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1.
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The $\pi^+\pi^-$ Coulomb interaction study and its use in the data processing
/ Adeva, B. (Santiago de Compostela U.) ; Afanasyev, L. (Dubna, JINR) ; Anania, A. (INFN, Messina) ; Aogaki, S. (Bucharest, IFIN-HH) ; Benelli, A. (Prague, Tech. U.) ; Brekhovskikh, V. (Serpukhov, IHEP) ; Cechak, T. (Prague, Tech. U.) ; Chiba, M. (Tokyo Metropolitan U.) ; Chliapnikov, P. (Serpukhov, IHEP) ; Drijard, D. (Prague, Tech. U. ; CERN) et al.
In this work the Coulomb effects (Coulomb correlations) were studied using experimental $\pi^+\pi^-$ pair distributions in $Q$, the relative momentum in the pair center of mass system (c.m.s), and its projections $Q_L$ (longitudinal component) and $Q_t$ (transverse component) relative to the pair direction in the laboratory system (l.s.). The major part of the pion pairs is produced by decay of $\rho, \omega$ and $\Delta$ and other short-lived sources (Coulomb pairs). [...]
arXiv:2409.12696; CERN-EP-2023-276.-
Geneva : CERN, 2024-11-01 - 11 p.
- Published in : Phys. Rev. D 110 (2024) 092005
Draft (restricted): PDF; Fulltext: DIRAC-Coulomb-correct - PDF; 2409.12696 - PDF;
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2.
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Investigation of $K^+K^-$ pairs in the effective mass region near $2m_K$
/ DIRAC Collaboration
The DIRAC experiment at CERN investigated in the reaction $\rm{p}(24~\rm{GeV}/c) + Ni$ the particle pairs $K^+K^-, \pi^+ \pi^-$ and $p \bar{p}$ with relative momentum $Q$ in the pair system less than 100 MeV/c. Because of background influence studies, DIRAC explored three subsamples of $K^+K^-$ pairs, obtained by subtracting -- using time-of-flight (TOF) technique -- background from initial $Q$ distributions with $K^+K^-$ sample fractions more than 70%, 50% and 30%. [...]
arXiv:2204.01857; CERN-EP-2022-058.-
2022-08-01 - 18 p.
- Published in : Phys. Rev. D 106 (2022) 032006
Fulltext: PhysRevD.106.032006 - PDF; 2204.01857 - PDF;
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3.
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First measurement of a long-lived $\pi^+ \pi^-$ atom lifetime
/ DIRAC Collaboration
The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $\pi^+\pi^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1~\textmu{}m thick platinum foil. [...]
arXiv:1811.08659; CERN-EP-2018-281; DIRAC-PUB-2019-01.-
Geneva : CERN, 2019-03-01 - 7 p.
- Published in : Phys. Rev. Lett. 122 (2019) 082003
Article from SCOAP3: PDF; Draft (restricted): PDF; Fulltext: 1811.08659 - PDF; CERN-EP-2018-281 - PDF;
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4.
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Measurement of the $\pi K$ atom lifetime and the $\pi K$ scattering length
/ DIRAC Collaboration
After having announced the statistically significant observation (5.6~$\sigma$) of the new exotic $\pi K$ atom, the DIRAC experiment at the CERN proton synchrotron presents the measurement of the corresponding atom lifetime, based on the full $\pi K$ data sample: $\tau = (5.5^{+5.0}_{-2.8}) \cdot 10^{-15}s$. By means of a precise relation ($<1\%$) between atom lifetime and scattering length, the following value for the S-wave isospin-odd $\pi K$ scattering length $a_0^{-}~=~\frac{1}{3}(a_{1/2}-a_{3/2})$ has been derived: $\left|a_0^-\right| = (0.072^{+0.031}_{-0.020}) M_{\pi}^{-1}$..
arXiv:1707.02184; CERN-EP-2017-137; DIRAC-PUB-2017-01.-
Geneva : CERN, 2017-09-19 - 18 p.
- Published in : Phys. Rev. D 96 (2017) 052002
Draft (restricted): PDF; Fulltext: CERN-EP-2017-137 - PDF; arXiv:1707.02184 - PDF; Fulltext from publisher: PDF;
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5.
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Observation of $\pi^- K^+$ and $\pi^+ K^-$ atoms
/ DIRAC Collaboration
The observation of hydrogen-like $\pi K$ atoms, consisting of $\pi^- K^+$ or $\pi^+ K^-$ mesons, is presented. The atoms have been produced by 24 GeV/$c$ protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. [...]
arXiv:1605.06103; CERN-EP-2016-128; DIRAC-PUB-2016-02.-
Geneva : CERN, 2016-09-08 - 6 p.
- Published in : Phys. Rev. Lett. 117 (2016) 112001
Draft (restricted): PDF; Fulltext: arXiv:1605.06103 - PDF; 10.1103_PhysRevLett.117.112001 - PDF; PhysRevLett.117.112001 - PDF; Preprint: PDF; External link: Fulltext
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6.
