In the meson exchange model of weak nucleon-nucleon (NN) interactions, the exchange of virtual mesons between the nucleons is parameterized by a set of weak meson exchange amplitudes. The strengths of these amplitudes from theoretical calculations are not well known, and experimental measurements of parity-violating (PV) observables in different nuclear systems have not constrained their values. Transversely polarized cold neutrons traveling through liquid helium experience a PV spin rotation due to the weak interaction with an angle proportional to a linear combination of these weak meson exchange amplitudes. A measurement of the PV neutron spin rotation in helium (φ PV ( n ,α)) would provide information about the relative strengths of the weak meson exchange amplitudes, and with the longitudinal analyzing power measurement in the p + α system, allow the first comparison between isospin mirror systems in weak NN interaction. An earlier experiment performed at NIST obtained a result consistent with zero: φ PV ( n ,α) = (8.0 ±14(stat) ±2.2(syst)) ×10(-7) rad / m[1]. We describe a modified apparatus using a superfluid helium target to increase statistics and reduce systematic effects in an effort to reach a sensitivity goal of 10(-7) rad/m.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4849584 | PMC |
| http://dx.doi.org/10.6028/jres.110.025 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Identification of the G(3900) Structure as the P-Wave DD[over ¯]^{*}/D[over ¯]D^{*} Resonance.
Phys Rev Lett
December 2024
School of Physics and Center of High Energy Physics, Peking University, Beijing 100871, China.
The BESIII Collaboration recently performed a precise measurement of the e^{+}e^{-}→DD[over ¯] Born cross sections, and confirmed the G(3900) structure reported by BABAR and Belle with high significance. We identify the G(3900) as the first P-wave DD[over ¯]^{*}/D[over ¯]D^{*} molecular resonance. The experimental and theoretical identification of the P-wave dimeson state holds paramount importance in enhancing our comprehension of the nonperturbative QCD and few-body physics.
View Article and Find Full Text PDFDark-Sector Search via Pion-Produced η and η^{'} Mesons Decaying Invisibly in the NA64h Detector.
Phys Rev Lett
September 2024
Authors affiliated with an international laboratory covered by a cooperation agreement with CERN.
We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar η and η^{'} mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV π^{-} on nuclei of an active target as the source of neutral mesons. The η,η^{'}→invisible events would exhibit themselves via a striking signature-the complete disappearance of the incoming beam energy in the detector.
View Article and Find Full Text PDFNonmesonic Quantum Many-Body Scars in a 1D Lattice Gauge Theory.
Phys Rev Lett
June 2024
Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wako-shi, Saitama 351-0198, Japan.
We investigate the meson excitations (particle-antiparticle bound states) in quantum many-body scars of a 1D Z_{2} lattice gauge theory coupled to a dynamical spin-1/2 chain as a matter field. By introducing a string representation of the physical Hilbert space, we express a scar state |Ψ_{n,l}⟩ as a superposition of all string bases with an identical string number n and a total length l. For the small-l scar state |Ψ_{n,l}⟩, the gauge-invariant spin exchange correlation function of the matter field hosts an exponential decay as the distance increases, indicating the existence of stable mesons.
View Article and Find Full Text PDFDiscrete phase space-continuous time relativistic Klein-Gordon and Dirac equations, and a new non-singular Yukawa potential.
Sci Rep
November 2023
Department of Applied Physics, New York University, 2 MetroTech Center, Brooklyn, NY, 11201, USA.
This paper deals with the second quantization of interacting relativistic Fermionic and Bosonic fields in the arena of discrete phase space and continuous time. The mathematical formulation involves partial difference equations. The corresponding Feynman diagrams and a new [Formula: see text]-matrix theory is developed.
View Article and Find Full Text PDFRevealing the nature of hidden charm pentaquarks with machine learning.
Sci Bull (Beijing)
May 2023
Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, Bonn D-53115, Germany; Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, Jïlich D-52425, Germany; Tbilisi State University, Tbilisi 0186, Georgia. Electronic address:
We study the nature of the hidden charm pentaquarks, i.e., the P4312,P4440 and P(4457), with a neural network approach in pionless effective field theory.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!