scholarly journals Effect of coupled channels of the multi-channel pion-pion scattering in two-pion transitions of the Υ mesons

2015 ◽  
Vol 39 ◽  
pp. 1560090
Author(s):  
Yurii S. Surovtsev ◽  
Petr Bydžovský ◽  
Thomas Gutsche ◽  
Robert Kamiński ◽  
Valery E. Lyubovitskij ◽  
...  
Keyword(s):  
Scattering Amplitudes ◽  
Mass Spectra ◽  
Final States ◽  
S Wave ◽  
Wave Processes ◽  
Crystal Ball ◽  
Combined Analysis ◽  
Pion Scattering ◽  
Scalar Mesons ◽  
Coupled Channels

The effect of isoscalar S-wave processes [Formula: see text] is considered in the analysis of data (from the ARGUS, CLEO, CUSB, Crystal Ball, Belle, BABAR collaborations) on the bottomonia decays — [Formula: see text] ([Formula: see text]). It is shown that the dipion mass spectra of these decays are explained by the unified mechanism related to the contribution of the multichannel [Formula: see text] scattering in the final states of these reactions. Since in the analysis the multichannel [Formula: see text]-scattering amplitudes did not change in comparison with the ones in our combined analysis of data on the multichannel [Formula: see text] scattering and on the charmonia decays — [Formula: see text] and [Formula: see text] (from the Crystal Ball, DM2, Mark II, Mark III, and BES II) — the results confirm all our earlier conclusions on the scalar mesons.

scholarly journals CHIRAL UNITARY APPROACH TO HADRON SPECTROSCOPY

2003 ◽  
Vol 18 (03) ◽  
pp. 387-396 ◽  
Author(s):  
E. Oset ◽  
T. Inoue ◽  
M. J. Vicente Vacas ◽  
A. Ramos ◽  
C. Bennhold
Keyword(s):  
Complex Plane ◽  
Final States ◽  
S Wave ◽  
Baryon Interaction ◽  
Hadron Spectroscopy ◽  
Dynamical Generation ◽  
Coupled Channels ◽  
Unitary Approach ◽  
Chiral Unitary Approach ◽  
Chiral Lagrangian

The s-wave meson-baryon interaction in the S = -1, S = 0 and S = -2 sectors is studied by means of coupled channels, using the lowest-order chiral Lagrangian and the N/D method or equivalently the Bethe-Salpeter equation to implement unitarity. This chiral approach leads to the dynamical generation of the Λ(1405), Λ(1670) and Σ(1620) states for S = -1, the N*(1535) for S = 0 and the Ξ(1620) for S = -2. We look for poles in the complex plane and extract the couplings of the resonances to the different final states. This allows identifying the Λ(1405) and the Λ(1670) resonances with [Formula: see text] and K Ξ quasibound states, respectively. Our results are found to be incompatible with the measured properties of the Ξ(1690) resonance, thus ruling this state out as the remaining member of this octet of dynamically generated resonances. We therefore assign 1/2- for the spin and parity of the Ξ(1620) resonance as the S = -2 member of the lowest-lying 1/2- octet.

S11 RESONANCES IN A COUPLED-CHANNEL DYNAMICAL MODEL

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1656-1661 ◽  
Author(s):  
SHIN NAN YANG ◽  
GUAN-YEU CHEN ◽  
SABIT S. KAMALOV ◽  
L. TIATOR ◽  
D. DRECHSEL
Keyword(s):  
Pion Photoproduction ◽  
Dynamical Model ◽  
S Wave ◽  
Pion Scattering ◽  
A Value ◽  
Multipole Analysis ◽  
Coupled Channels ◽  
Self Consistent ◽  
The Masses ◽  
Coupled Channel

A self-consistent analysis of pion scattering and pion photoproduction within a coupled channels dynamical model is presented. The results indicate the existence of a third and a fourth S11 resonance with the masses 1846±47 and 2113±70 MeV . In the case of pion photoproduction, we found that background contributions to the imaginary part of the S-wave multipole become large and negative in the region of the S11(1535) resonance. Due to this fact, much larger resonance contributions are required in order to explain the results of the recent multipole analysis. For the first S11(1535) resonance we obtain a value of 72±2×10-3 GeV -1/2 for the electromagnetic helicity amplitude A1/2.

scholarly journals Measuring Multijet Structure of Hadronic Energy Flow or, What is a jet?

