摘要:

The experimental check of the GDH sum rule is being performed at the tagged photon facilities of the electron accelerators MAMI (Mainz) and ELSA (Bonn), using circularly polarized photons impinging on a longitudinally polarized proton target, together with detector systems covering almost the whole solid angle range. Results from the MAMI experiment for the double polarized total photoabsorption cross section in the low energy region (200 MeV <E&ggr;< 800 MeV) will be shown together with their contribution to the GDH sum rule. Furthermore first results from the ELSA experiment in the higher energy region (680 MeV <E&ggr;< 1900 MeV) will be presented. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482481

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We present preliminary results of a Partial Wave Analysis of the centrally produced &fgr;&fgr; system at 800 GeV/c in the reactionpp→pslow(&fgr;&fgr;)pfast. Our preliminary results with one and twoM= 0 waves, indicate that most of the cross section can be described by two waves, withJPCLS&eegr;= 2++02−1, 0++00−1. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482482

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

To prove the existence of glueball we should check two photon width of all glueball candidates. Peripheral heavy ion collisions provides such possibility. Using some restrictions, which discussed below we can even find glueball in two‐photon collision. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482483

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

J/&psgr; production in photon‐pomeron, pomeron‐pomeron and photon‐gluon exchange in peripheral nuclear collision at energy of colliding nucleus of 100 GeV per nucleon was calculated. Production and decay J/&psgr; in these processes for STAR detector was simulated. I try to find such kinematics areas where pomeron processes will dominate above a background (photon‐gluon process). © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482484

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We present a new interpretation for the low‐lying states recently observed by Tatischeff et al. based on the assumption ofthe polarization of the baryon number. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482485

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

The determination of CKM matrix elements in the b‐sector is discussed, emphasizing the new measurements of |Vub| and |Vcb| by the CLEO collaboration. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482486

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We present a measurement of&OHgr;c0 → &OHgr;−&pgr;+decay. We also present measurements of the Cabibbo‐suppressed decays&Lgr;c+ → &Lgr;0K+and&Lgr;c+ → &Sgr;0K+(both first observations) and&Lgr;c+ → &Sgr;+K+&pgr;−(seen with large statistics for the first time). For the Cabibbo‐suppressed decays&Lgr;c+ → pK+K−and&Lgr;c+ → p&fgr;, and the W‐exchange decays&Lgr;c+ → &Sgr;+K+K−and&Lgr;c+ → &Sgr;+&fgr;, we present measurements with improved accuracy. We found the first evidence for&Lgr;c+ → &Ygr;(1690)K+and set an upper limit on non‐resonant&Lgr;c+ → &Sgr;+K+K−decay. This analysis was performed using 23.6 fb−1of data collected by the Belle detector at thee+e−asymmetric collider KEKB. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482487

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Results are presented for the 500 GeV/c pion production asymmetry and polarization of the &Lgr;c(&Lgr;c)charmed baryon from Fermilab experiment E791. An analysis of the decay to thepK¯&pgr; final state is described. Resonant sub‐channel fractionsand phasesare given and possible resonant effects in the low masspK¯system discussed. Significant decay to &Lgr;c→ &Dgr;++K−establishes for the first time the importance of aWexchange mechanism in charmed baryon decay. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482488

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

The high luminosity of PEP‐II in combination with the vertexing possibilities of the BABAR‐detector [1] offer unique opportunities on light meson spectroscopy. The basic interest in this domain is the search for exotic states. Many of the candidates for conventional mesons are under heavy discussion because of analysis ambiguities, mixing with conventional mesons and some are only seen in selected reactions. Many ambiguities can be resolved using a clean initial state which restricts the final state to specific quantum numbers, such as weak decays ofDs±‐mesons into three pseudoscalars, allowing only a few resonances to occur. The selections and the results of the Dalitz plot analyses of the decaysDs± → Ks0Ks0&pgr;±andDs± → &pgr;+&pgr;−&pgr;±are presented. These decays are of particular interest for the discussion of the existence and the spin of isoscalar resonances above 1.5GeV/c2. In this mass region the glueball ground state is conjectured to lie and might mix strongly with other isoscalarJPC= 0++‐states. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482489

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Inclusive production of two(KK¯&pgr;)0states in the mass region 1.22–1.56 GeV inZdecay at LEP I has been observed by the DELPHI Collaboration. The measured masses and widths are 1274 ± 4 and 29 ± 12 MeV for the first peak and 1426 ± 4 and 51 ± 14 MeV for the second. A partial‐wave analysis has been performed on the(KK¯&pgr;)0spectrum in the mass range; the first peak is consistent with the quantum numbersIG(JPC) = 0+(0−+/1++) and the second withIG(JPC) = 0+(1++). These measurements, as well as their total hadronic production rates per hadronicZdecay, are consistent with the mesons of the typenn¯, wheren= {u,d}. They are very likely to be thef1(1285) and thef1(1420), respectively. © 2002 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1482490

出版商:AIP    

年代:1902

数据来源: AIP