共查询到20条相似文献,搜索用时 15 毫秒
1.
Yu. M. Antipov V. A. Batarin V. A. Bessubov M. S. Bilenky N. P. Budanov D. S. Denisov O. V. Eroshin P. L. Frabetti Yu. P. Gorin Yu. A. Gornushkin V. G. Kartasheva P. A. Kulinich A. A. Nosdrin A. G. Olshevski F. Palombo A. I. Petrukhin R. V. Pirtzkhalava S. A. Polovnikov V. N. Roinishvili D. A. Stoianova A. V. Vishnevski 《Zeitschrift fur Physik C Particles and Fields》1989,42(2):185-187
In the diffraction dissociation of π? into μ+μ?π? on a Cu nucleus at 50 GeV/c, the cross section \(\sigma _{\mu ^ + \mu ^ - \pi ^ - } \) for the 1+S(ρ0π) wave was measured. The branching ratio of ρ0→μ+μ? could be calculated from the ratio of this and the corresponding cross sections in the diffraction dissociation of π? into π+π?π?. The obtained value \(BR_{\rho ^0 \to \mu ^ + \mu ^ - } = (4.6 \pm 0.2_{stat^ \pm } \pm 0.2_{syst} )10^{ - 5} \) is in good agreement with the branching ratio \(BR_{\rho ^0 \to e^ + e^ - } \) , as expected ifeμ universality holds. 相似文献
2.
《Physics letters. [Part B]》1997,415(4):452-462
A search for φ radiative decays has been performed using a data sample of about 2.0 million φ decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e+e−→π+π−γ events the following results were obtained:B(φ→f0(980)γ)<1×10−4 for destructive andB(φ→f0(980)γ)<7×10−4 for constructive interference with the Bremsstrahlung process respectively,B(φ→γ→π+π−γ)<3×10−5 for Eγ>20 MeV,B(φ→ργ)<7×10−4. From the selected e+e−→μ+μ−γ eventsB(φ→μ+μ−γ)=(2.3±1.0)×10−5 has been obtained for Eγ>20 MeV. The upper limit on the P,CP-violating decay η→π+π− has also been placed:B(η→π+π−)<9×10−4. All upper limits are at 90% C.L. 相似文献
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V. M. Aul’chenko R. R. Akhmetshin B. Sh. Banzarov L. M. Barkov N. S. Bashtovoi A. E. Bondar’ A. V. Bragin A. A. Grebenyuk D. N. Grigor’ev D. A. Epifanov A. S. Zaitsev F. V. Ignatov V. F. Kazanin S. V. Karpov I. A. Koop P. P. Krokovny A. S. Kuz’min I. B. Logashenko P. A. Lukin K. Yu. Mikhailov I. N. Nesterenko A. V. Otboev V. S. Okhapkin E. A. Perevedentsev A. S. Popov S. I. Redin A. A. Ruban N. M. Ryskulov A. L. Sibidanov V. P. Smakhtin I. G. Snopkov E. P. Solodov G. V. Fedotovich B. I. Khazin Yu. M. Shatunov B. A. Shvarts S. I. Eidel’man Yu. V. Yudin 《JETP Letters》2008,88(2):85-90
The ? → π+π?γγ and ? → π+π?η decays are sought in the experimental data obtained with the CMD-2 detector in the region of the ?-meson resonance. Upper limits ?(? → ππγγ)< 1.2 × 10?4 and ?(? → ππη) < 6.1 × 10?5 (both at a C.L. of 90%) are determined for the branching ratios of these decays. 相似文献
5.
