共查询到20条相似文献,搜索用时 31 毫秒
1.
Bockhorst M. Burbach G. Burgwinkel R. Empt J. Guse B. Guse B. Haas K. -M. Hannappel J. Heinloth K. Hey T. Hoffmann-Rothe P. Honscheid K. Jahnen T. Jakob H. P. Jöpen N. Jüngst H. Kirch U. Klein F. -J. Kostrewa D. Lindemann L. Link J. Manns J. Menze D. Merkel H. Merkel R. Neuerburg W. Paul E. Plötzke R. Schenk U. Schmidt S. Scholmann J. Schütz P. Schultz-Coulon H. -C. Schweitzer M. Schwille W. J. Tran M. -Q. Umlauf G. Vogl W. Wedemeyer R. Wehnes F. Wißkirchen J. Wolf A. 《Zeitschrift fur Physik C Particles and Fields》1994,63(1):37-47
The reactions pK
+ and pK
+ 0 have been measured with the multiparticle detector system SAPHIR at ELSA in Bonn. Besides the differential cross sections the polarization and, for the first time, the 0 polarization have been determined in a photon induced reaction. All data are presented as functions of the photon energy (from threshold up to 1.47 GeV) and of the kaon production angle (0°–180°). The polarization of both and 0 is substantial at all energies and varies strongly with the production angle.This work is supported by the Bundesminister für Forschung und Technologie (BMFT), FK 06 BN 621 I 相似文献
2.
S.V. Golovkin A.P. Kozhevnikov V.P. Kubarovsky V.F. Kurshetsov L.G. Landsberg V.V. Molchanov V.A. Mukhin S.V. Petrenko V.A. Senko D.V. Vavilov V.A. Victorov V.Z. Kolganov G.S. Lomkatsi A.F. Nilov V.T. Smolyankin 《The European Physical Journal A - Hadrons and Nuclei》1999,5(4):409-416
New data for the diffractive reaction p+N→ [Σ0
K
+] +N at E
p= 70 GeV were obtained with partially upgraded SPHINX setup. The data are in a good agreement with the results of our previous
study of this reaction. In the mass spectrum M(Σ0
K
+) a structure at the threshold region with a mass ∼1810 MeV and a distinct X(2000) peak with M= 1989 ± 6 MeV and γ= 91 ± 20 MeV are observed. Unusual features of the massive X(2000) state (narrow decay width, anomalously
large branching ratio for the decay channel with strange particle emission) make it a serious candidate for cryptoexotic pentaquark
baryon with hidden strangeness |qqqsˉs>. We also present new results on the narrow threshold structure X(1810) with M= 1807 ± 7 MeV and γ= 62 ± 19 MeV which is produced in the region of very small P
2
T < 0.01 GeV2. The possibility of the Coulomb production mechanism for X(1810) is discussed.
Received: 28 April 1999 相似文献
3.
4.
I. Horn A. V. Anisovich G. Anton R. Bantes O. Bartholomy R. Beck Y. Beloglazov R. Bogendörfer R. Castelijns V. Credé A. Ehmanns J. Ernst I. Fabry H. Flemming A. Fösel M. Fuchs Ch. Funke R. Gothe A. Gridnev E. Gutz S. Höffgen J. Hößl J. Junkersfeld H. Kalinowsky F. Klein E. Klempt H. Koch M. Konrad B. Kopf B. Krusche J. Langheinrich H. Löhner I. Lopatin J. Lotz H. Matthäy D. Menze J. Messchendorp V. Metag V. A. Nikonov D. Novinski M. Ostrick H. van Pee A. V. Sarantsev C. Schmidt H. Schmieden B. Schoch G. Suft V. Sumachev T. Szczepanek U. Thoma D. Walther Ch. Weinheimer 《The European Physical Journal A - Hadrons and Nuclei》2008,38(2):173-186
The reaction γp → pπ0η has been studied with the CBELSA detector at the tagged photon beam of the Bonn electron stretcher facility. The reaction
shows contributions from Δ+(1232)η , N(1535)+π0 and pa
0(980) as intermediate states. A partial-wave analysis suggests that the reaction proceeds via formation of six Δ -resonances,
Δ(1600)P
33 , Δ(1920)P
33 , Δ(1700)D
33 , Δ(1940)D
33 , Δ(1905)F
35 , Δ(2360)D
33 , and two nucleon resonances N(1880)P
11 and N(2200)P
13 , for which pole positions and decay branching ratios are given. 相似文献
5.
