| Article | |
| Report number | arXiv:2409.12696 ; CERN-EP-2023-276 |
| Title | The $\pi^+\pi^-$ Coulomb interaction study and its use in the data processing |
| Author(s) | 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) ; Dudarev, A. (Dubna, JINR) ; Dumitriu, D. (Bucharest, IFIN-HH) ; Federicova, P. (Prague, Tech. U.) ; Gorin, A. (Serpukhov, IHEP) ; Gritsay, K. (Dubna, JINR) ; Guaraldo, C. (Frascati) ; Gugiu, M. (Bucharest, IFIN-HH) ; Hansroul, M. (CERN) ; Hons, Z. (Rez, Nucl. Phys. Inst.) ; Horikawa, S. (U. Zurich (main)) ; Iwashita, Y. (Kyoto U.) ; Kluson, J. (Prague, Tech. U.) ; Kobayashi, M. (KEK, Tsukuba) ; Kruglova, L. (Dubna, JINR) ; Kulikov, A. (Dubna, JINR) ; Kulish, E. (Dubna, JINR) ; Lamberto, A. (INFN, Messina) ; Lanaro, A. (Wisconsin U., Madison) ; Lednicky, R. (Prague, Inst. Phys.) ; Marinas, C. (Santiago de Compostela U.) ; Martincik, J. (Prague, Tech. U.) ; Nemenov, L. (Dubna, JINR) ; Nikitin, M. (Dubna, JINR) ; Okada, K. (Kyoto Sangyo U.) ; Olchevskii, V. (Dubna, JINR) ; Pentia, M. (Bucharest, IFIN-HH) ; Penzo, A. (INFN, Trieste) ; Plo, M. (Santiago de Compostela U.) ; Prusa, P. (Prague, Tech. U.) ; Rappazzo, G. (INFN, Messina) ; Romero Vidal, A. (Santiago de Compostela U.) ; Ryazantsev, A. (Serpukhov, IHEP) ; Rykalin, V. (Serpukhov, IHEP) ; Saborido, J. (Santiago de Compostela U.) ; Schacher, J. (U. Bern, AEC) ; Sidorov, A. (Serpukhov, IHEP) ; Smolik, J. (Prague, Tech. U.) ; Takeutchi, F. (Kyoto Sangyo U.) ; Trojek, T. (Prague, Tech. U.) ; Trusov, S. (SINP, Moscow) ; Urban, T. (Prague, Tech. U.) ; Vrba, T. (Prague, Tech. U.) ; Yazkov, V. (SINP, Moscow) ; Yoshimura, Y. (KEK, Tsukuba) ; Zrelov, P. (Dubna, JINR) |
| Corporate author(s) | DIRAC Collaboration |
| Publication | 2024-11-01 |
| Imprint | 22 Dec 2023 |
| Number of pages | 11 |
| Published in: | Phys. Rev. D 110 (2024) 092005 |
| DOI | 10.1103/PhysRevD.110.092005 |
| Subject category | Particle Physics - Experiment |
| Accelerator/Facility, Experiment | CERN PS ; PS212 |
| Keywords | QCD ; detector ; particle correlations and fluctuations |
| Abstract | 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). In these pairs the significant Coulomb interaction at small $Q$ occurs. The minor part of the pairs is produced if one or both pions arose from long-lived sources like $\eta, \eta'$ or in different interactions (non-Coulomb pairs). In this case the Coulomb interaction in the final state is practically absent. The $Q$, $Q_L$ and $Q_t$ distributions of Coulomb pairs in the c.m.s. were simulated assuming that they are described by the phase space modified by the known Coulomb correlation function $A_C(Q)$. The same spectra of non-Coulomb pairs were simulated without $A_C(Q)$. In all $Q_t$ intervals, the experimental $Q_L$ spectrum shows a peak around $Q_L = 0$ caused by the Coulomb final state interaction. The full width at half maximum increases with $Q_t$ from 3 MeV/$c$ for $0<Q_t<0.25$ MeV/$c$ to 11 MeV/$c$ for $4.0<Q_t < 5.0$ MeV/$c$. The experimental $Q_L$ distributions were fitted with two free parameters: the fraction of Coulomb pairs and the normalization constant. The precision of the description of these distributions is better than $2\%$ in $Q_t$ intervals 2-3, 3-4 and 4-5 MeV/$c$, and better than $0.5\%$ in the total $Q_t$ interval 0-5 MeV/$c$. It was shown that the number of Coulomb pairs in all $Q_t$ intervals, including the small $Q_t$ (small openning angles $\theta$ in the l.s.) is calculated with the theoretical precision better than 2\%. The comparison of the simulated and experimental number of Coulomb pairs at small $Q_t$ allows to check and to correct the detection efficiency for the pairs with small $\theta$ (0.06 mrad and smaller) in the laboratory system. It was shown that Coulomb pairs can be used as a new physical tool to check and to correct the simulated events quality. The special property of the Coulomb pairs is the possibility to check and to correct the detection efficiency, especially for the pairs with small opening angles. |
| Other source | Inspire |
| Copyright/License | Preprint: © 2023-2024 CERN (License: CC-BY-4.0) |
| Submitted by | mircea.pentia@cern.ch |
Zapis kreiran 2023-11-25, zadnja izmjena 2024-11-11