Triangle Singularity as the Origin of the 
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Alexeev, G. D.; Alexeev, M.; Amoroso, A.; Andrieux, V.; Аносов, В.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Antequera, J. Berenguer; Bernhard, J.; Bodlak, M.; Bradamante, F.; Bressan, A.; Burtsev, V.E.; Chang, W. C.; Chatterjee, C.; Chiosso, M.; Chumakov, A.G.; Chung, S. U.; Cicuttin, A.; Correia, P.M.M.; Crespo, M.L.; D’Ago, D.; Torre, S.; Dasgupta, S.; Denisenko, I.; Денисов, О.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R. R.; Efremov, A.; Eversheim, P.D.; Faccioli, P.; Faessler, M.; Finger, M.; Fischer, H.; Franco, C.; Friedrich, Jan; Frolov, V. V.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Perdekamp, M. Grosse; Grube, B.; Guskov, A.; Harrach, D. von; Heitz, R.; Herrmann, F.; Horikawa, N.; d’Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Иванов, А.; Iwata, T.; Jandek, M.; Jarý, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kašpar, F.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Horikawa, K. Kondo; Konorov, I.; Константинов, В.Ф.; Kotzinian, A.M.; Kouznetsov, O.; Koval, A.; Král, Zdeněk; Krinner, F.; Kulinich, Y. P.; Kunne, F.; Kurek, K.; Kurjata, R.; Kveton, A.; Lavičková, K.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Lin, P.-J.; Longo, Riccardo; Lyubovitskij, Valery E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Maltsev, A.; Mamon, S.A.; Mariański, B.; Martin, A.; Marzec, J.; Matoušek, Jan; Matsuda, T.; Mattson, G.; Meshcheryakov, G.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Naim, C.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Оlshevsky, А.G.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pekeler, H.; Peng, J.-C.; Pešek, M.; Peshekhonov, D.V.; Pešková, M.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Reicherz, G.; Riedl, C.; Rudnicki, T.; Ryabchikov, D. I.; Рыбников, А.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schmieden, H.; Selyunin, A.; Sinha, L.; Slunečka, M.; Smolík, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Šulc, M.; Suzuki, Hiromasa; Sznajder, P.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Townsend, A.; Tskhay, V.; Uhl, S.; Vasilishin, B. I.; Vauth, A.; Veit, B.M.; Veloso, J.F.C.A.; Ventura, Bartolomeo Della; Vidon, A.; Virius, M.; Wagner, M. N.; Wallner, S.; Заремба, К.; Závada, P.; Zavertyaev, M.; Zemko, M.; Zemlyanichkina, E.; Zhao, Y. X.; Ziembicki, M.

doi:10.1103/physrevlett.127.082501

Cited by 20 publications

(9 citation statements)

References 47 publications

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“…The mass of the a 1 (1420) is slightly above the K * K threshold. In [474,475] it was suggested that the signal could be a consequence of final-state interactions in the a 1 (1260) decaying to 3π and K Kπ, in particular, a triangle singularity, finding an excellent agreement with the data [388].…”

Section: Studies Of a 1 (1260) Resonance In The 3π Systemmentioning

confidence: 67%

“…It is well-established experimentally that many resonances couple strongly to three-or more particle channels [386]. Some of the most intriguing particles, which do not fit the naïve quark model predictions, like the Roper resonance N * (1440), the a 1 (1420) seen by COMPASS [387,388], and the exotic π 1 (1600) [191,389], X(3872), and other XYZ states have significant three-particle decay modes [1]. Three-body couplings might lead to non-standard line shapes and complicated structure of the amplitudes [268,390], allowing for ambiguities in interpretations of the hadron of interest [3,7,391,392].…”

Section: → 3 Scatteringmentioning

confidence: 99%

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Novel approaches in Hadron Spectroscopy

Albaladejo,

Bibrzycki,

Dawid

et al. 2021

Preprint

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The last two decades have witnessed the discovery of a myriad of new and unexpected hadrons. The future holds more surprises for us, thanks to new-generation experiments. Understanding the signals and determining the properties of the states requires a parallel theoretical effort. To make full use of available and forthcoming data, a careful amplitude modeling is required, together with a sound treatment of the statistical uncertainties, and a systematic survey of the model dependencies. We review the contributions made by the Joint Physics Analysis Center to the field of hadron spectroscopy.

