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New finite energy sum rules (FESR's) for extracting ms from hadronic tau decay data are constructed which (1) significantly reduce potential theoretical uncertainties present in existing sum rule analyses and (2) remove problems... more
New finite energy sum rules (FESR's) for extracting ms from hadronic tau decay data are constructed which (1) significantly reduce potential theoretical uncertainties present in existing sum rule analyses and (2) remove problems associated with both the poor convergence of the OPE representation of the longitudinal part of the us vector and axial vector correlators and the large statistical errors in the us spectral data above the K* region. .
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Starting from a relativistic formulation of the pion-nucleon-delta system, the most generral structure of 1/M correctionns for a heavy baryon chiral lagrangian including spin 3/2 resonances is given. The heavy components of relativistic... more
Starting from a relativistic formulation of the pion-nucleon-delta system, the most generral structure of 1/M correctionns for a heavy baryon chiral lagrangian including spin 3/2 resonances is given. The heavy components of relativistic nucleon and delta fields are integrated out and their contributions to the next-to-leading order lagrangains 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.
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Reordering of the chiral perturbation series, proposed recently by Becher and Leutwyler in the framework of SU(2) baryonic ChPT, is applied to the SU(3) case. This results in improved convergence of the chiral expansion of static... more
Reordering of the chiral perturbation series, proposed recently by Becher and Leutwyler in the framework of SU(2) baryonic ChPT, is applied to the SU(3) case. This results in improved convergence of the chiral expansion of static properties of the lowest lying baryon octet, which in most cases is quite impressive. Finite renormalization of coupling constants and the role it plays in the interpretation of effective field theories is discussed. Some future tests of the viability of the scheme are proposed too.
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We demonstrate how heavy mass methods, previously applied to chiral perturbation theory calculations involving the interactions of nucleons and pions, can be generalized to include interactions with the $\Delta$(1232).
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Reordering of the chiral perturbation series, proposed recently by Becher and Leutwyler in the framework of SU(2) baryonic ChPT, is applied to the SU(3) case. This results in improved convergence of the chiral expansion of static... more
Reordering of the chiral perturbation series, proposed recently by Becher and Leutwyler in the framework of SU(2) baryonic ChPT, is applied to the SU(3) case. This results in improved convergence of the chiral expansion of static properties of the lowest lying baryon octet, which in most cases is quite impressive. Finite renormalization of coupling constants and the role it plays in the interpretation of effective field theories is discussed. Some future tests of the viability of the scheme are proposed too. * Work supported in part by VEGA grant No.1/4301/97, by Schweizerischer Nationalfonds and by the EEC-TMR Program, Contract No. CT98-0169. 1. The phenomenology of baryons at low energies is reasonably well described by the chiral symmetry SU(3)L× SU(3)R, broken spontaneously to SU(3)V , as well as it’s explicit breaking by non-vanishing quark masses. The most celebrated successes of chiral SU(3) symmetry go back to the sixties. These are now understood as tree level results of ch...
A number of recent determinations of m_s using hadronic τ decay data involve inclusive analyses based on the so-called (k,0) spectral weights. We show here that the OPE representations of the longitudinal contributions appearing in these... more
A number of recent determinations of m_s using hadronic τ decay data involve inclusive analyses based on the so-called (k,0) spectral weights. We show here that the OPE representations of the longitudinal contributions appearing in these analyses, which are already known to be poorly converging, have in addition an unphysical k dependence which produces a significant unphysical decrease in m_s with increasing k. We also show how, using additional sum rule constraints, the decay constants of the excited resonances in the strange scalar and pseudoscalar channels may be determined, allowing one to evaluate the longitudinal spectral contributions to the (k,0) sum rules. Taking into account the very-accurately known π and K pole contributions, we find that longitudinal contributions can be determined with an accuracy at the few involving the sum of longitudinal and transverse contributions, for which the OPE representation is much better converged.
