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arXiv 0709.3494hep-ph
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共振在标准模型内外重介子过程中的作用

Role of Resonances in Heavy Meson Processes within Standard Model and Beyond

Jernej F. Kamenik

摘要:

基于手征对称性和重夸克对称性的有效理论--重介子手征微扰理论,研究了共振态在标准模型内外重介子各种过程中的作用.计算了包含正负宇称重介子二重态的手征修正,包括对有效理论主导阶相互作用Lagrangian中的有效强耦合、半轻子B到D衰变中的Isgur-Wise函数以及介导重中性介子混合的超对称四夸克算符的完备集的手征修正.裸值的有效强耦合提取从所测量的衰减宽度的魅力共振。在主导对数近似下研究了耦合手征行为、Isgur-Wise函数和重介子袋参数。在半轻子重到轻的衰变中,我们在一个有效的理论启发的模型中确定了零反冲下共振对各种形状因子的贡献。我们采用一个基于有效理论极限的形状因子参数化方法,将我们的结果外推到粲衰变的整个运动学区域。我们将我们的结果与实验数据和晶格计算进行了比较。本文在标准模型中用盒环图研究了B_c介子的非常罕见的非轻子衰变,并在若干标准模型的推广中进行了研究。基于现有的实验搜索相关的B介子衰变,限制施加在一些模型的研究。在寻找这种新物理贡献的过程中,最有希望的B_c介子的非轻子二体和三体衰变通道被确定。

英文摘要:

The effective theory based on combined chiral and heavy quark symmetry, the heavy meson chiral perturbation theory, is applied to studying the role of resonances in various processes of heavy mesons within and beyond the Standard Model. Chiral corrections including both positive and negative parity heavy meson doublets are calculated to the effective strong couplings featuring in the effective theory leading order interaction Lagrangian, to the Isgur-Wise functions in semileptonic B to D decays and to the complete set of supersymmetric four-quark operators mediating heavy neutral meson mixing. Bare values of the effective strong couplings are extracted from the measured decay widths of charmed resonances. Chiral behavior of the couplings, Isgur-Wise functions and heavy meson bag parameters is studied in the leading logarithmic approximation. In semileptonic heavy to light decays we determine resonance contributions to the various form factors within an effective theory inspired model at zero recoil. We employ a form factor parameterization based on effective theory limits to extrapolate our results to the whole kinematical region in charm decays. We compare our results with experimental data and lattice calculations. Very rare nonleptonic decays of the B_c meson are studied within the Standard Model where they are mediated by box loop diagrams, and within a number of Standard Model extensions. Based on existing experimental searches for related B meson decays, limits are imposed on some of the models studied. The most promissing nonleptonic two- and three-body decay channels of the B_c meson in the search for such new physics contributions are identified.

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