Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Study of the Decay phi --> eta pi0 gamma with the KLOE detector  [PDF]
The KLOE Collaboration
Physics , 2002, DOI: 10.1016/S0370-2693(02)01821-X
Abstract: In a sample of 5.3x10^7 phi-decays observed with the KLOE detector at the Frascati phi-factory Dafne we find 605 eta pi0 gamma events with eta --> gamma\gamma and 197 eta pi0 gamma events with eta --> pi+ pi- pi0. The decay phi --> eta pi0 gamma is dominated by the process phi --> a0 gamma. From a fit to the eta pi0 mass spectrum we find BR(phi --> ao(980) gamma)= (7.4 +- 0.7)x10^-5.
Charmonium decays to gamma pi0, gamma eta, and gamma eta'  [PDF]
CLEO Collaboration,T. K. Pedlar
Physics , 2009, DOI: 10.1103/PhysRevD.79.111101
Abstract: Using data acquired with the CLEO-c detector at the CESR e+e- collider, we measure branching fractions for J/psi, psi(2S), and psi(3770) decays to gamma pi0, gamma eta, and gamma eta'. Defining R_n = B[ psi(nS)-->gamma eta ]/B[ psi(nS)-->gamma eta' ], we obtain R_1 = (21.1 +- 0.9)% and, unexpectedly, an order of magnitude smaller limit, R_2 < 1.8% at 90% C.L. We also use J/psi-->gamma eta' events to determine branching fractions of improved precision for the five most copious eta' decay modes.
Analysis of nature of phi -> gamma pi0 eta and phi -> gamma pi0 pi0 decays  [PDF]
N. N. Achasov
Physics , 2001, DOI: 10.1063/1.1482441
Abstract: We study interference patterns in the phi -> gamma a0 + pi0 rho -> gamma pi eta and phi -> gamma f0 + pi0 rho -> gamma pi0 pi0 reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the pi0eta spectrum in the decay phi -> gamma pi eta everywhere over the energy region and does not distort the pi0 pi0 spectrum in the decay phi -> gamma pi0 pi0 when the invariant mass m_{pi0 pi0} > 670 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are conclusive arguments in favor of the one-loop mechanism phi -> K+K- -> gamma a0 (or gamma f0). We discuss also distinctions between the four-quark, molecular, and two-quark models and argue that the establishment of the scalar meson production mechanism in the phi radiative decays gives new strong evidence in favor of the four-quark nature of the scalar a0(980) and f0(980) mesons.
Evidence of the PHI(1020)--->ETA+PI0+GAMMA Decay  [PDF]
M. N. Achasov,V. M. Aulchenko,S. E. Baru,A. V. Berdyugin,A. V. Bozhenok A. D. Bukin,D. A. Bukin,S. V. Burdin,T. V. Dimova,S. I. Dolinski,V. P. Druzhinin,M. S. Dubrovin,I. A. Gaponenko,V. B. Golubev,V. N. Ivanchenko,P. M. Ivanov,A. A. Korol,S. V. Koshuba,A. P. Lysenko,E. V. Pakhtusova,A. A. Salnikov,S. I. Serednyakov,V. V. Shary,Yu. M. Shatunov,V. A. Sidorov,Z. K. Silagadze,A. N. Skrinsky,Yu. V. Usov
Physics , 1998, DOI: 10.1016/S0370-2693(98)01152-6
Abstract: Signal of the rare radiative decay PHI--->ETA+PI0+GAMMA was observed in the SND experiment at VEPP-2M electron-positron collider.The result is based on the analysis of data, corresponding to a total integrated luminosity of 4 pb^{-1}, or 8x10^6 PHI mesons produced. The measured branching ratio of PHI--->ETA+PI0+GAMMA decay is equal to (0.83+-0.23)x10^{-4}.
The Anomalous Decay eta -> pi pi gamma gamma  [PDF]
G. Knoechlein,S. Scherer,D. Drechsel
Physics , 1995, DOI: 10.1016/0146-6410(96)00018-X
Abstract: We investigate the rare radiative eta decay modes eta -> pi+ pi- gamma gamma and eta -> pi0 pi0 gamma gamma within the framework of chiral lagrangians at o(p^4) and present photon spectra for both processes.
