共查询到20条相似文献,搜索用时 15 毫秒
1.
R. Barate et al. 《The European Physical Journal C - Particles and Fields》1998,4(4):557-570
The full statistics of hadronic Z decays collected with the ALEPH detector are analysed to measure, by three methods, the
ratio, , of the partial decay width of the Z into quarks to the total hadronic width. One method uses the inclusive and spectra of electrons. The other two use a double-tagging technique to measure independently of the charm-tagging efficiency. In one, the tagging procedure uses the reconstruction of high momentum charmed
mesons (, and to detect the charm quarks. In the other, a charm quark is tagged from the 's reconstructed in the decay channel and the other from the slow pion from the decay. The combination of these measurements leads to .
Received: 6 March 1998 / Published online: 2 July 1998 相似文献
2.
《Zeitschrift fur Physik C Particles and Fields》1997,76(3):425-440
Results are presented on the production of excited charm and excited charm-strange mesons in hadronic Z0 decays. The results are obtained from approximately 4.3 million hadronic Z0 decays, collected on or near the Z0 resonance using the OPAL detector at LEP. The D0 1(2420) and D*0 2 (2460) mesons are reconstructed in the D*+π-. final state and their separate production rates in charm fragmentation and in weak decays of b-hadrons are determined. Assuming that the decay widths of these mesons are saturated by the allowed D*π and Dπ final states, the charm hadronization fractions and the inclusive branching ratios of b-hadrons to these neutral P-wave charm mesons are determined to be 相似文献
3.
WANG Zhi-Gang 《理论物理通讯》2015,63(4):466-480
In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the C γμ- Cγνtype scalar, axial-vector and tensor tetraquark states in details with the QCD sum rules. In calculations, we use the formula μ = (M 2X/ Y /Z-(2Mc)2)~(1/2) to determine the energy scales of the QCD spectral densities. The predictions MJ =2=(4.02+0.09-0.09) GeV, MJ =1=(4.02+0.07-0.08) GeV favor assigning the Zc(4020) and Zc(4025) as the JP C= 1+-or 2++diquark-antidiquark type tetraquark states, while the prediction M++J =0=(3.85+0.15-0.09) GeV disfavors assigning the Z(4050) and Z(4250) as the JP C= 0diquark-antidiquark type tetraquark states. Furthermore, we discuss the strong decays of the 0++, 1+-, 2++diquark-antidiquark type tetraquark states in details. 相似文献
4.
The European Physical Journal C - In this article, we construct the axialvector-diquark–axialvector-antidiquark type tensor current to interpolate both the vector- and the... 相似文献
5.
We investigate hadronic molecule states of $K \bar K N$ and $\bar K \bar K N$ systems with I?=?1/2 and J P ?=?1/2?+?, assuming that Λ(1405) and the scalar mesons, f 0(980), a 0(980), are reproduced as quasi-bound states of $\bar KN$ and $K \bar K$ . Performing non-relativistic three-body calculations for these systems, we find weakly bound states for $K \bar K N$ and $\bar K \bar K N$ around 1900 MeV, which correspond to new baryon resonances of N * and Ξ * with J P ?=?1/2?+?. We find that these resonances have cluster structure of the two-body bound state keeping its properties as in the isolated two-particle system. 相似文献
6.
D. Ebert R. N. Faustov V. O. Galkin 《The European Physical Journal C - Particles and Fields》2008,58(3):399-405
The masses of the excited heavy tetraquarks with hidden charm are calculated within the relativistic diquark–antidiquark picture.
The dynamics of the light quark in a heavy–light diquark is treated completely relativistically. The diquark structure is
taken into account by calculating the diquark–gluon form factor. New experimental data on charmonium-like states above open
charm threshold are discussed. The obtained results indicate that X(3872), Y(4260), Y(4360), Z(4248), Z(4433) and Y(4660) could be tetraquark states with hidden charm. 相似文献
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9.
T. F. Hoang 《Zeitschrift fur Physik C Particles and Fields》1997,73(1):149-152
The charged multiplicity distribution of hadronic decays of Z 0 from LEP and those of inclusive $e^{+}+e^{-}?ghtarrow h{?erline h} at E_{? cm}=14 {? to} 60 {? GeV}$ at E cm = 14 to 61 GeV are analyzed using a Poisson-type distribution for photon statistics, due to Scully-Lamb. Its two parameters are expressed in terms of 〈n〉 and f 2 = 〈n(n ? 1)〉 ? 〈n〉2 of the data in order to perform no-free-parameter fits. It is found that f2 behaves like $E_{? cm}^{a}$ with a = 2.01 ± 0.11, whereas C 2 = 〈n 2〉/〈n〉2 ~ E cm with ΔC 2/ΔE cm = (1.81 ± 0.14)·10?3. 相似文献
10.
