共查询到20条相似文献,搜索用时 31 毫秒
1.
We discuss the mixing of pseudoscalar mesons, in particular SU(3) breaking effects, based on ideas abstracted from QCD. The admixtures of η and η′ in ηc are calculated and utilized to estimate the M1 radiative decays ψ → ηγ, η′γ. A reasonably consistent picture emerges for these decays as well as others involving only the light quarks. 相似文献
2.
G. Alexander L. Criegee H.C. Dehne K. Derikum R. Devenish G. Flügge G. Franke Ch. Gerke E. Hackmack P. Harms G. Horlitz Th. Kahl G. Knies E. Lehmann R. Schmitz R.L. Thompson U. Timm K. Wacker 《Physics letters. [Part B]》1978,76(5):652-656
The polarization of the f0(1270) and ?0(770) produced in the J/ψ decays into f0γ and ?0π0 are measured in e+e? collisions at 3.1 GeV. A fit to the f0 production and decay angular distributions yields the values A1/A0 = 0.6 ± 0.3 and A2/A0 = 0.3 ?1.6+0.6, where Aλ are the f0 helicity amplitudes. These results are in good agreement with the values predicted from a QCD two-gluon-exchange model. In addition an upper limit of 2.3 × 10?4 is obtained for the J/ψ → f′0(1514) γ decay branching ratio which implies Γ(J/ψ → f′γ)/Γ(J/ψ → f0γ) ? 0.12 ± 0.05. 相似文献
3.
We investigate in detail the light plane formulation of bound state equations and of the interactions of bound states. This formalism is particularly well suited to discuss bound states of heavy quarks since these states can be well approximated as two particle states but yet there are significant relativistic corrections to the conventional nonrelativistic approach. Applications are made to electromagnetic decays of charmonium (ψ→e + e ?, η c →γγ, ψ′→η c γ, etc.). 相似文献
4.
N. N. Achasov 《Physics of Atomic Nuclei》2011,74(3):437-445
The approach to the Z → γψ and Z → γ? decay study is presented in detail, based on the sum rules for the Z → c $ \bar c $ → γγ* and Z → b $ \bar b $ → γγ* amplitudes and their derivatives. The branching ratios of the Z → γψ and Z → γ? decays are calculated for different hypotheses on saturation of the sum rules. The lower bounds of Σ ψ BR(Z → γψ) = 1.95 × 10?7 and Συ BR(Z → γ?) = 7.23 × 10?7 are found. Deviations from the lower bounds are discussed, including the possibility of BR(Z → γJ/ψ(1S)) ~ BR(Z → γ?(1S)) ~ 10?6, that could be probably measured in LHC. The angular distributions in the Z → γψ and Z → γ? decays are also calculated. 相似文献
5.
The success of the Okubo-Iizuka-Zweig rule for decays of Ψ and Ψ′ suggests that the radiative decays Ψ → γ + hadrons should be dominated by intermediates like Ψ → Ψ′ hadrons. This mechanism is consistent with experimental data which show Γ(Ψ → ?0π0) and Γ(Ψ → ηγ) to be comparable. if all Ψ-like particles are isoscalar, should be very small. If all Ψ-like particles are SU(3) singlets, Γ(Ψ → η′γ)/Γ(Ψ → ηγ) should be large. Substantial violation of our predictions would be circumstantial evidence for the existence of non-singlet new quarks. 相似文献
6.
Describing the ψ → f+γ decay via an intermediate one-photon state avoids difficulties encountered in strong OZI- violating transitions. The ψ → γ →f+γ transition is enhanced an order of magnitude because amplitudes for the u and d components of the f are proportional to squares of quark charges and add constructively. A rough dynamical estimate agrees with the experimental decay rate. Branching ratios for f+γ,A2+γ and f′ + γ decays are shown to be very different for electromagnetic and strong transitions and can test models. Tests of the Han-Nambu model and contributions from the weak neutral current are discussed. 相似文献
7.
The width for decays of the type 1?→γ + 0? is evaluated using the two gluon mechanism of QCD. In particular we compute Γ(Ψ → γ + η′), Γ(Ψ → γ + η) and Γ(? → γ + ηc). The first two are found to be in reasonable agreement with the experimental results, while the latter leads to a branching ratio of 2 × 10?5. 相似文献
8.
