ترغب بنشر مسار تعليمي؟ اضغط هنا

The Kaon B-parameter with the Wilson Quark Action using Chiral Ward Identities

90   0   0.0 ( 0 )
 نشر من قبل Yoshinobu Kuramashi
 تاريخ النشر 1997
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

We present a detailed description of the method and results of our calculation of the kaon B parameter using the Wilson quark action in quenched QCD at $beta=5.9-6.5$. The mixing problem of the $Delta s=2$ four-quark operators is solved non-perturbatively with full use of chiral Ward identities. We find $B_K(NDR, 2 GeV)=0.562(64)$ in the continuum limit, which agrees with the value obtained with the Kogut-Susskind quark action.



قيم البحث

اقرأ أيضاً

82 - S.Aoki , M.Fukugita , S.Hashimoto 1999
A lattice QCD calculation of the kaon $B$ parameter $B_K$ is carried out with the Wilson quark action in the quenched approximation at $beta=6/g^2=5.9-6.5$. The mixing problem of the $Delta s=2$ four-quark operators is solved non-perturbatively with full use of chiral Ward identities employing four external quarks with an equal off-shell momentum in the Landau gauge. This method, without invoking any effective theory, enables us to construct the weak four-quark operators exhibiting good chiral behavior. Our results for $B_K$ with the non-perturbative mixing coefficients show small scaling violation beyond the lattice cut-off $a^{-1}sim 2.5 $GeV. Our estimate concludes $B_K(NDR, 2 GeV)=0.69(7)$ at $a^{-1}=2.7-4.3$GeV, which agrees with the value obtained with the Kogut-Susskind quark action. For comparison we also calculate $B_K$ with one-loop perturbative mixing coefficients. While this yields incorrect values at finite lattice spacing, a linear extrapolation to the continuum limit as a function of $a$ leads to a result consistent with those obtained with the Ward identity method.
We present results for the light quark masses for the Wilson quark action obtained with the PCAC relation for the one-link extended axial vector current in quenched QCD at $beta=5.9-6.5$. This method leads to a remarkable improvement of scaling behav ior of the light quark masses compared to the conventional method. We obtain ${bar m}_l=3.87(37)$MeV for the averaged up and down quark mass and ${bar m}_s=97(9)$MeV for the strange quark mass in the ${barMS}$ scheme at $mu=2$GeV.
The kaon B parameter is calculated in quenched lattice QCD with the Wilson quark action. The mixing problem of the Delta s=2 four-quark operators is solved non-perturbatively with full use of chiral Ward identities, and this method enables us to cons truct the weak four-quark operators exhibiting good chiral behavior. We find B_K(NDR, 2GeV)=0.562(64) in the continuum limit, which agrees with the value obtained with the Kogut-Susskind quark action.
We perform a nonperturbative determination of the $O(a)$-improvement coefficient $c_{rm SW}$ and the critical hopping parameter $kappa_c$ for $N_f$=3, 2, 0 flavor QCD with the RG-improved gauge action using the Schrodinger functional method. In order to interpolate $c_{rm SW}$ and $kappa_c$ as a function of the bare coupling, a wide range of $beta$ from the weak coupling region to the moderately strong coupling points used in large-scale simulations is studied. Corrections at finite lattice size of $O(a/L)$ turned out to be large for the RG-improved gauge action, and hence we make the determination at a size fixed in physical units using a modified improvement condition. This enables us to avoid $O(a)$ scaling violations which would remain in physical observables if $c_{rm SW}$ determined for a fixed lattice size $L/a$ is used in numerical simulations.
We present preliminary results of a new lattice computation of hadronic matrix elements of baryon number violating operators which appear in the low-energy effective Lagrangian of (SUSY-)Grand Unified Theories. The contribution of irrelevant form fac tor which has caused an underestimate of the matrix elements in previous studies is subtracted in this calculation. Our results are 2$sim$4 times larger than the most conservative values often employed in phenomenological analyses of nucleon decay with specific GUT models.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا