Light isovector resonances in ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}p$ at $190\text{ }\text{ }\mathrm{GeV}/c$

Open Access

Light isovector resonances in $π^{-} p \to π^{-} π^{-} π^{+} p$ at $190 GeV / c$

M. Aghasyan et al.

Phys. Rev. D 98, 092003 – Published 2 November 2018

Abstract

We have performed the most comprehensive resonance-model fit of $π^{-} π^{-} π^{+}$ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction $π^{-} + p \to π^{-} π^{-} π^{+} + p_{recoil}$ with a $190 GeV / c$ pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, $0.5 < m_{3 π} < 2.5 GeV / c^{2}$ , and simultaneously in 11 bins of the reduced four-momentum transfer squared, $0.1 < t^{'} < 1.0 (GeV / c)^{2}$ , are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with $J^{P C} = 0^{- +}$ , $1^{+ +}$ , $2^{+ +}$ , $2^{- +}$ , $4^{+ +}$ , and spin-exotic $1^{- +}$ quantum numbers. The model contains the well-known resonances $π (1800)$ , $a_{1} (1260)$ , $a_{2} (1320)$ , $π_{2} (1670)$ , $π_{2} (1880)$ , and $a_{4} (2040)$ . In addition, it includes the disputed $π_{1} (1600)$ , the excited states $a_{1} (1640)$ , $a_{2} (1700)$ , and $π_{2} (2005)$ , as well as the resonancelike $a_{1} (1420)$ . We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 $t^{'}$ bins. We extract the relative branching fractions of the $ρ (770) π$ and $f_{2} (1270) π$ decays of $a_{2} (1320)$ and $a_{4} (2040)$ , where the former one is measured for the first time. In a novel approach, we extract the $t^{'}$ dependence of the intensity of the resonances and of their phases. The $t^{'}$ dependence of the intensities of most resonances differs distinctly from the $t^{'}$ dependence of the nonresonant components. For the first time, we determine the $t^{'}$ dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances. We have performed extensive systematic studies on the model dependence and correlations of the measured physical parameters.

49 More

Received 21 February 2018

DOI:https://doi.org/10.1103/PhysRevD.98.092003

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Few-body systems Lifetimes & widths Models & methods for nuclear reactions Models based on symmetries Particle decays Particle interactions Particle phenomena Quantum chromodynamics Quark model Resonance reactions Strong interaction

Particles & FieldsNuclear Physics

Authors & Affiliations

Click to Expand

Article Text

Click to Expand

Supplemental Material

Click to Expand

References

Click to Expand

Issue

Vol. 98, Iss. 9 — 1 November 2018

Reuse & Permissions

Author publication services for translation and copyediting assistance advertisement

Physical Review D

covering particles, fields, gravitation, and cosmology

Light isovector resonances in $π^{-} p \to π^{-} π^{-} π^{+} p$ at $190 GeV / c$

M. Aghasyan et al.

Phys. Rev. D 98, 092003 – Published 2 November 2018

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text

Supplemental Material

References

Issue

Physical Review D

covering particles, fields, gravitation, and cosmology

Light isovector resonances in π−p→π−π−π+p at 190 GeV/c

M. Aghasyan et al.

Phys. Rev. D 98, 092003 – Published 2 November 2018

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text

Supplemental Material

References

Issue

Authorization Required

Other Options

Download & Share

Images

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Figure 31

Figure 32

Figure 33

Figure 34

Figure 35

Figure 36

Figure 37

Figure 38

Figure 39

Figure 40

Figure 41

Figure 42

Figure 43

Figure 44

Figure 45

Figure 46

Figure 47

Figure 48

Figure 49

Figure 50

Figure 51

Figure 52

Figure 53

Figure 54

Figure 55

Figure 56

Reuse & Permissions

Log In

Search

Article Lookup

Paste a citation or DOI

Enter a citation

Light isovector resonances in $π^{-} p \to π^{-} π^{-} π^{+} p$ at $190 GeV / c$