Michael A. Shifman Michael I. Vysotsky 《Zeitschrift fur Physik C Particles and Fields》1981,10(2):131-138
We propose a new method for estimating the radiative transitions between the excited 1? charmonium levels and ηc. The method is based on QCD (plus the hypothesis of local duality) and makes no reference to the standard potential picture. It is argued that the decay ψ′(3.698)→η c γ is essentially due to the gluon admixture in the Ψ′ wave function. The most naive analysis yields approximately 0.15 keV for the ψ′→η c γ decay width, five times smaller than preliminary data. The experimental number for Γ(ψ′→η c γ)—0.7 keV—can be reproduced only at a price of introducing a rather large ψ″(3.772)→η c γ amplitude, Γ(ψ″→η c γ)~1 keV. As a byproduct, we get a reliable prediction for the ρ→πγ decay rate, Γ(ρ→πγ)≈70 keV, in good agreement with a recent measurement. 相似文献
9.
W. Bartel P. Duinker J. Olsson D. Pandoulas P. Steffen J. Heintze G. Heinzelmann R.D. Heuer R. Mundhenke H. Rieseberg A. Wagner A.H. Walenta 《Physics letters. [Part B]》1977,68(5):489-504
The decay of J/ψ (3.1) into final states containing no charged particles has been studied experimentally. The partial decay width for the observed neutral decays is (470 ± 160) eV. The decay modes J/ψ → γη → 3γ and J/ψγη′ → 3γ are identified and the branching ratios , are derived. Upper limits for the decay modes J/ψ → γπ0 and J/ψ → γγ are given. 相似文献
10.
F. Binon S.V. Donskov P. Duteil M. Gouanère A.V. Inyakin V.A. Kachanov D.B. Kakauridze G.V. Khaustov A.V. Kulik J.P. Lagnaux A.A. Lednev Yu.V. Mikhailov Th. Mouthuy J.P. Peigneux A. Possoz Yu.D. Prokoshkin Yu.V. Rodnov V.P. Sugonyaev 《Nuclear Physics B》1984,239(2):311-324
The production of χ particles in the reaction π?p → χ + … has been studied near threshold. The measurements have been performed at the 70 GeV IHEP proton synchrotron using the hodoscope spectrometer GAMS-2000. The χ particles have been identified through their decay χ → J/ψ + γ, J/ψ → e+e?. In the region XF ?0.4 the fraction of obsered J/ψ particles which is obtained via the decay of χ states is 0.44 ± 0.16. The χ longitudinal and transverse momentum distributions are similar to those obtained for J/ψ. The inclusive production cross section of χ particles (3P1 and 3P2 states) at 38 GeV/c is σXF>0 (π?p → χ + …) = (28±11) nb. 相似文献
11.
The three-body decays χ b0,2 → J/ ψc $\bar c$ and the decays x bJ → J/ ψD $\bar D$ related to them are studied. The differential widths with respect to these decays are calculated analytically, and their total widths are evaluated numerically. The duality relation between these decays and the two-body decays x b0,2 → J/ ψ(c $\bar c$ ) is verified. The possibility of observing these decays at the LHC and Tevatron colliders is discussed. 相似文献
12.
H. Fritzsch 《Physics letters. [Part B]》1979,86(2):164-166
The weak decays B→ψ(J) + X are investigated. It is argued that these decays are dominated by B→ψ(J)Kπ (branching ratio of about 1%). Detailed predictions for these decays are made. 相似文献
13.
G. Cohen-Tannoudji G. Girardi F. Hayot U. Maor A. Morel 《Physics letters. [Part B]》1976,62(3):343-346
We apply duality diagrams to the ψ and ψ′ decays. We propose that the ψ → 3π decay is described by a Virasoro formula, and show that the low mass ππ suppression in ψ′ → ψ2π is a consequence of the threshold factor contained in the Pomeron-2π coupling. We stress the importance of the ψ and ψ′ decays for the study of heavy mesonic resonances. 相似文献
14.