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First observation of long-lived $\pi^+ \pi^-$ atoms
/ DIRAC Collaboration
After observing and investigating the double-exotic $\pi^+\pi^-$ atom with the ground state lifetime $\tau$ of about $3 \times 10^{-15}$~s, the upgraded DIRAC experiment at the CERN PS accelerator observes for the first time long-lived states of the same atom with lifetimes of about $10^{-11}$~s and more. The number of characteristic pion pairs resulting from the breakup (ionisation) of long-lived $\pi^+\pi^-$ atoms amounts to $436\pm61$, corresponding to a signal-to-error ratio of better than 7 standard deviations. [...]
arXiv:1508.04712; CERN-PH-EP-2015-175; DIRAC-PUB-2015-02; CERN-PH-EP-2015-175.-
Geneva : CERN, 2015-09-26 - 13 p.
- Published in : Phys. Lett. B 751 (2015) 12-18
Article from SCOAP3: plb-751-12 - PDF; scoap3-fulltext - PDF; Fulltext: PDF; External link: Preprint
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7.
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Analysis of low multiplicity jets produced by high-energy pions
/ Fretter, W B (Ecole Polytechnique) ; Hoang, T F (Ecole Polytechnique) ; Bellini, G (Milan U. ; INFN, Milan) ; Fiorini, E (Milan U. ; INFN, Milan) ; Herz, A J (Milan U. ; INFN, Milan) ; Negri, P (Milan U. ; INFN, Milan) ; Ratti, S (Milan U. ; INFN, Milan) ; Baglin, H (Ecole Polytechnique) ; Bingham, H (Ecole Polytechnique) ; Drijard, D (Ecole Polytechnique) et al.
1962 - 6 p.
- Published in : Vol: .1 (1962) , pp. 453-458
In : Conference Internationale d'Aix-en-Provence sur les Particules Elémentaires, Aix-en-Provence, France, 14 - 20 Sep 1961, pp.453-458
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8.
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The momentum spectrum of slow protons emitted in hydrogen-like interactions of negative pions of 6 and 18 Gev/c
/ Bellini, G (Milan U. ; INFN, Milan) ; Fiorini, F (Milan U. ; INFN, Milan) ; Herz, A J (Milan U. ; INFN, Milan) ; Negri, P (Milan U. ; INFN, Milan) ; Ratti, S (Milan U. ; INFN, Milan) ; Cresti, M (Padua U. ; INFN, Padua) ; Limentani, S (Padua U. ; INFN, Padua) ; Santangelo, R (Padua U. ; INFN, Padua) ; Fretter, W B (Ecole Polytechnique ; UC, Berkeley) ; Hoang, T F (Ecole Polytechnique) et al.
1962 - 4 p.
- Published in : Vol: .1 (1962) , pp. 449-452
In : Conference Internationale d'Aix-en-Provence sur les Particules Elémentaires, Aix-en-Provence, France, 14 - 20 Sep 1961, pp.449-452
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9.
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V$^{0}$ pairs produced in the Ecole ploytechnique 1 m propane bubble chamber by $\pi{-}$ of 6, 1, 11 and 18,1 Ge/c
/ Bingham, H H (College de France ; Ecole polytechnique) ; Di Corato, M (CERN) ; Gelsema, E S (CERN ; Milan U.) ; Minguzzi-Banzi, A (CERN) ; Drijard, D (College de France ; Ecole polytechnique) ; Bellière, J (Ecole Polytechnique ; College de France) ; Orkin-Lecourtois, A (Ecole Polytechnique ; College de France) ; Ferrero, M I (Turin U.) ; Garelli, C M (Turin U.) ; Vigone, M (Turin U.) et al.
1962 - 10 p.
- Published in : Vol: .1 (1962) , pp. 101-110
In : Conference Internationale d'Aix-en-Provence sur les Particules Elémentaires, Aix-en-Provence, France, 14 - 20 Sep 1961, pp.101-110
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10.
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Properties of the A$_{1}$ studied in 16 GeV/c $\pi^{-}$ - Interactions on nuclei
/ Allard, J F (Ecole Polytechnique) ; Drijard, D (Ecole Polytechnique) ; Hennessy, J (Ecole Polytechnique) ; Huson, R (Ecole Polytechnique) ; Lloret, A (Ecole Polytechnique) ; Musset, P (Ecole Polytechnique) ; Veillet, J J (Ecole Polytechnique) ; Bingham, H H (CERN) ; Dickinson, M (CERN) ; Diebold, R (CERN) et al.
CERN-TC-PHYSICS-64-29.-
Geneva : CERN, 1964 - 11 p.
Fulltext: PDF; Published version: PDF;
In : 12th International Conference on High-energy Physics, v.1, Dubna, Soviet Union, 5 - 15 Aug 1964, pp.452-456
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