1997 ◽  
Vol 12 (30) ◽  
pp. 5411-5529 ◽  
Author(s):  
Fyodor V. Tkachov
Keyword(s):  
Energy Flow ◽  
Mass Spectra ◽  
Analytical Control ◽  
Final States ◽  
C Algebra ◽  
Approximation Errors ◽  
Basic Class ◽  
Jet Algorithms ◽  
Hadronic Energy ◽  
Optimal Recombination

Ambiguities of jet algorithms are reinterpreted as instability wrt small variations of input. Optimal stability occurs for observables possessing property of calorimetric continuity (C-continuity) predetermined by kinematical structure of calorimetric detectors. The so-called C-correlators form a basic class of such observables and fit naturally into QFT framework, allowing systematic theoretical studies. A few rules generate other C-continuous observables. The resulting C-algebra correctly quantifies any feature of multijet structure such as the "number of jets" and mass spectra of "multijet substates." The new observables are physically equivalent to traditional ones but can be computed from final states bypassing jet algorithms which reemerge as a tool of approximate computation of C-observables from data with all ambiguities under analytical control and an optimal recombination criterion minimizing approximation errors.

scholarly journals Mass spectra of the low-lying nonet scalar mesons in the lattice QCD

2010 ◽  
Vol 3 ◽  
pp. 03010 ◽  
Author(s):  
T. Kunihiro ◽  
S. Muroya ◽  
A. Nakamura ◽  
C. Nonaka ◽  
M. Sekiguchi ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Mass Spectra ◽  
Scalar Mesons

scholarly journals Bootstrapping QCD Using Pion Scattering Amplitudes

2019 ◽  
Vol 122 (24) ◽  
Author(s):  
Andrea L. Guerrieri ◽  
João Penedones ◽  
Pedro Vieira
Keyword(s):  
Scattering Amplitudes ◽  
Pion Scattering

S-wave kaon-pion scattering

1966 ◽  
Vol 41 (1) ◽  
pp. 48-66
Author(s):  
M. Huq
Keyword(s):  
S Wave ◽  
Pion Scattering

RECENT RESULTS FROM THE REAL PHOTON EXPERIMENT AT MAMI

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1064-1075
Author(s):  
ANDREAS THOMAS
Keyword(s):  
High Intensity ◽  
Photon Beam ◽  
Real Photon ◽  
Final States ◽  
Detection Capability ◽  
Crystal Ball ◽  
The Real ◽  
The Future ◽  
Set Up

Experiments with real photons have been performed for many years at the Mainz accelerator MAMI with different detectors. The upgraded MAMI C accelerator recently delivered electrons with an energy of 1604MeV. The A2 collaboration performs experiments with energy tagged polarised real photons produced via 'Bremsstrahlung'. Linear and circular photon polarisation is possible. In the years 2005/2006 the Crystal Ball detector with its unique detection capability for multi photon final states was set up in Mainz. The Crystal Ball at MAMI setup offers an excellent possibility to study decays of the η and η′ mesons. Due to the high intensity photon beam the apparatus can be seen as an η-factory. Recent results from the Crystal Ball experiment at MAMI are presented. In the future we plan to use a longitudinal and transverse polarised frozen spin target to investigate the spin polarisibilities of the nucleons.

PHOTOPRODUCTION OF MESONS OFF LIGHT NUCLEI

2010 ◽  
Vol 19 (05n06) ◽  
pp. 915-926 ◽  
Author(s):  
B. KRUSCHE
Keyword(s):  
Excitation Function ◽  
Light Nuclei ◽  
Final States ◽  
Meson Photoproduction ◽  
Crystal Ball ◽  
Series Of Experiments ◽  
Nuclear Targets ◽  
Narrow Structure ◽  
Surprising Finding

In a series of experiments at the tagged photon facilities of the Bonn ELSA accelerator and the Mainz MAMI accelerator photoproduction of mesons from light nuclear targets (deuteron, 3 He ) has been studied. The experiments used the combined Crystal Barrel/TAPS setup in Bonn and the Crystal Ball/TAPS setup in Mainz. Meson photoproduction off the neutron has been investigated for the πo, πoπo, πoπ-, η, η′, and ηπo final states. A surprising finding was a narrow structure in the γn → nη excitation function, which is not seen in the proton case. Measurements of η- and πo-photoproduction off a liquid 3 He -target have provided further evidence for the formation of η-mesic 3 He .

I = 2S-wave pion scattering phase shift with two flavor full QCD

2005 ◽  
Vol 20 (15) ◽  
pp. 3476-3479
Author(s):  
◽  
T. Yamazaki
Keyword(s):  
Phase Shift ◽  
Center Of Mass ◽  
Laboratory System ◽  
Lattice Calculation ◽  
S Wave ◽  
Mass System ◽  
Pion Scattering ◽  
Scattering Phase ◽  
Volume Method ◽  
The Continuum

We present a lattice calculation of the scattering phase shift for the I = 2 S -wave pion-pion system in the continuum limit with two-flavor dynamical effect. Calculations are made at three lattice spacings, using the finite volume method proposed by Lüscher in the center of mass system, and its extension to the laboratory system by Rummukainen and Gottlieb.

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