Fernandez-Ramirez, C., Bernstein, A. M., Donnelly, T. W.
Contributions of D waves to physical observables for neutral pion photoproduction from the proton in the near-threshold region are studied and means to isolate them are proposed. Various approaches...
Low-Energy D-Wave Effects in Neutral Pion Photoproduction (2009)
Fernandez-Ramirez, C., Bernstein, A. M., Donnelly, T. W.
The contribution of D waves to physical observables for neutral pion photoproduction in the near threshold region is studied. Heavy Baryon Chiral Perturbation Theory to one loop, and up to ${\cal...
Virtual Compton Scattering measurements in the $\gamma^* N\to \Delta$ transition (2008)
Sparveris, N. F., Achenbach, P., Gayoso, C. Ayerbe, Baumann, D., Bernauer, J., Bernstein, A. M., ...
We report on new H$(e,e^\prime p)\gamma$ measurements in the $\Delta(1232)$ resonance at $Q^2=0.06$ (GeV/c) carried out simultaneously with H$(e,e^\prime p)\pi^0$. It is the lowest $Q^2$ for which...
Vellidis Kaloskamis, C. E. Vellidis, N. I. Kaloskamis, C. Mertz, C. N. Papanicolas, A. M. Bernstein, ...
Introduction The electromagnetic N!\Delta transition involves three multipoles, M1 (magnetic dipole), E2 (electric quadrupole) and C2 (Coulomb quadrupole). The transition is studied via...
Energy Dependence of the Delta Resonance: Chiral Dynamics in Action (2007)
There is an important connection between the low energy theorems of QCD and the energy dependence of the Delta resonance in pi-N scattering, as well as the closely related gamma^{*} N -> pi N...
Ovrview: The Shape of Hadrons (2007)
Bernstein, A. M., Papanicolas, C. N.
In this article we address the physical basis of the deviation of hadron shapes from spherical symmetry (non-spherical amplitudes) with focus on the nucleon and $\Delta$. An overview of both the...
Opening Remarks at Chiral Dynamics 2006:Experimental Tests of Chiral Symmetry Breaking (2007)
A physical introduction to the basics of chiral dynamics is presented. Emphasis is placed on experimental tests which have generally demonstrated a strong confirmation of the predictions of chiral...
Separated cross sections in \pi^0 electroproduction at threshold at Q^2 = 0.05 GeV^2/c^2 (2007)
Weis, M., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A. M., Bohinc, K., ...
The differential cross sections \sigma_0=\sigma_T+\epsilon \sigma_L, \sigma_{LT}, and \sigma_{TT} of \pi^0 electroproduction from the proton were measured from threshold up to an additional center of...
Accuracy of Extracted Multipoles from gamma* N -> Delta Data (2007)
Stave, S., Bernstein, A. M., Nakagawa, I.
This work evaluates the model dependence of the electric and Coulomb quadrupole amplitudes (E2, C2) in the predominantly M1 (magnetic dipole-quark spin flip) gamma* N -> Delta transition. Both the...
Sparveris, N. F., Achenbach, P., Gayoso, C. Ayerbe, Baumann, D., Bernauer, J., Bernstein, A. M., ...
We report new precise p$(\vec{e},e^\prime p)\pi^0$ measurements at the peak of the $\Delta^{+}(1232)$ resonance at $Q^2=\unit[0.20](GeV/c)^2$ performed at the Mainz Microtron (MAMI). The new data are...
Bourgeois, P., Sato, Y., Shaw, J., Alarcon, R., Bernstein, A. M., Bertozzi, W., ...
The mean square polarizability radii of the proton have been measured for the first time in a virtual Compton scattering experiment performed at the MIT-Bates out-of-plane scattering facility....
Lowest Q^2 Measurement of the gamma*p -> Delta Reaction: Probing the Pionic Contribution (2006)
Stave, S., Distler, M. O., Nakagawa, I., Sparveris, N., Achenbach, P., Gayoso, C. Ayerbe, ...
