly, proton charge radius, EDM of fermions and dark axion portal
• Can a protophobic vector boson explain the ATOMKI anomaly?
• Signals of the QCD axion with mass of 17 MeV/c^2: nuclear transitions and light meson decays
• New Physics Suggested by Atomki Anomaly
• Benchmark calculation of p-3H and n-3He scattering
• Is There a Sign of New Physics in Beryllium Transitions?
• Accommodating three low-scale anomalies (g-2, Lamb shift, and Atomki) in the framed standard model
• 17 MeV Atomki anomaly from short-distance structure of spacetime
• The $U$ boson, interpolating between a generalized dark photon or dark $Z$, an axial boson and an axionlike particle
• X17: A new force, or evidence for a hard $\gamma +\gamma$ process?

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• New anomaly observed in ${}^{12}$C supports the existence and the vector character of the hypothetical X17 boson
• QED Meson Description of the X17 and Other Anomalous Particles
• Resonant search for the X17 boson at PADME
• Solar fusion III: New data and theory for hydrogen-burning stars
• Neutrino Constraints and the ATOMKI X17 Anomaly
• Status of the X17 search in Montreal
• On the Atomki nuclear anomaly after the MEG-II result
• X17 discovery potential in the $\gamma N\to e^{+}{e}^{-}N$ process at electron scattering facilities
• Ab initio investigation of the ${}^7$Li($p,e^{+}{e}^{-}$)${}^8$Be process and the X17 boson
• Perspectives on few-body cluster structures in exotic nuclei
• On the question of quark confinement in the Abelian U(1) QED gauge interaction
• Dynamics of quarks and gauge fields in the lowest-energy states in QCD and QED
• QED meson description of the anomalous particles at ~17 and ~38 MeV
• Contributions to $Z^0$ decays from a X17 extension of the Standard Model