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Hyperon Physics—A Personal Overview, Br Holstein
Hyperon Physics—A Personal Overview, Br Holstein
Physics Department Faculty Publication Series
A range of issues in the field of hyperon physics is presented, together with an assessment of where important challenges remain.
Overlapping Branes In M-Theory, Jerome Gauntlett, David Kastor, Jennie Traschen
Overlapping Branes In M-Theory, Jerome Gauntlett, David Kastor, Jennie Traschen
Physics Department Faculty Publication Series
We construct new supersymmetric solutions of D = 11 supergravity describing n orthogonally “overlapping” membranes and fivebranes for n = 2,…,8. Overlapping branes arise after separating intersecting branes in a direction transverse to all of the branes. The solutions, which generalize known intersecting brane solutions, preserve at least 2−n of the supersymmetry. Each pairwise overlap involves a membrane overlapping a membrane in a 0-brane, a fivebrane overlapping a fivebrane in a 3-brane or a membrane overlapping a fivebrane in a string. After reducing n overlapping membranes to obtain n overlapping D-2-branes in D = 10, T-duality generates new overlapping D-brane …
Electric Dipole Moment Of A Bps Monopole, David Kastor, Euy Na
Electric Dipole Moment Of A Bps Monopole, David Kastor, Euy Na
Physics Department Faculty Publication Series
Monopole “superpartner” solutions are constructed by acting with finite, broken supersymmetry transformations on a bosonic N=2 BPS monopole. The terms beyond first order in this construction represent the back reaction of the fermionic zero-mode state on the other fields. Because of the quantum nature of the fermionic zero modes, the superpartner solution is necessarily operator valued. We extract the electric dipole moment operator and show that it is proportional to the fermion zero-mode angular momentum operator with a gyroelectric ratio g=2. The magnetic quadrupole operator is shown to vanish identically on all states. We comment on the usefulness of the …
Infrared Behavior Of Graviton-Graviton Scattering, Jf Donoghue, T Torma
Infrared Behavior Of Graviton-Graviton Scattering, Jf Donoghue, T Torma
Physics Department Faculty Publication Series
The quantum effective theory of general relativity, independent of the eventual full theory at high energy, expresses graviton-graviton scattering at one loop order O E4 with only one parameter, Newton’s constant. Dunbar and Norridge have calculated the one loop amplitude using string based techniques. We complete the calculation by showing that the 1 d−4 divergence which remains in their result comes from the infrared sector and that the cross section is finite and model independent when the usual bremsstrahlung diagrams are included.
Resonances In Weak Nonleptonic Omega(-) Decay, B Borasoy, Br Holstein
Resonances In Weak Nonleptonic Omega(-) Decay, B Borasoy, Br Holstein
Physics Department Faculty Publication Series
We examine the importance of JP=1/2+,1/2- resonances for weak nonleptonic Ω- decays within the framework of chiral perturbation theory. The spin-1/2 resonances are included into an effective theory and the tree contributions to the Ω- decays are calculated. We find significant contributions to the decay amplitudes and satisfactory agreement with experiment. This confirms and extends previous results wherein such spin-1/2 resonances were included in nonleptonic and radiative-nonleptonic hyperon decays.
Role Of Resonances In Nonleptonic Hyperon Decays, B Borasoy, Br Holstein
Role Of Resonances In Nonleptonic Hyperon Decays, B Borasoy, Br Holstein
Physics Department Faculty Publication Series
We examine the importance of resonances for the nonleptonic hyperon decays in the framework of chiral perturbation theory. Lower lying resonances are included in the effective theory. Integrating out the heavy degrees of freedom in the resonance saturation scheme generates higher order counterterms in the effective Lagrangian, providing an estimate of the pertinent coupling constants. A fit to the eight independent decay amplitudes that are not related by isospin symmetry is performed and reasonable agreement for both s and p waves is achieved.
Non-Leptonic Hyperon Decays In Chiral Perturbation Theory, B Borasoy, Br Holstein
Non-Leptonic Hyperon Decays In Chiral Perturbation Theory, B Borasoy, Br Holstein
Physics Department Faculty Publication Series
The non-leptonic hyperon decays are analyzed up to one-loop order including all counterterms in the framework of heavy baryon chiral perturbation theory. We use the exchange of the spin- decuplet resonances as an indication of which low-energy constants contribute significantly to these investigated processes. We choose four independent decay amplitudes that are not related by isospin relations in order to perform a fit for the pertinent low-energy constants and find a satisfactory fit both for s- and p-waves. The chiral corrections to the lowest order forms for the s-waves are moderate whereas there are significant modifications of the p-wave amplitudes.
Fine Tunings And Quark Masses: Phenomenology Of Multiple Domain Theories, John Donoghue
Fine Tunings And Quark Masses: Phenomenology Of Multiple Domain Theories, John Donoghue
Physics Department Faculty Publication Series
This talk describes some of the consequences for particle phenomenology of the hypothesis that the physical parameters may vary in different domains of the universe.