Application of Jain and Munczek's bound-state approach to gamma gamma-processes of pi0, eta_c and eta_b  [PDF]
D. Kekez,Bojan Bistrovic,Dubravko Klabucar
Physics , 1998, DOI: 10.1142/S0217751X99000087
Abstract: We point out the problems affecting most quark--antiquark bound state approaches when they are faced with the electromagnetic processes dominated by Abelian axial anomaly. However, these problems are resolved in the consistently coupled Schwinger-Dyson and Bethe-Salpeter approach. Using one of the most successful variants of this approach, we find the dynamically dressed propagators of the light u and d quarks, as well as the heavy c and b quarks, and find the Bethe-Salpeter amplitudes for their bound states pi0, eta_c and \eta_b. Thanks to incorporating the dynamical chiral symmetry breaking, the pion simultaneously appears as the (pseudo)Goldstone boson. We give the theoretical predictions for the gamma-gamma decay widths of pi0, eta_c and eta_b, and for the pi0 gamma* -> gamma transition form factor, and compare them with experiment. In the chiral limit, the axial-anomaly result for pi0->gamma-gamma is reproduced analytically in the consistently coupled Schwinger-Dyson and Bethe-Salpeter approach, provided that the quark-photon vertex is dressed consistently with the quark propagator, so that the vector Ward-Takahashi identity of QED is obeyed. On the other hand, the present approach is also capable of quantitatively describing systems of heavy quarks, concretely eta_c and possibly eta_b, and their gamma-gamma decays. We discuss the reasons for the broad phenomenological success of the bound-state approach of Jain and Munczek.
Evidence of phi --> pi0 pi0 gamma and phi --> pi0 eta gamma decays in SND experiment at VEPP-2M  [PDF]
M. N. Achasov,A. V. Berdyugin,A. V. Bozhenok,A. D. Bukin,D. A. Bukin,S. V. Burdin,T. V. Dimova,V. P. Druzhinin,M. S. Dubrovin,I. A. Gaponenko,V. B. Golubev,V. N. Ivanchenko,I. A. Koop,A. A. Korol,S. V. Koshuba,E. V. Pakhtusova,A. A. Salnikov,S. I. Serednyakov,V. V. Shary,Yu. M. Shatunov,V. A. Sidorov,Z. K. Silagadze,A. N. Skrinsky,Yu. V. Usov
Physics , 1997, DOI: 10.1063/1.56103
Abstract: Preliminary results on the study of e+e- --> phi(1020) --> pi0 pi0 gamma, eta pi0 gamma processes from SND experiment at VEPP-2M collider in Novosibirsk are presented. Branching ratios of rare radiative phi --> pi0 pi0 gamma and phi --> pi0 eta gamma decays are measured: B(phi --> pi0 pi0 gamma ) = (1.1 +- 0.2) * 10^-4 (invariant mass (pi0 pi0) < 800 MeV), B(phi --> eta pi0 gamma ) = (1.3 +- 0.5) * 10^-4.
Analysis of angular distributions in gamma N \to pi0 eta N  [PDF]
A. Fix,M. Ostrick,L. Tiator
Physics , 2008, DOI: 10.1140/epja/i2007-10551-x
Abstract: Angular distributions in the final state of pi0-eta photoproduction on nucleons are considered. As a formal base the familiar isobar model is used in which the (pi0 eta N) state is a product of the resonance decay into eta-Delta(1232) and pi-S_{11}(1535) channels. One of the principal assumptions used is that in the actual energy region the reaction is dominated by a single resonance state. The developed formalism can serve as a tool for testing spin and parity of that resonance.
Measurement of the eta'-meson mass using J/psi--> gamma eta'  [PDF]
CLEO Collaboration,J. Libby
Physics , 2008, DOI: 10.1103/PhysRevLett.101.182002
Abstract: We measure the mass of the eta' meson using psi(2S)--> pi+ pi- J/psi, J/psi--> gamma eta' events acquired with the CLEO-c detector operating at the CESR e+e- collider. Using three decay modes, eta'--> rho0 gamma, eta'--> pi+ pi- eta with eta--> gamma gamma, and eta'--> pi+ pi- eta with eta--> pi+ pi- pi0, we find M(eta') = 957.793 +- 0.054 +- 0.036 MeV, in which the first uncertainty is statistical and the second is systematic. This result is consistent with but substantially more precise than the current world average.
Measurement of the eta mass at KLOE  [PDF]
The KLOE collaboration
Statistics , 2007, DOI: 10.1140/epja/i2008-10659-5
Abstract: An integrated luminosity of 410 pb^(-1), corresponding to ~ 17 million of eta events, has been analyzed to measure the eta mass using the decay eta to gamma gamma. The measurement is insensitive to the calorimeter energy calibration and the systematic error on the measurement is dominated by the uniformity of the detector response. As a cross check of the method the pi0 mass from the decay phi to pi0 gamma, pi0 to gamma gamma has been measured and it is in agreement with the most accurate previous determinations. The result obtained is m(eta) = 547.873 +/- 0.007 (stat.) +/- 0.031 (syst.) MeV, that is today best measurement of the eta mass.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.