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Full-Text Articles in Physical Sciences and Mathematics
The Electromagnetic Mass Differences Of Pions And Kaons, John F. Donoghue, Antonio F. Pérez
The Electromagnetic Mass Differences Of Pions And Kaons, John F. Donoghue, Antonio F. Pérez
Physics Department Faculty Publication Series
We use the Cottingham method to calculate the pion and kaon electromagnetic mass differences with as few model dependent inputs as possible. The constraints of chiral symmetry at low energy, QCD at high energy and experimental data in between are used in the dispersion relation. We find excellent agreement with experiment for the pion mass difference. The kaon mass difference exhibits a strong violation of the lowest order prediction of Dashen’s theorem, in qualitative agreement with several other recent calculations.
The Quantum Theory Of General Relativity At Low Energies, John Donoghue
The Quantum Theory Of General Relativity At Low Energies, John Donoghue
Physics Department Faculty Publication Series
In quantum field theory there is now a well developed technique, effective field theory, which allows one to obtain low energy quantum predictions in “non-renormalizable” theories, using only the degrees of freedom and interactions appropriate for those energies. Whether or not general relativity is truly fundamental, at low energies it is automatically described as a quantum effective field theory and this allows a consistent framework for quantum gravity at ordinary energies. I briefly describe the nature and limits of the technique.
Dynamics Of A Suspension Of Spheres And Rigid Polymers: Effect Of Geometrical Mismatch, Radu P. Mondescu, M. Muthukumar
Dynamics Of A Suspension Of Spheres And Rigid Polymers: Effect Of Geometrical Mismatch, Radu P. Mondescu, M. Muthukumar
Physics Department Faculty Publication Series
No abstract provided.
Inverse-Moment Chiral Sum Rules, E Golowich, J Kambor
Inverse-Moment Chiral Sum Rules, E Golowich, J Kambor
Physics Department Faculty Publication Series
A general class of inverse-moment sum rules was previously derived by the authors in a chiral perturbation theory (ChPT) study at two-loop order of the isospin and hypercharge vector-current propagators. Here, we address the evaluation of the inverse-moment sum rules in terms of existing data and theoretical constraints. Two kinds of sum rules are seen to occur: those which contain as-yet undetermined O(q6) counterterms and those free of such quantities. We use the former to obtain phenomenological evaluations of two O(q6) counterterms. Light is shed on the important but difficult issue regarding contributions of higher orders in the ChPT expansion.
Low Energy Tests Of Chiral Symmetry1, Br Holstein
Low Energy Tests Of Chiral Symmetry1, Br Holstein
Physics Department Faculty Publication Series
The present status of low energy test of chiral invariance via chiral perturbation theory is reviewed, both in the meson and baryon sectors, and future prospects are discussed.
Chiral Anomaly And Gamma 3 Pi, Br Holstein
Chiral Anomaly And Gamma 3 Pi, Br Holstein
Physics Department Faculty Publication Series
Measurement of the γ3π process has revealed a possible conflict with what should be a solid prediction generated by the chiral anomaly. We show that inclusion of appropriate energy-momentum dependence in the matrix element reduces the discrepancy.
Future Lq Oscillation Experiments And Present Data, Jj Gomez-Cadenas, M.C Gonazles-Garcia
Future Lq Oscillation Experiments And Present Data, Jj Gomez-Cadenas, M.C Gonazles-Garcia
Physics Department Faculty Publication Series
Our goal in this paper is to examine the discovery potential of laboratory experiments searching for the oscillation lk(le)Plq, in the light of recent data on solar and atmospheric neutrino experiments, which we analyse together with the most restrictive results from laboratory experiments on neutrino oscillations. In order to explain simultaneously all present results we use a fourneutrino framework, with an additional sterile neutrino. Our predictions are rather pessimistic for the upcoming experiments NOMAD and CHORUS, which, we Þnd, are able to explore only a small area of the oscillation parameter space. On the other hand, the discovery potential of …
Systematics Of Soft Final-State Interactions In B Decays, Jf Donoghue, Eugene Golowich, Aa Petrov, Jm Soares
Systematics Of Soft Final-State Interactions In B Decays, Jf Donoghue, Eugene Golowich, Aa Petrov, Jm Soares
Physics Department Faculty Publication Series
By using very general and well established features of soft strong interactions we show, contrary to conventional expectations, that (i) soft final-state interactions (FSI) do not disappear for large mB, (ii) inelastic rescattering is expected to be the main source of soft FSI phases, and (iii) FSI which interchange charge and/or flavors are suppressed by a power of mB, but are quite likely to be significant at mB≃5GeV. We briefly discuss the influence of these interactions on tests of CP violation and on theoretical calculations of weak decays.
