摘要:

We show that because of the milder GIM suppression, the four-quark dipenguin operator contributes to the short distance piece of theD0−D¯0mixing amplitude at the same order of magnitude as the box diagram. In addition, we put an upper bound&Dgr;mDLDR⩽5mDboxon a long-distance resonant contribution induced by the penguin mixing. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.55989

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Applying two different versions of QCD sum-rules, we reanalyze rigourously the rich spectroscopy of mesons and baryons built from charm and beauty quarks. An improved determination of the masses and the leptonic decay constants ofBc(bc¯),Bc*(bc¯),and&Lgr;(bcu)is presented. Our optimal results, constrained by stability criteria, are consistent in both versions and support the general pattern common to potential models predictions. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.55990

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We present a chiral constituent quark model for light and strange baryons providing a unified description of their ground states and excitation spectra. The model relies on constituent quarks and Goldstone bosons arising as effective degrees of freedom of low-energy QCD from the spontaneous breaking of chiral symmetry. The spectra of the three-quark systems are obtained from a precise variational solution of the Schro¨dinger equation with a semirelativistic Hamiltonian. The theoretical predictions are found in close agreement with experiment. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.55991

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

HADRON ’97 covered a wide spectrum of particle physics, from high-Q2events ine+-proton collisions at DESY to the recent discovery of1−+exotic mesons. This paper reviews progress reported at the conference, in particular the status of glueballs and hybrids. Personal views and interpretations are offered, sometimes at variance with accepted views. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56100

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

This is a written version of the talk that I gave at the end of the Conference. It concentrates on the status of light flavoured hadrons with emphasis on gluonic excitations. The experimental aspects of the conference are summarized by E. Klempt. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56101

出版商:AIP    

年代:1998

数据来源: AIP