The mass of the Δ resonance in a finite volume: fourth-order calculation

We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective range because it can also handle a near-threshold zero in the D 0D * 0 S-wave. In terms of it we analyze the CDF data on inclusive pp scattering to J/ψπ + π − , and the Belle and BaBar data on B decays to K J/ψπ + π − and K DD * 0 around the D 0D * 0 threshold. It is shown that data can be reproduced with similar quality for X (3872) being a bound and/or a virtual state. We also find that X (3872) might be a higher-order virtual-state pole (double or triplet pole), in the limit in which the small D * 0 width vanishes. Once the latter is restored the corrections to the pole position are non-analytic and much bigger than the D * 0 width itself. The X (3872) compositeness coefficient in D 0D * 0 ranges from nearly 0 up to 1 in the different scenarios.

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“…[45,46]. Similar behavior has also been found as a function of quark masses for chiral extrapolations [47][48][49][50].…”

Section: Case 2: Virtual Statesupporting

confidence: 77%

“…Eq. (47). In this way, we have a quite intuitive decoupling limit g f → 0 in which two poles at ± √ 2μE R correspond to the bare state and an additional one at iγ V = −iβ stems from the direct coupling between the D 0D * 0 mesons.…”

Section: Case 2: Virtual Statementioning

confidence: 83%

Different pole structures in line shapes of the X(3872)

2017

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“…We refer for example to Refs. [64][65][66] for details. (26) and (30) respectively) providing an estimate of the uncertainty due to the chiral extrapolation.…”

Section: Chiral and Continuum Extrapolationmentioning

confidence: 99%

Baryon spectrum with Nf=2+1+1 twisted mass fermions

Alexandrou

Drach

Hadjiyiannakou

et al. 2015

Proceedings of the 32nd International Symposium on Lattice Field Theory — PoS(LATTICE2014)

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The masses of the low lying baryons are evaluated using a total of ten ensembles of dynamical twisted mass fermion gauge configurations. The simulations are performed using two degenerate flavors of light quarks, and a strange and a charm quark fixed to approximately their physical values. The light sea quarks correspond to pseudo scalar masses in the range of about 210 MeV to 430 MeV. We use the Iwasaki improved gluonic action at three values of the coupling constant corresponding to lattice spacing a = 0.094 fm, 0.082 fm and 0.065 fm determined from the nucleon mass. We check for both finite volume and cut-off effects on the baryon masses. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. We performed a chiral extrapolation of the forty baryon masses using SU(2) χPT. After taking the continuum limit and extrapolating to the physical pion mass our results are in good agreement with experiment. We provide predictions for the mass of the doubly charmed Ξ * cc , as well as of the doubly and triply charmed Ωs that have not yet been determined experimentally.

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“…In the volume-dependent spectrum of eigenvalues, "avoided level crossing" is usually taken as a signal of a resonance, but this criterion has been shown insufficient for resonances with larger widths [1][2][3][4][5]. For resonances with a single, two-body decay channel, one often uses Lüscher's approach to extract phase shifts from the discrete energy levels in the box [6,7].…”

Section: Introductionmentioning

confidence: 99%

Resonance Extraction from the Finite Volume

Döring¹,

Molina²

2016

Proceedings of the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015)

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The spectrum of excited hadrons becomes accessible in simulations of Quantum Chromodynamics on the lattice. Extensions of Lüscher's method allow to address multi-channel scattering problems using moving frames or modified boundary conditions to obtain more eigenvalues in finite volume. As these are at different energies, interpolations are needed to relate different eigenvalues and to help determine the amplitude. Expanding the T -or the K-matrix locally provides a controlled scheme by removing the known non-analyticities of thresholds. This can be stabilized by using Chiral Perturbation Theory. Different examples to determine resonance pole parameters and to disentangle resonances from thresholds are discussed, like the scalar meson f 0 (980) and the excited baryons N (1535)1/2 − and Λ(1405)1/2 − .

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The mass of the Δ resonance in a finite volume: fourth-order calculation

Cited by 23 publications

References 76 publications

Different pole structures in line shapes of the X(3872)

Different pole structures in line shapes of the X(3872)

Baryon spectrum with Nf=2+1+1 twisted mass fermions

Resonance Extraction from the Finite Volume

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