A.Ya. Berdnikov Ya.A. Berdnikov A.N. Ivanov V.F. Kosmach M.D. Scadron N.I. Troitskaya 《The European Physical Journal A - Hadrons and Nuclei》2000,9(3):425-432
The cross-sections for the reactions of the strange production p + p ↦ p + Λ + K+ and p + p ↦ p + Σ0 + K+ near thresholds of the final states pΛK+ and pΣ0K+ are calculated in the effective Lagrangian approach. Our approach is based on the dominant contribution of the one-pion exchange and strong interaction of the colliding protons in the initial state. The theoretical values of the cross-sections agree reasonably well with the experimental data. The polarization properties of the Λ- and Σ0-hyperons are discussed. 相似文献
6.
A.Ya. Berdnikov Ya.A. Berdnikov A.N. Ivanov V.A. Ivanova V.F. Kosmach M.D. Scadron N.I. Troitskaya 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):341-347
Polarization properties of strange baryons produced in pp reactions, p + p↦p + Λ0 + K+ and p + p↦p + Σ0 + K+, near thresholds of the final states pΛ0K+ and pΣ0K+ are analysed relative to polarizations of colliding protons. The cross-sections for pp reactions are calculated within the
effective Lagrangian approach accounting for strong pp rescattering in the initial state of colliding protons with a dominant
contribution of the one-pion exchange and strong final-state interaction of daughter hadrons (Eur. Phys. J. A 9, 425 (2000)).
Received: 22 October 2001 / Accepted: 14 November 2001 相似文献
7.
M. Aguilar-Benitez M. C. Albajar A. Ferrando J. A. Rubio J. Salicio I. Sjögren S. Rodebäck S. O. Holmgren R. Armenteros C. Dionisi Ph. Gavillet M. J. Losty P. F. Loverre M. Mazzucato L. Dobrzynski D. Pennino 《Zeitschrift fur Physik C Particles and Fields》1980,6(2):109-123
The reactionsπ ?p→K 0 ∑ 0(1385) andπ ? p→K + ∑ ?(1385) are studied at an incident momentum of 3.95 GeV/c using data from a high statistics bubble chamber experiment corresponding to approximately 90 events/μb. The total and differential cross sections and the density matrix elements of the Σ(1385) are presented. The results are compared with those obtained for the related processesπ pp→K + ∑ +(1385) and \(K^ - p \to \pi ^ \mp \sum ^ \pm (1385)\) in this energy range. Evidence is presented for the existence of production mechanisms with exotic exchanges in thet channel. 相似文献
8.
We have studied the p+p0+X inclusive reaction data of Carey et al. in the framework of the scaling in the mean hypothesis first proposed by Dao et al. These data have been used to obtain the gamma ray spectrum in terms of the average value of the Feynman variablex, written as x.A comparison with the observed gamma ray spectrum at Mt. Chacaltaya by the Japanese and Brazilian Group gives the energy dependence of x at very high energy. 相似文献
9.
