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Hadronic light-by-light contribution to the muon anomaly from lattice QCD with infinite volume QED at physical pion mass
The hadronic light-by-light scattering contribution to the muon anomalous magnetic moment, (g–2)/2, is computed in the infinite volume QED framework with lattice QCD. We report $a^{HLbL}_μ$ = 12.47(1.15)(0.95) ×10 –10 where the first error is statistical and the second systematic. The result is mainly based on the 2+1 flavor Möbius domain wall fermion ensemble with inverse lattice spacing a –1 = 1.73 GeV, lattice size L = 5.5 fm, and m π = 139 MeV, generated by the RBC-UKQCD collaborations. The leading systematic error of this result comes from the lattice discretization. This result is consistent with previous determinations.
Power counting of the pion-dilaton effective field theory
Confining QCD-like theories close to the conformal window have a “walking” coupling. This is believed to lead to a light singlet scalar meson in the low-energy spectrum, a dilaton, which is the pseudo-Nambu-Goldstone boson for the approximate scale symmetry. Extending chiral perturbation theory to include the dilaton requires a new small parameter to control the dilaton mass and its interactions. In our previous work we derived a systematic power counting for the dilaton couplings by matching the effective low-energy theory to the underlying theory using mild assumptions. In this paper we examine two alternative power countings which were proposed in the literature based on a phenomenological picture for the conformal transition. We find that one of these power countings fails, in fact, to generate a systematic expansion; the other coincides with the power counting we derived. We also point out that the so-called Δ -potential coincides with the tree-level potential of the former, invalid, power counting. Published by the American Physical Society 2025
Polarization observables in double neutral pion photoproduction
Abstract Measurements of target asymmetries and double-polarization observables for the reaction "Equation missing"<#comment/>are reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility (Bonn University) using the Bonn frozen-spin butanol ($$\hbox {C}_4\hbox {H}_9$$ C 4 H 9 OH) target, which provided transversely polarized protons. Linearly polarized photons were produced via bremsstrahlung off a diamond crystal. The data cover the photon energy range from "Equation missing"<#comment/>to "Equation missing"<#comment/>and nearly the complete angular range. The results have been included in the BnGa partial wave analysis. Experimental results and the fit agree very well. Observed systematic differences in the branching ratios for decays of "Equation missing"<#comment/>and$${\varDelta ^*}$$ Δ ∗ resonances are attributed to the internal structure of these excited nucleon states. Resonances which can be assigned to SU(6)$$\times $$ × O(3) two-oscillator configurations show larger branching ratios to intermediate states with non-zero intrinsic orbital angular momenta than resonances assigned to one-oscillator configurations.
Pions in the NOvA Test Beam
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Measuring Neutral Current Neutral Pion Cross Sections in MicroBooNE
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Modeling of GeV Neutrino-Argon Interactions with No Pions in the Short-Baseline Neutrino Program
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Measurements of Neutrino-Induced Charged Pion Production at MicroBooNE
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A comparison of resonance formulas for the /1236 MeV, 3/2/ pion nucleon resonance
Resonance formulas for energy dependence of relativistic particle resonances
Double charge exchange of 50-176 MeV negative pions in photoemulsion
Double charge exchange of 50-176 Mev pi mesons in photoemulsion
Interplanetary positrons near 1 MeV from other than the pion yields muon yields electron process
Satellite detection of interplanetary positrons with higher intensity than cosmic ray meson production
Interplanetary positrons near 1 MeV from other than the pion to muon to electron process
Interplanetary cosmic ray positrons energy spectral component with origin different from interstellar mesons decay
Observations by human subjects on radiation- induced light flashes in fast-neutron, X-ray, and positive-pion beams
Exposure of human subjects to fast neutron beam to determine cause of light flashes observed by astronauts on lunar missions
List of technical reports and conferences on pion research
Lists of the Ph.D. theses, publications, and talks given at professional meetings based on research in medium energy physics are presented.
Elastic scattering of negative pions from O-16 in the region of the /3, 3/ resonance.
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The two-photon absorptivity of rotational transitions in the A2 Sigma hyperon + (v prime = O) - X-2 pion (v prime prime = O) gamma band of nitric oxide
A predominantly single-mode pulsed dye laser system giving a well characterized spatial and temporal output suitable for absolute two-photon absorptivity measurements was used to study the NO gamma(0,0) S11 + R21 (J double prime = 7-1/2) transition. Using a calibrated induced-fluorescence technique, an absorptivity parameter of 2.8 + or - 1.4 x 10 to the minus 51st power cm to the 6th power was obtained. Relative strengths of other rotational transitions in the gamma(0,0) band were also measured and shown to compare well with predicted values in all cases except the O12 (J double prime = 10-1/2) transition.
Anuglar distribution of shower particles produced in the collisions of 20-GeV/c and 300-GeV negative pions with emulsion nuclei
For 435 accelerator produced antipions jets of 20 GeV/c and 300 GeV, in nuclear emulsion, eta(theta)'s have been individually calculated for each jet, where eta(theta) is a kinematic parameter introduced in order to approximate the LS (laboratory system) rapidity, eta = arctan h (beta cos theta). By taking further averages by dividing the samples into groupings of the LS energy E sub pi = m cos h eta sub pi N sub h, the number of heavy prongs with LS velocity beta 0.7, and n , the number of charged shower particles with LS velocity beta 0.7, much less than eta (theta) much greater than are obtained. By use of the KNO (Koba-Nielsen-Olesen) scaling variable, xi = n sub s/,n sub s. good fit is found of data to regression function.
Transverse momentum distribution of pion deg in the fragmentation region of super high energy interactions
The lateral distribution of gamma-families observed by emulsion chamber is sensitive to test transverse momentum of high energy interaction. But most part gamma-families are succesive interation's results which makes it necessary to analyze the propagation of gamma-ray in atmosphere. A gamma-ray with energy Er and transverse momentum Pt is produced at the altitude h. In the emulsion chamber experiment, Eob is estimated by decascade method. There are 30 gamma-families observed by Ganbala emulsion Chamber. A group of Monte-Carlo simulation gamma-families are used to compare with experimental data with the same treatment. It is found that both distributions are consistent.