The properties of light and heavy mesons, baryons and tetraquarks are discussed within a QCD-motivated relativistic quark
model. The results for the mass spectra, electroweak properties and Regge trajectories of hadrons are presented. 相似文献
11.
W. H. Liang R. Molina E. Oset 《The European Physical Journal A - Hadrons and Nuclei》2010,44(3):479-486
We determine the radiative decay amplitudes for the decay into D* and $ \bar{{D}}$ $ \gamma$ , or D * s and $ \bar{{D}}_{s}^{}$ $ \gamma$ of some of the charmonium-like states classified as X , Y , Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the $ \bar{{D}}$ $ \gamma$ or $ \bar{{D}}_{s}^{}$ $ \gamma$ invariant mass show a peculiar behavior as a consequence of the D * $ \bar{{D}}^{*}_{}$ nature of these states. The experimental search of these magnitudes can shed light on the nature of these states. 相似文献
12.
D. Gamermann E. Oset D. Strottman M.J. Vicente Vacas 《Progress in Particle and Nuclear Physics》2008,61(1):153-154
We briefly present our model for generating open and hidden charm resonances and present the most interesting results. 相似文献
13.
P. Abreu et al. 《The European Physical Journal C - Particles and Fields》2000,12(2):225-241
The partial decay width of the Z into quark pair and the number of charm quarks per b decay are measured with the DELPHI detector at LEP 1. Particle identification provides clear , , and signatures. The charm hadron production rate is measured in each channel by a fit to the scaled energy, impact parameter
information and the invariant mass spectrum. Two measurements of are presented, from the production rate and from the overall charm counting, including strange charm baryon production, in events. The multiplicity , which includes hidden and strange charm baryon production, is inferred from the charm counting in events. The final results are and .
Received: 1 June 1999 / Published online: 8 December 1999 相似文献
14.
A SU(4) flavor symmetrical Lagrangian is constructed for the interaction of the pseudo-scalar mesons with the vector mesons. SU(4) symmetry is broken to SU(3) by suppression of terms in the Lagrangian where the interaction should be driven by charmed mesons. Chiral symmetry can
be restored by setting this new SU(4) symmetry-breaking parameters to zero. Unitarization in coupled channels leads to the dynamical generation of resonances.
Many known axial resonances can be identified including the new controversial X(3872) and the structure found recently by Belle around 3875MeV in the hidden charm sector. Also new resonances are predicted,
some of them with exotic quantum numbers. 相似文献
15.
We investigate nonfactorizable contributions to charm meson decays into D → ππ/K K?/K K?*/K? K*/D → K*K?* modes. Obtaining the contributions from spectatorquark diagrams for N c = 3, we determine the nonfactorizable isospin amplitudes required to explain the data for these modes. For these decays, we observe that ππ, πρ, decay modes favor a nonfactorizable-isospin-amplitudes ratio A 0 nf /A 2 nf equal to (1.123±0.158) and for K K?, K K?*, K? K* and K*K?* modes, the ratio of nonfactorizable amplitudes A 0 nf and A 1 nf turns out to be unity. 相似文献
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17.
R. Molina D. Gamermann E. Oset L. Tolos 《The European Physical Journal A - Hadrons and Nuclei》2009,42(1):31-42
We study the renormalization of the properties of low-lying charm and hidden charm scalar mesons in a nuclear medium, concretely
of the D
s0(2317) and the theoretical hidden charm state X(3700) . We find that for the D
s0(2317) , with negligible width at zero density, the width becomes about 100MeV at normal nuclear-matter density, while in
the case of the X(3700) the width becomes as large as 200MeV. We discuss the origin of this new width and trace it to reactions occurring in
the nucleus, while offering a guideline for future experiments testing these changes. We also show how those medium modifications
will bring valuable information on the nature of the scalar resonances and the mechanisms of the interaction of D mesons with nucleons and nuclei. 相似文献
18.
Abrams GS Adolphsen CE Aleksan R Alexander JP Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D de Boer W Bonvicini G Boyarski A Brabson B Breakstone A Brom JM Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drell PS Drewer DC Elia R Fay J Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G 《Physical review letters》1989,63(15):1558-1561
19.
Kral JF Abrams GS Adolphsen CE Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D Bonvicini G Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drewer DC Elia R Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gatto C Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G Grosse-Wiesmann P Hanson G Harr R Harral B 《Physical review letters》1990,64(11):1211-1214
20.
Abe K Abt I Ahn CJ Akagi T Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Dasu S 《Physical review D: Particles and fields》1995,51(3):962-984