E. A. Kuraev Yu. M. Bystritskiy V. V. Bytev A. Dbeyssi E. Tomasi-Gustafsson 《Journal of Experimental and Theoretical Physics》2012,115(1):93-104
The s-channel annihilation of a proton and an antiproton into a neutral pion and a real or virtual photon followed by lepton pair emission is studied. Such a mechanism is expected to play a role at moderate values of the total energy $ \sqrt s $ , when the pion is emitted in the angular region around 90° in the center-of-mass system. A fair comparison with the existing data is obtained taking scattering and annihilation channels into account. The cross section is calculated and numerical results are given in the kinematical range accessible in the PANDA experiment at FAIR. 相似文献
10.
T. A. Armstrong I. J. Bloodworth J. N. Carney B. R. French B. Ghidini J. B. Kinson V. Lenti A. Palano I. C. Print G. Vassiliadis O. Villalobos Baillie M. F. Votruba G. Zito R. Zitoun WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,34(1):33-38
The reactions π+ p→π+(K + K ? π+ π? p andpp→p(K + K ? π+ π?)p where the (K + K ? π+ π?) system is centrally produced have been studied at 85 GeV/c. 48% of the final state proceeds through single or double vector meson resonant production i.e.,K *0(890) (37%), ? (4%),ρ 0 (7%). Evidence is found for associatedK *0 (890) \(\bar K\) *o (890) production (6.4±1.1%) with a cross section ten times higher than that found for associated ? ? production in the same experiment. 相似文献
11.
12.
13.
I. V. Ajinenko S. A. Akimenko G. A. Akopdzhanov K. S. Belous G. I. Britvich I. G. Britvich A. P. Filin V. N. Govorun A. V. Inyakin V. A. Khmelnikov A. S. Konstantinov V. F. Konstantinov I. Ya. Korolkov V. M. Leontiev V. P. Novikov V. F. Obraztsov V. A. Polyakov V. I. Romanovsky V. M. Ronjin V. A. Senko N. A. Shalanda M. M. Shapkin V. I. Shelikhov N. E. Smirnov A. A. Sokolov O. G. Tchikilev E. V. Vlasov O. P. Yushchenko V. N. Bolotov S. V. Laptev A. Yu. Polyarush V. E. Postoev S. V. Yashchenko B. Zh. Zalikhanov V. Z. Serdyuk 《Physics of Atomic Nuclei》2002,65(11):2064-2069
The decay K ? → e ? νπ 0 has been studied using in-flight decays detected with the ISTRA+ setup working at the 25-GeV negative secondary beam of the U-70 PS. About 130K events were used for the analysis. The λ + parameter of the vector form factor has been measured: λ +=0.0293±0.0015(stat.)±0.002(syst.). The limits on the possible tensor and scalar couplings have been derived: f T/f +(0)=?0.045±0.060(stat.) and f S/f +(0)=?0.019 ?0.016 +0.025 (stat.). 相似文献
14.
The exclusive decay of B + → D + K 0 is calculated by the QCD factorization method (QCDF) and final state interaction (FSI). First, the B + → D + K 0 decay is calculated via QCDF method. The result that is found by using the QCDF method is less than the experimental result. So FSI is considered to solve the B + → D + K 0 decay. For this decay, the D s + π0, D s + *ρ0, D s + *? via the exchange of \(\bar K^0\) , \(\bar K^{0*} \) , D ?, and D ?* mesons are chosen for the intermediate states. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on η as the phenomenological parameter. The range of this parameter is selected from 2 to 2.4. It is found that if η = 2.4 is selected, the numbers of the branching ratio are placed in the experimental range. The experimental branching ratio of this decay is less than 2.9 × 10?6 and our results calculated by QCDF and FSI are (0.16 ± 0.04) × 10?6 and (2.8 ± 0.09) × 10?6, respectively. 相似文献
15.
16.
