相关论文: Radiative Muon Capture and Induced Pseudoscalar Co…
While standard minimal coupling works well for Dirac fermions, its application to scalar fields features a known ``peculiarity'': the term linear in $A_\mu$ does not coincide with the conserved Noether current of the interacting theory. We…
We present a new experiment, Mu-MASS, aiming for a 1000-fold improvement in the determination of the 1S-2S transition frequency of Muonium (M), the positive-muon/electron bound state. This substantial improvement beyond the current…
A measurement is presented of the neutron production rate in lead by high energy cosmic-ray muons at a depth of 2850 m water equivalent (w.e.) and a mean muon energy of 260 GeV. The measurement exploits the delayed coincidences between…
In this work we study the contribution of the isoscalar tensor coupling to the realization of pseudospin symmetry in nuclei. Using realistic values for the tensor coupling strength, we show that this coupling reduces noticeably the…
The New Muon $(g-2)$ Collaboration at Fermilab has proposed to measure the anomalous magnetic moment of the muon, $a_\mu$, a factor of four better than was done in E821 at the Brookhaven AGS, which obtained $a_\mu = [116 592 089 (63)]…
A method to calculate the mean squared matrix element of weak interaction between compound states is developed. The result is expressed in terms of matrix elements of the nucleon-nucleon strong and weak interactions times the Fermi…
We discuss the lepton sector of a realistic string-inspired model based on the Pati-Salam $SU(4)\times SU(2)_L \times SU(2)_R$ gauge group supplemented by a U(1) family symmetry. The model involves third family Yukawa unification, predicts…
This paper reports on results from an experiment designed to search for exotic particles interacting with nuclear matter. These particles could be created through the Primakoff coupling between photons and an external magnetic field. Theory…
We present a precision measurement of the axial-vector coupling constant $g_A$ in the decay of polarized free neutrons. For the first time, a pulsed cold neutron beam was used for this purpose. By this method, leading sources of systematic…
Neutrino nuclear responses associated with medium momentum transfer of q=20-80 MeV for astro neutrinos and double beta decays were studied by using charge exchange reactions on Te128 and Te130. Gamow-Teller and spin dipole nuclear matrix…
The Mu2e and COMET collaborations will search for nucleus-catalyzed muon conversion to positrons ($\mu^-\rightarrow e^+$) as a signal of lepton number violation. A key background for this search is radiative muon capture where either: 1) a…
Pseudoscalar particles $\phi$ usually couple electromagnetically by an interaction of the form $\frc14 g \phi F {\widetilde F}$, allowing them to convert to photons in the presence of magnetic fields. Notably, new low-mass pseudoscalars…
We use QCD sum rules for the three point function of a pseudoscalar and two nucleonic currents in order to estimate the charge dependence of the pion nucleon coupling constant $g_{NN\pi}$ coming from isospin violation in the strong…
A secluded U(1) sector with weak admixture to photons, O(10^{-2}-10^{-3}), and the scale of the breaking below 1 GeV represents a natural yet poorly constrained extension of the Standard Model. We analyze g-2 of muons and electrons together…
Neutron production in lead by cosmic muons has been studied with a Gadolinium doped liquid scintillator detector. The detector was installed next to the Muon-Induced Neutron Indirect Detection EXperiment (MINIDEX), permanently located in…
Background: The recent disagreement between the proton charge radius extracted from Lamb shift measurements of muonic and electronic hydrogen invites speculation that new physics may be to blame. Several proposals have been made for new…
Very light particles with CP-violating couplings to ordinary matter, such as axions or axion-like particles, can mediate long-range forces between polarized and unpolarized fermions. We describe a new experimental search for such forces…
Measuring the muon anomalous magnetic moment g-2 and the rare decays of light pseudoscalar mesons into lepton pair P \to l+l- serve as important test of the standard model. To reduce the theoretical uncertainty in the standard model…
In this communication we discuss few topics related with modern experimental data on the physics of light pseudoscalar mesons. It includes the contribution of the pseudoscalar mesons to the muon anomalous magnetic moment (AMM), $g-2$, the…
The neutrino-nucleus cross section and the muon capture rate are discussed within a simple formalism which facilitates the nuclear structure calculations. The corresponding formulae only depend on four types of nuclear matrix elements,…