Theory Of Weak Hypernuclear Decay, Jf Dubach, Gb Feldman, Br Holstein, L Delatorre
Theory Of Weak Hypernuclear Decay, Jf Dubach, Gb Feldman, Br Holstein, L Delatorre
Physics Department Faculty Publication Series
The weak nomesonic decay ofΛ-hypernuclei is studied in the context of a one-meson-exchange model. Predictions are made for the decay rate, thep/nstimulation ratio and the asymmetry in polarized hypernuclear decay.
Final State Interactions In The Decay Of Heavy Quarks, John Donoghue
Final State Interactions In The Decay Of Heavy Quarks, John Donoghue
Physics Department Faculty Publication Series
I discuss some recent results on the systematic behavior of final state rescattering which makes use of the limit of a heavy B meson. The results suggest that soft final state interactions do not disappear in the large $m_B$ limit. Soft and hard final state phases can both contribute to CP violating asymmetries in B decay. The way that the soft phases occur is interesting theoretically and suggests the violation of local quark-hadron duality.
Virtual Compton Scattering And Generalized Polarizabilities Of The Nucleon In Heavy Baryon Chiral Perturbation Theory, Thomas Hemmert, Br Holstein, Et. Al
Virtual Compton Scattering And Generalized Polarizabilities Of The Nucleon In Heavy Baryon Chiral Perturbation Theory, Thomas Hemmert, Br Holstein, Et. Al
Physics Department Faculty Publication Series
The spin-independent part of the virtual Compton scattering (VCS) amplitude from the nucleon is calculated within the framework of heavy baryon chiral perturbation theory (HBChPT). The calculation is performed to third order in external momenta according to chiral power counting. The relation of the tree-level amplitudes to what is expected from the low-energy theorem is discussed. We relate the one-loop results to the structure coefficients of a low-energy expansion for the model-dependent part of the VCS amplitude recently defined by Fearing and Scherer. Finally we discuss the connection of our results with the generalized polarizabilities of the nucleon defined by …
Improving The Convergence Of Su(3) Baryon Chiral Perturbation Theory, John Donoghue, Barry Holstein
Improving The Convergence Of Su(3) Baryon Chiral Perturbation Theory, John Donoghue, Barry Holstein
Physics Department Faculty Publication Series
Baryon chiral perturbation theory as conventionally applied using dimensional regularization has a well-known problem with the convergence of the SU(3) chiral expansion. One can reformulate the theory equally rigorously using a momentum-space cutoff and we show that the convergence is thereby greatly improved for reasonable values of the cutoff. In effect, this is accomplished because the cutoff formalism removes the spurious physics of propagation at distance scales much smaller than the baryon size.
Exact Quantum Monte Carlo Process For The Statistics Of Discrete Systems, Nikolai Prokof'ev, Boris Svistunov, I Tupitsyn
Exact Quantum Monte Carlo Process For The Statistics Of Discrete Systems, Nikolai Prokof'ev, Boris Svistunov, I Tupitsyn
Physics Department Faculty Publication Series
We propose an exact Monte Carlo approach for the statistics of discrete quantum systems that does not employ the standard partition of the imaginary time into a mesh and does not contain small parameters. The method operates with discrete objects — kinks, describing virtual transitions at different moments in time. The global statistics of the kinks is reproduced by exact local procedures, the main one being based on the known solution for an asymmetric two-level system.
Nonperturbative Methods In Kaon Physics (Aside From The Lattice), John Donoghue
Nonperturbative Methods In Kaon Physics (Aside From The Lattice), John Donoghue
Physics Department Faculty Publication Series
I discuss the progress in the use of analytic techniques for low energy QCD, in particular as applied to kaon physics. These methods are becoming increasingly powerful and we have gained a good deal of control over the difficult hadronic interactions. There are continuing developments, and I speculate on the ways that these techniques may become yet more sophisticated in the future.
Is B→Xsγ Equal To B→Sγ? Spectator Contributions To Rare Inclusive B Decays, John Donoghue, Alexey A. Petrov
Is B→Xsγ Equal To B→Sγ? Spectator Contributions To Rare Inclusive B Decays, John Donoghue, Alexey A. Petrov
Physics Department Faculty Publication Series
In B→Xsγ, there are perturbative QCD corrections at order αs not only to the single quark line process b→sγ but also coming from a set of diagrams where the weak interaction vertex involves a gluon which interacts with the spectator quark in the B hadron. We discuss the impact of the full set of these diagrams. These can influence the decay rate and also the line shape of the photon spectrum as they favor a softer photon energy than does the pure spectator decay b→sγ. A subset of these diagrams generates differences in the decay rates for charged and neutral …