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Section: Studies Of a 1 (1260) Resonance In The 3π Systemmentioning

confidence: 67%

Section: → 3 Scatteringmentioning

confidence: 99%

Novel approaches in Hadron Spectroscopy

Albaladejo,

Bibrzycki,

Dawid

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Fig. 15 Mechanisms considered in Refs. [45,46,84] kinetic energy is large, m K + m d − m p − m Σ = 236.5 MeV, much larger than the average pΣ − potential.…”

Section: Discussionmentioning

confidence: 99%

“…Another relevant case was the explanation of the "a 1 (1420)" structure observed by the COMPASS collaboration [11], which is explained in terms of a TS in Refs. [12][13][14][15]. Some other recent examples can be seen in [16][17][18] and a rather complete list of reactions studied along TS is given in Ref.…”

Section: Introductionmentioning

confidence: 99%

$$\varLambda (1405)$$ mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ reaction

2022

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We study for the first time the $$p\varSigma ^-\rightarrow K^-d$$ p Σ - → K - d and $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reactions close to threshold and show that they are driven by a triangle mechanism, with the $$\varLambda (1405)$$ Λ ( 1405 ) , a proton and a neutron as intermediate states, which develops a triangle singularity close to the $${\bar{K}}d$$ K ¯ d threshold. We find that a mechanism involving virtual pion exchange and the $$K^-p\rightarrow \pi ^+\varSigma ^-$$ K - p → π + Σ - amplitude dominates over another one involving kaon exchange and the $$K^-p\rightarrow K^-p$$ K - p → K - p amplitude. Moreover, of the two $$\varLambda (1405)$$ Λ ( 1405 ) states, the one with higher mass around 1420 MeV, gives the largest contribution to the process. We show that the cross section, well within measurable range, is very sensitive to different models that, while reproducing $${\bar{K}}N$$ K ¯ N observables above threshold, provide different extrapolations of the $${\bar{K}}N$$ K ¯ N amplitudes below threshold. The observables of this reaction will provide new constraints on the theoretical models, leading to more reliable extrapolations of the $${\bar{K}}N$$ K ¯ N amplitudes below threshold and to more accurate predictions of the $$\varLambda (1405)$$ Λ ( 1405 ) state of lower mass.

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“…It is a known fact that most resonances couple strongly to three or more particles [1]. Some of these are exotics, as they do not fit the naïve quark model expectations, like the Roper resonance N (1440), the a 1 (1420) seen by COMPASS [62,63], and the hybrid candidate π 1 (1600) discussed above [27,64]. In the heavy sector, several XYZ states have significant three-particle decay modes, most notably the X(3872) and the T + cc [2].…”

Section: -Body Problemmentioning

confidence: 99%

Snowmass white paper: Need for amplitude analysis in the discovery of new hadrons

Albaladejo¹,

Battaglieri²,

Bibrzycki³

et al. 2022

Preprint

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We highlight the need for the development of comprehensive amplitude analysis methods to further our understanding of hadron spectroscopy. Reaction amplitudes constrained by first principles of S-matrix theory and by QCD phenomenology are needed to extract robust interpretations of the data from experiments and from lattice calculations.In the last two decades, high-energy physics experiments have delivered a lot of unexpected exotic hadron resonances, that challenge the minimal quark model lore of baryons with three quarks and mesons with a quark-antiquark pair. Candidates for tetraquarks, pentaquarks, molecules, and hadrons with gluonic degrees of freedom have been found [1,2]. Establishing the existence of isolated resonances that go beyond the minimal quark model is just the first step: one needs to identify the complete multiplets and study the differences and similarities among their members. This

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Triangle Singularity as the Origin of the a1(1420)

Cited by 20 publications

References 47 publications

Novel approaches in Hadron Spectroscopy

Novel approaches in Hadron Spectroscopy

$$\varLambda (1405)$$ mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ reaction

Snowmass white paper: Need for amplitude analysis in the discovery of new hadrons

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