Triangle Singularity as the Origin of the a1(1420); Physical Review Letters; Vol. 127, iss. 8

Bibliographic Details
Parent link:Physical Review Letters
Vol. 127, iss. 8.— 2021.— [082501, 7 p.]
Corporate Authors: Национальный исследовательский Томский политехнический университет Исследовательская школа физики высокоэнергетических процессов, Национальный исследовательский Томский политехнический университет Школа базовой инженерной подготовки Отделение математики и информатики
Other Authors: Alekseev G. D. Georgy Dmitrievich, Alekseev M. G. Maksim, Donskov S. V. Sergey Vasiljevich, Burtsev V. E. Vitaly Evgenjevich, Chumakov A. G. Aleksandr Grigorjevich, Dusaev R. R. Renat Ramilyevich, Lyubovitskiy (Lyubovitskij) V. E. Valery Efimovich, Mamon S. A. Sergey Aleksandrovich, Vasilishin B. I. Bogdan Ivanovich
Summary:Title screen
The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a1(1420), decaying to f0(980)π. With a mass too close to and a width smaller than the axial-vector ground state a1(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a1(1260) resonance into K∗(→Kπ)¯K and subsequent rescattering through a triangle singularity into the coupled f0(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.
Language:English
Published: 2021
Subjects:
Online Access:https://doi.org/10.1103/PhysRevLett.127.082501
Format: Electronic Book Chapter
KOHA link:https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=668069

MARC

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200 1 |a Triangle Singularity as the Origin of the a1(1420)  |f G. D. Alekseev, M. G. Alekseev, S. V. Donskov [et al.] 
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330 |a The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a1(1420), decaying to f0(980)π. With a mass too close to and a width smaller than the axial-vector ground state a1(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a1(1260) resonance into K∗(→Kπ)¯K and subsequent rescattering through a triangle singularity into the coupled f0(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect. 
461 |t Physical Review Letters 
463 |t Vol. 127, iss. 8  |v [082501, 7 p.]  |d 2021 
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701 1 |a Alekseev  |b M. G.  |g Maksim 
701 1 |a Donskov  |b S. V.  |g Sergey Vasiljevich 
701 1 |a Burtsev  |b V. E.  |c mathematician  |c Senior Lecturer of Tomsk Polytechnic University  |f 1991-  |g Vitaly Evgenjevich  |3 (RuTPU)RU\TPU\pers\38282 
701 1 |a Chumakov  |b A. G.  |c physicist  |c laboratory assistant-researcher of Tomsk Polytechnic University  |f 1992-  |g Aleksandr Grigorjevich  |3 (RuTPU)RU\TPU\pers\41079 
701 1 |a Dusaev  |b R. R.  |c specialist in the field of nuclear physics  |c Engineer of Tomsk Polytechnic University  |f 1988-  |g Renat Ramilyevich  |3 (RuTPU)RU\TPU\pers\30972  |9 15210 
701 1 |a Lyubovitskiy (Lyubovitskij)  |b V. E.  |c physicist  |c Professor of Tomsk Polytechnic University, Doctor of physical and mathematical sciences, Professor of the University of Tubingen (Germany)  |f 1963-  |g Valery Efimovich  |3 (RuTPU)RU\TPU\pers\33385  |9 17080 
701 1 |a Mamon  |b S. A.  |c physicist  |c laboratory assistant-researcher of Tomsk Polytechnic University  |f 1989-  |g Sergey Aleksandrovich  |3 (RuTPU)RU\TPU\pers\43559 
701 1 |a Vasilishin  |b B. I.  |c engineer-physicist  |c laboratory researcher at Tomsk Polytechnic University  |f 1990-  |g Bogdan Ivanovich  |3 (RuTPU)RU\TPU\pers\37572  |9 20428 
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