Abstract. Heavy baryon chiral perturbation theory including spin 3/2 delta resonances as effective degrees of freedom is reviewed. The theory admits a systematic expansion in the small scale ǫ, where ǫ collectively denotes soft momenta,... more
Abstract. Heavy baryon chiral perturbation theory including spin 3/2 delta resonances as effective degrees of freedom is reviewed. The theory admits a systematic expansion in the small scale ǫ, where ǫ collectively denotes soft momenta, the pion mass or the delta-nucleon mass difference. Renormalization is discussed in some detail on the example of the scalar sector of one-nucleon processes, and a reformulation of the principle of resonance saturation for counterterms of the HBChPT lagrangian is sketched. As an application, the polarizabilities of the nucleon are discussed at order ǫ 3.
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We study the utility of chains defined on causal sets in estimating continuum properties like the curvature, the proper time and the spacetime dimension through a numerical analysis. In particular, we show that in dS_2 and FLRW_3... more
We study the utility of chains defined on causal sets in estimating continuum properties like the curvature, the proper time and the spacetime dimension through a numerical analysis. In particular, we show that in dS_2 and FLRW_3 spacetimes the formalism of arXiv:1212.0631 with slight modifications gives the right continuum properties. We also discuss a possible test of manifoldlikeness using this formalism by considering two models of non-manifoldlike causal sets. This is a part of a broader idea of the geometrical reconstruction of continuum properties given a discrete sub structure, in this case the causal set.
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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... more
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 nucleon and delta fields are integrated out and their contributions to the next-to-leading order lagrangians are constructed explicitly. The effective theory obtained admits a systematic expansion in terms of soft momenta, the pion mass Mπ and the delta-nucleon mass difference ∆. As an application, we consider neutral pion photoproduction at threshold to third order in this small scale expansion. 1 Chiral symmetry restricts the interactions of pions, nucleons and photons severely [1]. The consequences are most conveniently summarized by the
Standard SU(2) Heavy Baryon Chiral Perturbation Theory is extended in order to include the case of small or even vanishing quark condensate. The effective lagrangian is given to O(p 2) in its most general form and to O(p 3) in the scalar... more
Standard SU(2) Heavy Baryon Chiral Perturbation Theory is extended in order to include the case of small or even vanishing quark condensate. The effective lagrangian is given to O(p 2) in its most general form and to O(p 3) in the scalar sector. A method is developed to efficiently construct the relativistic baryonic effective lagrangian for chiral SU(2) to all orders in the chiral expansion. As a first application, mass- and wavefunction renormalization as well as the scalar form factor of the nucleon is calculated to O(p 3). The result is compared to a dispersive analysis of the nucleon scalar form factor adopted to the case of a small quark condensate. In this latter analysis, the shift of the scalar form factor between the Cheng-Dashen point and zero momentum transfer is found to be enhanced over the result assuming strong quark condensation by up to a factor of two, with substantial deviations starting to be visible for r = ms / ˆm � 12.
We calculate the correlator between two external vector-currents having the quantum-numbers of a charged kaon. We give the renormalized expression to two loops in standard chiral perturbation theory in the isospin limit, which, as a... more
We calculate the correlator between two external vector-currents having the quantum-numbers of a charged kaon. We give the renormalized expression to two loops in standard chiral perturbation theory in the isospin limit, which, as a physical result, is finite and scale-independent. Applications include a low energy theorem, valid at two loop order, of a flavor breaking combination of vector current correlators as well as a determination of the phenomenologically relevant finite O(p6)-counterterm combination QV by means of inverse moment finite energy sum rules. This determination is less sensitive to isospin-breaking effects than previous attempts. Preprint numbers: UW-PT/99-14, ZU-TH/15-98, hep-ph/9907539 PACS numbers: 12.39.Fe, 11.55.Hx ∗stephan.duerr@psi.ch †kambor@physik.unizh.ch
We perform a calculation of the isospin and hypercharge axialvector current propagators ( ∆ µν
We revisit the isovector pseudoscalar sum rule determination of mu + md, using families of finite energy sum rules known to be very accurately satisfied in the isovector vector channel. The sum rule constraints are sufficiently strong to... more
We revisit the isovector pseudoscalar sum rule determination of mu + md, using families of finite energy sum rules known to be very accurately satisfied in the isovector vector channel. The sum rule constraints are sufficiently strong to allow a determination of both mu + md and the excited resonance decay constants. The corresponding Borel transformed sum rules are also very well satisfied, providing a non-trivial consistency check on the treatment of direct instanton contributions. We obtain [mu +md](2 GeV) = 7.8±1.1 MeV (in the MS scheme), only marginally compatible with the most recent sum rule determinations, but in good agreement with recent unquenched lattice ∗e-mail: kmaltman@physics.adelaide.edu.au; permanent address: Department of Mathematics and Statistics, York University, 4700 Keele St., Toronto, Ontario, CANADA M3J 1P3 †e-mail: kambor@physik.unizh.ch
We present our calculation of the correlator T {VsV † s } between two external vector-currents with the quantum-numbers of a charged kaon. The renormalized expression to O(p 6) in SU (3) × SU (3) standard chiral perturbation theory is... more
We present our calculation of the correlator T {VsV † s } between two external vector-currents with the quantum-numbers of a charged kaon. The renormalized expression to O(p 6) in SU (3) × SU (3) standard chiral perturbation theory is finite and scale-independent. The result is used to determine, via an IMFESR, the phenomenologically relevant finite O(p 6)-counterterm combination QV in a way which is not sensitive to isospin breaking.
