Publications (40)
Spectrum and energy levels of the high-lying singly excited configurations of Nd III
M. Ding, A. N. Ryabtsev, E. Y. Kononov +2
Fourier transform spectra of Nd Penning and hollow cathode discharge lamps were recorded within the region 32,500-54,000 cm (3077-1852 Ã ) and grating spectra of Nd vacuum s…
Final State Interaction Effects in pol 3He(pol e,e'p)
C. Carasco, J. Bermuth, P. Merle +40
Asymmetries in quasi-elastic pol 3He(pol e,e'p) have been measured at a momentum transfer of 0.67 (GeV/c)^2 and are compared to a calculation which takes into account relativistic…
Emergence of pion parton distributions
Z. -F. Cui, M. Ding, J. M. Morgado +7
Supposing only that there is an effective charge which defines an evolution scheme for parton distribution functions (DFs) that is all-orders exact, strict lower and upper bounds o…
First measurements of the ^16O(e,e'pn)^14N reaction
D. G. Middleton, J. R. M. Annand, C. Barbieri +39
This paper reports on the first measurement of the ^16O(e,e'pn)^14N reaction. Data were measured in kinematics centred on a super-parallel geometry at energy and momentum transfers…
A short-orbit spectrometer for low-energy pion detection in electroproduction experiments at MAMI
D. Baumann, M. Ding, I. FriÅ¡ÄiÄ +7
A new Short-Orbit Spectrometer (SOS) has been constructed and installed within the experimental facility of the A1 collaboration at Mainz Microtron (MAMI), with the goal to detect…
Accelerating Atomic Fine Structure Determination with Graph Reinforcement Learning
M. Ding, V. -A. Darvariu, A. N. Ryabtsev +2
Atomic data determined by analysis of observed atomic spectra are essential for plasma diagnostics. For each low-ionisation open d- and f-subshell atomic species, around fin…
Measurement of the reaction close to threshold and at low
A1 Collaboration, I. FriÅ¡ÄiÄ, P. Achenbach +21
The cross section of the reaction has been measured for five kinematic settings at an invariant mass of MeV and for a four-momentum transfer of $Q^2 = 0.0…
Lowest Q^2 Measurement of the gamma*p -> Delta Reaction: Probing the Pionic Contribution
S. Stave, M. O. Distler, I. Nakagawa +29
To determine nonspherical angular momentum amplitudes in hadrons at long ranges (low Q^2), data were taken for the p(\vec{e},e'p)Ï^0 reaction in the Delta region at Q^2=0.060 (GeV…
Path Planning for UAV-Mounted Mobile Edge Computing with Deep Reinforcement Learning
Q. Liu, L. Shi, L. Sun +3
In this letter, we study an unmanned aerial vehicle (UAV)-mounted mobile edge computing network, where the UAV executes computational tasks offloaded from mobile terminal users (TU…
The neutron charge form factor and target analyzing powers from pol.3He(pol e,e'n)-scattering
J. Bermuth, P. Merle, C. C. Carasco +40
The charge form factor of the neutron has been determined from asymmetries measured in quasi--elastic pol.3He(pol e,e'n) at a momentum transfer of 0.67(GeV/c)^2. In addition, the t…
Measurement of the recoil polarization in the p (\vec e, e' \vec p) pi^0 reaction at the Î(1232) resonance
Th. Pospischil, P. Bartsch, D. Baumann +39
The recoil proton polarization has been measured in the p (\vec e,e'\vec p) pi^0 reaction in parallel kinematics around W = 1232 MeV, Q^2 = 0.121 (GeV/c)^2 and epsilon = 0.718 usin…
Distribution Functions of a Radially Excited Pion
Z. -N. Xu, Z. -Q. Yao, D. Binosi +3
A nonperturbatively-improved, symmetry-preserving approximation to the quantum field equations relevant in calculations of meson masses and interactions is used to deliver predicti…
Field-assisted birefringent Compton scattering
N. Ahmadiniaz, T. E. Cowan, M. Ding +4
Motivated by experimental initiatives such as the Helmholtz International Beamline for Extreme Fields (HIBEF), we study Compton scattering of x-rays at electrons in a strong extern…