The Leading Chiral Electromagnetic Correction To The Nonleptonic Delta I=3/2 Amplitude In Kaon Decays, V Cirigliano, Jf Donoghue, Eugene Golowich
The Leading Chiral Electromagnetic Correction To The Nonleptonic Delta I=3/2 Amplitude In Kaon Decays, V Cirigliano, Jf Donoghue, Eugene Golowich
Physics Department Faculty Publication Series
In kaon decay, electromagnetic radiative corrections can generate shifts in the apparent ΔI=3/2 amplitude of order αA0/A2not, vert, similar22α. In order to know the true ΔI=3/2 amplitude for comparison with lattice calculations and phenomenology, one needs to subtract off this electromagnetic effect. We provide a careful estimate of the leading electromagnetic shift in the chiral expansion of the amplitude, which shows that it is smaller than naive expectations, with a fractional shift of δA2(em)/A2=−0.016±0.01.
Su(3) Baryon Chiral Perturbation Theory And Long Distance Regularization, Jf Donoghue, Br Holstein, B Borasoy
Su(3) Baryon Chiral Perturbation Theory And Long Distance Regularization, Jf Donoghue, Br Holstein, B Borasoy
Physics Department Faculty Publication Series
The use of SU(3) chiral perturbation theory in the analysis of low energy meson-baryon interactions is discussed. It is emphasized that short distance effects, arising from propagation of Goldstone bosons over distances smaller than a typical hadronic size, are modeldependent and can lead to a lack of convergence in the SU(3) chiral expansion if they are included in loop diagrams. In this paper we demonstrate how to remove such effects in a chirally consistent fashion by use of a cutoff and demonstrate that such removal ameliorates problems which have arisen in previous calculations due to large loop effects.
Hadronic Atoms And Effective Interactions, Br Holstein
Hadronic Atoms And Effective Interactions, Br Holstein
Physics Department Faculty Publication Series
We examine the problem of hadronic atom energy shifts using the technique of effective interactions and demonstrate the equivalence with the conventional quantum mechanical approach.
Resonances In Radiative Hyperon Decays, B Borasoy, Br Holstein
Resonances In Radiative Hyperon Decays, B Borasoy, Br Holstein
Physics Department Faculty Publication Series
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.
Spin Of The M2-Brane And Spin-Spin Interactions Via Probe Techniques, Balasubramanian, David Kastor, Jennie Traschen, K.Z. Win
Spin Of The M2-Brane And Spin-Spin Interactions Via Probe Techniques, Balasubramanian, David Kastor, Jennie Traschen, K.Z. Win
Physics Department Faculty Publication Series
The 256-dimensional M2-brane multiplet contains solitons of many different intrinsic spins. Using the broken supersymmetry transformations of the M2-brane, we find supergravity solutions which explicitly display these spins. This amounts to quantizing the fermionic zero modes and computing the back reaction on the metric and gauge potential. These spacetime fields are therefore operator valued and acquire a conventional classical meaning only after taking expectations in given BPS states. Our spinning spacetimes are not of the standard Kerr form—there is a nonvanishing gravitino. Nevertheless, the solutions have angular momentum and magnetic dipole moments with a g factor of 2. We use …
Fully Localized Brane Intersections: The Plot Thickens, A Gomberoff, David Kastor, D Marolf, Jennie Traschen
Fully Localized Brane Intersections: The Plot Thickens, A Gomberoff, David Kastor, D Marolf, Jennie Traschen
Physics Department Faculty Publication Series
We study fully localized Bogomol’nyi-Prasad-Sommerfield brane solutions in classical supergravity using a perturbative approach to the coupled Born-Infeld or bulk supergravity system. We derive first order bulk supergravity fields for world-volume solitons corresponding to intersecting M2-branes and to a fundamental string ending on a D3-brane. One interesting feature is the appearance of certain off-diagonal metric components and the corresponding components of the gauge potentials. Making use of a supersymmetric ansatz for the exact fields, we formulate a perturbative expansion which applies to M2⊥M2(0), M5⊥M5(3) and Dp⊥Dp (p-2) intersections. We find that perturbation theory qualitatively distinguishes between certain cases: perturbation theory …
Dynamics Of The Dirac-Born-Infeld Spike Soliton, David Kastor, Jennie Traschen
Dynamics Of The Dirac-Born-Infeld Spike Soliton, David Kastor, Jennie Traschen
Physics Department Faculty Publication Series
We compare oscillations of a fundamental string ending on a D3-brane in two different settings: (1) a test string radially threading the horizon of an extremal black D3-brane and (2) the spike soliton of the DBI effective action for a D3-brane. Previous work has shown that overall transverse modes of the test string appear as l=0 modes of the transverse scalar fields of the DBI system. We identify DBI world-volume degrees of freedom that have dynamics matching those of the test-string relative transverse modes. We show that there is a map, resembling T duality, between relative and overall transverse modes …
Bps Force Balances Via Spin-Spin Interactions, David Kastor, Jennie Traschen
Bps Force Balances Via Spin-Spin Interactions, David Kastor, Jennie Traschen
Physics Department Faculty Publication Series
We study two systems of BPS solitons in which spin-spin interactions are important in establishing the force balances which allow static, multi-soliton solutions to exist. Solitons in the Israel-Wilson-Perjes (IWP) spacetimes each carry arbitrary, classical angular momenta. Solitons in the Aichelburg-Embacher `superpartner' spacetimes carry quantum mechanical spin, which originates in the zero modes of the gravitino field of N = 2 supergravity in an extreme Reissner-Nordström background. In each case we find a cancellation between gravitational spin-spin and magnetic dipole-dipole forces, in addition to the usual one between Newtonian gravitational attraction and Coulombic electrostatic repulsion. In both cases, we analyse …