To determine nonspherical angular momentum amplitudes in hadrons at long ranges (low Q^2), data were taken for the p(\vec{e},e'p)\pi^0 reaction in the Delta region at Q^2=0.060 (GeV/c)^2 utilizing...
Deviation of the Nucleon Shape From Spherical Symmetry: Experimental Status (2002)
In this brief pedagogical overview the physical basis of the deviation of the nucleon shape from spherical symmetry will be presented along with the experimental methods used to determine it by the...
The decay pi0 to gamma gamma to next to leading order in Chiral Perturbation Theory (2002)
Goity, J. L., Bernstein, A. M., Holstein, B. R.
The two photon decay width of the neutral pion is analyzed within the combined framework of Chiral Perturbation Theory and the 1/Nc expansion up to order p^6 and p^4 times 1/Nc in the decay...
Neutral pion threshold production at Q2=0.05 GeV2/c2 and chiral perturbation theory (2002)
Merkel, H., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A.M., Bohinc, K., ...
New data are presented on the p (e, e'p)pi(o) reaction at threshold at a four-momentum transfer of Q2=0.05 GeV2/c2 The data were taken with the three-spectrometer setup of the A1 Collaboration at the...
Test of low-energy theorems for p(\vec{gamma},\pi^{0})p in the threshold region (2001)
Schmidt, A., Achenbach, P., Ahrens, J., Arends, H. J., Beck, R., Bernstein, A. M., ...
The photon asymmetry in the reaction p(\vec{\gamma},\pi^{0})p close to threshold has been measured for the first time with the photon spectrometer TAPS using linearly polarized photons from the...
Test of low energy theorems for H(gamma, pi0)1 H in the threshold region (2001)
Schmidt, A., Achenbach, P., Ahrens, J., Arends, H. J., Beck, R., Bernstein, A. M., ...
This version is available at the following Publisher URL: http://prl.aps.org
Coherent pi0 threshold production from the deuteron at Q2=0.1 GeV2/c2 (2001)
Ewald, I., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A.M., Bohinc, K., ...
First data on coherent threshold pi (0) electroproduction from the deuteron taken by the Al Collaboration at the Mainz Microtron MAMI are presented. At a four-momentum transfer of q(2) =...
Test of low-energy theorems for H-1(gamma over-right- arrow,pi(0))H-1 in the threshold region (2001)
Schmidt, A., Achenbach, P., Ahrens, J., Arends, H.J., Beck, R., Bernstein, A.M., ...
The photon asymmetry in the reaction H-1([([gamma])over right arrow], pi (0))H-1 close to threshold has been measured for the first time with the photon spectrometer TAPS using linearly polarized...
Search for Quadrupole Strength in the Electroexcitation of the Delta+(1232) (2001)
Alarcon, R., Barkhuff, D. H., Bernstein, A. M., Mertz, C., Vellidis, C. E.
Search for Quadrupole Strength in the Electro-excitation of the Delta(1232) (1999)
Mertz, C., Vellidis, C., Alarcon, R., Barkhuff, D. H., Bernstein, A. M., Bertozzi, W., ...
High-precision H(e,e'p)pi0 measurements at Q2=0.126 (GeV/c)2 are reported, which allow the determination of quadrupole amplitudes in the gamma* N->Delta transition; they simultaneously test the...
Light Quark Mass Difference and Isospin Breaking In Electromagnetic Pion Production (1998)
It is demonstrated that there is a dynamic isospin breaking effect in the near threshold $\gamma^{*} N\to \pi N$ reaction due to the mass difference of the up and down quarks, which also causes...
Bernstein, A. M., Pavan, M. M.
Experiments on pion (Goldstone Boson) photoproduction from the nucleon tests the ability to make QCD predictions at confinement scale energies. Experiments with both polarized beams and targets have...