Measurement of the cosmic-ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite
Q. An, R. Asfandiyarov, P. Azzarello +151
The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in th…
Measurement of the beam-helicity asymmetry in the p(e_pol,e'p)pi_0 reaction at the energy of the Delta(1232) resonance
P. Bartsch, D. Baumann, J. Bermuth +32
In a p(e_pol,e'p)pi_0 out-of-plane coincidence experiment at the 3-spectrometer setup of the Mainz Microtron MAMI, the beam-helicity asymmetry has been precisely measured around th…
Nucleon Gravitational Form Factors
Z. -Q. Yao, Y. -Z. Xu, D. Binosi +6
A symmetry-preserving analysis of strong interaction quantum field equations is used to complete a unified treatment of pion, kaon, nucleon electromagnetic and gravitational form f…
Diquark Correlations in Hadron Physics: Origin, Impact and Evidence
M. Yu. Barabanov, M. A. Bedolla, W. K. Brooks +24
The last decade has seen a marked shift in how the internal structure of hadrons is understood. Modern experimental facilities, new theoretical techniques for the continuum bound-s…
A neural network approach for line detection in complex atomic emission spectra measured by high-resolution Fourier transform spectroscopy
M. Ding, S. Z. J. Lim, X. Yu +2
The atomic spectra and structure of the open d- and f-shell elements are extremely complex, where tens of thousands of transitions between fine structure energy levels can be obser…
Measurement of the Electric Form Factor of the Neutron at Q^2 = 0.3-0.8 (GeV/c)^2
D. I. Glazier, M. Seimetz, J. R. M. Annand +41
The electric form factor of the neutron, G_En, has been measured at the Mainz Microtron by recoil polarimetry in the quasielastic D(e_pol,e'n_pol)p reaction. Three data points have…
A new measurement of the structure functions and in virtual Compton scattering at 0.33 (GeV/c)
A1 Collaboration, P. Janssens, L. Doria +36
The cross section of the reaction has been measured at (GeV/c). The experiment was performed using the electron beam of the MAMI accelerator and…
Concerning pion parton distributions
Z. -F. Cui, M. Ding, J. M. Morgado +7
Analyses of the pion valence-quark distribution function (DF), , which explicitly incorporate the behaviour of the pion wave function prescribed by quantum chromodyna…
Measurement of the asymmetries in 3He(e,e'p)d and 3He(e,e'p)np
P. Achenbach, D. Baumann, R. Boehm +48
The electron-target-asymmetries A_parallel and A_perpendicular with target spin parallel and perpendicular to the momentum transfer q were measured for both the two-- and three-bod…
Laboratory confirmation and improved Accuracy of 4f and 5d energy levels of Fe II previously identified from stellar spectra
M. Ding, H. Kozuki, F. Concepcion +2
Many energy levels of singly ionised iron (Fe II, ) remain uncertain or experimentally unknown. Their identification and spectral line data are required in reliable astrophys…
Virtual Compton Scattering measurements in the $γ^* N\to Î$ transition
N. F. Sparveris, P. Achenbach, C. Ayerbe Gayoso +30
We report on new H measurements in the resonance at (GeV/c) carried out simultaneously with H. It is the lowest fo…
Investigation of the Exclusive ^{3}He(e,e'pn)p Reaction
D. G. Middleton, J. R. M. Annand, M. Ases Antelo +46
Cross sections for the ^{3}He(e,e'pn)p reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c…
Measurements of the γ* p --> Î(1232) reaction at low Q2
N. Sparveris, S. Stave, P. Achenbach +29
We report new p measurements in the resonance at the low momentum transfer region utilizing the magnetic spectrometers of the A1 Collab…
Polarization transfer in the HeH reaction
S. Dieterich, P. Bartsch, D. Baumann +39
Polarization transfer in the 4He(e,e'p)3H reaction at a Q^2 of 0.4 (GeV/c)^2 was measured at the Mainz Microtron MAMI. The ratio of the transverse to the longitudinal polarization…