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... perturbation theory J. Kambor ab, J. Missimer and D. Wyler ad ' Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 ... acknowledge discussions with or comments on the manuscript by J. Donoghue,... more
... perturbation theory J. Kambor ab, J. Missimer and D. Wyler ad ' Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 ... acknowledge discussions with or comments on the manuscript by J. Donoghue, G. Ecker, J. Gasser, JM Gerard, J. Goity, B. Holstein ...
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New finite energy sum rules (FESR's) for extracting ms from hadronic � decay data are constructed which (1) significantly reduce potential theoretical uncer- tainties present in existing sum rule analyses and (2) remove problems... more
New finite energy sum rules (FESR's) for extracting ms from hadronic � decay data are constructed which (1) significantly reduce potential theoretical uncer- tainties present in existing sum rule analyses and (2) remove problems associated with both the poor convergence of the OPE representation of the longitudinal part of the us vector and axial vector correlators and the large statistical errors in the us spectral data above the Kregion. with y = s/m2�, Vij the f = ij CKM matrix element, SEW an electroweak correction, and � (J) V/A;ij(s) the spectral function of � (J) V/A;ij(s), � (J) V/A;ij(s) (J = 0,1) being the spin J part of the f = ij vector (V) or axial vector (A) correlator. The second line follows from the first as a consequence of the general FESR relation, valid for anywithout kinematic singularities, and any w(s) analytic in the region of the contour, R s 0 sth dsw(s)�(s) = 1 2�i H |s|=s0 dsw(s)�(s). Experimental data thus allows access to the ud-us spectral differ...
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Agreement between the experimental value Γ(KS-->γγ) and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand, the one-loop prediction for the closely... more
Agreement between the experimental value Γ(KS-->γγ) and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand, the one-loop prediction for the closely related process KL-->π0γγ has been found to be a factor 3 below the experimental value. Using the inputs of unitarity and dispersion relations, we demonstrate the importance of higher order loop effects to both of these processes.
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Agreement between the experimental value $\Gamma (K_S\rightarrow \gamma\gamma)$ and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand the one-loop... more
Agreement between the experimental value $\Gamma (K_S\rightarrow \gamma\gamma)$ and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand the one-loop prediction for the closely related process $K_L\rightarrow \pi^0\gamma\gamma$ has been found to be a factor three below the experimental value. Using the inputs of unitarity and dispersion relations, we demonstrate the importance of higher order loop effects to both of these processes.
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The chiral lagrangian for nonleptonic weak interactions of mesons is computed up to one loop order, including all counterterms of order p4 in the low energy expansion. Applications to CP-conserving K --> 2pi, 3pi decays reveal that... more
The chiral lagrangian for nonleptonic weak interactions of mesons is computed up to one loop order, including all counterterms of order p4 in the low energy expansion. Applications to CP-conserving K --> 2pi, 3pi decays reveal that corrections to the lowest order results are large, e.g. 30-100 % depending on the amplitude considered. This may have consequence on calculational techniques which use chiral lagrangians in lowest order. Neglecting terms of order M2pi/M2k, we derive three parameter free sum rules which correct the usual soft pion theorems.