Resonance production and 
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Adolph, C.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Аносов, В.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boër, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Chang, W. C.; Chiosso, M.; Choi, I. J.; Chung, S. U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; Torre, S.; Dasgupta, S.; Денисов, О.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Fischer, H.; Franco, C.; Hohenesche, N. du Fresne von; Friedrich, Jan; Frolov, V. V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Perdekamp, M. Grosse; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, Florian; Hahne, D.; Harrach, D. von; Hashimoto, Ryo; Heinsius, F. H.; Herrmann, F.; Hinterberger, F.; Horikawa, N.; d’Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Иванов, А.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V.N.; Kondo, K.; Königsmann, K.; Konorov, I.; Константинов, В.Ф.; Kotzinian, A.M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Longo, Riccardo; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Marchand, Claude; Mariański, B.; Martin, A.; Marzec, J.; Matoušek, Jan; Matsuda, Hiroki; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Miyachi, Y.; Montuenga, P.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nikolaenko, V.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Оlshevsky, А.G.; Орлов, И.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D.V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rossiyskaya, N.S.; Ryabchikov, D. I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schiavon, P.; Schlüter, T.; Schmidt, K.; Schmieden, H.; Schönning, K.; Schopferer, S.; Selyunin, A.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunečka, M.; Sozzi, F.; Srnka, A.; Stolarski, M.; Šulc, M.; Suzuki, Hiromasa; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.F.C.A.; Virius, M.; Weisrock, T.; Wilfert, M.; Wolbeek, J. ter; Заремба, К.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

doi:10.1103/physrevd.95.032004

Cited by 55 publications

(101 citation statements)

References 55 publications

(121 reference statements)

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“…The importance of different decay channels can be estimated by the relative branching fractions of the a 1 (1260) decay. The latest measurements were carried out by the CLEO experiment from τ decay [38,39] and by the COMPASS experiment in diffractive production [40]. The extraction of branching ratios is model-dependent and is influenced by the production mechanism; however, we get a rough estimate of their relative importance.…”

Section: The Reaction Modelmentioning

confidence: 99%

Pole position of the a1(1260) from τ -decay

et al. 2018

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We perform an analysis of the three-pion system with quantum numbers J P C = 1 ++ produced in the weak decay of τ leptons. The interaction is known to be dominated by the axial meson a1(1260). We build a model based on approximate three-body unitary and fix the free parameters by fitting it to the ALEPH data on τ − → π − π + π − ντ decay. We then perform the analytic continuation of the amplitude to the complex energy plane. The singularity structures related to the ππ subchannel resonances are carefully addressed. Finally, we extract the a1(1260) pole position m (a 1 (1260)) p − iΓ (a 1 (1260)) p /2 with m (a 1 (1260)) p = (1209 ± 4 +12 −9 ) MeV, Γ (a 1 (1260)) p = (576 ± 11 +89 −20 ) MeV.

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Section: The Reaction Modelmentioning

confidence: 99%

Pole position of the a1(1260) from τ -decay

et al. 2018

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“…We employ the method of partial-wave analysis in a two-step approach. In the first step, called partial-wave decomposition, data are decomposed into contributions from various partial waves [1]. To this end, we construct a model for the intensity distribution I (τ) of the π − π − π + final state in terms of the five-dimensional phase-space variables of the 3π system that are represented by τ.…”

Section: Analysis Methods 21 Partial-wave Decompositionmentioning

confidence: 99%

“…Our flagship channel is the decay into three charged pions: π − + p → π − π − π + + p recoil . COMPASS has acquired the so far world's largest dataset of about 50 M exclusive events for this channel, which allows us to apply novel analysis methods [1].…”

Section: Light-meson Spectroscopy At Compassmentioning

confidence: 99%

Light-Quark Resonances at COMPASS

Wallner¹

2019

Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)

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The main goal of the spectroscopy program at COMPASS is to explore the light-meson spectrum in the mass range below about 2 GeV/c 2 using diffractive dissociation reactions. Our flagship channel is the production of three charged pions in the reaction: π − + p → π − π − π + + p recoil , for which COMPASS has acquired the so far world's largest dataset of roughly 50 M exclusive events using an 190 GeV/c π − beam. Based on this dataset, we performed an extensive partial-wave analysis. In order to extract the parameters of the π J and a J resonances that appear in the π − π − π + system, we performed the so far most comprehensive resonance-model fit, using Breit-Wigner parametrizations. This method in combination with the high statistical precision of our data allows us to study ground and excited states. We study the a 4 (2040) resonance in the ρ(770)πG and f 2 (1270)πF decays. In addition to the ground state resonance a 1 (1260), we have found evidence for the a 1 (1640), which is the first excitations of the a 1 (1260), in our data. We also study the spectrum of π 2 states by simultaneously describing four J PC = 2 −+ waves using three π 2 resonances, the π 2 (1670), the π 2 (1880), and the π 2 (2005). Using a novel analysis approach, where the resonance-model fit is performed simultaneously in narrow bins of the squared four-momentum transfer t between the beam pion and the target proton, allows us to study the t dependence of resonant and non-resonant components included in our model. We observe that for most of the partial waves, the non-resonant components show a steeper t spectrum compared to the resonances and that the t spectrum of most of the resonances becomes shallower with increasing resonance mass. We also study the t dependence of the relative phases between resonance components. The pattern we observe is consistent with a common production mechanism of these states.

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“…To describe the reaction one indeed needs to have a model for the dynamics of the full system, which is not part of the approach considered here. An alternative way to proceed is a mass-independent analysis, widely used by the COMPASS and VES experiments [20]. The idea here is to perform the Khuri-Treiman analysis independently in bins of w without any assumptions on c (i) (w) (essentially constants at every bin).…”

Section: Systematic Approach To Rescatteringmentioning

confidence: 99%

Beyond the isobar model: Rescattering in the system of three particles.

Mikhasenko¹,

Ketzer²

2016

Proceedings of 54th International Winter Meeting on Nuclear Physics — PoS(BORMIO2016)

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The isobar model is an essential part of partial wave analyses (PWA) of multi-body hadronic final states. In the isobar model, all final states are described as sequential two-body decays of intermediate resonances. It turned out to work surprisingly well in the past, despite the fact that it neglects rescattering, i.e. interactions in the final state. With the advent of data samples of extremely high statistical significance from ongoing experiments, effects due to final state interactions may become important in order to understand the data. We discuss the example of the recently observed a 1 (1420) in the 3π final state using PWA techniques. In our model, we interpret the signal as a result of rescattering in the final state. In the presence of coupled πππ / KKπ channels, final-state interaction causes a redistribution of events between the πππ and KKπ systems. We compare our interpretation to the genuine resonance hypothesis and discuss a sophisticated approach to clarify the nature of the signal.

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Resonance production and ππ S -wave in π−+

Cited by 55 publications

References 55 publications

Pole position of the a1(1260) from τ -decay

Pole position of the a1(1260) from τ -decay

Light-Quark Resonances at COMPASS

Beyond the isobar model: Rescattering in the system of three particles.

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