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Full-Text Articles in Physics
Generalized Polarizabilities And The Chiral Structure Of The Nucleon, Thomas R. Hemmert, Barry R. Holstein, Germar Knöchlein, Stefan Scherer
Generalized Polarizabilities And The Chiral Structure Of The Nucleon, Thomas R. Hemmert, Barry R. Holstein, Germar Knöchlein, Stefan Scherer
Barry R Holstein
No abstract provided.
Delta(1232) And The Polarizabilities Of The Nucleon, Tr Hemmert, Br Holstein, J Kambor
Delta(1232) And The Polarizabilities Of The Nucleon, Tr Hemmert, Br Holstein, J Kambor
Barry R Holstein
Previous calculations of the polarizabilities of the nucleon within the framework of heavy baryon chiral perturbation theory have included the contribution of the Δ(1232) only in its effects on various contact terms or have been performed in chiral SU(3) where systematic errors are difficult to control. Herein, we perform a corresponding calculation in chiral SU(2) wherein Δ(1232) is treated as an explicit degree of freedom and the expansion is taken to third order in soft momenta, the pion mass, and the quantity MΔ-MN, collectively denoted ε. We present the results of a systematic O(ε3) calculation of forward Compton scattering off …
Photon-Photon Scattering, Pion Polarizability, And Chiral-Symmetry, Jf Donoghue, Br Holstein
Photon-Photon Scattering, Pion Polarizability, And Chiral-Symmetry, Jf Donoghue, Br Holstein
Barry R Holstein
Recent attempts to detect the pion polarizability via analysis of γγ→ππ measurements are examined. The connection between calculations based on dispersion relations and on chiral perturbation theory is established by matching the low-energy chiral amplitude with that given by a full dispersive treatment. Using the values for the polarizability required by chiral symmetry, predicted and experimental cross sections are shown to be in agreement.
Dispersion-Relations And The Nucleon Polarizability, Br Holstein, Am Nathan
Dispersion-Relations And The Nucleon Polarizability, Br Holstein, Am Nathan
Barry R Holstein
Recent experimental results on the proton and neutron polarizabilities are examined from the point of view of backward dispersion relations. Results are found to be in reasonable agreement with the measured values. A rigorous relationship between the nucleon and pion polarizabilities is derived and shown to be in excellent agreement with several models.
Compton Scattering And The Spin Structure Of The Nucleon At Low Energies, Tr Hemmert, Br Holstein, J Kambor, G Knochlein
Compton Scattering And The Spin Structure Of The Nucleon At Low Energies, Tr Hemmert, Br Holstein, J Kambor, G Knochlein
Barry R Holstein
We analyze polarized Compton scattering which provides information on the spin-structure of the nucleon. For scattering processes with photon energies up to 100 MeV the spin-structure dependence can be encoded into four independent parameters—the so-called spin-polarizabilities γi, i=1,…,4, of the nucleon, which we calculate within the framework of the “small scale expansion” in SU(2) baryon chiral perturbation theory. Specific application is made to “forward” and “backward” spin-polarizabilities.
Resonances In Radiative Hyperon Decays, B Borasoy, Br Holstein
Resonances In Radiative Hyperon Decays, B Borasoy, Br Holstein
Barry R Holstein
The importance of resonances for the radiative hyperon decays is examined in the framework of chiral perturbation theory. Low lying baryon resonances are included into the effective theory and tree contributions to these decays are calculated. We find significant contributions to both the parity-conserving and parity-violating decay amplitudes and a large negative value for the asymmetry parameter in polarized Σ+→pγ is found, in agreement with the experimental result αγpΣ+=-0.76±0.08.
Effective Interactions Are Effective Interactions, Br Holstein
Effective Interactions Are Effective Interactions, Br Holstein
Barry R Holstein
In recent years it has been realized that effective interactions—those valid over a limited range of energy-momentum—are often preferable even when more complete theories are available. We shall here present examples of such methods over a range of physical applications—from classical and quantum mechanics, to quantum gravity.
A Brief Introduction To Chiral Perturbation Theory, Br Holstein
A Brief Introduction To Chiral Perturbation Theory, Br Holstein
Barry R Holstein
A brief introduction to the subject of chiral perturbation theory (Xpt) is presented, including a discussion of effective field theory and applications of Xpt in the arena of purely mesonic interactions as well as in the πN sector.
A Derivative Of The Gerasimov-Drell-Hearn Sum Rule, V Pascalutsa, Br Holstein, M Vanderhaeghen
A Derivative Of The Gerasimov-Drell-Hearn Sum Rule, V Pascalutsa, Br Holstein, M Vanderhaeghen
Barry R Holstein
We derive a sum rule which establishes a linear relation between a particle's anomalous magnetic moment and a quantity connected to the photoabsorption cross section. This quantity cannot be measured directly. However, it can be computed within a given theory. As an example, we demonstrate validity of the sum rule in QED at tree level—the renowned Schwinger's correction to the anomalous magnetic moment is readily reproduced. In the case of the strong interactions, we also consider the calculation of the nucleon magnetic moment within chiral theories.