Search for Massive Neutrinos in the Decay pi --> e nu
PIENU Collaboration, M. Aoki, M. Blecher +20
Evidence of massive neutrinos in the pi --> e nu decay spectrum was sought with the background pi --> mu --> e decay chain highly suppressed. Upper limits (90% C.L.) on the neutrin…
Determination of quadrupole strengths in the gamma*p-->Delta(1232) transition at Q2= 0.20 (GeV/c)2
N. F. Sparveris, P. Achenbach, C. Ayerbe Gayoso +29
We report new precise p measurements at the peak of the resonance at $Q^2=\unit[0.20](GeV/c)^2$ performed at the Mainz Microtron (MAMI). Th…
The on-orbit calibration of DArk Matter Particle Explorer
G. Ambrosi, Q. An, R. Asfandiyarov +155
The DArk Matter Particle Explorer (DAMPE), a satellite-based cosmic ray and gamma-ray detector, was launched on December 17, 2015, and began its on-orbit operation on December 24,…
Separated cross sections in Ï^0 electroproduction at threshold at Q^2 = 0.05 GeV^2/c^2
M. Weis, P. Bartsch, D. Baumann +26
The differential cross sections Ï_0=Ï_T+εÏ_L, Ï_{LT}, and Ï_{TT} of Ï^0 electroproduction from the proton were measured from threshold up to an additional center of mass ene…
Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
A. Accardi, P. Achenbach, D. Adhikari +441
This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a…
Improved measurement of the $Ï\rightarrow \mbox{e} ν$ branching ratio
A. Aguilar-Arevalo, M. Aoki, M. Blecher +23
A new measurement of the branching ratio, $R_{e/μ} =Î(Ï^+ \rightarrow \mbox{e}^+ ν+ Ï^+ \rightarrow \mbox{e}^+ νγ)/ Î(Ï^+ \rightarrow μ^+ ν+ Ï^+ \rightarrow μ^+ νγ)$…
Beam-helicity asymmetry in photon and pion electroproduction in the Delta(1232) resonance region at Q^2= 0.35 (GeV/c)^2
A1 Collaboration, I. K. Bensafa, P. Achenbach +40
The beam-helicity asymmetry has been measured simultaneously for the reactions (e p \to e p γ) and (e p \to e p Ï^0) in the resonance region at 0.35 (GeV/c)…
Measurement of the Beam-Recoil Polarization in Low-Energy Virtual Compton Scattering from the Proton
L. Doria, P. Janssens, P. Achenbach +38
Double-polarization observables in the reaction have been measured at . The experiment was performed at the spectrometer set…
Constraining the pion distribution amplitude using Drell-Yan reactions on a proton
H. -Y. Xing, M. Ding, Z. -F. Cui +3
Using a reaction model that incorporates pion bound state effects and continuum results for proton parton distributions and the pion distribution amplitude, , we deliver par…
Consistent threshold pi0 electro-production at Q^2=0.05, 0.10, and 0.15 GeV^2/c^2
H. Merkel, P. Achenbach, C. Ayerbe Gayoso +22
New, accurate data are presented on the near threshold p(e,e'p)pi^0 reaction in the range of four-momentum transfers between Q^2=0.05 and 0.15GeV^2/c^2. The data were taken with th…
Measurement of the LT-asymmetry in Ï^0 electroproduction at the energy of the Î(1232) resonance
D. Elsner, A. Süle, P. Barneo +29
The reaction p(e,e'p)pi^0 has been studied at Q^2=0.2 (GeV/c)^2 in the region of W=1232 MeV. From measurements left and right of q, cross section asymmetries Ï_LT have been obtain…
The focal plane proton-polarimeter for the 3-spectrometer setup at MAMI
T. Pospischil, P. Bartsch, D. Baumann +46
For experiments of the type A(\vec e,e'\vec p) the 3-spectrometer setup of the A1 collaboration at MAMI has been supplemented by a focal plane proton-polarimeter. To this end, a ca…
Search for Narrow Nucleon Resonances below Pion Threshold in the H(e,e'pi^+)X and D(e,e'p)X Reactions
M. Kohl, M. Ases Antelo, C. Ayerbe +23
In two series of high-resolution coincidence experiments at the three-spectrometer facility at MAMI, the H(e,e'pi^+)X and D(e,e'p)X reactions were studied to search for narrow nucl…