W. Bartel P. Duinker J. Olsson P. Steffen J. Heintze G. Heinzelmann R.D. Heuer R. Mundhenke H. Rieseberg B. Schürlein A. Wagner A.H. Walenta 《Physics letters. [Part B]》1976,64(4):483-487
Decays of the J/ψ (3.1) resonance into final states with two charged hadrons and two photons are investigated. Branching ratios for the decays J/ψ → ?π and J/ψ → γη′ are determined to be Upper limits for the same decay modes of ψ′ (3.7) are also determined. 相似文献
15.
R. Brandelik W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff D. Cords R. Felst R. Fries E. Gadermann H. Hultschig P. Joos W. Koch U. Kötz H. Krehbiel D. Kreinick S. Yamada 《Physics letters. [Part B]》1978,74(3):292-296
The radiative decays of into f/γ, f′γ, ππγ and KKγ have been measured using the double arm spectrometer DASP at DORIS. We find B(J/φ→fγ)=(J/φ→fγ)/(J/φ→all)=(0.9±0.3)×10?3 to (1.5±0.4)×10?3 depending on the multi- pole mode of the decay and that . 相似文献
16.
We discuss a general leptonic model based on the SU(2)L ? U(1) ? SU(2)R gauge group and we present general results for the ? → ?′ γ and ν? → ν?′γ processes, which can be used for any model based on the SU(2)L ? U(1) ? SU(2)R gauge group or on any of its subgroups. The predictions of the μ → eγ branching ratio and of the neutrino lifetime for various models discussed in the literature are reviewed. The main results are summarized in tables. 相似文献
17.
T.N. Pham 《Physics letters. [Part B]》1979,87(3):267-270
The problem of η-η′ mixing is reexamined within the nonet scheme. It is shown that the mixing angle θp is quite sensitive to a small SU(3) violating piece. Taking SU(3) violating q annihilation terms into account, we obtain a large ratio which is largely independent of the mixing angle and agrees with the measured value to within 20–30%. 相似文献
18.
V. V. Anisovich L. G. Dakhno V. N. Markov V. A. Nikonov A. V. Sarantsev 《Physics of Atomic Nuclei》2005,68(12):2081-2092
We determine the $c\bar c$ component of the photon wave function on the basis of (i) the data on the transitions e + e ? → J/ψ(3096), ψ(3686), ψ(4040), ψ(4415), (ii) partial widths of the two-photon decays η c0(2979), χ c0(3415), χ c2(3556) → γγ, and (iii) wave functions of the charmonium states obtained by solving the Bethe-Salpeter equation for the $c\bar c$ system. Using the obtained $c\bar c$ component of the photon wave function, we calculate the γγ-decay partial widths for radial excitation of the 2S state, η c0(3594) → γγ, and 2P states χ c0(3849), χ c2(3950) → γγ. 相似文献
19.
W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff K. Berkelman D. Cords R. Felst E. Gadermann H. Hultschig P. Joos W. Koch U. Kötz H. Krehbiel D. Kreinick W.A. McNeely K.C. Moffeit S. Yamada 《Physics letters. [Part B]》1977,67(2):243-248
The three photon final state produced in e+e? collisions has been measured at the mass of the resonance using the nonmagnetic part of the double arm spectrometer DASP. The decays and πoγ were observed and their branching ratios are given. A four standard deviation signal was observed in the γγ mass spectrum at a mass of (2.83 ± 0.03) GeV. An upper limit is given for the direct decay . 相似文献
20.
B. Niczyporuk Z. Jakubowski T. Zełudziewicz G. Folger B. Lurz H. Vogel U. Volland H. Wegener J. K. Bienlein R. Graumann H. -J. Trost M. Schmitz F. H. Heimlich R. Nernst A. Schwarz U. Strohbusch P. Zschorsch K. W. Chen A. C. König D. J. Schotanus M. Coles A. Engler R. W. Kraemer D. Marlow F. Messing C. Rippich S. Youssef A. Fridman G. Alexander A. Av-Shalom G. Bella J. Grunhaus W. Langguth M. Scheer LENA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1983,17(3):197-202
A search for the decays γ→ρπ, γ→J/ψX and γ→γa (whereX is undetermined and a is an axion) has been completed using the LENA detector at the DORIS storage ring. No evidence for any of these processes was found. For these decay modes we set branching fraction upper limits (90% C.L.) of 2.1×10?3, 2.0×10?2 and 9.1×10?4, respectively. 相似文献