Aaij R Abellan Beteta C Adeva B Adinolfi M Adrover C Affolder A Ajaltouni Z Albrecht J Alessio F Alexander M Alkhazov G Alvarez Cartelle P Alves AA Amato S Amhis Y Anderson J Appleby RB Aquines Gutierrez O Archilli F Arrabito L Artamonov A Artuso M Aslanides E Auriemma G Bachmann S Back JJ Bailey DS Balagura V Baldini W Barlow RJ Barschel C Barsuk S Barter W Bates A Bauer C Bauer T Bay A Bediaga I Belogurov S Belous K Belyaev I Ben-Haim E Benayoun M Bencivenni G Benson S Benton J Bernet R 《Physical review letters》2012,108(18):181806
The angular distributions and the partial branching fraction of the decay B0 → K*0 μ+ μ- are studied by using an integrated luminosity of 0.37 fb(-1) of data collected with the LHCb detector. The forward-backward asymmetry of the muons, A(FB), the fraction of longitudinal polarization, F(L), and the partial branching fraction dB/dq2 are determined as a function of the dimuon invariant mass. The measurements are in good agreement with the standard model predictions and are the most precise to date. In the dimuon invariant mass squared range 1.00-6.00 GeV2/c4, the results are A(FB)=-0.06(-0.14)(+0.13)±0.04, F(L)=0.55±0.10±0.03, and dB/dq2=(0.42±0.06±0.03)×10(-7) c4/GeV2. In each case, the first error is statistical and the second systematic. 相似文献
17.
18.
A. Kreutz M. Holder M. Rost R. Werthenbach K. J. Peach H. Blümer R. Heinz K. Kleinknecht P. Mayer B. Panzer B. Renk H. Rohrer A. Wagner E. Augé D. Fournier L. Iconomidou-Fayard O. Perdereau A. C. Schaffer L. Serin L. Bertanza A. Bigi P. Calafiura M. Calvetti R. Carosi R. Casali C. Cerri I. Mannelli V. Marzulli A. Nappi G. M. Pierazzini 《Zeitschrift fur Physik C Particles and Fields》1995,65(1):67-74
Improved branching ratios were measured for theK
L30 decay in a neutral beam at the CERN SPS with the NA31 detector:
相似文献
19.
《Nuclear Physics A》1986,451(4):701-727
The mechanism of the reaction 3He + p → p + p + d is studied by making use of the ITEP 80 cm liquid-hydrogen bubble chamber exposed to a beam of 5 GeV/c 3He nuclei. The reaction cross section is equal to 20.6 ± 0.3 mb. The phase-space regions associated with quasifree scattering (QFS) and final-state interactions (FSI) are selected. Angular, mass and momentum distributions of the reaction products are obtained in the entire kinematically allowed range. The experimental data in the QFS region are compared with theoretical calculations based on the simplest pole-diagram approximation. The 3He and deuteron wave functions (WF) correspond to the realistic RSC potential. The D-wave components of these WF are taken into account. The absolute value of the cross section and shape of the distributions are described as a whole reasonably well within the frame of the model considered in the kinematical region where FSI may be neglected. But at large spectator momenta there is an essential disagreement. The possible reasons for this are discussed. 相似文献
20.
T. A. Armstrong M. Benayoun W. Beusch I. J. Bloodworth J. N. Carney R. Childs B. R. French B. Ghidini A. Jacholkowski J. Kahane J. B. Kinson A. Kirk K. Knudson V. Lenti Ph. Leruste A. Malamant J. L. Narjoux F. Navach A. Palano E. Quercigh N. Redaelli L. Rossi M. Sené R. Sené M. Stassinaki M. T. Trainor G. Vassiliadis O. Villalobos Baillie M. F. Votruba G. Zito R. Zitoun WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(3):405-410
The reactionpp→p f (K + K -π+π-)p s , where theK + K ? π+π- system is centrally produced, has been studied at 300 GeV/c. TheK *0 \(K^{*0} \bar K^{*0} \) final state has been observed and the cross sections for its central production are found to be the same at 300 and 85 GeV/c. TheK *0 \(K^{*0} \bar K^{*0} \) final state appears to be produced as a non-resonant threshold enhancement. 相似文献
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