V. Dorofeev A. Ekimov Yu. Gouz A. Ivashin I. Kachaev A. Karyukhin Yu. Khokhlov V. Konstantinov V. Matveev V. Nikolaenko B. Polyakov D. Ryabchikov N. Shalanda M. Soldatov A. A. Solodkov A. V. Solodkov O. Solovianov A. Zaitsev 《The European Physical Journal A - Hadrons and Nuclei》2011,47(5):1-7
The isospin symmetry-breaking (ISB) decay f 1(1285) → π+π?π0 has been studied at the VES facility. The branching ratio is measured: $\frac{{BR\left( {f_1 \to \pi ^ + \pi ^ - \pi ^0 } \right)}} {{BR\left( {f_1 \to \eta \pi ^ + \pi ^ - } \right)}} = 0.86 \pm 0.16_{ - 0.20}^{ + 0.70} \%Low-energy resonances in 31P(p, α 28Si and 35Cl(p, α)32S were studied directly in order to gain a better understanding of reaction cycling in the Si-Ar region in novae. New resonance strengths at E c.m. = 600 and 622 keV in 31P(p, α)28Si were measured (ωγ p, α = (2.2#x00B1;0.7) × 10?2 eV and ωγ p, α = (0.99±0.08) eV, respectively) as well as the E c.m. = 610 keV resonance in 35Cl(p, α)32S [ωγ p, α = (1.2±0.2) × 10?2 eV], the lowest energy that any resonance in this reaction has been observed, directly or indirectly. The strengths of these resonances were found to be lower than previously determined, resulting in even weaker cycling in the Si-Ar region. 相似文献
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V. Dorofeev R. Dzhelyadin A. Ekimov Yu. Gavrilov Yu. Gouz A. Ivashin V. Kabachenko I. Kachaev A. Karyukhin Yu. Khokhlov V. Konstantinov M. Makouski V. Matveev A. Myagkov V. Nikolaenko A. Ostankov B. Polyakov D. Ryabchikov N. Shalanda M. Soldatov A. A. Solodkov A. V. Solodkov O. Solovianov E. Starchenko A. Zaitsev 《The European Physical Journal A - Hadrons and Nuclei》2008,38(2):149-154
The isospin-violating decay f
1(1285) → π+π-π0 has been studied at the VES facility. This study is based on the statistics acquired in π-
Be interactions at 27, 36.6 and 41 GeV/c in the diffractive reaction π-
N → (f
1π-)N . The f
1(1285) → π+π-π0 decay is observed. The preliminary ratio of decay probabilities BR(f
1(1285) → π+π-π0) to BR(f
1(1285) → ηπ+π-).
BR(η → γγ) is ∼ 2% .
Original article based on material presented at HADRON 2007. 相似文献
8.
The KLOE- collaboration A. Anastasi D. Babusci G. Bencivenni M. Berlowski C. Bloise F. Bossi P. Branchini A. Budano L. Caldeira Balkest?hl B. Cao F. Ceradini P. Ciambrone F. Curciarello E. Czerwinski G. D’Agostini E. Danè V. De Leo E. De Lucia A. De Santis P. De Simone A. Di Cicco A. Di Domenico R. Di Salvo D. Domenici A. D’Uffizi A. Fantini G. Felici S. Fiore A. Gajos P. Gauzzi G. Giardina S. Giovannella E. Graziani F. Happacher L. Heijkenskj?ld W. Ikegami Andersson T. Johansson D. Kaminska W. Krzemien A. Kupsc S. Loffredo G. Mandaglio M. Martini M. Mascolo R. Messi S. Miscetti G. Morello D. Moricciani P. Moskal M. Papenbrock A. Passeri V. Patera E. Perez del Rio A. Ranieri P. Santangelo I. Sarra M. Schioppa M. Silarski F. Sirghi L. Tortora G. Venanzoni W. Wislicki M. Wolke 《Journal of High Energy Physics》2016,2016(5):19
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F. Buccella O. Pisanti F. Sannino 《Zeitschrift fur Physik C Particles and Fields》1995,66(1-2):135-140
We relate the asymmetries in the charged pions energy in the decay into π+π?π0 ofK L and of the tagged neutral kaons. The former asymmetry is a given combination of $\Re (\varepsilon ), \Im (\varepsilon )$ , and üε'ü. Moreover, the non-violating CP asymmetry allows a test for theχ PT predictions within the Zel'dovich approach for the final state interaction. 相似文献
11.
M. N. Achasov K. I. Beloborodov A. V. Berdyugin A. A. Botov A. V. Vasil’ev V. B. Golubev T. V. Dimova V. P. Druzhinin D. P. Kovrizhin I. A. Koop A. A. Korol’ S. V. Koshuba A. E. Obrazovsky E. V. Pakhtusova S. I. Serednyakov Z. K. Silagadze A. G. Kharlamov Yu. M. Shatunov D. A. Shtol’ 《Journal of Experimental and Theoretical Physics》2009,109(3):379-392
The cross section for the process e + e ? → π+π?π0π0 has been measured in an experiment with a spherical neutral detector, with the cross section at energies √s < 920 MeV having been measured for the first time. The model of vector dominance describes well the data obtained if the ρ, ρ′, and ρ″ resonances are taken into account. The probability of the decay ρ → π+π?π0π0 is B(ρ → π+π?π0π0) = (1.60 ± 0.74 ± 0.18) × 10?5. The upper limit for the decay ω → π+π?π0π0 has been improved by two orders of magnitude compared to previous measurements and is B(ω → π+π?π0π0) < 2 × 10?4 at a 90% confidence level. 相似文献
12.
The size of π+π− atom in the low lying states is considerably smaller than the radius of atomic screening. Due to that we can neglect this
screening calculating the contribution of multi-photon exchanges. We obtain the analytic formula for Coulomb corrections which
works with a very good accuracy for the ground state of π+π− atom.
Received: 30 November 1998 相似文献
13.
