A Comparative Study of f_B within QCD Sum Rules with Two Typical Correlators up to Next-to-Leading Order  

作　　者：吴兴刚 余耀 陈古 韩华勇 

机构地区：[1]Department of Physics,Chongqing University

出　　处：《Communications in Theoretical Physics》2011年第4期635-639,共5页理论物理通讯（英文版）

基　　金：Supported by Natural Science Foundation Project of CQ CSTC under Grant No.2008BB0298;by Natural Science Foundation of China under Grant Nos.10805082 and 11075225;by the Fundamental Research Funds for the Central Universities under Grant No.CDJZR101000616

摘　　要：The B-meson decay constant fB is an important component for studying the B-meson decays, which can be studied through QCD sum rules. We make a detailed discussion on f B from two sum rules up to next-to- leading order, i.e. sum rules I and II, which are derived from the conventional correlator and the correlator with chiral currents respectively. It is found that these two sum rules are consistent with each other. The sum rules H involves less non-perturbative condensates as that of sum rules I, and in principle, it can be more accurate if we know the dimensionfour gluon condensate well. It is found that fB decreases with the increment of mb, and to compare with the Belle experimental data on fB, both sum rules I and H prefer smaller pole b-quark mass, mb= 4.68 ± 0.07 GeV. By varying all the input parameters within their reasonable regions and by adding all the uncertainties in quadrature, we obtain fB=172-25^＋23 MeV for sum rules I and fB =214-34^26 MeV for sum rules П.

关 键 词：QCD sum rules decay constant CORRELATOR 

分 类 号：O572.243[理学—粒子物理与原子核物理] TP391.41[理学—物理]