Chiral Symmetry And The Parity-Violating Nn Pi Yukawa Coupling, Sl Zhu, Sj Puglia, Br Holstein, Mj Ramsey-Musolf
Chiral Symmetry And The Parity-Violating Nn Pi Yukawa Coupling, Sl Zhu, Sj Puglia, Br Holstein, Mj Ramsey-Musolf
Barry R Holstein
We construct the complete SU(2) parity-violating (PV) π,N,Δ interaction Lagrangian with one derivative, and calculate the chiral corrections to the PV Yukawa NNπ coupling constant hπ through O(1/Λχ3) in the leading order of heavy baryon expansion. We discuss the relationship between the renormalized hπ, the measured value of hπ, and the corresponding quantity calculated microscopically from the standard model four-quark PV interaction. We observe that the renormalized hπ depends strongly on a number of a priori unknown parameters in the PV effective Lagrangian.
Quantum Corrections To The Reissner-Nordstrom And Kerr-Newman Metrics, Jf Donoghue, Br Holstein, B Garbrecht, T Konstandin
Quantum Corrections To The Reissner-Nordstrom And Kerr-Newman Metrics, Jf Donoghue, Br Holstein, B Garbrecht, T Konstandin
Barry R Holstein
We use effective field theory techniques to examine the quantum corrections to the gravitational metrics of charged particles, with and without spin. In momentum space the masslessness of the photon implies the presence of non-analytic pieces Image , q2log(−q2), etc. in the form factors of the energy–momentum tensor. We show how the former reproduces the classical non-linear terms of the Reissner–Nordström and Kerr–Newman metrics while the latter can be interpreted as quantum corrections to these metrics, of order Gαplanck constant over two pi/mr3.
Allowed Eta-Decay Modes And Chiral Symmetry, Br Holstein
Allowed Eta-Decay Modes And Chiral Symmetry, Br Holstein
Barry R Holstein
Recently, the development of chiral perturbation theory has allowed the generation of rigorous low-energy theorems for various hadronic processes based only on the chiral invariance of the underlying QCD Lagrangian. Such techniques are highly developed and well-tested in the domain of pionic and kaonic reactions. In this note we point out that with the addition of a few additional and reasonable assumptions similar predictive power is available for processes involving the eta meson
Chiral Anomaly And Eta-Eta ' Mixing, Ep Venugopal, Br Holstein
Chiral Anomaly And Eta-Eta ' Mixing, Ep Venugopal, Br Holstein
Barry R Holstein
We determine the η-η′ mixing angle via a procedure relatively independent of theoretical assumptions by simultaneously fitting η,η′ reactions involving the anomaly η,η′→γγ, π+π-γ. We extract reasonably precise renormalized values of the octet and singlet pseudoscalar decay constants F8, F0, as well as the mixing angle θ.
Quantum Corrections To The Schwarzschild And Kerr Metrics, Nej Bjerrum-Bohr, Jf Donoghue, Br Holstein
Quantum Corrections To The Schwarzschild And Kerr Metrics, Nej Bjerrum-Bohr, Jf Donoghue, Br Holstein
Barry R Holstein
No abstract provided.
An Eft For The Weak Lambda N Interaction, A Parreno, C Bennhold, Br Holstein
An Eft For The Weak Lambda N Interaction, A Parreno, C Bennhold, Br Holstein
Barry R Holstein
The nonleptonic weak |ΔS|=1 ΛN interaction, responsible for the dominant, nonmesonic decay of all but the lightest hypernuclei, is studied in the framework of an effective field theory. The long-range physics is described through tree-level exchange of the SU(3) Goldstone bosons (π and K), while the short-range potential is parametrized in terms of lowest-order contact terms obtained from the most general non-derivative local four-fermion interaction. Fitting to available weak hypernuclear decay rates for 5ΛHe, 11ΛB and 12ΛC yields reasonable values for the low-energy constants.
Chiral Corrections To The Vector And Axial Couplings Of Quarks And Baryons, A Faessler, T Gutsche, Br Holstein, Ve Lyubovitskij
Chiral Corrections To The Vector And Axial Couplings Of Quarks And Baryons, A Faessler, T Gutsche, Br Holstein, Ve Lyubovitskij
Barry R Holstein
We calculate chiral corrections to the semileptonic vector and axial quark coupling constants using a manifestly Lorentz covariant chiral quark approach up to order O(p4) in the two- and three-flavor pictures. These couplings are then used in the evaluation of the corresponding couplings which govern the semileptonic transitions between octet baryon states. In the calculation of baryon matrix elements we use a general ansatz for the spatial form of the quark wave function, without referring to a specific realization of hadronization and confinement of quarks in baryons. Matching the physical amplitudes calculated within our approach to the model-independent predictions of …
Systematic 1/M Expansion For Spin 3/2 Particles In Baryon Chiral Perturbation Theory, Tr Hemmert, Br Holstein, J Kambor
Systematic 1/M Expansion For Spin 3/2 Particles In Baryon Chiral Perturbation Theory, Tr Hemmert, Br Holstein, J Kambor
Barry R Holstein
Starting from a relativistic formulation of the pion-nucleon-delta system, the most general structure of 1/M corrections for a heavy baryon chiral lagrangian including spin 3/2 resonances is given. The heavy components of relativistic nucleons and delta fields are integrated out and their contributions to the next-to-leaing order lagrangians are constructed explicitly. The effective theory obtained admits a systematic expansion in terms of soft momenta, the pion mass $m_\pi$ and the delta-nucleon mass difference $\Delta$. As an application, we consider neutral pion photoproduction at threshold to third order in this small scale expansion.