Abouzaid E Arenton M Barker AR Bellantoni L Blucher E Bock GJ Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Glazov A Golossanov A Gomes RA Gouffon P Hsiung YB Jensen DA Kessler R Kotera K Ledovskoy A McBride PL Monnier E Nguyen H Niclasen R Phillips DG Ping H Ramberg EJ Ray RE Ronquest M Santos E Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Velissaris C Wah YW Wang J White HB Whitmore J Wilking MJ Winston R Worcester ET Worcester M Yamanaka T Zimmerman ED 《Physical review letters》2011,107(20):201803
The KTeV E799 experiment has conducted a search for the rare decays, K(L)→π(0)π(0)μ(+)μ(-) and K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-), where the X(0) is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3 ± 0.5) MeV/c(2). We find no evidence for either decay. We obtain upper limits of Br(K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-)) < 1.0 × 10(-10) and Br(K(L)→π(0)π(0)μ(+)μ(-)) < 9.2 × 10(-11) at the 90% confidence level. This result rules out the pseudoscalar X(0) as an explanation of the HyperCP result under the scenario that the dsX(0) coupling is completely real. 相似文献
14.
《Physics letters. [Part B]》1988,214(4):651-656
New constributions to the KL→π0e+e− amplitude are presented. Short-distance penguin induced diagrams for the s→dγ1 transition supplement the previously considered electromagnetic penguin. The new CP-violating amplitude corresponds to a new piece of the relevant anomalous dimension matrix. Strong interaction corrections to the new part of the effective hamiltonian are calculated in the leading logarithmic approximation. The role of subleading terms is also discussed. 相似文献
15.
M. K. Pidcock 《Czechoslovak Journal of Physics》1976,26(4):425-429
Using scattering data, the integrated cross-section for p¯p+–, and unitarity, we derive upper bounds to the differential cross-section for p¯p+ –. Comparison with experimental data shows that in general the bounds are several times larger than the measured value, but that at certain points this factor is only about two or three.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.I would like to thank Dr. A. K.Common for useful discussions and collaboration in the early stages of this work. 相似文献
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The narrow structure K(1630) is singled out in the effective-mass spectrum of the K S 0 π+π? system originating from π? p collisions at 16 GeV/c. This structure is predominantly formed in inelastic collisions accompanied by high momentum transfers. For events from the K(1630) region, kinematical distributions show special features that may be associated with spin manifestations and with correlations between the products arising from the decays of the hypothesized exotic resonance state. Experimental observations of narrow hadronic structures formed at high momentum transfers are reviewed. 相似文献
18.
R.Aaij C.Abellán Beteta T.Ackernley B.Adeva M.Adinolfi H.Afsharnia C.A.Aidala S.Aiola Z.Ajaltouni S.Akar 《中国物理C(英文版)》2021,(9):10-21
The first search for the doubly heavy Ω0bc baryon and a search for the Ξ0bc baryon are performed using pp collision data collected via the LHCb experiment from ... 相似文献
19.
Contributions from the semi-exclusive channels γd → π± NN + π0 d and γd → π0 X (X=pn or d) to the deuteron spin asymmetry and the Gerasimov-Drell-Hearn (GDH) integral are explicitly evaluated using an enhanced elementary pion photoproduction operator and a realistic, high-precision potential model for the deuteron wave function. The sensitivity of the results to the elementary pion photoproduction operator is also investigated and considerable dependence is found. Results for the deuteron GDH integral are compared with the measurements from A2 and GDH@MAMI Collaborations. 相似文献
20.
Ch. Schlegel P. von Neumann-Cosel J. de Boer J. Gerl M. Kaspar I. Kozhoukharov M. Loewe H.J. Maier P.J. Napiorkowsky I. Peter M. Rejmund A. Richter H. Schaffner J. Srebrny M. Würkner H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):135-138
In-beam Coulomb excitation of the exotic odd-odd nucleus 180Ta has been studied by using a 136Xe beam and a setup consisting of five EUROBALL CLUSTER detectors and the Darmstadt-Heidelberg Crystal Ball array. Spectroscopic
information on the extremely rare 180Ta is obtained from the comparison between an enriched (3.6±0.3% 180Ta) and a natural tantalum target. Possible evidence for a depopulation from the long-lived high-spin J
π = 9- isomer to the short-lived J
π = 1+ ground state is searched for by different methods. The decay of low-K bandheads, which are nanosecond isomers, towards the ground-state band can be demonstrated in delayed spectroscopy. A γγ
coincidence analysis provides indications of K = 5 in-band transitions. Finally, when the Crystal Ball is used as an energy and γ multiplicity filter, signals of decay
into the K = 0 band are observed.
Received: 23 January 2001 / Accepted: 8 February 2001 相似文献