Observation of a unitary cusp in the threshold {\gamma}p -> \pi^{0}p reaction (1996)
Bernstein, A. M., Shuster, E., Beck, R., Fuchs, M., Krusche, B., Merkel, H., ...
A rigorous multipole analysis of the recent {\gamma}p -> \pi^{0}p cross section measurement is presented. The data were taken using the photon spectrometer TAPS at the tagged photon beam of the Mainz...
Exclusive $\varrho^{0}$ production in deep inelastic electron-proton scattering at HERA (1995)
Derrick, Malcolm, Krakauer, D A, Magill, S, Mikunas, D, Musgrave, B, Repond, J, ...
Inclusive jet cross sections for events with a large rapidity gap with respect to the proton direction from the reaction ep \rightarrow jet \; + \; X with quasi-real photons have been measured with...
Observation of hard scattering in photoproduction events with a large rapidity gap at HERA (1994)
Derrick, Malcolm, Krakauer, D A, Magill, S, Musgrave, B, Repond, J, Schlereth, J L, ...
Inclusive jet differential cross sections in photoproduction at HERA (1994)
Derrick, Malcolm, Krakauer, D A, Magill, S, Musgrave, B, Repond, J, Schlereth, J L, ...
A search for excited fermions in electron-proton collisions at HERA (1994)
Derrick, Malcolm, Krakauer, D A, Magill, S, Musgrave, B, Repond, J, Schlereth, J L, ...
Measurement of the proton structure function F$_{2}$ from the 1993 HERA data (1994)
Derrick, Malcolm, Krakauer, D A, Magill, S, Musgrave, B, Repond, J, Schlereth, J L, ...
Coherent pi0 threshold production from the deuteron at Q2=0.1 GeV2/c2
Ewald, I., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A.M., Bohinc, K., ...
First data on coherent threshold pi (0) electroproduction from the deuteron taken by the Al Collaboration at the Mainz Microtron MAMI are presented. At a four-momentum transfer of q(2) =...
Neutral pion threshold production at Q2=0.05 GeV2/c2 and chiral perturbation theory
Merkel, H., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A.M., Bohinc, K., ...
New data are presented on the p (e, e'p)pi(o) reaction at threshold at a four-momentum transfer of Q2=0.05 GeV2/c2 The data were taken with the three-spectrometer setup of the A1 Collaboration at the...
Test of low-energy theorems for H-1(gamma over-right- arrow,pi(0))H-1 in the threshold region
Schmidt, A., Achenbach, P., Ahrens, J., Arends, H.J., Beck, R., Bernstein, A.M., ...
The photon asymmetry in the reaction H-1([([gamma])over right arrow], pi (0))H-1 close to threshold has been measured for the first time with the photon spectrometer TAPS using linearly polarized...
Coherent pi0 threshold production from the deuteron at Q2=0.1 GeV2/c2
Ewald, I., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A.M., Bohinc, K., ...
First data on coherent threshold pi (0) electroproduction from the deuteron taken by the Al Collaboration at the Mainz Microtron MAMI are presented. At a four-momentum transfer of q(2) =...
Neutral pion threshold production at Q2=0.05 GeV2/c2 and chiral perturbation theory
Merkel, H., Bartsch, P., Baumann, D., Bermuth, J., Bernstein, A.M., Bohinc, K., ...
New data are presented on the p (e, e'p)pi(o) reaction at threshold at a four-momentum transfer of Q2=0.05 GeV2/c2 The data were taken with the three-spectrometer setup of the A1 Collaboration at the...
Test of low-energy theorems for H-1(gamma over-right- arrow,pi(0))H-1 in the threshold region
Schmidt, A., Achenbach, P., Ahrens, J., Arends, H.J., Beck, R., Bernstein, A.M., ...
The photon asymmetry in the reaction H-1([([gamma])over right arrow], pi (0))H-1 close to threshold has been measured for the first time with the photon spectrometer TAPS using linearly polarized...